UNIT 1(1).pptx

C) They are threaded into the interior of the Rough ER for modification

Explanation: After proteins are synthesized by ribosomes on the Rough ER, they are threaded into the interior of the Rough ER where they undergo modification and transport.

B) Grana

Explanation: Stacks of thylakoids in chloroplasts are referred to as grana, which are essential for the light-dependent reactions of photosynthesis.

C) They digest and eliminate waste

Explanation: Lysosomes are responsible for digesting waste materials within the cell, ensuring that cellular processes remain efficient and clean.

B) The process by which different kinds of living organisms develop from earlier forms

Explanation: Evolution is defined as the process through which various living organisms are believed to have developed from earlier forms throughout the history of the Earth, highlighting the gradual changes over time.

B) It is digested by lysosomes

Explanation: After food is taken in by phagocytosis, lysosomes digest the food, breaking it down into usable components for the cell.

C) Sacs modified from the inner membrane

Explanation: Thylakoids are sacs that are modified from the inner membrane of the chloroplast, playing a crucial role in photosynthesis.

B) True

Explanation: The prefix 'eu' in eukaryotic means 'true,' indicating that these organisms have a true nucleus and more complex cellular structures compared to prokaryotic organisms.

C) Cell membrane and cell wall

Explanation: Prokaryotic cells are surrounded by both a cell membrane and a cell wall, which is primarily composed of peptidoglycan, providing structural support.

B) To provide a medium for chemical reactions

Explanation: The cytoplasm serves as a jelly-like substance that provides a medium for chemical reactions to occur, making it essential for cellular processes.

C) Nucleoid region

Explanation: In prokaryotes, the nucleoid region is the area where the DNA is located, distinguishing it from eukaryotic cells that have a defined nucleus.

B) From the cytoplasm in the egg cell

Explanation: Mitochondria are inherited from the cytoplasm of the egg cell during fertilization, meaning that individuals inherit their mitochondria exclusively from their mother.

C) Storage

Explanation: Vacuoles are fluid-filled sacks primarily used for storage in cells, holding various substances such as sugars, proteins, minerals, and more.

C) One or more target tissues

Explanation: Each hormone secreted by the endocrine system has specific effects on one or more target tissues, influencing various physiological processes throughout the body.

B) Photosynthesis

Explanation: Thylakoids are primarily involved in the process of photosynthesis, where they house chlorophyll and facilitate the light-dependent reactions.

C) Near the nucleus

Explanation: Centrioles are paired structures located near the nucleus, playing a significant role in cell division.

B) Phagocytosis

Explanation: Cells take in food through the process of phagocytosis, which involves engulfing particles or other cells to form a food vacuole.

B) Membrane proteins and proteins for export

Explanation: The Rough ER is responsible for synthesizing membrane proteins and proteins that are exported out of the cell, highlighting its role in cellular function.

B) It is a complex unit of physicochemical materials

Explanation: A living organism is defined as a complex unit of physicochemical materials that is capable of self-regulation, metabolism, and reproduction, highlighting its intricate nature.

B) It is enclosed by the cell membrane

Explanation: The cytoplasm is indeed enclosed by the cell membrane, which helps maintain the internal environment of the cell.

C) Made of a bundle of microtubules

Explanation: Centrioles are composed of a bundle of microtubules, which are essential for their function during cell division.

B) Metabolism

Explanation: Metabolism is a fundamental process that living organisms undergo, involving chemical reactions that provide energy and support growth and reproduction.

B) Free ribosomes

Explanation: Prokaryotes contain ribosomes that are not membrane-bound, located freely in their cytoplasm, and are essential for protein synthesis.

C) Double membrane

Explanation: Chloroplasts are surrounded by a double membrane, consisting of an outer smooth membrane and an inner membrane that is modified into structures called thylakoids.

C) Interaction with the environment

Explanation: The ability to interact with the environment is crucial for living organisms, enabling them to respond to changes and adapt accordingly.

B) Inside the nucleus

Explanation: The nucleolus is specifically located inside the nucleus of a cell, playing a crucial role in ribosome production.

B) Stroma

Explanation: The stroma is the gel-like material that surrounds the thylakoids within the chloroplast, providing a medium for the light-independent reactions of photosynthesis.

B) Actin

Explanation: Microfilaments are threadlike structures that are primarily composed of the protein actin, which is essential for various cellular functions including movement.

C) They can reproduce

Explanation: Reproduction is one of the key capabilities of living organisms, allowing them to produce offspring and ensure the continuation of their species.

C) They are tube-like and made of tubulin

Explanation: Microtubules are characterized as tube-like structures composed of the protein tubulin, playing a key role in maintaining cell shape and facilitating the movement of organelles.

D) Photosynthesis

Explanation: Photosynthesis is a process used by plants to convert light energy into chemical energy, and it is not a mechanism of homeostasis, which focuses on maintaining internal stability.

B) They have a nucleus and membrane-bound organelles

Explanation: Eukaryotic cells are characterized by the presence of a nucleus and membrane-bound organelles, distinguishing them from prokaryotic cells, which lack these features.

C) Attached to the Rough ER or free in the cytoplasm

Explanation: Ribosomes can either be attached to the Rough Endoplasmic Reticulum (ER) or exist freely in the cytoplasm, allowing them to synthesize proteins in different cellular locations.

E) Nutrient absorption

Explanation: Nutrient absorption is not a component of homeostasis. The components include the sensor, afferent pathway, integration center, efferent pathway, and effector organ(s).

B) It has ribosomes on its surface

Explanation: The Rough Endoplasmic Reticulum is characterized by the presence of ribosomes on its surface, which are essential for protein synthesis.

C) They contain a nucleus

Explanation: Eukaryotic organisms are characterized by having cells that contain a nucleus and a fuller repertoire of organelles, distinguishing them from prokaryotic organisms.

D) Monera

Explanation: The kingdom Monera is composed of prokaryotic organisms, primarily bacteria, which lack a nucleus and many specialized organelles.

C) Chemical bonds of sugars

Explanation: Chloroplasts convert sunlight energy into chemical energy, which is stored in the chemical bonds of sugars, primarily glucose, during the process of photosynthesis.

B) The maintenance of a stable internal environment

Explanation: Homeostasis refers to the processes that organisms use to maintain a stable internal environment despite external changes, which is crucial for survival.

D) Digest (Photosynthesis)

Explanation: While cells metabolize, respire, reproduce, and multiply, 'Digest (Photosynthesis)' is not a recognized process associated with cell functions, as photosynthesis is specific to certain organisms like plants.

B) To regulate bodily functions through hormones

Explanation: The primary function of the endocrine system is to regulate various bodily functions by releasing hormones into the bloodstream, which act as chemical messengers to control processes such as metabolism, growth, and mood.

B) Organelles perform various functions for a cell

Explanation: Organelles are essential components of a cell that perform various functions, contributing to the cell's overall operation and health.

B) To digest food and eliminate waste

Explanation: Lysosomes are organelles that digest food taken in by the cell and help get rid of waste, playing a crucial role in cellular digestion and waste management.

D) Bacteria

Explanation: Prokaryotic organisms are unicellular and lack a nucleus and many specialized cell parts, with bacteria being the primary example of this classification.

D) Inability to adapt

Explanation: Living organisms are characterized by their ability to adapt to their environment, along with self-regulation, metabolism, growth, and reproduction.

B) They have their own DNA

Explanation: Mitochondria are unique organelles that possess their own DNA, which is inherited maternally, indicating their distinct evolutionary origin and function within the cell.

B) To help maintain cell shape

Explanation: The cytoskeleton plays a crucial role in maintaining the shape of the cell, providing structural support and enabling cellular organization.

C) Cell

Explanation: The cell is recognized as the basic unit of life, serving as the smallest living form that can carry out all necessary life processes.

C) Proteins and rRNA

Explanation: Ribosomes are composed of proteins and ribosomal RNA (rRNA), which play a crucial role in the synthesis of proteins within the cell.

E) Animalia

Explanation: Animalia is indeed one of the five kingdoms, but the question asks for one that is NOT among them. The five kingdoms are Monera, Protista, Fungi, Plantae, and Animalia.

B) They contain their own DNA

Explanation: Chloroplasts are unique organelles that contain their own DNA, which is essential for their function in photosynthesis and indicates their evolutionary origin.

B) Protein synthesis

Explanation: Ribosomes in prokaryotes are responsible for synthesizing proteins, which are crucial for various cellular functions.

B) Photosynthesis

Explanation: Chloroplasts are specifically involved in photosynthesis, the food-making process in plants, where they utilize light energy to convert carbon dioxide and water into glucose and oxygen.

C) Only in producers

Explanation: Chloroplasts are specifically found in producers, which are organisms that contain chlorophyll and can perform photosynthesis to create their own food.

C) Only in animal cells

Explanation: Centrioles are specifically found only in animal cells, distinguishing them from plant and other types of cells.

B) To secrete hormones into the bloodstream

Explanation: The endocrine system is primarily responsible for secreting hormones into the bloodstream, which then affect various target tissues and regulate metabolism and development in the body.

C) Jean Baptiste Lamarck

Explanation: Jean Baptiste Lamarck proposed the idea of spontaneous generation of species according to their needs and functionalities, suggesting that organisms evolve based on their requirements.

C) Prokaryotic cells lack organelles

Explanation: A key difference is that prokaryotic cells lack a nucleus and many specialized organelles, while eukaryotic cells contain a nucleus and a wider variety of organelles.

B) Muscle cells

Explanation: More active cells, such as muscle cells, have a higher number of mitochondria to meet their increased energy demands during physical activity.

C) Matrix

Explanation: The interior of the mitochondria is called the matrix, which contains enzymes and other molecules necessary for the biochemical processes that occur within the organelle.

C) Prokaryotic cells

Explanation: The Monera kingdom is characterized by organisms that have prokaryotic cells, meaning they lack a defined nucleus and membrane-bound organelles.

B) To maintain and regulate other body parts

Explanation: The nervous system plays a crucial role in maintaining homeostasis by controlling and regulating the functions of other parts of the body, ensuring that internal conditions remain stable.

E) All of the above

Explanation: Chloroplasts are never found in animal or bacterial cells; they are exclusive to plant cells and some protists, highlighting their role in photosynthesis.

A) Insulin

Explanation: Insulin is the hormone produced by the pancreas that plays a crucial role in regulating blood sugar levels by facilitating the uptake of glucose into cells.

B) They make proteins

Explanation: Ribosomes produced by the nucleolus are responsible for synthesizing proteins, which are vital for various cellular functions.

C) They regulate physiological processes

Explanation: Hormones are chemical messengers that regulate various physiological processes in the body, including growth, metabolism, and mood, by binding to specific receptors on target cells.

C) Cell recognition and signaling

Explanation: Carbohydrate chains attached to proteins and lipids in the cell membrane play a crucial role in cell recognition and communication, allowing cells to interact with their environment.

C) By exhibiting behaviors or changes in response to stimuli

Explanation: Organisms respond to their environment through various behaviors or physiological changes, allowing them to adapt and survive in changing conditions.

C) To use energy from sunlight to make food

Explanation: Chloroplasts utilize energy from sunlight to synthesize glucose, which serves as food for the organism, highlighting their role in photosynthesis.

C) Organelles

Explanation: The cytoplasm contains various organelles that carry out specific jobs necessary for the cell's survival and function.

B) Cristae

Explanation: The folded inner membrane of mitochondria is known as cristae, which increases the surface area available for chemical reactions, enhancing the organelle's ability to produce energy.

E) Viruses

Explanation: Whittaker's five kingdoms include Monera, Protista, Fungi, Plantae, and Animalia. Viruses are not classified within these kingdoms as they do not meet the criteria for living organisms.

C) In all cells

Explanation: Cytoplasm is a fundamental component found in all types of cells, including both prokaryotic and eukaryotic cells.

B) Mitosis

Explanation: Mitosis is the process by which cells reproduce asexually, resulting in two identical daughter cells, while meiosis is involved in sexual reproduction.

B) It helps move organelles around

Explanation: The cytoskeleton is essential for the movement of organelles within the cell, providing tracks along which organelles can be transported.

B) Energy production

Explanation: Mitochondria are often referred to as the powerhouses of the cell because their primary function is to produce energy in the form of ATP through cellular respiration.

B) Cellular respiration

Explanation: Mitochondria are the site of cellular respiration, where glucose is 'burned' to produce ATP, the energy currency of the cell.

C) Fungi

Explanation: Eukaryotes include protists, fungi, plants, and animals, making fungi a clear example of a eukaryotic organism.

B) A receptor

Explanation: A deviation from the normal set point acts as a stimulus to a receptor, which then sends nerve impulses to the brain, initiating the homeostatic response.

B) They have a structured arrangement of cells and systems

Explanation: Being organized means that organisms have a complex structure, typically composed of one or more cells that work together in systems to perform various functions.

C) Heterotrophic nutrition

Explanation: Fungi are primarily heterotrophic, meaning they obtain their nutrients by absorbing organic matter, and they have cell walls made of chitin.

B) They pinch off with modified proteins

Explanation: Transport vesicles in the Golgi Bodies pinch off from the ends after receiving and modifying proteins, facilitating their transport to various destinations within or outside the cell.

A) Blood clotting

Explanation: Blood clotting is an example of a positive feedback mechanism that helps maintain homeostasis by rapidly responding to injury and preventing excessive blood loss.

B) Sympathetic and parasympathetic

Explanation: The autonomic nervous system has two divisions: the sympathetic and parasympathetic systems, which work together to regulate involuntary functions.

B) Change in heritable characteristics over generations

Explanation: Evolution is characterized by changes in the heritable characteristics of biological populations over successive generations, indicating a gradual process of adaptation and change.

B) Synthesis of cell products and transport

Explanation: The Endoplasmic Reticulum (ER) is primarily involved in the synthesis of cell products and their transport within the cell, making it essential for cellular function.

C) They help pull chromosome pairs apart

Explanation: Centrioles appear during cell division and are crucial for forming the mitotic spindle, which helps pull chromosome pairs apart to opposite ends of the cell.

C) In the cytoplasm

Explanation: Organelles are found in the cytoplasm of a cell, where they perform various functions necessary for the cell's operation.

B) Survival of the fittest

Explanation: Charles Darwin's theory of evolution is primarily based on the principle of survival of the fittest, which emphasizes that organisms best adapted to their environment are more likely to survive and reproduce.

B) It disappears

Explanation: The nucleolus disappears when the cell divides, which is a characteristic behavior during the cell division process.

B) They require energy (food)

Explanation: One of the fundamental characteristics of organisms is that they require energy, typically in the form of food, to sustain their biological processes and functions.

B) 1859

Explanation: Charles Darwin published his groundbreaking work on evolution in 1859, which laid the foundation for modern evolutionary biology.

B) Prophase

Explanation: Centrioles appear during cell division, specifically in prophase, where they help in forming the mitotic spindle.

D) Protista

Explanation: The Protista kingdom consists mainly of unicellular eukaryotic organisms, which can be either autotrophic or heterotrophic.

B) Double layer of phospholipids and proteins

Explanation: The cell membrane is composed of a double layer of phospholipids interspersed with proteins, which contributes to its fluidity and functionality.

C) DNA

Explanation: Cells utilize DNA to store and transmit genetic information, which is crucial for inheritance and the functioning of living organisms.

C) They are small or absent in animal cells

Explanation: In animal cells, vacuoles are typically small or absent, whereas plant cells contain a large central vacuole for storage.

B) Fungi

Explanation: The Fungi kingdom includes multicellular organisms that absorb nutrients from organic matter, playing a crucial role in decomposition and nutrient cycling in ecosystems.

B) Internal organs

Explanation: The autonomic nervous system, which is part of the peripheral nervous system, contains motor neurons that control internal organs, regulating involuntary bodily functions.

B) They are microscopic

Explanation: Organelles are described as very small or microscopic structures within a cell, highlighting their size relative to the overall cell.

B) Cellular energy generation (ATP)

Explanation: Mitochondria are known as the 'powerhouse' of the cell because their main function is to generate cellular energy in the form of ATP, which is essential for various cellular processes.

A) 1 to 3

Explanation: A cell may contain between 1 to 3 nucleoli, which are involved in the synthesis of ribosomes.

C) Protein synthesis

Explanation: Ribosomes are often referred to as the 'protein factories' of the cell because their main function is to join amino acids together to form proteins through the process of protein synthesis.

C) Both plant and animal cells have mitochondria

Explanation: Mitochondria are present in both plant and animal cells, playing a crucial role in energy production through cellular respiration.

C) Peptidoglycan

Explanation: The cell wall of prokaryotes is primarily composed of peptidoglycan, which provides structural integrity and protection to the cell.

C) They have membrane-bound organelles

Explanation: Eukaryotic cells are more complex than prokaryotic cells because they contain membrane-bound organelles, which perform specific functions within the cell.

B) Enzymes and pigments

Explanation: Chloroplasts contain enzymes and pigments that are essential for the process of photosynthesis, allowing plants to convert light energy into chemical energy.

D) Animalia

Explanation: The Animalia kingdom is primarily composed of heterotrophic organisms, which means they obtain their food by consuming other organisms, distinguishing them from autotrophic kingdoms like Plantae.

B) They undergo a series of changes and maturation processes

Explanation: Growth and development in organisms involve a series of changes that lead to maturity, including cellular division and differentiation, which are essential for their life cycle.

E) Cells can spontaneously generate from non-cellular materials

Explanation: Cell theory asserts that all cells arise from pre-existing cells, and the idea that cells can spontaneously generate from non-cellular materials is not part of cell theory.

C) Nuclear envelope

Explanation: The nucleus is bounded by a nuclear envelope (membrane) that has pores, allowing for the exchange of materials between the nucleus and the cytoplasm.

C) Energy production

Explanation: Mitochondria are known as the powerhouse of the cell, primarily responsible for producing energy in the form of ATP through cellular respiration.

C) Optimization and problem-solving

Explanation: Genetic algorithms are computational methods used to find optimal solutions to complex problems by mimicking the process of natural selection.

C) Nuclear envelope and cell membrane

Explanation: The Endoplasmic Reticulum (ER) connects to both the nuclear envelope and the cell membrane, facilitating communication and transport between these structures.

C) Plant cells

Explanation: Plant cells are characterized by having a large central vacuole, which plays a crucial role in storage and maintaining turgor pressure.

D) Regulating heart rate

Explanation: While sex hormones have various functions such as activating sebaceous glands and governing reproduction, they do not regulate heart rate, which is primarily controlled by the nervous system.

C) Monera

Explanation: The kingdom Monera consists of unicellular organisms that have prokaryotic cells, such as bacteria, distinguishing it from other kingdoms that include eukaryotic organisms.

C) Jelly-like

Explanation: The cytoplasm is described as a jelly-like substance, which allows for the movement of organelles and the occurrence of chemical reactions.

B) In the central nervous system

Explanation: The regulating centers for homeostasis are located in the central nervous system, which includes the brain and spinal cord, playing a crucial role in maintaining internal balance.

C) Homeostasis

Explanation: Homeostasis refers to the ability of organisms to maintain stable internal conditions despite changes in their external environment, which is crucial for survival.

B) Protein synthesis

Explanation: The process of joining amino acids to form proteins is known as protein synthesis, which is a key function of ribosomes in the cell.

B) To contain digestive enzymes

Explanation: Lysosomes are primarily known for containing digestive enzymes that break down food, bacteria, and worn-out cell parts, playing a crucial role in cellular digestion and recycling.

B) They may or may not be membrane-bound

Explanation: Some organelles are membrane-bound, while others are not, which is a key characteristic that differentiates them within the cellular environment.

B) To control the movement of substances in and out of the cell

Explanation: The cell membrane serves as a selective barrier that regulates the entry and exit of substances, maintaining the internal environment of the cell.

B) To control the normal activities of the cell

Explanation: The nucleus is known as the control organelle because it regulates the normal activities of the cell, including growth, metabolism, and reproduction.

A) All living organisms are made up of cells

Explanation: One of the fundamental principles of cell theory states that all living organisms are composed of one or more cells, emphasizing the cellular basis of life.

C) Endoplasmic Reticulum (ER)

Explanation: Golgi Bodies receive proteins that are synthesized by the endoplasmic reticulum (ER), which they then modify and transport.

C) Schleiden and Schwann

Explanation: The development of cell theory is primarily attributed to scientists Matthias Schleiden and Theodor Schwann, who contributed significantly to the understanding of cells as the basic units of life.

A) Rough and Smooth

Explanation: The Endoplasmic Reticulum (ER) consists of two types: Rough ER, which is studded with ribosomes, and Smooth ER, which lacks ribosomes and is involved in different functions.

C) Bacterial cells

Explanation: Bacterial cells do not have vacuoles, distinguishing them from plant and animal cells that may contain these storage organelles.

B) It has ribosomes on its surface

Explanation: Rough Endoplasmic Reticulum (RER) is characterized by the presence of ribosomes on its surface, which are essential for protein synthesis.

C) Cell sap, including sugars, proteins, and minerals

Explanation: In plant cells, vacuoles store cell sap, which includes a variety of substances such as sugars, proteins, minerals, lipids, wastes, salts, water, and enzymes.

B) Cis and Trans

Explanation: The Golgi Bodies have a receiving side known as the cis face and a shipping side known as the trans face, which are essential for their function in processing and transporting proteins.

B) Mitochondria

Explanation: The plural form of mitochondrion is mitochondria, which refers to multiple organelles within a cell.

D) Bacterial cell

Explanation: Bacterial cells are prokaryotic and do not have a nucleus or membrane-bound organelles, distinguishing them from eukaryotic cells such as plant, animal, fungal, and protist cells.

C) Plantae

Explanation: The Plantae kingdom is characterized by organisms that are primarily autotrophic (photosynthetic) and have cell walls made of cellulose.

B) They lyse and release enzymes

Explanation: During autolysis, lysosomes lyse (break open) and release their digestive enzymes to break down and recycle cell components, which is essential for cellular maintenance.

B) Golgi apparatus

Explanation: The Golgi apparatus modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles.

B) To digest waste materials and cellular debris

Explanation: Lysosomes contain digestive enzymes that break down waste materials and cellular debris, playing a crucial role in cellular cleanup.

B) To control what enters or leaves the cell

Explanation: The cell membrane is responsible for regulating the movement of substances in and out of the cell, ensuring that essential materials enter while waste products are expelled.

A) Respiration

Explanation: Respiration is the process through which cells produce energy, utilizing oxygen and glucose to generate ATP, which is essential for cellular functions.

B) By secreting hormones into the bloodstream

Explanation: The endocrine system regulates body functions by secreting hormones into the bloodstream, which then travel to target tissues to exert their effects on metabolism and development.

C) Hypothalamus

Explanation: The hypothalamus is specifically mentioned as a portion of the brain that is particularly concerned with homeostasis, influencing various bodily functions.

B) Activating sebaceous glands

Explanation: One of the functions of sex hormones is to activate sebaceous glands, which are involved in the production of oils in the skin, among other roles in the body.

B) Maintenance of relative stability of the internal environment

Explanation: Homeostasis is defined as the maintenance of relative stability of the physical and chemical aspects of the internal environment, which is crucial for cellular function.

B) Outside of the cell

Explanation: The cell membrane surrounds the outside of all cells, acting as a barrier that separates the internal environment from the external environment.

A) More complex than prokaryotic cells

Explanation: Eukaryotic cells are classified as more complex due to their structure, which includes a nucleus and various membrane-bound organelles, unlike prokaryotic cells.

C) DNA in chromosomes

Explanation: The nucleus contains the cell's DNA organized into chromosomes, which carry the genetic information necessary for the cell's functions and characteristics.

B) Nervous system, endocrine system, and immune system

Explanation: The physiological control systems involved in maintaining homeostasis include the nervous system, endocrine system, and immune system, which operate through feedback mechanisms.

C) A constant internal environment with O2, glucose, minerals, and ions

Explanation: For individual cells to survive, it is necessary to maintain a constant internal environment that includes essential elements such as oxygen, glucose, minerals, ions, and effective waste removal.

C) Pituitary gland

Explanation: The pituitary gland is often called the 'master gland' because it regulates the functions of other endocrine glands and controls various hormonal activities in the body.

B) To make ribosomes

Explanation: The primary function of the nucleolus is to make ribosomes, which are essential for protein synthesis in the cell.

B) Nervous system

Explanation: The nervous system plays a crucial role in regulating homeostasis by sending signals to various organs and systems to maintain balance and respond to changes in the environment.

C) Plantae

Explanation: The Plantae kingdom is characterized by organisms that can perform photosynthesis, utilizing sunlight to produce their own food, which is a key feature of plants.

B) Lipid synthesis and detoxification

Explanation: Smooth Endoplasmic Reticulum (SER) is primarily involved in lipid synthesis and detoxification processes, distinguishing it from Rough ER.

C) Their location

Explanation: The primary distinction between ribosomes attached to the Rough ER and free ribosomes lies in their location; attached ribosomes are involved in synthesizing proteins that are usually secreted or incorporated into membranes, while free ribosomes synthesize proteins that function within the cytoplasm.

B) Autolysis

Explanation: Lysosomes are programmed for autolysis, which is the process of breaking down and recycling cell parts, including the release of enzymes to facilitate this breakdown.

B) It directs an effector to create an adaptive response

Explanation: The brain acts as a regulating center that processes the nerve impulses received from receptors and directs an effector to respond appropriately, facilitating an adaptive response to maintain homeostasis.

B) Stacks of flattened sacs

Explanation: Golgi Bodies are composed of stacks of flattened sacs, which are essential for their function in modifying and packaging proteins.

B) The structure and function of cells

Explanation: Cell theory primarily focuses on the understanding that all living organisms are composed of cells, which are the basic unit of life, emphasizing their structure and function.

C) Food, bacteria, and worn-out cell parts

Explanation: Lysosomes are responsible for breaking down food, bacteria, and worn-out cell parts, making them vital for cellular health and recycling.

B) It regulates calcium

Explanation: In muscle cells, the Smooth Endoplasmic Reticulum plays a crucial role in regulating calcium levels, which is vital for muscle contraction.

C) Each cell has a fixed number of chromosomes

Explanation: Each cell contains a fixed number of chromosomes within the nucleus, which carry genes that control the characteristics of the cell.

B) The specialization of cells into different types

Explanation: Tissue differentiation is the process by which unspecialized cells develop into specialized cells with distinct functions, forming various types of tissues in an organism.

C) To modify and transport proteins

Explanation: Golgi Bodies are responsible for modifying proteins received from the endoplasmic reticulum (ER) and then transporting them in vesicles, highlighting their crucial role in protein processing.

C) Both plant and animal cells

Explanation: Organelles are present in both plant and animal cells, indicating their fundamental role in cellular structure and function across different types of organisms.

C) Ribosomes

Explanation: Ribosomes are not a component of the cytoskeleton; they are involved in protein synthesis. The cytoskeleton is made up of microfilaments and microtubules, which are composed of actin and tubulin, respectively.

C) They act as chemical messengers

Explanation: Hormones are chemical messengers that help regulate various physiological processes in the body, playing a key role in maintaining homeostasis by coordinating responses to internal and external changes.

A) Central and peripheral nervous systems

Explanation: The nervous system is divided into two major portions: the central nervous system (CNS) and the peripheral nervous system (PNS), each serving distinct functions in regulating body processes.

D) Production of antibodies

Explanation: The production of antibodies is primarily a function of the immune system, not the endocrine system, which focuses on hormone regulation and maintaining homeostasis.

C) Mitochondria

Explanation: Mitochondria are known as the powerhouse of the cell, as they are responsible for producing ATP, the energy currency of the cell, through cellular respiration.

C) A deviation from the normal set point occurs

Explanation: The homeostatic process begins with a deviation from the normal set point, which acts as a stimulus that triggers the entire response mechanism involving receptors, the brain, and effectors.

C) Making membrane lipids

Explanation: The Smooth Endoplasmic Reticulum is responsible for synthesizing membrane lipids, including steroids, which are essential for cell membrane structure and function.

B) Digestive enzymes

Explanation: Lysosomes contain digestive enzymes that are crucial for breaking down various substances within the cell, including food and cellular debris.

B) Cells come from the reproduction of existing cells

Explanation: Cell theory states that cells arise from the reproduction of existing cells, which is a key principle in understanding cell division and growth.

C) Cells can arise from non-cellular matter

Explanation: The statement that cells can arise from non-cellular matter is not part of the cell theory; instead, it emphasizes that all cells come from pre-existing cells.

C) Both A and B

Explanation: The nervous system is primarily classified into two main divisions: the Central Nervous System (CNS) and the Peripheral Nervous System (PNS), which work together to control bodily functions.

B) It connects the CNS to the limbs and organs

Explanation: The Peripheral Nervous System (PNS) serves as a communication network that connects the Central Nervous System (CNS) to the rest of the body, including limbs and organs, facilitating sensory and motor functions.

B) It lacks ribosomes on its surface

Explanation: The Smooth Endoplasmic Reticulum is characterized by the absence of ribosomes on its surface, distinguishing it from the Rough Endoplasmic Reticulum.

C) It compares the current state to the desired state

Explanation: The integration center, or comparator, is responsible for comparing the current state of the internal environment to the desired state, facilitating the regulation of homeostasis.

B) Medulla oblongata

Explanation: The hypothalamus influences the action of the medulla oblongata, which is a lower part of the brain involved in autonomic functions, contributing to homeostasis.

B) Theodor Schwann and Matthias Jakob Schleiden

Explanation: The cell theory was suggested by German scientists Theodor Schwann and Matthias Jakob Schleiden in 1838, marking a significant advancement in biological science.

C) Cell

Explanation: According to cell theory, cells are recognized as the basic unit of structure and function in an organism, emphasizing their fundamental role in life.

B) The maintenance of stable internal conditions

Explanation: Homeostasis refers to the processes that organisms use to maintain stable internal conditions despite changes in the external environment.

B) To process information and coordinate responses

Explanation: The Central Nervous System (CNS), which includes the brain and spinal cord, is responsible for processing sensory information and coordinating the body's responses.

B) It can change shape and composition

Explanation: The cell membrane is often referred to as a 'living layer' because it is dynamic, capable of changing shape and composition to respond to the needs of the cell and its environment.

B) To synthesize proteins

Explanation: Ribosomes are the cellular structures responsible for protein synthesis, translating messenger RNA into polypeptide chains.

C) Cells are the building blocks of all living organisms

Explanation: Cell theory implies that cells are the fundamental building blocks of all living organisms, whether unicellular or multicellular.

C) The study of cells is essential for understanding life

Explanation: A key consequence of cell theory is that understanding cells is crucial for comprehending the biological processes of all living organisms.

E) Protista

Explanation: While Protista is indeed one of the kingdoms in Whitaker's classification, the question asks for something that is NOT one of the five kingdoms. The correct answer should be a category that does not belong to Whitaker's classification, such as 'Viruses'.

C) Liver

Explanation: The Smooth Endoplasmic Reticulum in liver cells is responsible for detoxifying harmful substances, making it essential for maintaining metabolic health.

C) Rough Endoplasmic Reticulum

Explanation: The Smooth Endoplasmic Reticulum is attached to the ends of the Rough Endoplasmic Reticulum, facilitating the transport of materials within the cell.

B) A German botanist

Explanation: Matthias Schleiden was a German botanist who, along with Theodor Schwann, formulated the cell theory, contributing significantly to the field of biology.

C) Somatic Nervous System

Explanation: The Somatic Nervous System (SNS) is responsible for voluntary movements and the transmission of sensory information to the CNS, allowing for conscious control of skeletal muscles.

B) They control cell characteristics

Explanation: Genes located in the chromosomes within the nucleus are responsible for controlling the characteristics of the cell, influencing traits and functions.

B) To create new cells for growth and repair

Explanation: The primary purpose of cell replication is to produce new cells, which is essential for growth, development, and repair of tissues in living organisms.

B) Tissue repair and regeneration

Explanation: Stem cells have the unique ability to develop into various cell types, making them crucial for applications in tissue repair and regeneration in medical treatments.

C) Autonomic Nervous System

Explanation: The Autonomic Nervous System (ANS) regulates involuntary bodily functions, including heart rate and digestion, distinguishing it from the voluntary control of the Somatic Nervous System.

B) Control of normal activities of the cell

Explanation: The nucleus is known as the control organelle because it regulates the normal activities of the cell, including growth, metabolism, and reproduction.

C) Cell

Explanation: According to Cell Theory, cells are recognized as the basic unit of structure and function in an organism, emphasizing their fundamental role in life.

C) Pituitary gland

Explanation: The pituitary gland is often called the 'master gland' because it regulates the functions of other endocrine glands and controls various hormonal activities in the body.

B) To maintain and regulate body functions

Explanation: The nervous system plays a crucial role in maintaining homeostasis by controlling and regulating various parts of the body, ensuring that internal conditions remain stable.

C) It maintains optimal conditions for cellular functions

Explanation: Homeostasis is vital because it ensures that internal conditions remain optimal for cellular functions, which is essential for the survival and health of the organism.

B) A receptor

Explanation: A deviation from a normal set point acts as a stimulus to a receptor, which then sends nerve impulses to the brain, initiating the homeostatic response.

B) Change in heritable characteristics over generations

Explanation: Evolution is characterized by changes in the heritable traits of biological populations across successive generations, indicating a gradual process of adaptation and change.

D) Cells can spontaneously generate

Explanation: Cell theory asserts that all cells arise from pre-existing cells, and the idea of spontaneous generation is not supported by modern biology.

C) Jean Baptiste Lamarck

Explanation: Jean Baptiste Lamarck proposed the concept of spontaneous generation of species, suggesting that species evolve according to their needs and functionalities, which was an early theory of evolution.

B) Photosynthesis

Explanation: Thylakoids are essential for photosynthesis, as they contain chlorophyll and are the site of the light-dependent reactions that convert solar energy into chemical energy.

B) They synthesize proteins

Explanation: Ribosomes attached to the Rough ER are responsible for synthesizing proteins, which are essential for various cellular functions and processes.

D) They facilitate the assembly of amino acids into proteins

Explanation: Ribosomes facilitate the assembly of amino acids into proteins, effectively acting as the site where protein synthesis occurs.

B) 1859

Explanation: Charles Darwin published his groundbreaking work on evolution in 1859, which laid the foundation for modern evolutionary biology.

C) In the chemical bonds of sugars

Explanation: The energy captured from sunlight during photosynthesis is stored in the chemical bonds of sugars, allowing plants to use this energy for growth and metabolism.

B) Photosynthesis

Explanation: Chloroplasts are primarily responsible for photosynthesis, the process by which plants convert light energy into chemical energy in the form of food.

C) Cell

Explanation: The cell is recognized as the basic unit of life, serving as the smallest living form that can carry out all necessary life processes.

B) Phagocytosis

Explanation: Cells take in food through the process of phagocytosis, which involves engulfing particles or other cells to form a food vacuole.

B) To digest food and eliminate waste

Explanation: Lysosomes are organelles that digest food taken in by the cell and help get rid of waste products, playing a crucial role in cellular digestion.

B) Only in producers (organisms containing chlorophyll)

Explanation: Chloroplasts are specifically found in producers, which are organisms that contain chlorophyll and can perform photosynthesis.

D) Bacteria

Explanation: Prokaryotic organisms are unicellular and lack a nucleus and many specialized cell parts, with bacteria being the primary example of this kingdom.

C) It is digested by lysosomes

Explanation: Once food is taken in by the cell, lysosomes digest it, breaking it down into usable components and helping to eliminate waste.

C) To use energy from sunlight to make food (glucose)

Explanation: Chloroplasts utilize sunlight to convert carbon dioxide and water into glucose, a process known as photosynthesis, which is essential for producers.

C) They digest and eliminate waste

Explanation: Lysosomes are responsible for digesting food and getting rid of waste, making them essential for maintaining cellular health and cleanliness.

C) They contain a nucleus

Explanation: Eukaryotic organisms are defined by the presence of a nucleus and a fuller repertoire of organelles, distinguishing them from prokaryotic organisms.

C) DNA in chromosomes

Explanation: The nucleus houses the DNA organized into chromosomes, which carry the genetic information necessary for the cell's functions and characteristics.

C) They lack specialized organelles

Explanation: Prokaryotic organisms, such as bacteria, are characterized by their lack of a nucleus and many specialized organelles, making them simpler in structure compared to eukaryotic organisms.

C) Nucleoid region

Explanation: In prokaryotic cells, the DNA is located in the nucleoid region, which is not enclosed by a membrane, distinguishing it from eukaryotic cells that have a defined nucleus.

C) Cell membrane and cell wall

Explanation: Prokaryotic cells are surrounded by both a cell membrane and a cell wall, which is primarily composed of peptidoglycan, providing structural support and protection.

B) To help maintain cell shape

Explanation: The cytoskeleton plays a crucial role in maintaining the shape of the cell, providing structural support and stability.

C) It is capable of self-regulation, metabolism, and reproduction

Explanation: A living organism is defined as a complex unit that can self-regulate, metabolize, and reproduce, highlighting its intricate biological functions.

B) Feedback loops

Explanation: Feedback loops are crucial mechanisms in homeostasis, allowing organisms to regulate internal conditions by responding to changes in the environment.

C) Both A and B

Explanation: The nervous system is primarily classified into two main divisions: the Central Nervous System (CNS) and the Peripheral Nervous System (PNS), which work together to control bodily functions.

D) Inability to adapt

Explanation: Living organisms are characterized by their ability to adapt to their environment, along with other abilities such as interaction, growth, movement, and reproduction.

C) Peptidoglycan

Explanation: The cell wall of prokaryotic cells is primarily composed of peptidoglycan, which provides structural integrity and protection against environmental stresses.

B) Internal organs

Explanation: The autonomic nervous system, part of the peripheral nervous system, contains motor neurons that control internal organs, regulating involuntary bodily functions.

C) Proteins and rRNA

Explanation: Ribosomes are composed of proteins and ribosomal RNA (rRNA), which are essential for their function in protein synthesis.

B) The process by which different kinds of living organisms develop from earlier forms

Explanation: Evolution is defined as the process through which various living organisms are believed to have evolved from earlier forms throughout Earth's history, highlighting the dynamic nature of life.

B) Autolysis

Explanation: Lysosomes are programmed for autolysis, which is the process of breaking down and recycling cell parts through the release of digestive enzymes.

B) Membrane-bound organelles

Explanation: Prokaryotic cells do not have membrane-bound organelles, which is a key distinction from eukaryotic cells that contain such structures.

D) Digestive organ

Explanation: The components of homeostasis include the sensor, afferent pathway, integration center, efferent pathway, and effector organ(s). The digestive organ is not a component of the homeostatic process.

D) Digest

Explanation: While cells metabolize, respire, reproduce, and multiply, digestion is a process that occurs at a higher level of organization, not directly within the cell itself.

B) True

Explanation: The prefix 'eu' in eukaryotic means 'true,' indicating that these organisms have a true nucleus and a more complex cellular structure compared to prokaryotic organisms.

C) To produce hormones that regulate various body functions

Explanation: The primary function of the endocrine system is to produce and secrete hormones that regulate a wide range of bodily functions, including metabolism, growth, and mood.

C) Animal cells

Explanation: Chloroplasts are never found in animal or bacterial cells; they are exclusive to plant cells and some protists, highlighting their role in photosynthesis.

C) Hypothalamus

Explanation: The hypothalamus is specifically mentioned as a portion of the brain that is particularly concerned with homeostasis, influencing various bodily functions.

B) To contain digestive enzymes

Explanation: Lysosomes are primarily responsible for containing digestive enzymes that break down food, bacteria, and worn-out cell parts, playing a crucial role in cellular maintenance and recycling.

B) Maintenance of relative stability of the internal environment

Explanation: Homeostasis is defined as the maintenance of relative stability of the physical and chemical aspects of the internal environment, which is crucial for cellular function.

C) Photosynthesis

Explanation: The primary process facilitated by chloroplasts is photosynthesis, which is the food-making process in plants, converting light energy into chemical energy.

B) Grana

Explanation: Thylakoids are organized into stacks known as grana, which play a crucial role in the light-dependent reactions of photosynthesis.

C) Autonomic Nervous System

Explanation: The Autonomic Nervous System (ANS) regulates involuntary bodily functions such as heart rate and digestion, distinguishing it from the Somatic Nervous System, which controls voluntary movements.

B) Cellular energy generation (ATP)

Explanation: Mitochondria are known as the 'powerhouse' of the cell because their main function is to generate cellular energy in the form of ATP, which is essential for various cellular processes.

B) Medulla oblongata

Explanation: The hypothalamus influences the action of the medulla oblongata, which is a lower part of the brain involved in autonomic functions, thereby playing a role in homeostasis.

B) Homeostasis

Explanation: Homeostasis refers to the ability of organisms to maintain stable internal conditions despite changes in their external environment, which is crucial for survival.

B) Schleiden and Schwann

Explanation: The cell theory was formulated by scientists Matthias Schleiden and Theodor Schwann in the 19th century, establishing the foundation for modern biology.

B) Accumulation of waste materials

Explanation: If lysosomes do not function properly, waste materials can accumulate within the cell, leading to various cellular dysfunctions and diseases.

B) They contain their own DNA

Explanation: Chloroplasts have their own DNA, which is distinct from the nuclear DNA of the cell, indicating their unique role and evolutionary history.

D) Monera

Explanation: The kingdom Monera consists of prokaryotic organisms, primarily bacteria, which are unicellular and lack a nucleus.

B) Actin

Explanation: Microfilaments are threadlike structures made of actin, which is a protein that contributes to the cytoskeleton's ability to maintain cell shape and facilitate movement.

B) From the cytoplasm in the egg cell

Explanation: Mitochondria are inherited from the cytoplasm of the egg cell during fertilization, meaning that individuals inherit their mitochondria exclusively from their mother.

B) Brain and spinal cord

Explanation: The Central Nervous System (CNS) is composed of the brain and spinal cord, which are responsible for processing information and coordinating responses.

B) It is enclosed by the cell membrane

Explanation: The cytoplasm is indeed enclosed by the cell membrane, which helps maintain the internal environment of the cell and supports the organelles within it.

C) They regulate physiological processes

Explanation: Hormones are chemical messengers that travel through the bloodstream to target organs, where they regulate various physiological processes such as growth, metabolism, and mood.

B) A German botanist

Explanation: Matthias Schleiden was a German botanist who, along with Theodor Schwann, formulated the Cell Theory, contributing significantly to our understanding of biology.

B) They lyse and release enzymes

Explanation: During autolysis, lysosomes lyse (break open) and release their digestive enzymes to break down and recycle cellular components, which is essential for cell maintenance.

B) They regulate the internal environment through feedback mechanisms

Explanation: Physiological control systems, such as the nervous system, endocrine system, and immune system, help regulate the internal environment of the body through feedback mechanisms, which are essential for maintaining homeostasis.

B) It directs an effector to create an adaptive response

Explanation: The brain acts as a regulating center that directs an effector to respond appropriately to stimuli, facilitating an adaptive response to maintain homeostasis.

A) Oxygen

Explanation: Maintaining a constant internal environment with all that cells need to survive, including oxygen, glucose, minerals, ions, and waste removal, is necessary for individual cells to function properly.

B) They have a structured arrangement of cells and systems

Explanation: Being organized means that organisms have a complex structure, typically composed of one or more cells that work together to perform various functions necessary for life.

B) They are transported to the Golgi apparatus

Explanation: After proteins are modified in the Rough ER, they are typically transported to the Golgi apparatus for further processing and sorting before being sent to their final destinations.

B) Theodor Schwann and Matthias Jakob Schleiden

Explanation: The Cell Theory was formulated by German scientists Theodor Schwann and Matthias Jakob Schleiden in 1838, marking a significant development in biological science.

C) Nuclear envelope

Explanation: The nucleus is bounded by a nuclear envelope (membrane) that contains pores, allowing for the exchange of materials between the nucleus and the cytoplasm.

B) The maintenance of stable internal conditions

Explanation: Homeostasis refers to the processes that organisms use to maintain stable internal conditions, such as temperature, pH, and hydration, despite external changes.

B) They have their own DNA

Explanation: Mitochondria are unique organelles that possess their own DNA, which is inherited maternally, indicating their distinct evolutionary origin and function within the cell.

B) Produce energy

Explanation: Cells are responsible for producing energy through various metabolic processes, which is essential for their survival and function.

C) The genes carried by chromosomes

Explanation: Each cell has a fixed number of chromosomes that carry genes, which control the characteristics and functions of the cell.

B) It has ribosomes on its surface

Explanation: The Rough Endoplasmic Reticulum is characterized by the presence of ribosomes on its surface, which distinguishes it from the Smooth ER and is crucial for its function in protein synthesis.

C) The chemical processes that occur within a living organism

Explanation: Metabolism refers to the sum of all chemical processes that occur within a living organism, essential for maintaining life.

B) Membrane proteins and proteins for export

Explanation: The Rough ER is responsible for synthesizing membrane proteins and proteins that are exported out of the cell, highlighting its role in cellular function and communication.

C) Protein synthesis

Explanation: Ribosomes play a crucial role in the process of protein synthesis, where they join amino acids to create proteins necessary for various cellular functions.

C) Adaptation

Explanation: Adaptation is the ability of living organisms to respond and adjust to changes in their environment, which is crucial for survival.

C) Attached to the Rough ER or free in the cytoplasm

Explanation: Ribosomes can either be attached to the Rough Endoplasmic Reticulum (ER) or exist freely in the cytoplasm, allowing them to synthesize proteins in different cellular locations.

C) A stimulus is detected by a receptor

Explanation: The homeostatic process begins when a deviation from a normal set point is detected by a receptor, which then triggers a series of responses to restore balance.

E) Archaea

Explanation: The five kingdoms traditionally recognized are Monera, Protista, Fungi, Plantae, and Animalia. Archaea is a domain, not a kingdom in this classification system.

C) Only in animal cells

Explanation: Centrioles are specifically found only in animal cells, distinguishing them from plant and other types of cells.

B) In the central nervous system

Explanation: The regulating centers for homeostasis are located in the central nervous system, which includes the brain and spinal cord, playing a crucial role in maintaining internal balance.

C) They are found in the cytoplasm

Explanation: Prokaryotic cells contain ribosomes in their cytoplasm, which are not membrane-bound and are essential for protein synthesis.

B) Cells come from the reproduction of existing cells

Explanation: Cell Theory states that cells arise from the reproduction of existing cells, which is a key principle in understanding cell division and life processes.

E) Viruses

Explanation: Whittaker's five kingdoms include Monera, Protista, Fungi, Plantae, and Animalia. Viruses are not classified within these kingdoms as they do not meet the criteria for living organisms.

C) Cells can arise from non-cellular materials

Explanation: The statement that cells can arise from non-cellular materials is not part of the Cell Theory; rather, it emphasizes that all cells come from pre-existing cells.

C) Protein synthesis

Explanation: Ribosomes are often referred to as the 'protein factories' of the cell because they are responsible for joining amino acids to form proteins through the process of protein synthesis.

A) Central and peripheral nervous systems

Explanation: The nervous system is divided into two major portions: the central nervous system (CNS) and the peripheral nervous system (PNS), each playing distinct roles in body function.

B) They detect changes in the environment

Explanation: Sensors are critical in homeostasis as they detect changes in the internal or external environment, allowing the organism to respond appropriately to maintain stability.

C) They are threaded into the interior of the Rough ER for modification

Explanation: After being synthesized by ribosomes on the Rough ER, proteins are threaded into its interior where they undergo modifications before being transported to their final destinations.

C) Monera

Explanation: The kingdom Monera is characterized by prokaryotic organisms, which lack a defined nucleus, distinguishing it from the other kingdoms that contain eukaryotic organisms.

C) Mitochondria are found in both plant and animal cells

Explanation: Mitochondria are present in both plant and animal cells, highlighting their essential role in energy production across different types of organisms.

B) To compare and process information

Explanation: The integration center, or comparator, in homeostasis is responsible for comparing the information received from sensors and determining the appropriate response to maintain stability in the internal environment.

C) Reproduction

Explanation: Reproduction is a key process that allows organisms to produce new individuals, ensuring the continuation of their species.

B) Bundle of microtubules

Explanation: Centrioles are made of a bundle of microtubules, which are essential for their function during cell division.

B) Mitosis

Explanation: Mitosis is the process by which cells reproduce asexually, resulting in two identical daughter cells, while meiosis is involved in sexual reproduction.

B) It is usually the largest organelle

Explanation: The nucleus is typically the largest organelle in the cell, playing a crucial role in controlling cellular activities and housing genetic material.

B) Enzymes and pigments

Explanation: Chloroplasts contain enzymes and pigments that are essential for the photosynthesis process, allowing plants to convert sunlight into food.

C) Sacs modified from the inner membrane

Explanation: Thylakoids are structures within chloroplasts that are modified from the inner membrane and are essential for the process of photosynthesis.

C) They are tube-like and made of tubulin

Explanation: Microtubules are characterized as tube-like structures composed of tubulin, playing a vital role in maintaining cell shape and facilitating the movement of organelles.

B) Cristae

Explanation: The folded inner membrane of mitochondria is known as cristae, which increases the surface area available for chemical reactions, enhancing the organelle's ability to produce energy.

B) Sympathetic and parasympathetic

Explanation: The autonomic nervous system has two divisions: the sympathetic system, which prepares the body for stress, and the parasympathetic system, which promotes rest and digestion.

B) Organelles to carry out specific jobs

Explanation: The cytoplasm contains various organelles that perform specific functions necessary for the cell's survival and operation, making it a vital component of all cells.

C) A living organism

Explanation: A living organism is defined as a complex unit of physicochemical materials, distinguishing it from non-living entities.

D) Facilitating muscle contraction

Explanation: While the endocrine system regulates many bodily functions, facilitating muscle contraction is primarily the role of the nervous system, not the endocrine system.

C) In all cells

Explanation: Cytoplasm is a fundamental component found in all types of cells, including prokaryotic and eukaryotic cells, highlighting its universal importance in cellular biology.

B) Energy production

Explanation: Mitochondria are often referred to as the powerhouse of the cell because their primary function is to produce energy in the form of ATP through cellular respiration.

C) Jelly-like

Explanation: The cytoplasm is described as a jelly-like substance, which allows for the movement of organelles and the facilitation of chemical reactions within the cell.

B) They are composed of many cells that work together

Explanation: The cell theory implies that multicellular organisms are made up of numerous cells that collaborate to perform various functions, highlighting the complexity of life.

C) Cells can perform all life processes

Explanation: A key characteristic of cells, as stated in cell theory, is that they can carry out all necessary life processes, making them the fundamental units of life.

C) Double membrane

Explanation: Chloroplasts are surrounded by a double membrane, which consists of an outer smooth membrane and an inner membrane that is modified into structures called thylakoids.

B) To provide a medium for chemical reactions

Explanation: The cytoplasm serves as a jelly-like substance that provides a medium for chemical reactions to occur, which is essential for the cell's metabolic processes.

A) Insulin

Explanation: Insulin is the hormone produced by the pancreas that plays a crucial role in regulating blood sugar levels by facilitating the uptake of glucose into cells.

C) DNA

Explanation: Cells utilize DNA to store and transmit genetic information, which is crucial for inheritance and cellular function.

C) Fungi have cell walls made of chitin

Explanation: Fungi are characterized by having cell walls made of chitin, whereas plants have cell walls made of cellulose. This distinction is crucial in classifying these two kingdoms.

D) Skin color

Explanation: Skin color is not regulated by homeostasis; rather, it is a characteristic determined by genetics and environmental factors, while homeostasis regulates internal conditions like temperature and pH.

B) They require energy (food)

Explanation: One of the fundamental characteristics of organisms is that they require energy, typically in the form of food, to sustain their biological processes and functions.

D) Protista

Explanation: The kingdom Protista consists mainly of unicellular eukaryotic organisms, which distinguishes it from the other kingdoms that include multicellular organisms.

C) Ribosomes

Explanation: Ribosomes are not part of the cytoskeleton; they are involved in protein synthesis. The cytoskeleton consists of microfilaments and microtubules made of actin and tubulin, respectively.

B) Muscle cells

Explanation: More active cells, such as muscle cells, have a higher number of mitochondria to meet their increased energy demands during physical activity.

C) Survival of the fittest

Explanation: Charles Darwin's theory of evolution is primarily based on the principle of 'survival of the fittest,' which emphasizes natural selection as a driving force in the evolution of species.

C) By adapting and reacting to stimuli

Explanation: Organisms respond to their environment by adapting and reacting to various stimuli, which is essential for survival and interaction with their surroundings.

C) Prokaryotic cells

Explanation: The Monera kingdom is characterized by organisms that have prokaryotic cells, meaning they lack a defined nucleus and membrane-bound organelles.

C) Protists, fungi, plants, and animals

Explanation: Eukaryotes include a diverse range of organisms such as protists, fungi, plants, and animals, all of which possess complex cellular structures.

C) They are more complex

Explanation: Eukaryotic cells are considered more complex than prokaryotic cells due to their larger size, presence of a nucleus, and various membrane-bound organelles.

A) All living organisms are made up of cells

Explanation: One of the fundamental principles of cell theory states that all living organisms are composed of one or more cells, emphasizing the cellular basis of life.

C) Matrix

Explanation: The interior of the mitochondria is called the matrix, which contains enzymes and other molecules necessary for the biochemical processes that occur within the organelle.

B) To connect the CNS to the limbs and organs

Explanation: The Peripheral Nervous System (PNS) serves as a communication network that connects the Central Nervous System (CNS) to the limbs and organs, facilitating sensory and motor functions.

C) Plant cells

Explanation: Plant cells are characterized by having a large central vacuole, which plays a crucial role in storage and maintaining turgor pressure.

D) Hormonal regulation

Explanation: While the nervous system is responsible for sensory input, integration, motor output, and reflex actions, hormonal regulation is primarily a function of the endocrine system.

B) Double layer of phospholipids and proteins

Explanation: The cell membrane is primarily composed of a double layer of phospholipids and proteins, which is essential for its structure and function in surrounding the cell.

C) Plantae

Explanation: The kingdom Plantae is primarily composed of multicellular organisms that are autotrophic, meaning they produce their own food through photosynthesis.

B) They have a nucleus and membrane-bound organelles

Explanation: Eukaryotic cells are characterized by the presence of a nucleus and membrane-bound organelles, distinguishing them from prokaryotic cells, which lack these features.

B) Outside of the cell

Explanation: The cell membrane surrounds the outside of all cells, acting as a boundary between the cell's internal environment and the external surroundings.

B) The structure and function of cells

Explanation: Cell theory primarily focuses on the understanding that all living organisms are composed of cells, which are the basic unit of life, emphasizing the structure and function of cells in biological systems.

C) They absorb nutrients from their environment

Explanation: Fungi are heterotrophic organisms that absorb nutrients from their surroundings, often through decomposition, and they have cell walls made of chitin.

B) By secreting hormones that regulate body cells

Explanation: The endocrine system regulates metabolism by secreting hormones that influence the activity and development of most body cells and systems.

D) Bacterial cell

Explanation: Bacterial cells are prokaryotic and do not have a nucleus or membrane-bound organelles, distinguishing them from eukaryotic cells like plant, animal, fungal, and protist cells.

C) Energy production

Explanation: Mitochondria are known as the powerhouse of the cell, primarily responsible for producing energy in the form of ATP through cellular respiration.

B) To make ribosomes

Explanation: The primary function of the nucleolus is to produce ribosomes, which are essential for protein synthesis in the cell.

B) It helps move organelles around

Explanation: The cytoskeleton is essential for the movement of organelles within the cell, allowing for proper cellular function and organization.

B) Fluid-filled sacks for storage

Explanation: Vacuoles are primarily fluid-filled sacks that serve as storage compartments within cells, holding various substances necessary for cellular function.

B) Stroma

Explanation: The stroma is the gel-like material that surrounds the thylakoids within chloroplasts, providing a medium for the light-independent reactions of photosynthesis.

B) It lacks ribosomes on its surface

Explanation: The Smooth Endoplasmic Reticulum is characterized by the absence of ribosomes on its surface, distinguishing it from the Rough Endoplasmic Reticulum.

C) Food, bacteria, and worn-out cell parts

Explanation: Lysosomes are involved in breaking down food, bacteria, and worn-out cell parts, making them vital for cellular health and recycling.

B) Making membrane lipids (steroids)

Explanation: The Smooth ER is responsible for synthesizing membrane lipids, including steroids, which are essential for various cellular functions.

C) Bacterial cells

Explanation: Bacterial cells are noted for having no vacuoles, distinguishing them from plant and animal cells that may contain these storage structures.

B) It is attached to the ends of the Rough ER

Explanation: The Smooth Endoplasmic Reticulum is anatomically connected to the ends of the Rough Endoplasmic Reticulum, allowing for the transport of materials between them.

B) They perform various functions for a cell

Explanation: Organelles are specialized structures within a cell that perform various essential functions, contributing to the overall operation and maintenance of the cell.

B) Mitochondria

Explanation: The plural form of mitochondrion is mitochondria, which refers to multiple organelles within a cell.

C) They facilitate the transport of substances

Explanation: Protein channels in the cell membrane are crucial for allowing specific molecules to pass through, thus aiding in the transport of substances across the membrane.

B) Microscopic

Explanation: Organelles are very small and microscopic, which allows them to fit within the confines of a cell and perform their specialized functions.

C) They are secreted into the bloodstream

Explanation: Hormones are special compounds secreted by glands in the endocrine system into the bloodstream, allowing them to travel to various target tissues and exert their effects.

C) Nuclear envelope and cell membrane

Explanation: The Endoplasmic Reticulum (ER) connects to both the nuclear envelope and the cell membrane, facilitating its role in transport and communication within the cell.

B) To secrete hormones into the bloodstream

Explanation: The endocrine system's primary function is to secrete hormones into the bloodstream, which then regulate various bodily functions, including metabolism and development.

B) Cellular respiration

Explanation: Mitochondria are the site of cellular respiration, where glucose is burned to produce ATP, making them crucial for energy metabolism.

B) Plant cells have a large central vacuole, while animal cells have small or absent vacuoles

Explanation: Plant cells typically contain a large central vacuole for storage, whereas animal cells may have small vacuoles or none at all, highlighting a key difference in their cellular structure.

C) They help pull chromosome pairs apart

Explanation: Centrioles appear during cell division and form the mitotic spindle, which helps to pull chromosome pairs apart to opposite ends of the cell.

A) 1 to 3

Explanation: A cell may contain between 1 to 3 nucleoli, which are involved in the synthesis of ribosomes.

B) The ability to maintain a stable internal environment

Explanation: Homeostasis refers to the mechanisms that organisms use to maintain a stable internal environment despite external changes, crucial for survival.

C) Cell sap, including sugars, proteins, minerals, and more

Explanation: In plant cells, vacuoles store cell sap, which includes a variety of substances such as sugars, proteins, minerals, lipids, wastes, salts, water, and enzymes.

B) Regulating calcium

Explanation: In muscle cells, the Smooth Endoplasmic Reticulum plays a crucial role in regulating calcium levels, which is vital for muscle contraction.

D) Plantae

Explanation: The Plantae kingdom consists mainly of multicellular organisms that are capable of photosynthesis, utilizing sunlight to produce their own food.

B) Eukaryotes

Explanation: Eukaryotes are defined as cells that are more complex and contain a nucleus, setting them apart from prokaryotic cells.

B) To control what enters or leaves the cell

Explanation: The cell membrane functions as a selective barrier that regulates the movement of substances into and out of the cell, maintaining homeostasis.

C) In the cytoplasm

Explanation: Organelles are located in the cytoplasm of a cell, where they carry out their specific functions necessary for the cell's survival and operation.

D) Regulating heart rate

Explanation: While sex hormones have various functions such as activating sebaceous glands and governing reproduction, they do not directly regulate heart rate, which is primarily controlled by the nervous system.

B) It disappears

Explanation: The nucleolus disappears during cell division, which is a characteristic behavior of this organelle.

B) Golgi apparatus

Explanation: The Golgi apparatus modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles, playing a crucial role in the cell's secretory pathway.

B) Synthesis of cell products and transport

Explanation: The Endoplasmic Reticulum (ER) is primarily involved in the synthesis of cell products and their transport within the cell, making it essential for cellular function.

A) Smooth and Rough

Explanation: The Endoplasmic Reticulum (ER) is classified into two types: Rough ER, which has ribosomes on its surface, and Smooth ER, which does not, each serving different functions in the cell.

B) One or more target tissues

Explanation: Each hormone released by the endocrine system has specific effects on one or more target tissues, influencing various physiological processes.

C) Destroying toxic substances

Explanation: The Smooth Endoplasmic Reticulum in liver cells is involved in detoxifying harmful substances, making it essential for maintaining cellular health.

B) To control the movement of substances in and out of the cell

Explanation: The cell membrane serves as a selective barrier that regulates the entry and exit of substances, maintaining homeostasis within the cell.

B) Protista

Explanation: The Protista kingdom includes a diverse group of primarily unicellular organisms that can be either autotrophic (like algae) or heterotrophic (like protozoa).

B) To synthesize proteins

Explanation: Ribosomes are the cellular structures that facilitate the synthesis of proteins by translating messenger RNA into polypeptide chains.

B) Organelles may or may not be membrane-bound

Explanation: Some organelles are membrane-bound, like the nucleus and mitochondria, while others, like ribosomes, are not, indicating the diversity in organelle structure.

E) Protista

Explanation: While Protista is one of the kingdoms in Whitaker's classification, it is often considered a part of the broader classification system. The five kingdoms include Monera, Fungi, Plantae, Animalia, and Protista, but Protista is sometimes debated in its classification.

C) Mitochondria

Explanation: Mitochondria are known as the powerhouse of the cell, as they are responsible for producing ATP through cellular respiration, providing energy for cellular activities.

B) They are paired structures near the nucleus

Explanation: Centrioles are paired structures that are located near the nucleus, playing a crucial role in cell division.

B) They make proteins

Explanation: Ribosomes produced by the nucleolus are responsible for synthesizing proteins, which are vital for various cellular functions.

B) Lipid synthesis and detoxification

Explanation: Smooth Endoplasmic Reticulum (SER) primarily functions in lipid synthesis and detoxification processes, distinguishing it from Rough ER.

B) Inside the nucleus

Explanation: The nucleolus is specifically located inside the nucleus of a cell, playing a crucial role in ribosome production.

C) Cell recognition and signaling

Explanation: Carbohydrate chains attached to proteins and lipids in the cell membrane play important roles in cell recognition and signaling, facilitating communication between cells.

B) During cell division

Explanation: Centrioles appear during cell division, specifically to assist in the formation of the mitotic spindle.

C) To replace damaged cells

Explanation: The main purpose of cell replication is to produce new cells to replace damaged or dead cells, ensuring the continuity of life and proper functioning of tissues.

B) To digest waste materials and cellular debris

Explanation: Lysosomes contain digestive enzymes that break down waste materials and cellular debris, playing a key role in cellular cleanup and recycling.

C) Regenerative medicine

Explanation: Stem cells have significant applications in regenerative medicine, where they can be used to repair or replace damaged tissues and organs due to their ability to differentiate into various cell types.

B) It has ribosomes on its surface

Explanation: Rough Endoplasmic Reticulum (RER) is characterized by the presence of ribosomes on its surface, which are essential for protein synthesis.

C) Plant cell

Explanation: The text specifically mentions plant cells in relation to organelles, indicating that organelles are present in both plant and animal cells but highlighting their significance in plant cells.

B) The specialization of cells into different types

Explanation: Tissue differentiation is the process by which unspecialized cells develop into specialized cells with distinct functions, forming various tissues in an organism.