What is the primary function of chloroplasts?
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To harness energy from sunlight through photosynthesis.
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What is the primary function of chloroplasts?
To harness energy from sunlight through photosynthesis.
Who proposed the theory of endosymbiosis for eukaryotes?
Lynn Margulis.
What are two key characteristics of mitochondria and chloroplasts?
They are semi-autonomous and can grow and multiply independently from the cell.
How do mitochondria and chloroplasts replicate?
By fission, similar to prokaryotes.
What structural features do mitochondria and chloroplasts have?
They have a double membrane and their own circular DNA and ribosomes.
What similarity do mitochondria and chloroplasts share with certain types of bacteria?
They resemble and have similar DNA to certain types of bacteria.
How does temperature affect the fluidity of the cell membrane?
Higher temperatures increase kinetic energy, making the membrane more fluid.
What type of fatty acids are associated with warmer environments?
Longer and more saturated fatty acids.
What happens to molecules in colder temperatures regarding membrane composition?
They have less kinetic energy, leading to shorter and less saturated fatty acid chains.
What is the basic premise of Cell Theory?
All organisms are composed of one or more cells, and life processes occur within these cells.
What role do sterol molecules play in cell membranes?
They act as buffers to maintain membrane fluidity.
What are cells considered in terms of living organisms?
Cells are the smallest living things and the basic units of organization of all organisms.
Which sterol is found only in animal cells?
Cholesterol.
What model describes the structure of the cell membrane?
Fluid Mosaic Model.
How do cells arise?
Cells arise only by division of previously existing cells.
What are the functions of membrane proteins?
Transporters, enzymes, cell-surface receptors, identity markers, adhesion, and cytoskeleton anchoring.
What is one of the primary functions of the cell membrane?
Defines the boundary of the cell.
What defines a cell and separates it from the external environment?
The plasma membrane.
How does the cell membrane maintain homeostasis?
By regulating the movement of molecules in and out.
What are integral membrane proteins?
Proteins that span the entire membrane.
What is compartmentalization in cells?
It refers to the organization of cellular functions, which is only present in eukaryotic cells.
What are peripheral membrane proteins?
Proteins that are temporarily associated with either the internal or external side of the membrane.
What type of molecules can move freely through the plasma membrane?
Small, nonpolar molecules like O2 or CO2.
What is the role of genetic formation in cells?
It involves the processes of transcription and translation to create proteins and modulate cellular processes.
What factors affect movement across the cell membrane?
Size and charge of the molecules.
What is metabolism?
The breakdown of molecules to harvest energy and transform one form of energy into another.
How do most drugs interact with the cell membrane?
They utilize a liposome that fuses with the phospholipid bilayer.
Why are viruses not considered living cells?
Because they do not undergo metabolism.
What is Passive Transport?
Movement of molecules from high to low concentration without energy.
What are glycoproteins?
Proteins with carbohydrates attached.
What are the two types of Passive Transport?
Simple diffusion and facilitated diffusion (using protein transporters).
How do cells in normal tissue stick together?
Through cell-to-cell adhesion.
What is the function of cholesterol in the cell membrane?
It helps to maintain membrane fluidity and stability.
Does Passive Transport require energy?
No, it does not require energy (ATP).
What is the difference between channels and carriers in cell transport?
Channels are unspecific and open to both sides, while carriers are specific to the type of molecule they transport.
What does hydrophilic mean?
It means 'loves' water, indicating attraction to water.
What characterizes the channels involved in Passive Transport?
They are always open and do not require energy.
What is required for active transport across the cell membrane?
Energy (ATP) is required.
What is a uniport carrier?
A carrier that moves only one molecule at a time.
What do carriers in active transport require?
Carriers are always gated and require energy to work.
What does a symport carrier do?
Moves both or multiple molecules to one side of the gradient/membrane.
What is the role of the proton pump in secondary active transport?
It generates an electrochemical gradient with a higher concentration of protons outside the cell.
What is the function of an antiport carrier?
Moves one or more molecules to opposite sides of the gradient/membrane.
What is an antiporter?
A transporter that uses the proton electrochemical gradient to move a different molecule out of the cell against its concentration gradient.
What happens during primary active transport with a proton pump?
The pump moves H^+ ions to one side, making that side positive along the membrane wall.
What are the important carriers to remember in active transport?
Antiporter and Simporter.
What is passive transport?
The movement of molecules in and out of the cell without requiring energy, from high to low concentration.
What does the Fluid Mosaic Model describe about the cell membrane?
The membrane is not rigid.
What is osmosis?
The movement of solvent (usually water) across a semipermeable membrane.
What types of proteins are found in the cell membrane according to the Fluid Mosaic Model?
Integral proteins and peripheral proteins.
What does hydrophobic mean?
It means 'hates' water.
What occurs in a hypertonic environment?
Water moves from the cell to the extracellular space, causing the cell to shrink.
What components are included in the cell membrane structure?
Hopanoid, phospholipid, glycolipid, integral protein, peripheral protein, oligosaccharide, and hydrophobic alpha helix.
What determines the behavior of a molecule in water?
The structure of the molecule.
What is turgor pressure in plant cells?
The pressure exerted by the central vacuole against the cell wall, helping maintain cell shape.
What type of structure do molecules with two chains form?
Bilayers, such as in cell membranes and liposomes.
What is the significance of a selectively permeable membrane?
It helps maintain homeostasis by regulating what enters and exits the cell.
What is the significance of membrane fluidity?
It is important for cell communication and function.
How does the membrane maintain its fluidity?
Through the structure and length of fatty acid tails and the presence of sterols.
What effect do saturated fatty acids have on membrane fluidity?
They make the membrane less fluid due to tight packing.
What is passive transport by diffusion?
Molecules can diffuse without energy through a concentration gradient.
What effect do unsaturated fatty acids have on membrane fluidity?
They increase fluidity by introducing kinks in the phospholipids.
What is active transport?
The movement of molecules against a concentration gradient, requiring energy.
What role do sterol molecules play in the cell membrane?
They help maintain membrane fluidity.
What does 'Pro' in Prokaryotes signify?
Before in time or space.
What is the function of cholesterol in animal cells?
To help maintain fluidity of the membrane.
What does 'Eu' in Eukaryotes signify?
True.
What is the role of sitosterol in plant cells?
It helps maintain fluidity of the membrane, similar to cholesterol in animals.
What does 'Karyo' refer to?
Nucleus.
What are hopanoids and where are they found?
They are found in bacteria and help maintain membrane fluidity.
What is a key feature of Prokaryotes?
All have a cell wall and a nucleoid that is circular.
How does temperature affect membrane fluidity?
Increased temperature increases fluidity, while decreased temperature decreases fluidity.
What is the difference between cytoplasm and cytosol?
Cytoplasm is the space inside the cell, while cytosol is the liquid in which cellular structures float.
What is the composition of the cell membrane?
It is amphipathic, having polar heads and nonpolar tails.
How is DNA organized in Prokaryotes?
In circular chromosomes.
What adaptations can be seen in the lipid composition of cell membranes?
Variations appear to adapt to specific environmental conditions.
What is the endomembrane system?
A system of compartmentalization within eukaryotic cells.
What are some similarities between Prokaryotes and Eukaryotes?
Both have ribosomes, DNA, reproduce by division, have a plasma membrane, and contain cytoplasm.
What are unique features of Eukaryotes?
They have a nucleus, are membrane-bound, more complex, and have linear chromosomes.
What is the function of mitochondria in Eukaryotic cells?
They harness energy from chemical compounds through cellular respiration.
What is a unique characteristic of mitochondria?
They have their own circular DNA and a double membrane.
Can mitochondria divide independently?
Yes, they can divide independently.
