Key terms include carbohydrates, monosaccharides, disaccharides, polysaccharides, glycosidic bonds, and biochemical tests.
Reactions include the formation and hydrolysis of glycosidic bonds.
Monosaccharides are the simplest form of carbohydrates, consisting of single sugar units.
Glucose is a common monosaccharide that serves as a primary energy source for cells.
Glucose, galactose, and fructose have the same molecular formula.
Branching enables more free ends where glucose molecules can be added or removed, allowing for faster condensation and hydrolysis reactions.
The monomer for cellulose is glucose.
They differ in the arrangement of their atoms, leading to slightly different molecular structures and properties.
No, lipid molecules are not made from monomers or polymers; each fatty acid joins to a glycerol molecule.
Amylose is one of the two polysaccharides that is used to form starch, which is the storage polysaccharide in plants.
Carbohydrates, Proteins, Lipids, Nucleic Acids, Water
Cellulose exists in parallel chains bonded by many hydrogen bonds, which gives it high mechanical strength.
To create a standard to compare unknown concentrations against.
During the hydrolysis of polymers, covalent bonds are broken when water is added.
Amylopectin is one of the two polysaccharides used to form starch, which is the storage polysaccharide in plants.
The high tensile strength of cellulose allows it to be stretched without breaking, enabling cell walls to withstand turgor pressure.
Glycogen acts as a readily available energy source for animals.
The absorbance value provides a quantitative measure of the strength of the orange color in the solution.
Instead of waiting a fixed amount of time for color changes, time how long it takes for the first color change to occur (blue to green).
α and β glucose
The arrangement of the glycosidic bond in cellulose depends on the position of the OH group on carbon 1 and 4.
Covalent bonds in organic molecules are broken during hydrolysis.
Beta glucose has a straight chain form with the hydroxyl group on the first carbon atom oriented upward.
When counting bacteria or yeast populations and determining unknown glucose, starch, or protein concentrations.
Glycogen.
Different types of glycosidic bonds form because there are many different monosaccharides.
Paper chromatography
Glycogen is a highly branched molecule used as a storage polysaccharide in animals and fungi.
A molecule of glucose and a molecule of fructose are formed.
Visually, through a calibration/standard curve, or using a colourimeter.
A glycosidic bond is a type of covalent bond that connects a carbohydrate molecule to another group, which can be another carbohydrate.
Each glycosidic bond is catalyzed by enzymes specific to the interacting OH groups.
Qualitative tests, which do not provide a quantitative value.
Cellulose fibers are freely permeable, allowing water and solutes to leave or reach the cell surface membrane.
Copper (II) sulfate is reduced to copper (I) oxide, which forms a precipitate.
A condensation reaction is one in which two molecules join together, forming a new chemical bond and releasing a molecule of water.
A glycosidic bond is a type of covalent bond that connects a carbohydrate molecule to another group, which can be another carbohydrate.
Monomers are the smaller units from which larger molecules are made.
Alpha glucose has a straight chain form with the hydroxyl group on the first carbon atom oriented downward.
Sucrose.
Amylose and amylopectin.
Colorless molecules, such as a mixture of monosaccharides, must be stained before being placed on the chromatography paper.
Benedict's solution is used to carry out a semi-quantitative test on a reducing sugar solution to determine the concentration of reducing sugar present in the sample.
The different monosaccharides within the mixture separate out at different distances from the line as the solvent travels up through the chromatography paper.
Colorimeters must be calibrated to ensure accurate measurements, starting with a blank that should read 0 absorbance.
Maltose is formed from two α-glucose monomers.
Hydrolysis is a chemical reaction that involves the addition of water to break down covalent bonds in organic molecules.
Glucose and fructose.
The addition of water to the glycosidic bond breaks it.
Unknown concentrations can be determined using a calibration curve created from the quantitative data.
Paper chromatography is used to separate a mixture of monosaccharides by allowing them to travel different distances on chromatography paper when a solvent is applied.
Maltose has an α-1,4 glycosidic bond.
An excess of Benedict's solution ensures that there is more than enough copper (II) sulfate present to react with any sugar in the sample.
Covalent bonds are very stable because high energies are required to break them.
A colorimeter can measure the absorbance or transmission of light through the sugar solutions of known concentration, establishing a range of values for comparison against an unknown sample.
Examples include the digestion of food in the alimentary tract and the breakdown of stored carbohydrates in muscle and liver cells for use in cellular respiration.
The strength and insolubility of cellulose fibers make it a suitable molecule to construct cell walls.
Chromatogram
Polymers are molecules made from a large number of monomers joined together in a chain.
Separate lipid molecules, such as triglycerides, are not held together by covalent bonds.
Amylopectin constitutes 70 - 90% of starch.
The formation of a glycosidic bond occurs by condensation between two monosaccharides, such as glucose, to form a disaccharide like maltose.
Color filters are used to control the light wavelength emitted, ensuring the color used contrasts with the color of the solution being tested.
Liver and muscle cells have a high concentration of glycogen because the cellular respiration rate is high in these cells, as animals are mobile.
Benedict's reagent is a blue solution that contains copper (II) sulfate ions (CuSO4).
C6H12O6
Hydrolytic reactions are catalyzed by enzymes that are different from those present in condensation reactions.
Paper chromatography is a specific form of chromatography where the mobile phase is a liquid solvent and the stationary phase is chromatography paper.
A spot of the mixture is placed on chromatography paper, which is then suspended in a solvent, causing the components to move at different speeds and separate into spots or bands.
Examples of reducing sugars include glucose, fructose, and galactose.
Starch and glycogen are classified as polysaccharides.
Polysaccharides can be branched or unbranched, folded, straight, or coiled.
The concentration of glucose can be determined using Benedict's test.
Due to the many monomers in a starch molecule, it takes longer to digest than glucose.
You must be able to recognise and draw the isomers of α and β glucose.
Polysaccharides must undergo many hydrolytic reactions until they form monosaccharides.
The color changes from blue towards red if a reducing sugar is present.
A calibration curve is created by plotting the quantitative data obtained from the colorimeter.
A glycosidic bond is a strong covalent bond formed when two hydroxyl (-OH) groups from different monosaccharides interact, linking them together.
Cellulose contributes to the strength of cell walls through many hydrogen bonds that form between the parallel chains of microfibrils.
Starch serves as the primary energy storage molecule in plants.
Blue light is absorbed by an orange solution because orange light is reflected, giving the solution its orange appearance.
Standard solutions are set up using a serial dilution of an existing stock solution of a reducing sugar, such as glucose, and treated the same way with Benedict's solution.
Disaccharides and polysaccharides are broken down in hydrolysis reactions.
A glycosidic bond is the new chemical bond that forms between two monosaccharides during the formation of a disaccharide.
A condensation reaction, also known as dehydration synthesis, occurs when monomers combine to form polymers or macromolecules, with water being removed.
Cellulose consists of long chains of β-glucose.
Neutralise the solution with sodium hydrogencarbonate.
Disaccharides are carbohydrates formed by the combination of two monosaccharides through a glycosidic bond.
A color change occurs in the solution.
Amylose is an unbranched helix-shaped chain with 1,4 glycosidic bonds between α-glucose molecules.
It shows that starch in a sample has been digested by enzymes.
Sucrose is formed from α-glucose and fructose monomers.
Identifying the glycosidic bond is crucial for understanding the structure and function of carbohydrates, as it determines how they are linked and how they can be broken down.
Doubling dilutions and a desired range (e.g. 0, 2, 4, 6, 8, 10 mmol dm⁻³).
Hydrolysis means 'lyse' (to break) and 'hydro' (with water).
The result is the formation of the disaccharide sucrose.
During the formation of a glycosidic bond, one water molecule is removed, which is a process known as condensation.
Known standard solutions of different monosaccharides are placed on the chromatography paper beside the sample spot to help identify the unknown monosaccharides by comparing distances.
The intensity of any color change seen relates to the concentration of reducing sugar present in the sample, ranging from green (low concentration) to brick-red (high concentration).
Chromatography is a technique used to separate a mixture into its individual components.
Add Benedict's reagent to a sample solution, heat it in a boiling water bath, and observe for a color change.
The formation of glycosidic bonds involves the reaction between monosaccharides, resulting in the creation of polysaccharides such as amylopectin.
To calculate the chemical formula of a disaccharide, add all the carbons, hydrogens, and oxygens in both monomers, then subtract 2 × H and 1 × O for the water molecule lost.
Each carbon atom can form four covalent bonds, making compounds very stable.
A glycosidic bond is a type of covalent bond that links monosaccharides together to form disaccharides and polysaccharides.
Very large molecules that contain 1000 or more atoms, therefore having a high molecular mass.
An example of a non-reducing sugar is sucrose.
Starch is constructed from amylose and amylopectin.
Disaccharides hydrolyse to two monosaccharides.
Visibly separated components after the chromatography run has finished.
A condensation reaction is the removal of water to form a covalent bond between two or more monomers.
No, lipids cannot be classified as polymers because they do not form from monomers joining together.
Monosaccharides are bonded together to make them more suitable for transport and storage, and to reduce their influence on a cell’s osmolarity.
Glycogen is the storage polysaccharide of animals and fungi, characterized by being highly branched and not coiled.
Cellulose fibers, along with other molecules like lignin, form a matrix that increases the strength of the cell walls.
Sucrose has an α-1,2 glycosidic bond.
A glycosidic bond is broken when water is added in a hydrolysis reaction.
Multiple pairs of electrons can be shared, forming double bonds (e.g., unsaturated fats C=C) or triple bonds.
Polysaccharide chains may be branched or unbranched, folded, straight, or coiled.
Polysaccharides are insoluble in water.
Sucrose is a non-reducing sugar which gives a negative result in a Benedict’s test.
The process by which small single subunits (monomers) bond with many repeating subunits to form large molecules (polymers).
Polysaccharides are formed by many monosaccharides joined by glycosidic bonds in a condensation reaction.
OILRIG stands for 'Oxidation Is Loss, Reduction Is Gain', which helps remember what happens to a molecule when electrons are lost or gained.
Water is added to break down covalent bonds during hydrolysis reactions.
A colorimeter is used to obtain quantitative data that can be plotted to create a calibration curve to find unknown concentrations.
A glycosidic bond is formed by condensation between α-glucose and β-fructose.
The branches in amylopectin result in many terminal glucose molecules that can be easily hydrolysed for use during cellular respiration or added to for storage.
Starch consists of amylose (linear) and amylopectin (branched), while glycogen is more highly branched than amylopectin.
A blue light filter is used to shine blue light through the sample, as Benedict's solution turns orange in the presence of sugar.
Glycogen is more branched than amylopectin, making it more compact and allowing animals to store more.
A disaccharide is formed when two monosaccharides join together via condensation reactions.
Alpha (α) glucose and beta (β) glucose
Serial dilutions are created by taking a series of dilutions of a stock solution, where the concentration decreases by the same quantity between each test tube.
Add dilute hydrochloric acid to the sample and heat in a water bath that has been brought to the boil.
Fructose and galactose have the same molecular formula as glucose but different structural formulas, leading to slightly different properties.
No, not all macromolecules are polymers as the subunits of polymers have to be the same repeating units.
Biochemical tests include Benedict's test for reducing sugars and iodine test for starch.
Amylose makes up 10-30% of starch.
A nucleic acid is a polymer made of nucleotide monomers.
Galactose, Glucose, Fructose, and Maltose.
The position of the hydroxyl group on the first carbon atom distinguishes alpha glucose (downward) from beta glucose (upward).
Cellulose is the main structural component of cell walls due to its strength from hydrogen bonds between β-glucose molecules.
The oxygen link in a glycosidic bond holds the two monosaccharide molecules together.
If a spot from the monosaccharide sample mixture is at the same distance from the line as a spot from one of the known standard solutions, it indicates that the mixture contains that monosaccharide.
The two types are nonpolar covalent bonds (equal sharing) and polar covalent bonds (unequal sharing).
The two phases are the mobile phase and the stationary phase.
Polysaccharides are formed by many monosaccharides joined by glycosidic bonds in a condensation reaction.
When sucrose is heated with hydrochloric acid, it provides the water that hydrolyzes the glycosidic bond.
The result is a chromatogram, which shows the separated components of the original mixture.
Chromatography is a technique used to separate and analyze monosaccharides.
Non-reducing sugars must first be hydrolysed to break the disaccharide into its two monosaccharides before a Benedict’s test can be performed.
The addition of acid will hydrolyse any glycosidic bonds present in carbohydrate molecules.
Because iodine is insoluble in water.
Amylopectin contains 1,4 glycosidic bonds between α-glucose molecules and also 1,6 glycosidic bonds between glucose molecules.
A colorimeter beams a specific wavelength of light through a sample and measures how much of this light is absorbed by the sample.
Glycogen is primarily found in liver and muscle cells, where it is present as visible granules.
Sugars are classified as reducing or non-reducing.
Hydrogen can form 1 bond, while carbon can form 4 bonds.
A calibration curve plots absorbance against known concentrations, allowing unknown concentrations to be determined from the graph.
Components with higher solubility travel further because they spend more time in the mobile phase.
Carbon (C) and hydrogen (H), making them organic compounds.
Reducing sugars can be detected using Benedict’s test, which reduces soluble copper sulfate to insoluble brick-red copper oxide.
Cellulose has 1,4 glycosidic bonds.
Non-reducing sugars cannot donate electrons and therefore cannot be oxidised.
Cellulose is a polysaccharide that provides structural support in plant cell walls.
Add a few drops of orange/brown iodine in potassium iodide solution to the sample.
A covalent bond is the sharing of two or more electrons between two atoms.
Cellulose is considered a source of fiber because few organisms have the enzyme cellulase to hydrolyze it.
Cellulose is a polysaccharide.
To ensure there is more than enough copper (II) sulfate present to react with any sugar in the sample.
Glycosidic bonds are covalent bonds that link monosaccharides together to form disaccharides and polysaccharides.
Straight chains, branched chains, or rings.
A suitable indicator such as red litmus paper.
Carry out the Benedict’s test by adding Benedict’s reagent to the sample and heating in a boiled water bath.
Monosaccharides, disaccharides, and polysaccharides.
Components separate as the mobile phase travels over the stationary phase, with differences in solubility affecting how far each component can travel.
Monosaccharide
Glucose is of central importance to most forms of life.
Sucrose is the main sugar produced in plants.
To ensure the conditions are slightly alkaline for the Benedict’s test to work.
The ratio is always 2:1.
A distinctive blue-black color.
A color change from blue to green, yellow, orange, or brown/brick-red indicates the presence of reducing sugar.
Amylopectin is a type of polysaccharide formed by the glycosidic bonding of glucose units.
Common examples of disaccharides include maltose, sucrose, and lactose.
Glucose exists as two structurally different forms, alpha (α) and beta (β), making it an isomer.
Lactose is a sugar found only in milk.
One of the main carbon-based compounds in living organisms, containing carbon (C), hydrogen (H), and oxygen (O).
They have an aldehyde or ketone functional group.
Polymerisation occurs when two monomers are close enough that their outer orbitals overlap, resulting in the formation of covalent bonds.
Reducing sugars can donate electrons, causing the carbonyl group to become oxidised, and they act as reducing agents.
Trioses (3C) like glyceraldehyde, Pentoses (5C) like ribose, Hexoses (6C) like glucose.
Larger molecules move slower than smaller ones, affecting the separation of components.
Many hydrogen bonds form between the long chains of cellulose, giving it strength.
They are compact and insoluble, allowing for large quantities to be stored without affecting osmotic balance.
It can give an indication of the concentration of reducing sugar present, making the test semi-quantitative.
Maltose is the sugar formed in the production and breakdown of starch.
Consecutive β-glucose molecules must be rotated 180° to each other.
Starch and glycogen are polysaccharides that serve as energy storage in plants and animals, respectively.
Starch is stored as granules in plastids, such as chloroplasts.
