Question 1

How many molecules of water are needed to completely hydrolyze a polymer that is 11 monomers long?

Accepted Answer

To completely hydrolyze a polymer that is 11 monomers long, we need to break the bonds between each monomer using water molecules. Since there are 10 bonds that need to be broken between the 11 monomers, we need 10 water molecules to do so. Therefore, the answer is C) 10.

Question 2

On food packages,to what does the term insoluble fibre refer?

Accepted Answer

Insoluble fiber refers to cellulose, which is a type of plant-based fiber that cannot be broken down by the human body. It promotes regular bowel movements and can help prevent constipation.

Question 3

Humans can digest starch but not cellulose because

Accepted Answer

Humans have enzymes, such as amylase, that can hydrolyze the α glycosidic linkages of starch but not the β glycosidic linkages of cellulose. This means that humans are able to break down the starch molecules into smaller glucose molecules, which can be used for energy, but are not able to digest cellulose, which is a type of dietary fiber.

Question 4

Which of these molecules is not formed by dehydration reactions?

Accepted Answer

Fatty acids are not formed by dehydration reactions; they are basic building blocks of lipids and are synthesized through various pathways involving the addition of two-carbon units, not through the removal of water molecules, which is characteristic of dehydration synthesis. Dehydration reactions are involved in forming disaccharides, DNA, proteins, and amylose by linking monomers and releasing water.

Question 5

Lactose,a sugar in milk,is composed of one glucose molecule joined by a glycosidic linkage to one galactose molecule.How is lactose classified?

Accepted Answer

Lactose is composed of two monosaccharides (glucose and galactose) joined by a glycosidic linkage, making it a disaccharide.

Question 6

The enzyme amylase can break glycosidic linkages between glucose monomers only if the monomers are the α form.Which of the following molecules could amylase break down?

Accepted Answer

Amylase can break down glycogen because it contains α-1,4 and α-1,6 glycosidic linkages between glucose monomers. Cellulose and chitin have β-glycosidic linkages, which amylase cannot break.

Question 7

What is the chemical reaction mechanism by which cells make polymers from monomers?

Accepted Answer

Cells make polymers from monomers through dehydration reactions, which involve the removal of a water molecule between two monomers to form a covalent bond known as a polymer linkage. This is the chemical reaction mechanism by which proteins, polysaccharides, and nucleic acids are synthesized in the cell.

Question 8

Which of the following is not a polymer?

Accepted Answer

Glucose is a monosaccharide and not a polymer, while the other choices are all polysaccharides or nucleic acids that consist of repeating units.

Question 9

All of the following are polysaccharides except

Accepted Answer

Lactose is a disaccharide composed of glucose and galactose. The other answer choices are all polysaccharides.

Question 10

Which of these classes of biological molecules consist of both small molecules and macromolecular polymers?

Accepted Answer

The answer of Which of these classes of biological molecules...

Question 11

The molecular formula for glucose is C₆H₁₂O₆.What would be the molecular formula for a molecule made by linking three glucose molecules together by dehydration reactions?

Accepted Answer

Dehydration synthesis involves removing a water molecule between two functional groups. When three glucose molecules are linked together, there are two water molecules that can be removed, leaving behind two glycosidic bonds. This results in a molecule with a molecular formula of C18H32O16.

Question 12

A molecule with the chemical formula C₆H₁₂O₆ is probably a

Accepted Answer

The chemical formula C₆H₁₂O₆ is characteristic of a simple sugar or monosaccharide, which is a type of carbohydrate. This excludes lipids and makes both carbohydrate and monosaccharide correct.

Question 13

Which of the following is true of cellulose?

Accepted Answer

Cellulose is a major structural component of plant cell walls, providing rigidity and strength to the cell. It is a polymer composed of repeating units of glucose monomers, but unlike its enantiomer starch, it is not an energy storage molecule. Additionally, cellulose is not digestible by most animals, including humans, due to the lack of necessary enzymes for breaking down its bonds.

Question 14

Which of the following statements concerning saturated fats is not true?

Accepted Answer

The statement "They have multiple double bonds in the carbon chains of their fatty acids" is not true. Saturated fats have no double bonds in the carbon chains of their fatty acids, which is what makes them "saturated" with hydrogen atoms.

Question 15

Humans and mice differ because of which of the following?

Accepted Answer

Humans and mice have differences in their DNA sequences, which leads to differences in the proteins produced by their cells. This is because DNA provides the instructions for making proteins through the sequence of nucleotides in the DNA code. While the basic structure of proteins is the same in all organisms, the specific amino acid sequence that makes up each protein can vary, leading to differences in their function and overall biology.

Question 16

Which of the following is true of both starch and cellulose?

Accepted Answer

Both starch and cellulose are made up of glucose monomers linked together in a polymer chain.

Question 17

Which of the following polymers contain nitrogen?

Accepted Answer

Chitin is a polymer that contains nitrogen. It is a structural polysaccharide found in the cell walls of fungi and the exoskeletons of arthropods such as insects, spiders, and crustaceans. It provides strength and support to these organisms. Starch, glycogen, cellulose, and amylopectin are all polysaccharides that do not contain nitrogen.

Question 18

Molecules with which functional groups may form polymers via dehydration reactions?

Accepted Answer

Hydroxyl and carboxyl groups both contain -OH groups that can participate in dehydration reactions to form polymers. Carboxyl groups also contain a carbonyl group (-C=O) which can participate in the dehydration reaction. Therefore, either hydroxyl or carboxyl groups are able to form polymers via dehydration reactions.

Question 19

Which of the following best summarizes the relationship between dehydration reactions and hydrolysis?

Accepted Answer

Dehydration reactions involve the removal of a water molecule to form a bond between two monomers, while hydrolysis reactions involve the addition of water to break down a polymer into its constituent monomers. Therefore, A is the best choice because it accurately summarizes the relationship between dehydration reactions and hydrolysis.

Question 20

A molecule with the formula C₁₈H₃₆O₂ is probably a

Accepted Answer

The formula C₁₈H₃₆O₂ suggests a long-chain hydrocarbon with a carboxylic acid functional group at one end (the "acid" in fatty acid). This is characteristic of the structure of fatty acids, which are important building blocks of lipids. Carbohydrates, proteins, and nucleic acids have different chemical formulas and functional groups.

Quiz 5: The Structure and Function of Large Biological Molecules