proteins are polymers of 20 molecules called

HESI RN

Biology Test

1. Proteins are polymers of 20 molecules called:

A. Amino acids
B. Phospholipids
C. Carbohydrates
D. Fatty acids

Correct answer: A

Rationale: Proteins are indeed polymers made up of amino acids. Amino acids are the building blocks of proteins, where each protein has a unique sequence of amino acids that determines its structure and function. Phospholipids, carbohydrates, and fatty acids are not molecules that make up proteins. Phospholipids are the main components of cell membranes, carbohydrates are sugars used for energy and structural purposes, and fatty acids are building blocks of lipids.

2. Which of the following describes the set of metabolic reactions and processes that take place in the cells of organisms to convert biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products?

A. Cellular respiration
B. Meiosis
C. Photosynthesis
D. Mitosis

Correct answer: A

Rationale: The correct answer is A: Cellular respiration. Cellular respiration is the process in cells that converts biochemical energy from nutrients into ATP and releases waste products. This process occurs in the mitochondria of the cell. Choice B, Meiosis, is a type of cell division that produces gametes with half the chromosome number. Choice C, Photosynthesis, is the process by which plants, algae, and some bacteria convert light energy into chemical energy to produce glucose. Choice D, Mitosis, is a type of cell division that results in two daughter cells with identical sets of chromosomes as the parent cell.

3. A water molecule contains two types of atoms that are covalently bonded. Which of the following makes up a water molecule?

A. One hydrogen atom and one oxygen atom
B. One hydrogen atom and two oxygen atoms
C. Two hydrogen atoms and two oxygen atoms
D. Two hydrogen atoms and one oxygen atom

Correct answer: D

Rationale: The correct answer is D: Two hydrogen atoms and one oxygen atom. A water molecule consists of two hydrogen atoms covalently bonded to one oxygen atom. This forms a stable structure known as H2O. Choice A is incorrect as water molecule contains two hydrogen atoms. Choices B and C are incorrect as they do not reflect the correct composition of a water molecule.

4. Which of the following statements is true if a molecule exhibits adhesion?

A. Two molecules of the same substance have the ability to stay bonded to one another
B. The molecule has the ability to bond to or attract other molecules
C. A molecule has the ability to increase its heat when necessary
D. The molecule has the ability to form hydrogen bonds

Correct answer: B

Rationale: The correct statement is that if a molecule exhibits adhesion, it has the ability to bond to or attract other molecules. Adhesion refers to the ability of a molecule to bind to or attract different types of molecules. Choice A is incorrect because adhesion is about bonding to different molecules, not the same substance. Choice C is incorrect as adhesion does not relate to the ability of a molecule to increase its heat. Choice D is incorrect because forming hydrogen bonds is a specific type of interaction and not a general characteristic of molecules exhibiting adhesion.

5. What percentage of the parents' offspring is predicted to have a cleft chin if one parent carries the recessive gene for a cleft chin (c) while the other parent does not?

A. 25%
B. 50%
C. 0%
D. 75%

Correct answer: C

Rationale: The correct answer is C (0%). If one parent carries the recessive gene for a cleft chin while the other parent does not carry it, none of their offspring is predicted to have a cleft chin. This is because the cleft chin trait is recessive, so for an offspring to express this trait, they would need to inherit the gene from both parents. In this scenario, none of the offspring will inherit the recessive gene from both parents, so the percentage of offspring predicted to have a cleft chin is 0%. Choices A, B, and D are incorrect because in this situation, the offspring will not express the cleft chin phenotype, although they could be carriers of the recessive gene.