where is keratin

ATI TEAS 7

TEAS Practice Test Science

1. Where is keratin found?

A. It is a protein-digesting enzyme released by the stomach.
B. It is released in the neuromuscular junction.
C. It is a protein found in the hypodermis.
D. It is a protein found in hair.

Correct answer: D

Rationale: Keratin is a structural protein found in hair, skin, and nails, providing strength and protection. It forms the main structural component of hair, making choice D the correct answer. Choices A, B, and C are incorrect because keratin is not an enzyme released by the stomach, not released in the neuromuscular junction, and not found in the hypodermis. Remember that keratin is primarily associated with structural support in epithelial cells.

2. What property of a substance refers to its ability to undergo a chemical change and form new substances?

A. Density
B. Mass
C. Reactivity
D. Volume

Correct answer: C

Rationale: Reactivity is the property of a substance that describes its ability to undergo a chemical change and form new substances. Density (A), mass (B), and volume (D) are physical properties of a substance and do not directly relate to its ability to undergo chemical changes. Density is the measure of how much mass is contained in a given volume, mass is the amount of matter in an object, and volume is the amount of space an object occupies. Therefore, reactivity (C) is the correct answer as it specifically addresses the substance's ability to undergo chemical changes.

3. How does meiosis differ from mitosis?

A. Meiosis is used for repairing the body. Mitosis is used for cell reproduction.
B. Meiosis is used for sexual reproduction. Mitosis is used for asexual reproduction.
C. Meiosis occurs in various organisms. Mitosis occurs in various organisms.
D. Meiosis produces cells that are genetically different. Mitosis produces cells that are genetically identical.

Correct answer: D

Rationale: Meiosis is the process of cell division that results in the formation of sex cells (gametes) with only half the number of chromosomes as the parent cell, leading to genetically different cells. In contrast, mitosis is a cell division process that produces two daughter cells that are genetically identical to each other and the parent cell, maintaining the same chromosome number. Therefore, the correct answer is D, as meiosis and mitosis differ in their genetic outcomes - meiosis results in genetic diversity, while mitosis maintains genetic identity. Choices A, B, and C are incorrect because they do not accurately distinguish between meiosis and mitosis. Meiosis is not used for repairing the body or asexual reproduction, and the occurrence of both processes in various organisms does not highlight their primary differences in genetic outcomes.

4. What property best describes the characteristic that nuclear forces are much stronger than electromagnetic forces at the nuclear level?

A. Short-range interaction
B. Long-range interaction
C. Repulsive force
D. Dependent on charge only

Correct answer: A

Rationale: The correct answer is A: Short-range interaction. Nuclear forces are much stronger than electromagnetic forces at the nuclear level because they are short-range interactions that act over distances on the order of the size of an atomic nucleus. This short-range nature of nuclear forces allows them to be much stronger than the long-range electromagnetic forces, which weaken with distance according to the inverse square law. Choice B, long-range interaction, is incorrect because nuclear forces are short-range. Choice C, repulsive force, is incorrect as nuclear forces include both attractive and repulsive components. Choice D, dependent on charge only, is incorrect because nuclear forces are not solely determined by charge but also involve other factors like spin and isospin.

5. Which type of isomerism arises due to differences in the arrangement of atoms around a double bond?

A. Chain isomerism
B. Functional group isomerism
C. Cis-trans isomerism
D. Stereoisomerism

Correct answer: C

Rationale: Cis-trans isomerism, also known as geometric isomerism, arises due to differences in the arrangement of atoms around a double bond. In cis isomers, similar groups are on the same side of the double bond, while in trans isomers, similar groups are on opposite sides of the double bond. This type of isomerism is a subset of stereoisomerism, which includes all isomers that have the same connectivity but differ in spatial arrangement. Chain isomerism involves differences in the carbon chain arrangement, functional group isomerism involves different functional groups, and stereoisomerism is a broader category that encompasses isomers with the same connectivity but different spatial arrangement.