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 is the process by which the body reabsorbs water from the large intestine?

A. Dehydration
B. Osmosis
C. Filtration
D. Secretion

Correct answer: B

Rationale: Osmosis (Option B) is the correct process by which the body reabsorbs water from the large intestine. Osmosis is the movement of water across a semi-permeable membrane from an area of low solute concentration to an area of high solute concentration. In the large intestine, water is reabsorbed through osmosis to maintain the body's fluid balance. Dehydration (Option A) refers to the condition of having insufficient water in the body, not the process of water reabsorption in the large intestine. Filtration (Option C) is a process where a liquid or gas passes through a filter to separate the components, not the primary mechanism for water reabsorption in the large intestine. Secretion (Option D) is the release of substances from cells, but it is not the process by which the body reabsorbs water from the large intestine.

3. What happens to the density of a gas when its temperature increases at constant pressure?

A. It increases.
B. It decreases.
C. It remains the same.
D. Information is insufficient.

Correct answer: B

Rationale: When the temperature of a gas increases at constant pressure, the average kinetic energy of the gas molecules increases. This leads to the gas molecules moving faster and spreading out more, which causes them to occupy a larger volume. As a result, the density of the gas decreases because the same number of gas molecules are now distributed over a larger space. Choice A is incorrect because as the gas molecules spread out, the density decreases. Choice C is incorrect because the increase in temperature leads to a decrease in density due to the increased volume occupied by the gas molecules. Choice D is incorrect because with the provided scenario of temperature increase at constant pressure, the effect on density can be determined.

4. Differentiate between epithelial and connective tissue.

A. Epithelial tissue lines surfaces and glands, while connective tissue supports tendons.
B. Both are composed of cells, but epithelial tissue lines surfaces and glands, while connective tissue binds other tissues.
C. Epithelial tissue covers surfaces and connective tissue supports muscle contraction.
D. Epithelial tissue is the largest tissue type, while connective tissue is the smallest.

Correct answer: B

Rationale: Epithelial tissue covers surfaces and lines organs, while connective tissue provides support and structure throughout the body. Both are composed of cells, but their functions and locations differ. Epithelial tissue acts as a barrier to protect underlying tissues and organs, while connective tissue connects, supports, and separates different types of tissues and organs in the body. Choice A is incorrect as connective tissue supports and binds other tissues, not just tendons. Choice C is incorrect because connective tissue does not support muscle contraction; it provides support to various structures in the body. Choice D is incorrect as the size of a tissue type does not define its function; epithelial tissue and connective tissue serve different purposes in the body.

5. What is the process by which one element changes into another through radioactive decay known as?

A. Transmutation
B. Fission
C. Fusion
D. Oxidation

Correct answer: A

Rationale: The correct answer is A: Transmutation. Transmutation is the correct term to describe the process by which one element changes into another element through radioactive decay. In transmutation, the atomic structure of the element is altered, leading to a change in the element's identity. Choice B, Fission, refers to the splitting of a heavy nucleus into lighter nuclei. Choice C, Fusion, involves the merging of lighter nuclei to form a heavier nucleus. Choice D, Oxidation, is not related to the process of one element changing into another through radioactive decay.