what is the 3d structure of a protein called

ATI TEAS 7

TEAS Test 7 science

1. What is the 3D structure of a protein called?

A. Tertiary structure
B. Secondary structure
C. Primary structure
D. Quaternary structure

Correct answer: A

Rationale: - Primary structure refers to the linear sequence of amino acids in a protein. - Secondary structure refers to local folded structures within a protein, such as alpha helices and beta sheets. - Tertiary structure is the overall 3D shape of a protein, which is determined by interactions between amino acid side chains and the environment. - Quaternary structure refers to the arrangement of multiple protein subunits in a protein complex. Therefore, the 3D structure of a protein is called the tertiary structure because it represents the overall folding of the protein into a specific shape.

2. When testing how quickly a rat dies based on the amount of poison it eats, which of the following is the independent variable and which is the dependent variable?

A. How quickly the rat dies is the independent variable; the amount of poison is the dependent variable.
B. The amount of poison is the independent variable; how quickly the rat dies is the dependent variable.
C. Whether the rat eats the poison is the independent variable; how quickly the rat dies is the dependent variable.
D. The cage the rat is kept in is the independent variable; the amount of poison is the dependent variable.

Correct answer: B

Rationale: The correct answer is B. In this experiment, the independent variable is the amount of poison because it is what is being manipulated by the researcher. The dependent variable is how quickly the rat dies, as it is the outcome that is being measured based on the different amounts of poison administered. Choice A is incorrect because the independent variable should be what is being manipulated or changed, which is the amount of poison in this case. Choice C is incorrect because whether the rat eats the poison is not being varied or controlled by the researcher. Choice D is incorrect because the cage the rat is kept in is not relevant to the relationship being studied between the amount of poison and the rat's survival time.

3. Which of the following sets of valves is primarily responsible for preventing blood flow from major blood vessels to the heart?

A. atrioventricular valves
B. semilunar valves
C. tricuspid valves
D. bicuspid valves

Correct answer: B

Rationale: The correct answer is B: semilunar valves. Semilunar valves are primarily responsible for preventing blood flow from major blood vessels to the heart. These valves are located at the base of the aorta and the pulmonary artery, ensuring blood flows in one direction only by closing when the ventricles relax to prevent blood from flowing back into the heart. Choices A, C, and D are incorrect. Atrioventricular valves (choice A) include the tricuspid and bicuspid valves, which prevent backflow between the atria and ventricles, not major blood vessels. Tricuspid valves (choice C) and bicuspid valves (choice D) are specific types of atrioventricular valves located between the atria and ventricles, not at the base of major blood vessels.

4. What is the function of arrector pili muscles?

A. To control sweat production
B. To contract and cause goosebumps
C. To produce sebum
D. To sense touch

Correct answer: B

Rationale: The correct function of arrector pili muscles is to contract and cause goosebumps. These small muscles are attached to hair follicles in mammals. When they contract, they cause the hair to stand on end, resulting in goosebumps. This physiological response is often triggered by cold temperatures or emotional states like fear, helping mammals conserve heat or appear larger in threatening situations. Choices A, C, and D are incorrect. Arrector pili muscles are not involved in controlling sweat production (Choice A), producing sebum (Choice C), or sensing touch (Choice D).

5. Which of the following is a constant?

A. The number of protons in an oxygen atom
B. The temperature at which iron ore will melt
C. The human population size
D. The time the sun rises each day

Correct answer: A

Rationale: The number of protons in an oxygen atom is a constant. This value is determined by the atomic number of the element and does not change regardless of the isotope of oxygen. The number of protons defines the element and remains consistent under normal conditions. Choices B, C, and D are not constants. The temperature at which iron ore will melt can vary depending on factors like pressure, the human population size is constantly changing, and the time the sun rises each day varies with the seasons and location.