which type of cells make up the myelin sheaths

ATI TEAS 7

ATI TEAS Science Test

1. Which type of cells make up the myelin sheaths?

A. Glial cells.
B. Dendrites.
C. Melanocytes.
D. Squamous cells.

Correct answer: A

Rationale: The correct answer is A: Glial cells. Glial cells are responsible for producing the myelin sheaths that surround and insulate nerve cells in the central and peripheral nervous systems. Schwann cells in the peripheral nervous system and oligodendrocytes in the central nervous system are types of glial cells that form the myelin sheaths. Choice B, dendrites, are not involved in forming myelin sheaths; they are extensions of neurons that receive signals. Choice C, melanocytes, are cells responsible for producing melanin, not myelin. Choice D, squamous cells, are flat epithelial cells found in various tissues but are not involved in myelin sheath formation.

2. What are polymers?

A. Large molecules formed by repeating units called monomers
B. Simple organic molecules with low boiling points
C. Highly reactive compounds used in industrial processes
D. Insoluble solids with no definite structure

Correct answer: A

Rationale: Polymers are large molecules formed by repeating units called monomers. These monomers link together to form long chains or networks, giving polymers their unique properties such as flexibility, strength, and durability. Choice B is incorrect because polymers are not simple organic molecules with low boiling points, but rather complex structures formed by polymerization. Choice C is incorrect as polymers are not necessarily highly reactive compounds, and they are not exclusively used in industrial processes. Choice D is incorrect because polymers can have varying solubilities and structures depending on their composition and properties.

3. Which factor most significantly affects the kinetic energy of an object?

A. The object's mass
B. The object's velocity
C. The object's displacement
D. The object's potential energy

Correct answer: B

Rationale: Kinetic energy is directly proportional to the square of an object's velocity. This means that changes in velocity have a greater impact on the kinetic energy of an object compared to changes in mass, displacement, or potential energy. The mass of an object affects its kinetic energy, but the effect is linear, not squared like velocity. Displacement does not directly affect kinetic energy, as it is a measure of the change in position, not related to motion. Potential energy is a different form of energy and is not directly related to the kinetic energy of an object. Therefore, the velocity of an object has the most significant effect on its kinetic energy.

4. What is the term for the process of a liquid changing into a gas?

A. Evaporation
B. Boiling
C. Condensation
D. Sublimation

Correct answer: A

Rationale: The correct answer is 'Evaporation.' Evaporation is the process by which a liquid changes into a gas at any temperature, while boiling specifically refers to the rapid vaporization of a liquid only at its boiling point. Condensation is the opposite process of gas turning into a liquid, and sublimation is the direct transition from solid to gas without passing through the liquid phase.

5. What enzyme plays a key role in breaking down carbohydrates in the small intestine?

A. Pepsin
B. Lipase
C. Amylase
D. Trypsin

Correct answer: C

Rationale: Amylase is the enzyme responsible for breaking down carbohydrates in the small intestine. It specifically targets starches and sugars, breaking them down into smaller molecules like maltose and glucose that can be absorbed by the body. Pepsin is an enzyme that breaks down proteins in the stomach, not the small intestine. Lipase is responsible for breaking down fats, not carbohydrates. Trypsin is an enzyme that breaks down proteins in the small intestine, not carbohydrates.