binding membrane of an animal cell is called

HESI A2

HESI A2 Biology Practice Test

1. What is the binding membrane of an animal cell called?

A. Biological membrane
B. Cell coat
C. Unit membrane
D. Plasma membrane

Correct answer: D

Rationale: The correct answer is D: Plasma membrane. The plasma membrane surrounds the cell and acts as an interface between the living interior of the cell and the nonliving exterior. It plays a vital role in maintaining the cell's integrity, regulating the passage of substances in and out of the cell, and facilitating communication with other cells. Choices A, B, and C are incorrect because the term 'plasma membrane' specifically refers to the binding membrane of an animal cell, distinguishing it from other types of membranes or coatings found in cells.

2. In a phospholipid molecule, the head:

A. Is hydrophilic
B. Is hydrophobic
C. Is on the inner side of the layer
D. Both A and C

Correct answer: D

Rationale: The head of a phospholipid is hydrophilic (water-loving) and is located on the outer side of the lipid bilayer, interacting with water molecules. This arrangement positions the hydrophobic tails inward, away from water. Therefore, the correct answer is D. Choice A is incorrect because the head is hydrophilic, not hydrophobic. Choice B is incorrect as the head is on the outer side, not the inner side of the layer.

3. Prokaryotic cells:

A. Have a nucleus
B. Have a capsule
C. Have membrane-bound organelles
D. Cannot move on their own

Correct answer: B

Rationale: Prokaryotic cells do not have a nucleus or membrane-bound organelles. One characteristic feature of prokaryotic cells is the presence of a capsule, which is a protective layer outside the cell wall. This capsule helps the prokaryotic cell adhere to surfaces, evade the host immune system, and protect against desiccation. Choice A is incorrect because prokaryotic cells lack a nucleus. Choice C is incorrect as prokaryotic cells do not have membrane-bound organelles. Choice D is incorrect as prokaryotic cells can move using structures like flagella or pili.

4. What happens during the S phase of the cell cycle?

A. Chromosomes are duplicated.
B. Cell growth occurs.
C. DNA is synthesized.
D. DNA is destroyed.

Correct answer: A

Rationale: During the S phase of the cell cycle, chromosomes are duplicated. This is a critical step in cell division as each chromosome is replicated to ensure that the resulting daughter cells receive an identical set of genetic information. Choices B, C, and D are incorrect because cell growth primarily occurs in the G1 phase, DNA synthesis happens during the S phase, and DNA destruction does not occur during any phase of the cell cycle.

5. Most enzymes are made up of what?

A. proteins
B. lipids
C. starches
D. simple sugars

Correct answer: A

Rationale: Most enzymes are made up of proteins. Proteins are large biomolecules composed of amino acids that are vital for the structure and function of enzymes. Enzymes act as catalysts in biochemical reactions, speeding up the rate of chemical reactions in living organisms. They exhibit high specificity and efficiency due to their unique protein structures. Lipids, starches, and simple sugars are not typically the primary components of enzymes, making them incorrect choices.