which of the following is the primary function of the cell membrane

ATI TEAS 7

TEAS 7 science practice

1. What is the primary function of the cell membrane?

A. To provide structural support for the cell
B. To transport substances in and out of the cell
C. To synthesize proteins and lipids
D. To store genetic material

Correct answer: B

Rationale: The primary function of the cell membrane, also known as the plasma membrane, is to regulate the movement of substances in and out of the cell. It acts as a selectively permeable barrier, allowing specific molecules to pass through while blocking others. This role is crucial for maintaining the internal environment of the cell by enabling essential nutrients to enter and waste products to exit. While the cell membrane provides some structural support for the cell, its main function is substance transport. Protein and lipid synthesis predominantly occur in organelles like the endoplasmic reticulum and Golgi apparatus, and storing genetic material is the nucleus's responsibility. Therefore, choices C (To synthesize proteins and lipids) and D (To store genetic material) are incorrect as these functions are carried out by other cell organelles, not the cell membrane.

2. Which of the following is a balanced chemical equation?

A. H2 + O2 → H2O
B. 2H2 + O2 → 2H2O
C. 3H2O → 2H2 + O2
D. H2O → H2 + O2

Correct answer: B

Rationale: A balanced chemical equation must have the same number of atoms of each element on both sides of the equation. In option B, 2H2 + O2 → 2H2O, the equation is balanced as there are 2 hydrogen atoms and 2 oxygen atoms on both the reactant and product sides after balancing, satisfying the law of conservation of mass. Option A is unbalanced as there are 2 oxygen atoms on the reactant side but only 1 oxygen atom on the product side. Option C is unbalanced with 3 hydrogen atoms on the reactant side and 2 hydrogen atoms on the product side. Option D is unbalanced with 1 oxygen atom on the reactant side and 2 oxygen atoms on the product side.

3. Which of the following structures can serve as a passageway for both food and air?

A. Esophagus
B. Laryngopharynx
C. Nasopharynx
D. Trachea

Correct answer: B

Rationale: The correct answer is the Laryngopharynx. It is a common passageway for both food and air. The Esophagus (Choice A) is solely for transporting food from the throat to the stomach. The Nasopharynx (Choice C) is primarily involved in the passage of air. The Trachea (Choice D) is responsible for conducting air to and from the lungs and does not play a role in the passage of food.

4. What is a condition characterized by an overactive thyroid gland and excessive production of thyroid hormones called?

A. Diabetes mellitus
B. Hyperthyroidism
C. Hypothyroidism
D. Cushing's syndrome

Correct answer: B

Rationale: Hyperthyroidism is a condition where the thyroid gland is overactive and produces an excessive amount of thyroid hormones. This can lead to symptoms such as weight loss, rapid heartbeat, sweating, and nervousness. Diabetes mellitus is a condition characterized by high blood sugar levels due to either insufficient insulin production or the body's inability to respond to insulin. Hypothyroidism is the opposite of hyperthyroidism, where the thyroid gland is underactive and produces insufficient thyroid hormones. Cushing's syndrome is a disorder that occurs when the body has a high level of the hormone cortisol for a long time.

5. The outermost layer of your skin, responsible for waterproofing and providing a barrier against pathogens, is the:

A. Stratum basale (Basal layer)
B. Stratum corneum
C. Stratum granulosum
D. Stratum spinosum

Correct answer: B

Rationale: The correct answer is B: Stratum corneum. The stratum corneum is the outermost layer of the epidermis, consisting of dead skin cells that are constantly shed and replaced. It serves as a protective barrier against pathogens and helps to prevent water loss from the body. Choice A, Stratum basale, is the deepest layer of the epidermis where new skin cells are produced. Choice C, Stratum granulosum, is a layer of the epidermis where the cells begin to flatten and lose their nuclei. Choice D, Stratum spinosum, is a layer of the epidermis where cells become irregular in shape and have spiny projections.