what is the function of the cell membrane

ATI TEAS 7

TEAS version 7 quizlet science

1. What is the function of the cell membrane?

A. To protect the cell and control what enters and exits
B. To store energy
C. To produce proteins
D. To synthesize lipids

Correct answer: A

Rationale: The cell membrane, also known as the plasma membrane, serves as a protective barrier for the cell, separating the internal environment of the cell from the external environment. It is selectively permeable, meaning it controls the passage of substances in and out of the cell. This regulation of what enters and exits the cell is crucial for maintaining the cell's internal environment and ensuring proper functioning. Options B, C, and D are incorrect because storing energy, producing proteins, and synthesizing lipids are functions carried out by other cellular structures such as mitochondria, ribosomes, and endoplasmic reticulum, respectively, not the cell membrane.

2. Which element is found in water and is crucial for biological functions like nerve impulses and muscle contraction?

A. Sodium
B. Potassium
C. Calcium
D. Magnesium

Correct answer: A

Rationale: The correct answer is Sodium. Sodium is found in water and is crucial for biological functions like nerve impulses and muscle contraction. It plays a key role in maintaining electrolyte balance and transmitting nerve impulses, affecting both muscles and nerves. Potassium (Choice B), although essential for nerve function and muscle control, is not typically found in water. Calcium (Choice C) is important for bone health and muscle function, but it is not the element found in water. Magnesium (Choice D) is also essential for various biological functions but is not the element commonly found in water.

3. What information does a genotype provide that a phenotype does not?

A. The genotype necessarily includes the proteins coded for by its alleles.
B. The genotype will always display an organism's recessive alleles.
C. The genotype must include the organism's physical characteristics.
D. The genotype indicates what an organism's parents looked like.

Correct answer: A

Rationale: The genotype provides information about the specific genetic makeup of an organism, including the alleles it possesses for a particular trait. This information is not always directly reflected in the phenotype, which is the observable physical characteristics of an organism. The genotype determines the proteins coded for by its alleles, but the phenotype is the expression of those proteins in the organism's traits. Therefore, the genotype necessarily includes the proteins coded for by its alleles, a detail not provided solely by the phenotype.\nChoice B is incorrect because the genotype may include dominant alleles as well, not just recessive ones. Choice C is incorrect because the genotype refers to genetic information, not physical characteristics. Choice D is incorrect because the genotype does not directly indicate what an organism's parents looked like; it primarily describes the genetic information inherited from parents.

4. A car is moving in a circle at a constant speed. Which of the following is NOT true about its motion?

A. It has a constant centripetal acceleration
B. Its tangential velocity remains constant
C. It experiences a force directed towards the center of the circle
D. It covers the same distance in equal time intervals along its circular path

Correct answer: B

Rationale: In circular motion at a constant speed, the car has a constant centripetal acceleration (choice A), experiences a force directed towards the center of the circle (choice C), and covers the same distance in equal time intervals along its circular path (choice D). However, the tangential velocity of an object in circular motion at a constant speed changes continuously as it moves around the circle, so it is not constant (choice B). The change in tangential velocity allows the car to maintain its motion in a circular path despite moving at a constant speed. Choice A is incorrect because centripetal acceleration is indeed present to keep the car moving in a circular path. Choice C is incorrect as a force towards the center is required to keep the car in circular motion. Choice D is incorrect because the car covers equal distances in equal time intervals to maintain its circular trajectory.