antigenic variation a common strategy used by some viruses allows them to

ATI TEAS 7

TEAS Test 7 science quizlet

1. Antigenic variation, a common strategy used by some viruses, allows them to:

A. Produce toxins
B. Evade the immune system
C. Survive outside a host
D. Replicate rapidly

Correct answer: B

Rationale: Antigenic variation is a strategy used by some viruses to evade the host's immune response. By constantly changing their surface antigens, viruses can avoid recognition and destruction by the immune system. This allows the virus to persist in the host and continue replicating, leading to prolonged infection and potential transmission to other hosts. Antigenic variation does not directly involve the production of toxins, survival outside a host, or rapid replication, making options A, C, and D incorrect in this context.

2. What is the function of ribosomes?

A. Packaging and transporting proteins
B. Storing genetic material
C. Controlling cell division
D. Synthesizing proteins

Correct answer: D

Rationale: The correct answer is D: Synthesizing proteins. Ribosomes are cellular organelles responsible for protein synthesis. They read the messenger RNA (mRNA) and utilize the information to assemble amino acids into proteins through a process known as translation. Choice A, packaging and transporting proteins, is incorrect as this function is typically performed by the Golgi apparatus and vesicles. Choice B, storing genetic material, is incorrect as genetic material is usually stored in the nucleus in the form of DNA. Choice C, controlling cell division, is incorrect as this function is primarily regulated by the cell cycle checkpoints and specific proteins involved in cell cycle regulation.

3. Which of the following is a dense, interconnected mass of nerve cells located outside the central nervous system?

A. ganglion
B. dendrite
C. cranial nerve
D. pons

Correct answer: A

Rationale: A ganglion is a dense, interconnected mass of nerve cells located outside the central nervous system. Ganglia serve as relay points where nerve cells communicate and integrate signals. They are found along peripheral nerves, processing sensory information and coordinating motor responses. Choice B, dendrite, refers to a part of a neuron that receives signals, not a mass of nerve cells. Choice C, cranial nerve, is a bundle of nerves that emerge from the brain, not a mass of nerve cells. Choice D, pons, is a part of the brainstem, which is within the central nervous system, not located outside of it.

4. A ball is thrown upwards. Which of the following statements is TRUE about its potential energy and kinetic energy at the peak of its trajectory?

A. Both potential and kinetic energy are zero.
B. Potential energy is maximum and kinetic energy is minimum.
C. Potential energy is minimum and kinetic energy is maximum.
D. Both potential and kinetic energy remain constant.

Correct answer: B

Rationale: At the peak of its trajectory, the ball momentarily stops moving before falling back down. This means its kinetic energy is at a minimum because it has come to a stop. At the same time, its potential energy is at a maximum because it is at the highest point in its trajectory, where it has the most potential to fall and convert that potential energy into kinetic energy as it descends. Choice A is incorrect because at the peak, the ball still has potential energy due to its height. Choice C is incorrect because kinetic energy is at a minimum when the ball is momentarily at rest. Choice D is incorrect because the energy conversion between potential and kinetic energy occurs at different points in the trajectory.

5. Which of the following functions is not controlled by the autonomic nervous system?

A. Digestion
B. Walking
C. Heartbeat
D. Temperature regulation

Correct answer: B

Rationale: The correct answer is B: Walking. Walking is not directly controlled by the autonomic nervous system. Walking is a voluntary action governed by the somatic nervous system, which controls voluntary skeletal muscle movement. The autonomic nervous system, on the other hand, regulates functions that are involuntary, such as digestion, heartbeat, and temperature regulation. Choices A, C, and D are all functions controlled by the autonomic nervous system. Digestion involves processes like peristalsis and secretion of digestive enzymes, heartbeat is regulated by the autonomic nervous system to maintain blood pressure and circulation, and temperature regulation includes responses like sweating or shivering to maintain body temperature within a narrow range.