what is the main function of the endoplasmic reticulum er in the cell

ATI TEAS 7

TEAS 7 practice test science

1. What is the main function of the endoplasmic reticulum (ER) in the cell?

A. To synthesize and transport proteins and lipids
B. To package and transport proteins
C. To break down macromolecules
D. To store genetic material

Correct answer: A

Rationale: The endoplasmic reticulum (ER) is a network of membranes within the cell that plays a crucial role in protein and lipid synthesis. It consists of two types: rough ER, which is studded with ribosomes and involved in protein synthesis, and smooth ER, which is involved in lipid synthesis and detoxification. The ER's main function is to synthesize proteins and lipids, not just package and transport them. While the ER is involved in transporting these synthesized proteins and lipids to other parts of the cell or outside the cell, its primary role is in their synthesis. Breaking down macromolecules is primarily the function of lysosomes, which are membrane-bound organelles containing enzymes for digestion. Storing genetic material is the function of the nucleus, which houses the cell's DNA. The ER is not involved in storing genetic material.

2. What property of matter explains why ice floats on water?

A. Viscosity
B. Density
C. Buoyancy
D. Surface tension

Correct answer: C

Rationale: The correct answer is C, buoyancy. Ice floats on water due to buoyancy, a property of matter. When water freezes into ice, it becomes less dense than liquid water, causing it to float. This phenomenon occurs because the molecules in ice are more spread out compared to liquid water, resulting in ice being less dense and able to float on the surface. Choice A, viscosity, is incorrect because viscosity refers to a fluid's resistance to flow, not its ability to float. Choice B, density, is incorrect because while ice being less dense than water is the reason it floats, this choice does not explain the specific property that causes this phenomenon. Choice D, surface tension, is incorrect as it pertains to the cohesive forces between molecules at the surface of a liquid, not the reason why ice floats on water.

3. What does bradycardia refer to in terms of heart rate?

A. Normal (60-100 bpm)
B. Slightly elevated (100-120 bpm)
C. Significantly elevated (>120 bpm)
D. Abnormally slow (<60 bpm)

Correct answer: D

Rationale: Bradycardia refers to an abnormally slow heart rate, typically defined as less than 60 beats per minute. This condition can result in inadequate blood flow to meet the body's demands. It is crucial to distinguish between bradycardia and tachycardia, which is a fast heart rate, as they require different management strategies. Options A, B, and C are incorrect because they describe normal, slightly elevated, and significantly elevated heart rates, respectively, rather than an abnormally slow heart rate characteristic of bradycardia. Recognizing bradycardia is essential for appropriate evaluation and intervention in clinical settings.

4. Urine, the liquid waste product of the body, travels from the kidneys to the bladder through tubes called:

A. Ureters
B. Urethra
C. Nephrons
D. Renal pelvis

Correct answer: A

Rationale: The correct answer is 'Ureters.' Ureters are tubes that connect each kidney to the bladder. They transport urine from the kidneys to the bladder for storage before excretion. The urethra, which is not the correct answer, is responsible for carrying urine from the bladder out of the body. Nephrons, another incorrect choice, are microscopic units within the kidneys that filter blood and produce urine. The renal pelvis, also an incorrect choice, is a structure in the kidney where urine collects before moving into the ureters for further passage to the bladder.