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 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.

3. What does the phrase 'survival of the fittest' refer to?

A. Organisms with the most complex anatomical structures are more likely to survive and reproduce.
B. Organisms that demonstrate the best adaptations to their environment have a higher chance of survival and reproduction.
C. All organisms have an equal probability of survival and reproductive success regardless of their traits.
D. Only the strongest and most aggressive individuals within a population will survive and reproduce.

Correct answer: B

Rationale: The phrase 'survival of the fittest' is often associated with the concept of natural selection, proposed by Charles Darwin. Natural selection is the process by which organisms best adapted to their environment are more likely to survive and reproduce, passing on their advantageous traits to the next generation. This process does not necessarily favor the most complex anatomical structures (option A) or the strongest and most aggressive individuals (option D). Instead, it emphasizes the importance of adaptations that enhance an organism's ability to survive and reproduce in a specific environment. Option C is incorrect because natural selection results in differential reproductive success based on an organism's traits, meaning that not all organisms have an equal probability of survival and reproductive success.

4. What happens to the frequency of a wave if its wavelength decreases while the speed remains constant?

A. Frequency decreases
B. Frequency increases
C. Frequency remains constant
D. Frequency becomes zero

Correct answer: B

Rationale: The correct answer is B: Frequency increases. Frequency and wavelength are inversely proportional in a wave with a constant speed. When the wavelength decreases while the speed remains constant, the frequency must increase to maintain the constant speed of the wave. This relationship is governed by the equation: speed = frequency x wavelength. Choice A is incorrect as frequency increases when wavelength decreases. Choice C is incorrect as the frequency changes in this scenario. Choice D is incorrect as the frequency does not become zero but increases when the wavelength decreases.

5. Which of the following is the carbohydrate monomer?

A. Disaccharide
B. Lactose
C. Monosaccharide
D. Thymine

Correct answer: C

Rationale: The correct answer is C: Monosaccharide. Monosaccharides are the simplest form of carbohydrates, consisting of a single sugar unit. They are considered the carbohydrate monomers from which larger carbohydrates like disaccharides (composed of two sugar units) and polysaccharides (containing multiple sugar units) are built. Choices A and B, Disaccharide and Lactose, are not monomers but rather specific types of carbohydrates made up of multiple sugar units. Choice D, Thymine, is a nitrogenous base present in DNA and RNA, not a carbohydrate monomer.