which of the following is not found in a prokaryotic cell

HESI RN

Biology Test

1. Which of the following is not found in a prokaryotic cell?

A. Plasma membrane
B. Cytoplasm
C. Nucleus
D. Ribosomes

Correct answer: C

Rationale: The correct answer is C, 'Nucleus.' Prokaryotic cells do not have a defined nucleus, unlike eukaryotic cells. The plasma membrane, cytoplasm, and ribosomes are all components found in prokaryotic cells. The plasma membrane surrounds the cell and regulates what enters and exits, the cytoplasm is the gel-like substance that fills the cell, and ribosomes are responsible for protein synthesis.

2. Which of the following is not one of the four nitrogenous bases that make up the DNA structure?

A. Adenine
B. Guanine
C. Uracil
D. Thymine

Correct answer: C

Rationale: The correct answer is C: Uracil. Uracil is found in RNA, not DNA. The four nitrogenous bases in DNA are adenine, thymine, cytosine, and guanine. Choice A, Adenine, is a nitrogenous base in DNA. Choice B, Guanine, is another nitrogenous base in DNA. Choice D, Thymine, is also one of the four nitrogenous bases in DNA. Therefore, the correct answer is Uracil (Choice C).

3. Which of the following is responsible for the synthesis of carbohydrates, lipids, and steroid hormones?

A. Smooth endoplasmic reticulum (ER)
B. Rough endoplasmic reticulum (ER)
C. Golgi apparatus
D. Ribosomes

Correct answer: A

Rationale: The smooth endoplasmic reticulum (ER) is the correct answer. It is responsible for the synthesis of lipids, including steroids, and also plays a role in carbohydrate metabolism. The rough endoplasmic reticulum (ER) is involved in protein synthesis and processing, not lipid or carbohydrate synthesis. The Golgi apparatus is responsible for modifying, sorting, and packaging of proteins and lipids, but not for their synthesis. Ribosomes are the cellular organelles responsible for protein synthesis, not lipid or carbohydrate synthesis.

4. Proteins are polymers of 20 molecules called:

A. Amino acids
B. Phospholipids
C. Carbohydrates
D. Fatty acids

Correct answer: A

Rationale: Proteins are indeed polymers made up of amino acids. Amino acids are the building blocks of proteins, where each protein has a unique sequence of amino acids that determines its structure and function. Phospholipids, carbohydrates, and fatty acids are not molecules that make up proteins. Phospholipids are the main components of cell membranes, carbohydrates are sugars used for energy and structural purposes, and fatty acids are building blocks of lipids.

5. What is the main objective of the translation stage of protein synthesis?

A. To produce amino acids
B. To produce nucleotides
C. To produce fatty acids
D. To produce proteins

Correct answer: D

Rationale: The main objective of the translation stage of protein synthesis is to produce proteins. During translation, ribosomes decode mRNA sequences to synthesize proteins by linking amino acids together. Choice A, 'To produce amino acids,' is incorrect as amino acids are the building blocks of proteins and are not produced during translation. Choices B and C, 'To produce nucleotides' and 'To produce fatty acids,' are also incorrect as these molecules are not the direct products of the translation stage of protein synthesis.