what is the main objective of the translation stage of protein synthesis

HESI RN

Biology Practice Test

1. 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.

2. Water is held together by which of the following bonds?

A. Electrostatic attraction
B. Van der Waals forces
C. Hydrogen
D. Oxygen

Correct answer: C

Rationale: Water molecules are held together by hydrogen bonds, which are weak bonds formed between the slightly positive hydrogen atom of one water molecule and the slightly negative oxygen atom of another. Choice A, electrostatic attraction, is a general term for the attraction between opposite charges but does not specifically describe the bonds in water. Choice B, Van der Waals forces, are weak intermolecular forces that arise from temporary fluctuations in electron distribution, not the primary bonds in water. Choice D, oxygen, is incorrect as oxygen is part of the water molecule but not the bond holding water molecules together.

3. What is the difference between saturated and unsaturated fatty acids?

A. There is no difference between saturated and unsaturated fatty acids.
B. Saturated fatty acids contain double bonds, unlike unsaturated fatty acids.
C. Saturated fatty acids often contain two or more pairs of double bonds, unlike unsaturated fatty acids.
D. Saturated fatty acids contain no double bonds, unlike unsaturated fatty acids.

Correct answer: D

Rationale: The correct answer is D. Saturated fatty acids contain no double bonds between the carbon atoms in their hydrocarbon chains, making them more solid at room temperature. Choice A is incorrect because there is a significant difference between saturated and unsaturated fatty acids. Choice B is incorrect as it inaccurately states that saturated fatty acids contain double bonds, which is a property of unsaturated fatty acids. Choice C is also incorrect as saturated fatty acids do not contain double bonds, let alone two or more pairs of double bonds.

4. What is the composition of the cellular membrane?

A. A bilayer of phospholipid molecules
B. A single layer of phospholipid molecules
C. Proteins that act as transport highways
D. Carbohydrates

Correct answer: A

Rationale: The cellular membrane is primarily composed of a phospholipid bilayer, which consists of two layers of phospholipid molecules. These molecules have a hydrophilic (water-attracting) head and hydrophobic (water-repelling) tail, creating a barrier that separates the internal cellular environment from the external surroundings. While proteins are embedded within this bilayer and act as transport channels, receptors, and structural support, carbohydrates are found on the outer surface of the membrane for cell recognition and signaling purposes. Therefore, the correct answer is a bilayer of phospholipid molecules.

5. Which organelle is responsible for the synthesis of lipids and steroid hormones?

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

Correct answer: B

Rationale: The smooth endoplasmic reticulum is the correct organelle responsible for the synthesis of lipids, including phospholipids, cholesterol, and steroid hormones. The rough endoplasmic reticulum is primarily involved in protein synthesis and processing, making choice A incorrect. The Golgi apparatus is responsible for modifying, sorting, and packaging proteins and lipids for transportation, so it is not directly involved in lipid and steroid hormone synthesis, making choice C incorrect. Ribosomes are responsible for protein synthesis and are not involved in lipid or steroid hormone synthesis, making choice D incorrect.