what is the role of transfer rna trna in protein synthesis

ATI TEAS 7

ati teas 7 science

1. What is the role of transfer RNA (tRNA) in protein synthesis?

A. Transcribes DNA into mRNA
B. Decodes the genetic code on mRNA
C. Carries specific amino acids to the ribosomes
D. Modifies the structure of proteins

Correct answer: C

Rationale: A) Transcribes DNA into mRNA: This is the function of RNA polymerase, not transfer RNA (tRNA). tRNA is involved in protein synthesis, not transcription. B) Decodes the genetic code on mRNA: This is the function of tRNA during translation. tRNA molecules carry specific amino acids and recognize the codons on mRNA, ensuring the correct amino acid is added to the growing polypeptide chain. C) Carries specific amino acids to the ribosomes: This is the primary role of tRNA in protein synthesis. Each tRNA molecule is specific for a particular amino acid and carries it to the ribosome, where it is added to the growing protein chain. D) Modifies the structure of proteins: This is not a function of tRNA. Protein modification can occur after translation is complete and involves other cellular processes and molecules.

2. What is the process of breaking down proteins into amino acids called?

A. Proteolysis
B. Lipolysis
C. Carbohydrate catabolism
D. Nucleic acid catabolism

Correct answer: A

Rationale: Proteolysis is the specific process of breaking down proteins into amino acids. Lipolysis refers to the breakdown of fats into fatty acids and glycerol, not proteins. Carbohydrate catabolism involves the breakdown of carbohydrates into glucose for energy production, not proteins. Nucleic acid catabolism is the breakdown of nucleic acids into nucleotides, not proteins. Therefore, in the context of breaking down proteins into amino acids, the correct term is proteolysis.

3. Which organelle is responsible for controlling the activities of the cell?

A. Golgi apparatus
B. Mitochondria
C. Nucleus
D. Ribosomes

Correct answer: C

Rationale: The nucleus is the organelle responsible for controlling the activities of the cell. It contains the cell's genetic material (DNA) and serves as the command center of the cell, regulating gene expression and directing cellular activities. The nucleus plays a crucial role in cell growth, metabolism, and reproduction. While the Golgi apparatus is involved in processing and packaging proteins, the mitochondria are responsible for producing energy in the form of ATP, and ribosomes are involved in protein synthesis, none of these organelles have the primary function of controlling the activities of the cell like the nucleus does. Therefore, the correct answer is the nucleus.

4. Which of the following best describes the relationship among density, volume, and mass?

A. As volume increases, density decreases.
B. As volume decreases, density increases.
C. An object's mass does not affect its density.
D. As volume decreases, mass increases.

Correct answer: B

Rationale: The correct answer is B: 'As volume decreases, density increases.' This is because density is defined as mass divided by volume. When volume decreases and mass remains constant, the ratio of mass to volume increases, leading to higher density. Choice A is incorrect because as volume increases, density typically remains constant or increases due to the mass also increasing. Choice C is incorrect because an object's density is directly influenced by its mass. Choice D is incorrect as decreasing volume does not lead to an increase in mass.

5. Which type of joint allows for the widest range of motion, similar to the shoulder joint?

A. Hinge joint
B. Ball-and-socket joint
C. Gliding joint
D. Fixed joint

Correct answer: B

Rationale: The correct answer is B: Ball-and-socket joint. Ball-and-socket joints, like the shoulder joint, allow for the widest range of motion in multiple directions. This type of joint consists of a rounded bone (the 'ball') fitting into a cup-like socket, enabling movements such as flexion, extension, abduction, adduction, and rotation. Choice A, Hinge joint, allows movement in one plane, like a door hinge, and does not offer the same range of motion as a ball-and-socket joint. Choice C, Gliding joint, permits limited motion in various directions but not as wide as a ball-and-socket joint. Choice D, Fixed joint, does not allow any motion as it is immovable, unlike the shoulder joint which is highly mobile.