during protein synthesis what process uses an rna strand to produce a complementary strand of dna

HESI A2

HESI A2 Practice Test Biology

1. During protein synthesis, what process uses an RNA strand to produce a complementary strand of DNA?

A. Transcription
B. Translation
C. Transfer synthesis
D. Codon synthesis

Correct answer: A

Rationale: The correct answer is 'Transcription.' During transcription, an RNA strand is used to produce a complementary strand of DNA. This process is essential for converting the genetic information stored in DNA into RNA. Choice B, 'Translation,' is incorrect as it involves the synthesis of proteins from mRNA. Choice C, 'Transfer synthesis,' is not a recognized term in molecular biology. Choice D, 'Codon synthesis,' is also incorrect as it does not refer to the process of using an RNA strand to produce a complementary DNA strand.

2. How many pairs of chromosomes do all humans have?

A. 24 pairs
B. 23 pairs
C. 22 pairs
D. 20 pairs

Correct answer: B

Rationale: All humans have 23 pairs of chromosomes, totaling 46 chromosomes. Choice A is incorrect because humans do not have 24 pairs. Choice C is incorrect as humans have 23 pairs, not 22 pairs. Choice D is incorrect as humans have 23 pairs of chromosomes, not 20 pairs.

3. How many chromosomes do sperm and egg produce in meiosis?

A. 23
B. 46
C. 25
D. 50

Correct answer: A

Rationale: During meiosis, sperm and egg cells produce half the number of chromosomes found in somatic cells. Each contributes 23 chromosomes, which combine to form a zygote with a total of 46 chromosomes. Choice B (46) is incorrect because this is the number of chromosomes produced in mitosis, not meiosis. Choices C (25) and D (50) are also incorrect as they do not align with the chromosome count in sex cells during meiosis.

4. Which organelle is responsible for making proteins?

A. Ribosome
B. Chloroplast
C. Lysosome
D. Mitochondrion

Correct answer: A

Rationale: Ribosomes are the organelles responsible for protein synthesis within the cell. They are the sites where amino acids are linked together to form proteins based on the instructions carried by mRNA (messenger RNA). Ribosomes can be found free-floating in the cytoplasm or attached to the endoplasmic reticulum, and they play a crucial role in translating genetic information into proteins. Chloroplasts are responsible for photosynthesis, lysosomes are involved in digestion and waste removal, and mitochondria are known as the powerhouse of the cell responsible for energy production through cellular respiration. Therefore, the ribosome is the correct organelle responsible for making proteins.

5. Where is the ovary located in a flowering plant?

A. Anther
B. Pistil
C. Stamen
D. Calyx

Correct answer: B

Rationale: The ovary is located in the pistil of a flowering plant. The pistil is the female reproductive part of the flower, and it consists of the ovary, style, and stigma. The ovary contains ovules, which develop into seeds after fertilization. Choice A, 'Anther,' is incorrect because the anther is the part of the flower's stamen that produces pollen. Choice C, 'Stamen,' is incorrect because the stamen is the male reproductive part of the flower, consisting of the anther and filament. Choice D, 'Calyx,' is incorrect because the calyx is the outermost whorl of a flower, composed of sepals that protect the flower bud.