Biology Test Biology Cellular and Molecular 2

Question 1

Which enzyme is responsible for unwinding the DNA double helix during replication?

Accepted Answer

Helicase

Answer

Helicase breaks hydrogen bonds between base pairs to unwind and separate the two DNA strands at the replication fork.

Question 2

What is the primary function of the smooth endoplasmic reticulum (SER)?

Accepted Answer

Lipid synthesis and detoxification

Answer

The SER synthesizes lipids, phospholipids, and steroids, and detoxifies drugs and harmful substances.

Question 3

During which phase of mitosis do chromosomes align at the cell's equatorial plate?

Accepted Answer

Metaphase

Answer

During metaphase, chromosomes are moved by spindle fibers to align at the metaphase plate in the center of the cell.

Question 4

Which type of RNA carries amino acids to the ribosome during translation?

Accepted Answer

tRNA

Answer

Transfer RNA (tRNA) has an anticodon that matches mRNA codons and carries specific amino acids to the ribosome.

Question 5

What structural feature distinguishes prokaryotic cells from eukaryotic cells?

Accepted Answer

Absence of a membrane-bound nucleus

Answer

Prokaryotes lack a membrane-bound nucleus; their genetic material is located in an unenclosed nucleoid region.

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