Biology Cellular and Molecular Flashcards

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

Answer: Helicase

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

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

Answer: Lipid synthesis and detoxification

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

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

Answer: Metaphase

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

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

Answer: tRNA

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

What structural feature distinguishes prokaryotic cells from eukaryotic cells?

Answer: Absence of a membrane-bound nucleus

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

What is the term for the programmed cell death pathway that removes damaged or unnecessary cells?

Answer: Apoptosis

Apoptosis is a regulated process of cell death that involves characteristic changes like DNA fragmentation and cell shrinkage.

Which bond connects amino acids together to form a polypeptide chain?

Answer: Peptide bond

Peptide bonds form between the carboxyl group of one amino acid and the amino group of the next during translation.