Biology Test Biology Cellular and Molecular 2 — Questions and Answers
Question 1: Which enzyme is responsible for unwinding the DNA double helix during replication?
- DNA polymerase
- Helicase (Correct answer)
- Ligase
- Primase
Correct answer: Helicase
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)?
- Protein synthesis
- Lipid synthesis and detoxification (Correct answer)
- DNA replication
- Packaging proteins for secretion
Correct answer: Lipid synthesis and detoxification
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?
- Prophase
- Anaphase
- Metaphase (Correct answer)
- Telophase
Correct answer: Metaphase
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?
- mRNA
- rRNA
- tRNA (Correct answer)
- snRNA
Correct answer: tRNA
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?
- Presence of ribosomes
- Absence of a membrane-bound nucleus (Correct answer)
- Ability to perform photosynthesis
- Presence of a cell membrane
Correct answer: Absence of a membrane-bound nucleus
Prokaryotes lack a membrane-bound nucleus; their genetic material is located in an unenclosed nucleoid region.
Question 6: What is the term for the programmed cell death pathway that removes damaged or unnecessary cells?
- Necrosis
- Apoptosis (Correct answer)
- Autolysis
- Lysis
Correct answer: Apoptosis
Apoptosis is a regulated process of cell death that involves characteristic changes like DNA fragmentation and cell shrinkage.
Question 7: Which bond connects amino acids together to form a polypeptide chain?
- Hydrogen bond
- Ionic bond
- Peptide bond (Correct answer)
- Disulfide bond
Correct answer: Peptide bond
Peptide bonds form between the carboxyl group of one amino acid and the amino group of the next during translation.
Biology Test Biology Cellular and Molecular 2
Which enzyme is responsible for unwinding the DNA double helix during replication?