ADAT ADAT Biomedical Sciences 3 — Questions and Answers
Question 1: Which organelle is primarily responsible for the post-translational modification and packaging of proteins?
- Golgi apparatus (Correct answer)
- Rough endoplasmic reticulum
- Lysosome
- Peroxisome
Correct answer: Golgi apparatus
The Golgi apparatus modifies, sorts, and packages proteins for secretion or delivery to organelles.
Question 2: A resting neuron maintains a negative membrane potential primarily due to which mechanism?
- Na+/K+ ATPase pump activity (Correct answer)
- Passive chloride influx
- Calcium sequestration
- Glucose transport
Correct answer: Na+/K+ ATPase pump activity
The Na+/K+ ATPase pumps 3 Na+ out and 2 K+ in, helping establish the resting potential.
Question 3: Which of the following bacteria is a primary etiologic agent in the initiation of dental caries?
- Streptococcus mutans (Correct answer)
- Escherichia coli
- Staphylococcus aureus
- Lactobacillus casei
Correct answer: Streptococcus mutans
Streptococcus mutans produces acid and adheres to enamel, initiating the caries process.
Question 4: Which vitamin is essential for the hydroxylation of proline and lysine in collagen synthesis?
- Vitamin C (Correct answer)
- Vitamin A
- Vitamin D
- Vitamin K
Correct answer: Vitamin C
Vitamin C is a cofactor for prolyl and lysyl hydroxylase, required for stable collagen.
Question 5: Which region of the nephron is the primary site of glucose and amino acid reabsorption?
- Proximal convoluted tubule (Correct answer)
- Loop of Henle
- Distal convoluted tubule
- Collecting duct
Correct answer: Proximal convoluted tubule
Most glucose and amino acids are reabsorbed via secondary active transport in the proximal convoluted tubule.
Question 6: MHC class I molecules present antigens primarily to which type of T cell?
- CD8+ cytotoxic T cells (Correct answer)
- CD4+ helper T cells
- Regulatory T cells
- Natural killer cells
Correct answer: CD8+ cytotoxic T cells
MHC class I presents endogenous peptides to CD8+ cytotoxic T lymphocytes.
Question 7: Which muscle of mastication is primarily responsible for protrusion of the mandible?
- Lateral pterygoid (Correct answer)
- Masseter
- Temporalis
- Medial pterygoid
Correct answer: Lateral pterygoid
The lateral pterygoid muscles pull the mandibular condyles forward, protruding the jaw.
ADAT ADAT Biomedical Sciences 3
Which organelle is primarily responsible for the post-translational modification and packaging of proteins?