Free COMSAE Basic Biomedical Sciences Questions and Answers — Questions and Answers
Question 1: What is the primary function of mitochondria in eukaryotic cells?
- Energy production (Correct answer)
- Protein synthesis
- DNA replication
- Structural support
Correct answer: Energy production
Mitochondria are often referred to as the 'powerhouses' of the cell because their primary function is energy production. Through cellular respiration, they generate adenosine triphosphate (ATP), the main energy currency of the cell, from glucose and other fuel molecules. This process is crucial for nearly all cellular activities requiring energy.
Question 2: Which type of epithelium lines the respiratory tract?
- Simple squamous epithelium
- Stratified squamous epithelium
- Pseudostratified columnar epithelium with cilia (Correct answer)
- Transitional epithelium
Correct answer: Pseudostratified columnar epithelium with cilia
The respiratory tract, from the nasal cavity down to the bronchi, is primarily lined by pseudostratified columnar epithelium with cilia. This specialized epithelium appears stratified but is actually a single layer of cells of varying heights, all attached to the basement membrane. The cilia on the surface, along with goblet cells that produce mucus, work together to trap and sweep foreign particles and pathogens out of the respiratory system.
Question 3: In glycolysis, what is the end product that enters the citric acid cycle under aerobic conditions?
- Pyruvate
- Lactate
- Acetyl-CoA (Correct answer)
- Glucose
Correct answer: Acetyl-CoA
Under aerobic conditions, the end product of glycolysis, pyruvate, does not directly enter the citric acid cycle. Instead, pyruvate is transported into the mitochondria and undergoes oxidative decarboxylation, where it is converted into Acetyl-CoA. This Acetyl-CoA then serves as the crucial entry point for the carbon atoms into the citric acid cycle, where further energy is extracted.
Question 4: Which cranial nerve is responsible for motor innervation to the muscles of mastication?
- Facial nerve (CN VII)
- Trigeminal nerve (CN V3 - mandibular branch) (Correct answer)
- Hypoglossal nerve (CN XII)
- Glossopharyngeal nerve (CN IX)
Correct answer: Trigeminal nerve (CN V3 - mandibular branch)
The Trigeminal nerve (CN V) is responsible for motor innervation to the muscles of mastication (chewing). Specifically, the mandibular branch (V3) of the trigeminal nerve innervates muscles such as the masseter, temporalis, and pterygoids. It also provides sensory innervation to the face, but its motor component is critical for jaw movement.
Question 5: What type of immune cell is primarily involved in antibody production?
- T lymphocytes
- Macrophages (Correct answer)
- B lymphocytes
- Natural killer cells
Correct answer: Macrophages
Macrophages are crucial antigen-presenting cells (APCs) that phagocytose pathogens and present their antigens to T helper cells. This antigen presentation is a critical step in initiating the adaptive immune response, which includes the activation and differentiation of B lymphocytes into plasma cells, the actual antibody producers. Therefore, while not directly producing antibodies, macrophages play a primary and indispensable role in orchestrating the immune response that leads to antibody production.
Free COMSAE Basic Biomedical Sciences Questions and Answers
What is the primary function of mitochondria in eukaryotic cells?