BMST Cellular Processes and Organelles 5 — Questions and Answers
Question 1: Which cellular process produces lactic acid in muscle cells under low-oxygen conditions?
- Aerobic respiration
- Lactic acid fermentation (Correct answer)
- Alcoholic fermentation
- Photosynthesis
Correct answer: Lactic acid fermentation
Lactic acid fermentation regenerates NAD⁺ from NADH so glycolysis can continue producing ATP when oxygen is scarce.
Question 2: What is the endosymbiotic theory?
- Cells divide by binary fission
- Eukaryotic organelles like mitochondria evolved from ancient prokaryotes engulfed by larger cells (Correct answer)
- All cells arose from a single common ancestor
- The nucleus controls all cellular activities
Correct answer: Eukaryotic organelles like mitochondria evolved from ancient prokaryotes engulfed by larger cells
The endosymbiotic theory proposes that mitochondria and chloroplasts originated as free-living bacteria that were engulfed by ancestral eukaryotic cells.
Question 3: Which molecule acts as the electron carrier between the Krebs cycle and the electron transport chain?
- ATP
- ADP
- NADH (Correct answer)
- Pyruvate
Correct answer: NADH
NADH carries high-energy electrons from the Krebs cycle to the electron transport chain, where they drive ATP synthesis.
Question 4: What type of cellular transport involves the cell engulfing large particles by wrapping its membrane around them?
- Exocytosis
- Pinocytosis
- Phagocytosis (Correct answer)
- Facilitated diffusion
Correct answer: Phagocytosis
Phagocytosis is a form of endocytosis where the cell membrane engulfs large solid particles like bacteria or debris.
Question 5: Which phase of the cell cycle involves DNA replication?
- G1 phase
- S phase (Correct answer)
- G2 phase
- M phase
Correct answer: S phase
DNA replication occurs during the S (synthesis) phase of interphase, producing two identical copies of the genome.
Question 6: What is the primary pigment in chloroplasts that absorbs light energy?
- Hemoglobin
- Melanin
- Chlorophyll (Correct answer)
- Carotene
Correct answer: Chlorophyll
Chlorophyll is the main photosynthetic pigment that absorbs red and blue light while reflecting green light.
Question 7: Which cellular process is responsible for the secretion of insulin from pancreatic cells?
- Endocytosis
- Phagocytosis
- Exocytosis (Correct answer)
- Pinocytosis
Correct answer: Exocytosis
Exocytosis is the process by which vesicles fuse with the cell membrane to release their contents outside the cell.
BMST Cellular Processes and Organelles 5
Which cellular process produces lactic acid in muscle cells under low-oxygen conditions?