GCSE Cell Biology 4 — Questions and Answers
Question 1: Active transport differs from diffusion because it:
- Moves substances down a concentration gradient
- Does not require a membrane
- Moves substances against a concentration gradient using energy (Correct answer)
- Only moves water molecules
Correct answer: Moves substances against a concentration gradient using energy
Active transport uses ATP energy to move substances from low to high concentration — against the concentration gradient.
Question 2: What is the main function of the large permanent vacuole in a plant cell?
- To carry out photosynthesis
- To store water and maintain turgor pressure (Correct answer)
- To produce proteins
- To control the cell's activities
Correct answer: To store water and maintain turgor pressure
The large permanent vacuole stores cell sap and helps maintain turgor pressure, which keeps plant cells firm.
Question 3: A student counts 20 cells undergoing mitosis in a sample of 200 cells. What is the mitotic index?
- 10
- 0.1 (Correct answer)
- 40
- 0.4
Correct answer: 0.1
Mitotic index = cells in mitosis ÷ total cells = 20 ÷ 200 = 0.1.
Question 4: Which of the following best describes a stem cell?
- A cell that has fully differentiated and cannot change
- An undifferentiated cell that can divide and develop into different cell types (Correct answer)
- A cell found only in bone tissue
- A cell that undergoes meiosis to form gametes
Correct answer: An undifferentiated cell that can divide and develop into different cell types
Stem cells are unspecialised cells capable of self-renewal and differentiation into various specialised cell types.
Question 5: Why do multicellular organisms need specialised cells?
- Because all cells must look identical
- Because different functions require cells with different structures (Correct answer)
- Because specialised cells can reproduce faster
- Because single cells cannot carry out respiration
Correct answer: Because different functions require cells with different structures
Different functions — like oxygen transport, nerve impulse transmission, or photosynthesis — require cells adapted with specific structural features.
Question 6: What happens to the chromosomes during the anaphase stage of mitosis?
- Chromosomes condense and become visible
- Chromosomes align at the cell's equator
- Sister chromatids are pulled to opposite poles of the cell (Correct answer)
- A new nuclear envelope forms around each set of chromosomes
Correct answer: Sister chromatids are pulled to opposite poles of the cell
During anaphase, spindle fibres contract and pull sister chromatids to opposite ends of the cell.
Question 7: Which feature is found in animal cells but NOT in plant cells?
- Mitochondria
- Cell membrane
- Centrioles (Correct answer)
- Ribosomes
Correct answer: Centrioles
Centrioles organise the spindle fibres during cell division in animal cells but are absent in most plant cells.
GCSE Cell Biology 4
Active transport differs from diffusion because it: