Cell Biology Quiz for Grade 10

What is the function of the cell membrane?

• To produce energy for the cell

• To control what enters and exits the cell

• To carry out photosynthesis

• To store genetic information

Which organelle is responsible for producing proteins in a cell?

• Mitochondria

• Vacuole

• Ribosome

• Chloroplast

What is the name of the process by which a cell divides to produce two genetically identical daughter cells?

• Meiosis

• Mitosis

• Fertilisation

• Differentiation

Which of the following correctly describes the role of enzymes in biological reactions?

• Enzymes are permanently consumed during a reaction

• Enzymes increase the activation energy required for a reaction

• Enzymes act as biological catalysts that speed up chemical reactions

• Enzymes only function at temperatures above 50°C

A student observes a plant cell and an animal cell under a microscope. Which structure would be present in the plant cell but **not** in the animal cell?

• Cell membrane

• Mitochondria

• Cell wall

• Nucleus

An enzyme works most efficiently at 37°C. A student increases the temperature to 70°C. What would happen to the enzyme's activity and why?

• Activity increases because higher temperatures always speed up enzyme reactions

• Activity stops because the enzyme's active site has been denatured and can no longer bind to the substrate

• Activity remains the same because enzymes are not affected by temperature

• Activity decreases temporarily but returns to normal once cooled

During mitosis, a cell with 46 chromosomes undergoes division. Which of the following correctly describes the outcome?

• Two daughter cells, each with 23 chromosomes

• Four daughter cells, each with 46 chromosomes

• Two daughter cells, each with 46 chromosomes

• Four daughter cells, each with 23 chromosomes

A student investigates the effect of pH on amylase activity by measuring the time taken to break down starch at pH values of 3, 5, 7, and 9. The results show that starch is broken down most rapidly at pH 7. Using your knowledge of enzyme structure, explain why amylase activity decreases at pH 3.

• At pH 3, there are fewer substrate molecules available for the enzyme to act upon

• At pH 3, the acidic conditions alter the shape of the active site, reducing the enzyme's ability to bind to starch

• At pH 3, the temperature of the solution decreases, slowing the reaction

• At pH 3, the enzyme produces more products, which inhibit further reactions

A scientist is studying a tumour and notices that the cells are dividing uncontrollably. Using your understanding of mitosis and cell cycle regulation, which of the following best explains why uncontrolled mitosis is harmful to the organism?

• Uncontrolled mitosis produces cells with half the normal number of chromosomes, causing genetic disorders

• Uncontrolled mitosis produces a mass of abnormal cells that can invade surrounding tissues and disrupt normal organ function

• Uncontrolled mitosis causes all cells to differentiate into the same cell type, reducing organ diversity

• Uncontrolled mitosis depletes the cell's ribosomes, preventing protein synthesis throughout the body

A student is comparing the efficiency of two cells: Cell A is a highly specialised muscle cell, and Cell B is an unspecialised stem cell. The student claims that Cell A must have fewer types of proteins than Cell B because it only performs one function. Evaluate this claim using your knowledge of cell specialisation, gene expression, and organelle function.

• The claim is correct because specialised cells switch off all genes except those needed for their specific function, so fewer proteins are produced overall

• The claim is incorrect because specialised cells such as muscle cells require a large variety of structural and functional proteins, including contractile proteins, and may express as many or more specific proteins than stem cells

• The claim is correct because muscle cells only contain mitochondria and cell membranes, which require very few types of proteins

• The claim is incorrect because all cells produce identical proteins regardless of their function or level of specialisation