Question 1: Define a plant cell and explain how it differs from an animal cell.

Answer: A plant cell is a eukaryotic cell characterised by the presence of a cell wall, chloroplasts, and a large central vacuole. Unlike animal cells, plant cells have these features which provide structural support and enable photosynthesis.

Question 2: Describe the function of the chloroplast in a plant cell.

Answer: Chloroplasts are organelles that contain chlorophyll and are the site of photosynthesis, where light energy is converted into chemical energy to produce glucose.

Question 1: A plant cell's vacuole has a volume of 0.5 mm³. If the vacuole expands by 20% during cell growth, what is its new volume in mm³? Show your working.

Answer: 0.6 mm³

Question 2: The total surface area of a plant cell's chloroplasts is 1500 μm², and each chloroplast has an average surface area of 30 μm². How many chloroplasts are present in the cell? Show your working.

Answer: 50 chloroplasts

Question 1: Describe a simple experiment to demonstrate the presence of chloroplasts in plant cells. Include the main steps and safety precautions.

Answer: One experiment involves observing a thin slice of leaf tissue under a light microscope. Students should prepare the slide with a drop of water, place the leaf section on it, and add a cover slip. Safety precautions include handling the microscope carefully, avoiding contact with sharp edges, and washing hands afterwards.

Question 2: Identify and explain three variables that could affect the outcome of the chloroplast observation experiment.

Answer: Variables include light intensity (affects chloroplast visibility), temperature (affects cell activity), and sample thickness (affects clarity under the microscope).

Question 1: A researcher finds that a plant cell has a smaller vacuole than usual. Discuss possible reasons for this observation.

Answer: Possible reasons include water deficiency leading to reduced vacuole size, cellular stress or damage, or developmental stage where vacuole expansion has not yet occurred.

Question 2: In a nutrient-rich environment, the size of chloroplasts in plant cells increases. Explain how this impacts photosynthesis and plant growth.

Answer: Larger chloroplasts contain more chlorophyll and enzymes, enhancing the plant's capacity for photosynthesis. This increases glucose production, supporting faster growth and development.

Question 1: How is understanding plant cell structure important in developing genetically modified crops?

Answer: Understanding plant cell structure helps scientists modify genes related to photosynthesis, growth, and disease resistance, leading to crops with improved yield, resilience, and nutritional value.

Question 2: Explain how advances in plant cell research can contribute to sustainable agriculture and food security.

Answer: Advances enable development of crops that require less water and fertiliser, are resistant to pests and diseases, and can grow in marginal soils. This reduces environmental impact and increases food production, supporting global food security.