Biology: cells and evidence

Question 1 (1 mark)

Which feature is shared by a typical bacterium and a plant cell?

1. A membrane-bound nucleus
2. Ribosomes
3. Chloroplasts
4. Mitochondria

Question 2 (1 mark)

Water moves into a cell through a selectively permeable membrane. Which description best identifies osmosis?

1. Net water movement down a water concentration gradient
2. ATP-powered movement of every dissolved substance
3. Movement of solute through a cell wall
4. Movement of water only when both solutions are identical

Question 3 (1 mark)

A 40× objective is combined with a 10× eyepiece. What is the total magnification?

1. 4×
2. 50×
3. 400×
4. 4000×

Question 4 (1 mark)

A membrane protein transports ions against their concentration gradient using ATP. Which process is occurring?

1. Simple diffusion
2. Osmosis
3. Facilitated diffusion
4. Active transport

Question 5 (3 marks)

Explain how the nucleus, ribosomes and rough endoplasmic reticulum contribute to producing a protein that will be secreted.

Question 6 (3 marks)

A cell image is 24 mm wide at a stated magnification of 600×. Calculate the actual width in micrometres and explain one reason why magnification alone does not guarantee a clear image.

Question 7 (3 marks)

Distinguish a plant cell wall from its plasma membrane, relating each structure to a function.

Question 8 (3 marks)

Potato cylinders were left in solutions for 30 minutes. Calculate the mean percentage mass change in solution B. Use the data to infer which solution is closest to having no net mass change. State a limit to that inference.

Question 9 (3 marks)

Explain why a small cell generally has a higher surface-area-to-volume ratio than a geometrically similar large cell, and why this matters for exchange.

Question 10 (3 marks)

A student reports: ‘There was no net mass change, so osmosis stopped.’ Evaluate the claim.

Question 11 (4 marks)

Design a valid and reliable investigation of how solution concentration affects potato cylinder mass. Explain four design choices.

Question 12 (4 marks)

Compare what light microscopy and electron microscopy can reveal about cells. Explain why a scientist may need evidence from both rather than simply choosing the higher magnification.