Cell biology worksheet with answers

Which organelle breaks down hydrogen peroxide using the enzyme catalase?

1. APeroxisome
2. BRibosome
3. CLysosome
4. DGolgi apparatus

Which structure helps organise microtubules in animal cells and contains a pair of centrioles?

1. ARibosome
2. BNucleolus
3. CVacuole
4. DCentrosome

In chromatin, DNA is wrapped around which proteins?

1. AHistones
2. BActins
3. CCollagens
4. DTubulins

Which enzyme makes the second messenger cyclic AMP when activated by a Gs protein?

1. AAdenylyl cyclase
2. BPhosphodiesterase
3. CPhospholipase C
4. DProtein kinase A

Transcription produces:

1. AProtein from mRNA
2. BDNA from DNA
3. CDNA from RNA
4. DmRNA from a DNA template

A competitive inhibitor binds the active site of an enzyme. What can overcome its effect?

1. ARemoving the enzyme's cofactor
2. BRaising the substrate concentration
3. CLowering the temperature to 0 °C
4. DRaising the inhibitor concentration

Brown fat contains thermogenin (UCP1), which lets protons leak back across the inner mitochondrial membrane. What is the effect?

1. AThe cell switches to fermentation
2. BMore ATP is made per glucose
3. CEnergy from the proton gradient is released as heat instead of making ATP
4. DThe electron transport chain stops working because protons can no longer be pumped

Which statement about the sodium–potassium pump is correct?

1. AIt moves 2 Na⁺ out and 3 K⁺ in
2. BIt needs no energy
3. CIt moves Na⁺ and K⁺ in the same direction across the membrane
4. DIt moves 3 Na⁺ out and 2 K⁺ in for each ATP used