Cell biology worksheet with answers

When human muscle cells lack oxygen, pyruvate is converted into:

1. AEthanol
2. BGlucose
3. CLactate
4. DAcetyl-CoA

What is phagocytosis?

1. AThe uptake of small ions through channels
2. BThe release of proteins from the cell in membrane-bound vesicles
3. CThe uptake of large particles by engulfing them in membrane
4. DThe movement of water across a membrane

How do enzymes speed up chemical reactions?

1. AThey lower the activation energy
2. BThey change the reaction's final equilibrium
3. CThey raise the temperature of the cell
4. DThey are used up in the reaction

Glycolysis takes place in the:

1. AInner mitochondrial membrane
2. BNucleus
3. CCytoplasm
4. DMitochondrial matrix

Transcription produces:

1. AmRNA from a DNA template
2. BDNA from RNA
3. CProtein from mRNA
4. DDNA from DNA

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

1. AProtein kinase A
2. BPhosphodiesterase
3. CAdenylyl cyclase
4. DPhospholipase C

Bacteria moved to a much colder environment change the fatty acids in their membranes. Which change keeps the membrane fluid?

1. AMore saturated fatty acids
2. BMore unsaturated fatty acids
3. CLonger fatty acid tails
4. DFewer membrane proteins

A mutation in the lac repressor stops it binding to the operator. What is the result?

1. AThe bacteria can no longer take up glucose
2. BThe lac genes are expressed only when glucose is present in the medium
3. CThe lac genes are expressed all the time, even without lactose
4. DThe lac genes can never be expressed