IMO Practice Test — Cell - The Unit of Life
6 Questions • 15 min • Olympiad level
15:00
Question 1 of 6
Mitochondria and chloroplasts both have their own DNA and 70S ribosomes. This supports the idea that they:
Originated from free-living prokaryotes (endosymbiosis)
Are not living
Were made by the Golgi
Have no function
Explanation: Their own DNA and 70S ribosomes suggest an endosymbiotic prokaryotic origin.
Question 2 of 6
A cell actively pumps ions in against their concentration gradient. This requires:
ATP energy (active transport)
No energy (diffusion)
Osmosis only
The cell wall
Explanation: Moving substances against the gradient is active transport, which uses ATP.
Question 3 of 6
A gland cell that secretes large amounts of protein would be expected to have abundant:
Rough ER and Golgi apparatus
Chloroplasts
Cell wall
Centrioles
Explanation: Protein synthesis and packaging need plenty of rough ER and Golgi.
Question 4 of 6
Why can a plant cell placed in pure water not burst, while an animal cell may?
The rigid cellulose cell wall resists the swelling
Plant cells have no water
Animal cells have a cell wall
Plant cells have no membrane
Explanation: The plant cell wall withstands the turgor pressure, preventing bursting.
Question 5 of 6
The inner membrane of a mitochondrion is folded into cristae mainly to:
Increase the surface area for ATP-producing reactions
Store food
Make the cell wall
Digest waste
Explanation: Cristae increase surface area for the enzymes of respiration, boosting ATP output.
Question 6 of 6
Red blood cells of mammals lack a nucleus, which means they cannot:
Divide or make new proteins, so they have a short lifespan
Carry oxygen
Move in blood
Be living
Explanation: Without a nucleus they cannot divide or synthesise proteins, limiting their lifespan.