BioInteractive Photorespiration and Alternative Carbon Fixation

Question 1

What is photorespiration?

Accepted Answer

A process where RuBisCO fixes O2 instead of CO2, releasing CO2 and reducing photosynthetic efficiency

Answer

A process that produces ATP from light

Answer

An alternative way to split water

Answer

A method of cyclic electron flow

Question 2

Under what conditions is photorespiration most likely to occur?

Accepted Answer

High O2, low CO2, and high temperature

Answer

Low O2, high CO2, and low temperature

Answer

Darkness and cool temperatures

Answer

High humidity and low light

Question 3

How do C4 plants reduce photorespiration?

Accepted Answer

They concentrate CO2 around RuBisCO in bundle sheath cells using a CO2 pump

Answer

They lack RuBisCO entirely

Answer

They fix carbon only at night

Answer

They use a different electron transport chain

Question 4

What enzyme initially fixes CO2 in C4 plants?

Accepted Answer

PEP carboxylase

Answer

RuBisCO

Answer

Rubisco activase

Answer

Carbonic anhydrase

Question 5

What is the 4-carbon compound first produced when CO2 is fixed in C4 plants?

Accepted Answer

Oxaloacetate

Answer

3-phosphoglycerate

Answer

Pyruvate

Answer

Malate

Question 6

Which type of plants are best adapted to hot, sunny, arid environments due to reduced photorespiration?

Accepted Answer

C4 plants

Answer

C3 plants

Answer

Bryophytes

Answer

Shade-adapted ferns