Types of Photosynthesis in Plants: C3, C4, and CAM

The video revisits photosynthesis, focusing on the differences between C3, C4, and CAM pathways. C3 photosynthesis is common but inefficient in dry environments due to photorespiration. C4 plants, like corn, use a four-carbon compound to continue photosynthesis even when stomata are closed, showing convergent evolution. CAM plants, such as cacti, open stomata at night to conserve water, storing CO2 for daytime use. These adaptations help plants balance photosynthesis and water conservation in arid conditions.

What is the primary focus of this series on photosynthesis?

• The history of photosynthesis research

• The differences between metabolic pathways

• The diversity of plants

• The general mechanism of photosynthesis

Which enzyme is responsible for carbon fixation in C3 plants?

• NADP reductase

• ATP synthase

• Rubisco

• PEP carboxylase

Why is C3 photosynthesis less efficient in arid environments?

• It produces less oxygen

• It uses more water

• It leads to photorespiration

• It requires more sunlight

What is the initial carbon compound formed in C4 photosynthesis?

• OAA

• RuBP

• Glucose

• 3-PGA

How do C4 plants maintain photosynthesis during water stress?

• By storing CO2 in vacuoles

• By increasing photorespiration

• By using PEP carboxylase in mesophyll cells

• By opening stomata at night

What is a unique feature of CAM photosynthesis?

• Stomata open during the day

• Carbon fixation occurs in different cells

• CO2 is fixed into a four-carbon compound at night

• It is common in monocots

In CAM plants, when are the stomata open?

• When water is abundant

• At night

• Only during photosynthesis

• During the day