C3 and C4 Plant Adaptations

C3 carbon fixation is a photosynthetic process converting CO2 and ribulose bisphosphate into phosphoglycerate. It is the first step in the Calvin cycle and occurs in all plants. C3 plants thrive in moderate environments but struggle in hot, dry areas due to increased photorespiration. They lose significant water through transpiration. C4 and CAM plants have adaptations for hot, dry climates, outcompeting C3 plants. C3 plants show higher 13C depletion than C4 plants.

What are the three metabolic pathways for carbon fixation in photosynthesis?

• C3, C4, and CAM

• C1, C2, and C3

• C4, CAM, and C5

• C2, C3, and C5

In the C3 carbon fixation process, what is carbon dioxide converted into?

• Three phosphoglycerate

• Glucose

• Water

• Oxygen

Where do C3 plants tend to thrive?

• In areas with high sunlight intensity and low water availability

• In areas with moderate sunlight intensity and plentiful groundwater

• In areas with low carbon dioxide concentrations

• In cold and dry areas

What percentage of water do C3 plants lose through transpiration?

• 75%

• 50%

• 100%

• 97%

Which plants represent approximately 95% of Earth's plant biomass?

• C4 plants

• CAM plants

• C3 plants

• C2 plants

Why can't C3 plants grow well in hot areas?

• They require more sunlight

• They incorporate more oxygen into RuBP, leading to photorespiration

• They need more carbon dioxide

• They have a higher water requirement

What happens to C3 plants when they close their stomata to reduce water loss?

• They increase oxygen concentration in leaves

• They decrease CO2 concentration in leaves

• They stop photosynthesis completely

• They increase CO2 concentration in leaves

What adaptations do C4 and CAM plants have?

• They can survive in cold and wet areas

• They can survive in hot and dry areas

• They have a higher water requirement

• They require less sunlight

How do C4 and CAM plants outcompete C3 plants?

• By growing faster in cold climates

• By using less sunlight

• By requiring less carbon dioxide

• By thriving in hot and dry environments

What is the isotopic signature difference between C3 and C4 plants?

• C4 plants show higher 13C depletion

• C3 plants show higher 13C depletion

• Both have the same 13C depletion

• Neither shows 13C depletion