6. What is the difference between C3, C4 and CAM plants? Why do they exist? What

ID: 63751 • Letter: 6

Question

6. What is the difference between C3, C4 and CAM plants? Why do they exist? What are the energy trade-offs?

7. How can organisms regulate heat, water, and energy expenses?

8. Both temperatures and rainfall will increase in NJ in the coming years. So will evapotranspiration. Why does rainfall pattern matter and why would evapotranspiration increase even though rainfall increases? How might this impact plants in NJ?

9. Describe how a population grows. Explain why the 3 different phases occur.

10. What is carrying capacity? What factors affect carrying capacity?

*(all in ecological perspective)

Explanation / Answer

C3 Plants

C4 Plants

CAM (crassulacean acid metabolism) plants

Found in all photoactive plants

Found in tropical plants

Found specially in succulents growing under semi arid condition.

Photo active stomata

Scoto active stomata

Fast respiration and normal leaf anatomy

Slow or negligible respiration

Slow or negligible rate of respiration

The cycle used may be xerophytic, mesophytic or hydrophytic

The cycle used may be mesophytic

The cycle used may be xerophytic

Ist stable product is 3PGA (3- Phosphoglycerate)

Ist stable product is oxaloacetic acid (OAA)

Ist stable product is OAA

12NADPH and 18 ATP molecules are required to synthesise one glucose molecule

12NADPH and 30 ATP molecules are required to synthesise one glucose molecule

12NADPH and 39 ATP molecules are required to synthesise one glucose molecule

Eg: Elm

Eg: Corn, sugar cane

Eg: Pineapple

C4 can more efficient at photosynthesis than C3 plants, but 95% of plants on earth are C3 plants. C4 plants are evolved as a means to avoid carbon dioxide depletion during dry condition; they can concentrate carbon dioxide up to times than C3 plants. CAM plants can tolerate arid condition better than C4 plants; they conduct photosynthesis only during nights because their stomata remain closed during day time to avoid water evaporation.