객관식
In C3 plants, the conservation of water promotes _____.
226
views
9. Photosynthesis
C3, C4 & CAM Plants
객관식
Which of the following statements correctly describes the initial carbon fixation step in C3 plants during photosynthesis?
A
C3 plants use CO\(_2\) to form a 3-carbon molecule as the first stable product.
B
C3 plants initially fix CO\(_2\) at night to form malate.
C
C3 plants use CO\(_2\) to form a 4-carbon molecule as the first stable product.
D
C3 plants use phosphoenolpyruvate (PEP) carboxylase for the initial fixation of CO\(_2\).
검증된 단계별 안내1
Understand the process of carbon fixation in C3 plants: In C3 plants, the Calvin cycle is the primary pathway for carbon fixation. The enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) catalyzes the reaction between CO\(_2\) and ribulose-1,5-bisphosphate (RuBP), a 5-carbon molecule.
Recognize the first stable product: The reaction between CO\(_2\) and RuBP produces an unstable 6-carbon intermediate, which immediately breaks down into two molecules of 3-phosphoglycerate (3-PGA), a 3-carbon compound. This is why these plants are called C3 plants.
Eliminate incorrect options: C3 plants do not fix CO\(_2\) at night to form malate. This is a characteristic of CAM plants, not C3 plants. Similarly, C3 plants do not produce a 4-carbon molecule as the first stable product; this is a feature of C4 plants.
Clarify the role of enzymes: C3 plants use RuBisCO for the initial fixation of CO\(_2\), not phosphoenolpyruvate (PEP) carboxylase. PEP carboxylase is used in C4 and CAM plants for initial CO\(_2\) fixation.
Conclude the correct statement: The correct description of the initial carbon fixation step in C3 plants is that they use CO\(_2\) to form a 3-carbon molecule (3-PGA) as the first stable product.
관련 영상
관련 실천
