Chapter 6 Carbon Metabolism Flashcards
is the process by which organisms convert carbon-containing
compounds into energy and building blocks needed for growth and survival.
Carbon metabolism
C3 Cycle discovered by:
C4 Cycle discovered by:
Melvin Calvin, James Bassham, and Andrew Benson (c3);
Marshall Davidson Hatch and Charles Roger Slack (c4)
where it occurs:
c3=
C4=
c3= chloroplast stroma,
C4= chloroplast of mesophyll or bundle sheath cells
three basic phases of the Calvin cycle (C3)
Stage 1: Carbon Fixation
Stage 2: Reduction
Stage 3: Regeneration
C3 carbon fixation:
co2 combine with
a five-carbon molecule ____ to form an unstable six-carbon
intermediate that breaks down to form two ___molecules.
catalyzed by:___
ribulose-1,5-bisphosphate (RuBP);
3-phosphoglyceric acid (3-PGA) ;
RuBP carboxylase/oxygenase (rubisco)
C3 Reduction:
three-carbon compound, 3-PGA molecules, produced in the
carbon fixation stage, are converted into a three-carbon sugar ___
catalyzed by:___
glyceraldehyde-3-phosphate
(G3P). ;
glyceraldehyde 3-phosphate dehydrogenase
C3 regeneration:
the final stage of the Calvin cycle that starts with ___, the end product of the entire
pathway. Some is utilized in making glucose, while others are recycled to continue the
cycle by combining with a carbon acceptor that turns into RuBP.
G3P
it requires __ turns of the Calvin cycle to
produce one glucose molecule and ___ rounds to form a molecule of G3P.
six;
three
depicts two carboxylation reactions occurring in the chloroplasts of the
mesophyll cells and others in the chloroplast of the bundle sheath cells
C4 Cycle
Hatch and Slack
Cycle involves four steps;
- Carboxylation
- Malate production
- Decarboxylation
- Phosphorylation
carboxylation C4:
3-carbon compound,
___, collects carbon dioxide and in the presence of water, transforms to 4
carbon ___
catalyzed by:
Phosphoenolpyruvate;
oxaloacetate
phosphoenolpyruvate carboxylase
Malate production C4:
oxaloacetate disintegrates into 4 carbon __ or __ and The compounds formed
diffuse into the sheath cells from the mesophyll cells
catalyzed by:
malate or aspartate;
transaminase and malate dehydrogenase.
Decarboxylation C4:
malate or aspartate in the sheath cells enzymatically split to produce free ___ and 3-carbon ___. The carbon dioxide is accepted by the 5-carbon compound ___ with the activity
of the ___ enzyme, finally producing 3 ___
carbon dioxide and pyruvate;
ribulose diphosphate;
carboxy dismutase ;
phosphoglyceric acid
Decarboxylation C4:
For the formation
of sugars, some of the 3 phosphoglyceric acid is used and the remaining regenerates ___
ribulose
diphosphate.
Phosphorylation C4:
pyruvate molecules are moved to the chloroplasts of the mesophyll cells wherein,
in the presence of ATP, it is phosphorylated for the regeneration of ____
catalyzed by:
phosphoenolpyruvate;
Pyruvate phosphokinase
