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Zorluk: OrtaPlant Nutrition and Photosynthesis

Arrange the following sequential stages describing the journey of a carbon dioxide molecule from the surrounding atmosphere to its reduction during photosynthesis in a mesophyll cell in the correct chronological order from first to last.

  1. 1Diffusion of gaseous carbon dioxide through open stomata into the intercellular air spaces of the leaf.
  2. 2Dissolution of carbon dioxide in the thin film of moisture on mesophyll cell walls and diffusion into the chloroplast stroma.
  3. 3Carboxylation of ribulose 1,5-bisphosphate (RuBP) catalyzed by the enzyme Rubisco to form an unstable 6-carbon intermediate.
  4. 4Splitting of the unstable 6-carbon intermediate into two 3-carbon molecules of 3-phosphoglycerate (PGA).
  5. 5Phosphorylation and reduction of 3-phosphoglycerate (PGA) using ATP and NADPH to yield glyceraldehyde 3-phosphate (G3P).

Cevap

The correct sequence begins with gaseous diffusion through stomata, followed by dissolution on moist mesophyll cell walls and movement into the stroma, carboxylation of RuBP by Rubisco, breakdown into 3-phosphoglycerate (PGA), and finally reduction to glyceraldehyde 3-phosphate (G3P) using ATP and NADPH.
The process follows a logical spatial and biochemical progression: carbon dioxide gas enters leaf spaces through stomata, dissolves into the wet outer wall of mesophyll cells to cross into the chloroplast stroma, undergoes carboxylation with RuBP via Rubisco to form an unstable 6-carbon compound, hydrolyzes into two PGA molecules, and is reduced to G3P using NADPH and ATP.

Adım Adım Çözüm

1
Identify the physical entry of carbon dioxide into the leaf structure
Gaseous carbon dioxide diffuses from the atmosphere into intercellular air spaces via stomata.
Gas exchange occurs across stomata driven by concentration gradients.
2
Trace the movement of carbon dioxide across cellular boundaries
Carbon dioxide dissolves in the moist layer on mesophyll walls and diffuses into the chloroplast stroma.
Substances must be in aqueous solution to pass through biological membranes into the organelle.
3
Locate the carbon fixation step of the Calvin cycle
Carbon dioxide reacts with RuBP catalyzed by Rubisco to produce a short-lived 6-carbon compound.
Carbon fixation is the first enzymatic step of the light-independent reactions in the stroma.
4
Determine the immediate enzymatic cleavage product
The 6-carbon compound splits into two molecules of 3-phosphoglycerate (PGA).
The 6-carbon molecule is chemically unstable and instantly hydrolyzes into 3-carbon units.
5
Identify the reduction step yielding stable sugar precursor
PGA is phosphorylated and reduced by ATP and NADPH to form glyceraldehyde 3-phosphate (G3P).
Energy products from the light-dependent phase are consumed to reduce PGA into triose phosphate.

Anahtar Kavram

Pathway of carbon dioxide diffusion and carbon fixation during C3 photosynthesis
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Konular

Plant Nutrition and Photosynthesis

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