Factors Affecting Enzyme-Controlled Reactions in Photosynthesis and Respiration

Photosynthesis

• The primary function of photosynthesis is to produce glucose and oxygen from carbon dioxide and water.
• The site of photosynthesis in a plant cell is the chloroplast.

Factors Affecting Photosynthesis

• CO2 concentration is not the factor that does NOT determine the rate of photosynthesis.

Chloroplast Structure

• Grana in chloroplasts are responsible for increasing the surface area for light-dependent reactions.

Light-Dependent Stage

• During the light-dependent stage, ATP and NADPH are produced.
• Photophosphorylation plays a crucial role in generating ATP from light energy.

Light-Independent Stage

• If CO2 concentration is in short supply, the light-independent reaction will slow down.
• Low temperature affects Rubisco and other molecules, making them less efficient.

Cellular Compartmentation

• Glycolysis occurs in the cytoplasm.
• The end product of glycolysis is pyruvate.
• The Krebs cycle takes place in the mitochondrial matrix.
• The Krebs cycle produces 2 ATP, 6 NADH, and 2 FADH2 per glucose molecule.

Calvin Cycle

• The final stage of photosynthesis uses ATP and reduced NADP to produce glucose.
• The enzyme RuBisCo catalyzes the reaction of combining RuBP with carbon dioxide in the Calvin cycle.
• The main function of reduced NADP and ATP in the light-independent reaction is to produce glucose.

Limiting Factors

• A limiting factor in photosynthesis is light intensity.

Light-Independent Reaction

• If light intensity is low, the levels of GP, TP, and RuBP will decrease.
• Glucose is not produced during the light-independent reaction.

Oxidative Phosphorylation

• Oxidative phosphorylation occurs in the mitochondrial intermembrane space.
• The main source of ATP production in aerobic respiration is oxidative phosphorylation.
• During oxidative phosphorylation, the concentration of hydrogen ions in the intermembrane space increases.
• ATP synthase generates ATP from the energy released by the proton gradient.
• Hydrogen ions are moved across the inner mitochondrial membrane during oxidative phosphorylation through proton pumps.
• Reduced coenzymes (NADH and FADH) play a crucial role in generating ATP during oxidative phosphorylation.
• Oxygen acts as the final electron acceptor in the process of producing water.

Energy Yield

• The theoretical yield of 38 ATP molecules per glucose is rarely achieved in real life due to energy losses during oxidative phosphorylation.

Glycolysis

• Pyruvate produced during glycolysis in the cytoplasm needs to be transported into the mitochondrial matrix by active transport.

Respiratory Substrates

• The amount of energy released from respiratory substrates is determined by their energetic potential.
• The Respiratory Quotient (RQ) can be used to determine which respiratory substrate is being used.

Anaerobic Respiration

• Anaerobic respiration occurs in the absence of oxygen.

Explore the impact of CO2 concentration and temperature on the light independent reaction in photosynthesis. Learn about the effects of low temperature on Rubisco and enzyme-controlled reactions. Understand the processes of aerobic and anaerobic respiration.