Photosynthesis and Cellular Respiration Quiz

Photosynthesis and Cellular Respiration

• Metabolic pathways: Biological processes involving matter and energy, such as cellular respiration and photosynthesis.
• Photosynthesis: Stores energy from the sun in glucose; glucose is then released during cellular respiration.
• Photosynthesis → Cellular Respiration → Photosynthesis: A cyclical process where the product of each step is used as input for the next.

Metabolic Pathways and Enzymes

• Metabolism: Sum of all processes within a cell.
• Cellular respiration and photosynthesis representation via chemical equations, depicting net reactions only.
• Enzymes: Protein catalysts aiding reactions, ensuring metabolic processes occur.
• Activation energy: Energy required to initiate a reaction.
• Enzymes reduce activation energy needed for reactions to begin.
• Enzymes enhance reaction efficiency and reaction rates.
• Anabolic: Reactions/pathways build larger molecules from smaller ones (positive).
• Catabolic: Reactions/pathways break down large molecules into smaller ones (negative).
• Activation energy - necessary for starting reaction; reactions cannot naturally proceed without energy.

Oxidation and Reduction

• Oxidation: Atom/molecule loses electrons, resulting in energy loss.
  • LEO: Losing electrons = Oxidation.
• Reduction: Atom/molecule gains electrons, resulting in energy gain.
  • GER: Gaining electrons = Reduction.
• Oxidation and reduction occur simultaneously.

The Chloroplast

• Chloroplast: Site of photosynthesis in plant cells.
• Parts of the chloroplast: Stroma - fluid-filled matrix within; thylakoid - flattened sac-like structures organized into grana within stroma.
• Membranes surround the stroma, providing compartments for photosynthesis.

The Mitochondria

• Mitochondria: Site of cellular respiration in plant and animal cells.
• Matrix: Fluid-filled inner compartment containing necessary chemicals/proteins for carbohydrate breakdown, ATP generation. (ATP: adenosine triphosphate, cellular energy).
• Two membranes surround the matrix.
• Mitochondria assist in cellular respiration.

Photosynthesis

• Autotrophs: Organisms making their own food (e.g., plants).
• Heterotrophs: Organisms that consume other organisms for food (e.g., animals).
• Photosynthesis: Process of producing food (glucose) using light energy, carbon dioxide, and water.
• Photosynthesis reactants: Carbon dioxide (CO2) and water (H2O).
• Photosynthesis products: Glucose (C6H12O6) and oxygen (O2).
• Chlorophyll absorbs light energy, driving photosynthesis.

Absorption Spectra of Pigments

• Pigments absorb specific wavelengths, reflecting others. Chlorophyll A is vital for photosynthesis.
• Chlorophyll B and carotenoids are accessory pigments, widening the range of absorbed light.

The Reactions of Photosynthesis

• Light-dependent reactions: Light energy is converted into ATP and NADPH (high energy molecule).
  • Occurs in thylakoid membranes within chloroplasts.
• Water is split into oxygen, hydrogen ions (H+), and electrons during these reactions.
  • Water breakdown is called photolysis.
• Light-independent reactions: Use ATP and NADPH to convert CO2 into glucose.
  • Occurs in the stroma of chloroplasts.

Light-Independent Reactions (Calvin Cycle)

• CO2 enters a cycle of chemical reactions forming glucose.
• ATP and NADPH provide energy/reducing power for the Calvin Cycle.
• Cycle regenerates starting materials for further CO2 fixation, sustaining the cycle.
  • Three basic steps: Carbon fixation, reduction, and regeneration. Three phases overall.

Factors Affecting Photosynthesis

• Light: Rate increases with light intensity and diminishes at a certain point.
• Temperature: Optimal temperature range exists for optimal photosynthesis rate, reactions slowdown and stop at extreme temperatures.
• Carbon dioxide: Rate increases with carbon dioxide concentration and diminishes at a certain point.

Test your knowledge on the processes of photosynthesis and cellular respiration. This quiz covers metabolic pathways, the role of enzymes, and the cyclical nature of energy transformation in living organisms. Great for students studying biology concepts related to energy metabolism.