Photosynthesis and respiration

• What is the physiological process used by plants to convert light energy?

  Photosynthesis
• What do photosynthetic organisms synthesize using light energy?

  Large organic molecules
• What are organisms that photosynthesize called?

  Photoautotrophs
• Why are photoautotrophs described as producers?

  They provide food for other organisms
• What is the general equation for photosynthesis?

  6CO₂ + 6H₂O + energy → C₆H₁₂O₆ + 6O₂
• What is a photon?

  A particle of light with energy
• What is the main product of photosynthesis?

  Monosaccharide sugar
• What is carbon fixation?

  The process of converting CO₂ into organic molecules
• Why does carbon fixation require energy?

  It is an endergonic process
• What do most forms of life on Earth rely on?

  Photosynthesis
• How does photosynthesis contribute to the atmosphere?

  It produces oxygen and removes CO₂
• What is the average rate of energy capture by photosynthesis globally?

  1.3 × 10¹⁹ watts
• How much carbon is fixed by plants each year on Earth?

  3.5 × 10¹⁰ kg
• What do plants and photosynthetic organisms do during respiration?

  Oxidise organic molecules
• What do non-photosynthetic organisms obtain energy from?

  Digesting complex organic molecules
• What is the equation for respiration?

  C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energy
• How do photosynthesis and respiration interrelate?

  They cycle oxygen and carbon dioxide
• What is the compensation point for plants?

  The light intensity for optimal photosynthesis
• How do shade plants differ from sun plants regarding light intensity?

  Shade plants can utilize lower light intensity
• What is the structure of chloroplasts?

  Disc-shaped organelles with double membranes
• What is the stroma in chloroplasts?

  The fluid-filled matrix where light-independent reactions occur
• What are thylakoids?

  Flattened membrane-bound sacs in chloroplasts
• What are photosystems?

  Complexes of chlorophyll and proteins in thylakoids
• What is chlorophyll?

  A pigment that absorbs light for photosynthesis
• What is the role of accessory pigments in photosynthesis?

  They capture additional wavelengths of light
• What are the two main stages of photosynthesis and where do they occur?

  • Light-dependent stage: occurs in thylakoids
  • Light-independent stage: occurs in stroma
• What are the key differences between sun plants and shade plants regarding photosynthesis?

  • Sun plants: higher compensation point, require more light
  • Shade plants: lower compensation point, can photosynthesize in lower light
• What are the key definitions related to chloroplasts and photosynthesis?

  • Granum: stacks of thylakoid membranes
  • Stroma: fluid-filled matrix of chloroplasts
  • Photosynthetic pigment: absorbs specific light wavelengths
  • Photosystem: complex of chlorophyll and proteins
• How can thin layer chromatography (TLC) be used in studying photosynthetic pigments?

  • TLC separates pigments based on solubility
  • Allows identification of different pigments in chloroplasts
• What is glycolysis?

  First stage of respiration converting glucose to pyruvate
• Where does glycolysis occur?

  In the cytoplasm
• How many reactions are involved in glycolysis?

  Ten reactions
• What are the three main stages of glycolysis?

  1. Phosphorylation of glucose to hexose bisphosphate
  2. Splitting hexose bisphosphate into two triose phosphate molecules
  3. Oxidation of triose phosphate to pyruvate
• What is the role of NAD in glycolysis?

  Helps dehydrogenase enzymes in oxidation reactions
• What is the structure of NAD?

  Five carbon atoms, a nitrogenous base, two sugar rings
• What happens to NAD during glycolysis?

  It becomes reduced by accepting hydrogen atoms
• What is the net gain of ATP from glycolysis?

  Two molecules of ATP
• What are the products of glycolysis from one glucose molecule?

  Two pyruvate, two reduced NAD, two ATP
• Under what conditions do the last three stages of respiration occur?

  Aerobic conditions
• What are the four stages of respiration?

  1. Glycolysis
  2. The link reaction
  3. The Krebs cycle
  4. Oxidative phosphorylation