Bioenergetics

• Photosynthesis equation


  Carbon dioxide + Water → Glucose + Oxygen

  
• What type of reaction is photosynthesis?


  Endothermic - light energy is transferred from the environment to the chloroplasts

  
• Uses of glucose produced in photosynthesis


  -Respiration

  - Converted to starch (storage)

  - Makes fats/oil (storage)

  - Makes cellulose (strengthens the cell wall)

  - Makes amino acids (protein synthesis)
• What affects photosynthesis?


  - Amount of chlorophyll

  -Light intensity

  -Carbon dioxide concentration

  -Temperature
• How can farmers use their knowledge of limiting factors to increase their profits?


  They control limiting factors to ensure a fast rate of photosynthesis to increase yield:

  - Control temperature (greenhouse)

  - Control light intensity (artificial light)

  - Control CO2 concentration (pump/parrifin heater)

  - Use fertilisers and pesticides

  
• RP) Photosynthesis


  1) Place boiling tube 10cm away from LED lightsource

  2) Place pond weed in a boiling tube containing sodium carbonate solution

  3)Cut top end of pondweed then leave for 5 minutes to acclimatise to the conditions

  4) Start a stopwatch and count the numbers of bubbles produced in 1 minute

  5)Repeat this 2 more times and calculate the mean number of bubbles

  6)Repeat the whole experiment again from 20cm, 30 cm and 40cm

  
• RP Photosynthesis) Why is an LED light used?

  Lamp would emit heat energy, increasing temperature so affects rate of photosynthesis
• RP Photosynthesis) How can measurement of oxygen produced be made more accurate?

  Gas syringe so volume of gas can be calculated

  
• RP Photosynthesis) Why is sodium carbonate used?


  it releases lots ofCO2, required for photosynthesis

  
• RP Photosynthesis) Why is number of bubbles produced used to measure photosynthesis rate?


  Oxygen bubbles are a product of photosynthesis
• RP Photosynthesis) What are the control variables?


  - Temperature

  - Pondweed

  - Conc. of solution

  
• Inverse square law equation


  Light intensity ∝ 1 / Distance²

  
• What does the inverse square law state?


  light intensity is inversely proportional to the distance² from the source
• What type of reaction is respiration?

  Exothermic- it transfers energy to the environment
• Aerobic respiration equation


  Glucose + Oxygen → Carbon dioxide + Water (+ energy released)
• Where does aerobic respiration take place?

  mitochondria
• Where does anaerobic respiration take place?


  cytoplasm
• Why does anaerobic respiration release less energy than aerobic respiration?


  incomplete oxidation of glucose
• Anaerobic respiration equation (animals)

  Glucose → Lactic acid (+ energy released)

  
• Anaerobic respiration equation (fungi)

  Glucose →E thanol + Carbon dioxide (+ energy released)

  
• What are 2 economic uses of anaerobic respiration?

  -Yeast makes beer alcoholic

  - CO₂ makes bread rise

  
• What do organisms need energy for?

  -Chemical reactions to build larger molecules-Movement- Keeping warm

  
• What increases during exercise and why?

  Heart rate, Breathing rate and Breath volume increases to supply the muscles with more oxygenated blood

  
• Why can anaerobic respiration lead to muscle fatigue?

  lactic acid build up prevents efficient muscle contraction
• What is oxygen debt?

  amount of oxygen needed after exercise to convert lactic acid back into glucose and remove it from the cells
• What happens to lactic acid accumulated during exercise?

  blood in muscles transports lactic acid to the liver to be converted back into glucose
• What are the metabolic reactions?

  -Respiration- Glucose →Starch- Glucose →Glycogen- Glucose →Cellulose-Glucose + Nitrate ions→Amino acids-1glycerol +3fatty acids→ Lipid- Excessproteins→Urea(excretion)
• Metabolism

  All the chemical reactions in the cells of an organism, including respiration.