bioenergetics

• What is photosynthesis?

  The process in plants that converts solar energy and carbon dioxide into chemical energy (endothermic reaction)
• What is the word equation for photosynthesis?

  Carbon dioxide + water -> glucose + oxygen
• How does water and carbon dioxide get into plants?

  1) Water through the root hair cells

  2) Carbon dioxide through stomata
• What is the balancedchemical equation for photosynthesis?

  6CO2 + 6H2O ------> C6H12O6 + 6O2
• What is the waste product of photosynthesis?

  Oxygen or O2
• What are two equatic plants that photosynthesise?

  1) Algi - green organsims on surface of water

  2) Elodea pond weed
• What are the 5 uses of glucose?

  1) For cellulose - For cell walls

  2) Excess Stored as insoluable starch in roots in winter (potatoe)

  3) Energy source for aerobic respiration

  4) Stored as oily lipids in seeds

  5) To make amino acids from nitrates in the soil to protein
• Why is glucose so important?

  Because it can make protein, lipids and carbohydrates
• What are the external limiting factors of photosynthesis?

  1) Carbon dioxide

  2) The amount of light

  3) Temperature- increases rate of reaction (particle movement)

  4) The amount of chlorophyll due to magnesium deficiency
• Describe the photosynthesis light intensity practical:

  1) Place elodea cut end up in test tube filled with water

  2) Put bung on top with cappilalary tube leading to a gas syringe

  3) Place 30 cm ruler along side the cappilary tube to measure bubbles

  4) Place desk lamp on 0cm mark on meter ruler

  5) Place at varying distances from light and measure O2 produced
• What is the hypotheis for the photosynthesis practical?

  As distance increases, less oxygen is released because of less photosynthesis
• How would you calculate the rate of reaction in the photosynthesis practical?

  Size of the bubble in cm divided the the time measured in mins = cm per min (cm/min)
• What is meant by inversely proportional?

  As one variable increases the other decreases e.g. Distance from light increases the rate of photosynthesis decreases
• What is the inverse square law?

  For every meter the light moves the spread will increase by 1m squared

  1m = 1m squared

  2m = 2m sqaured
• How much does the light intensity decrease by in telation to the distance away?

  light intensity (arbitary units)

  = 1÷(distance sqared)
• Why are arbity units (A.U) used in the the photosynthesis practical?

  To simply prove the hypothesis
• What is it called when plant leaves turn yellow?

  This is chlorosis, and is caused by magnesium defficiency which is mineral needed to make chlorophyll
• What is it called when leaves are not entirely green?

  These are variegated leaves, and the white areas lack chlorophyll and will photosynthesise slower
• What happens when the light intensity is at its optimum in terms of a graph?

  The rate of photosynthesis will plateu and light intensity will no longer be the limiting factor, instead it will be either carbon dioxide or temperature
• How will rate of photosynthesis change based on temperature in terms of a graph?

  It will reach optimum temeperature where chemical reactions will happen faster and then the rate will fall as enzymes begin to denature
• What does more photosynthesis in the plant cause?

  An increased rate of growth and aerobic respiration.
• How can levels of Carbon dioxide be increased arificially?

  Using a paraffin heater in a green house which combusts paraffin and released CO2
• How can the temperature of plants be brought closer to their optimum?

  Using a green house or a paraffin heater which also gives a supply of CO2 aswell
• How can light intensity be retained at night?

  Using artificial light
• What are the benefits of a greenhouse?

  1) Decreased risk of disease

  2) Decreased competition because of weeds

  3) Fertiliser can be added for nutrients
• Why wouldnt the absolute most optimum conditions for plants be used?

  Because it might not be cost effective
• What is respiration?

  The transfer of energy from glucose in every cell
• What are the uses of respiration in living organisms?

  1) Muscle contraction to move

  2) Keeping warm- birds + mammal

  3) Moving minerals to cells in plants

  4) Build larger molecules from smaller ones like starch and glycogen from glucose
• What are amino acids made out of?

  1) Nitrate ions in soil

  2) Glucose
• What are lipids made of?

  1) Glycerol

  2) 3 fatty acids
• What is urea?

  Broken down excess protein that is excreted as part of urine
• What type of reaction is respiration?

  An exothermic reaction
• What is your metabolism?

  The sum of all the chemical reactions that occur in our body
• What is the word equation for aerobic respiration?

  glucose + oxygen = carbon dioxide + water
• What is ATP?

  The energy currency molecule of all living things measured in KJ

  (adenosine Triphosphate)
• What is the word equation for anaerobic repiration in humans?

  Glucose = Lactic acid + energy
• What is the word equation for anaerobic respiration in plants and fungi?

  Glucose = ethanol + CO2 + energy

  e.g. yeast
• How is anaerobic respiration different?

  1) Unsustainable

  2) Doesn't require oxygen

  3) Releases less energy

  4) Causes build up of lactic acid in humans and ethanol in plants

  5) It breaks down glucose incompletely
• Why is anaerobic respiration in plants

  useful to humans?

  1) To make bread (CO2 release cauaes bread to rise)

  2) Ethanol released used to make alchohol
• What is oxygen debt?

  the amount of oxygen needed to oxidise lactic acid to carbon dioxide and water