Biology paper 1

• What does photosynthesis do

  Uses light to produce glucose
• where does photosynthesis take place

  in the chloroplasts
• what kind of reaction is photosynthesis

  endothermic
• what is the equation for photosynthesis

  carbon dioxide + water ————> glucose + oxygen
• what 5 ways do plants use glucose

  for respiration

  making cellulose

  making amino acids

  stored as oils or fats

  stored as starch
• why is glucose used for respiration

  it transferred the energy

  enables the plant to convert the rest of the glucose into useful substances
• why is cellulose made

  for making strong plant cell walls
• how are amino acids made

  glucose is combined with nitrate ions to make amino acids which are converted into protons
• where are lipids stored in plants

  In the seeds
• where is glucose stored as starch

  in roots stems and leaves
• why is glucose stored as starch

  starch is insoluble unlike glucose

  a cell with lots of glucose would draw water in and swell up
• what 3 things effect the rate of photosynthesis

  light intensity

  co2 concentration

  temperature
• what is the limiting factor at night

  light
• what is the limiting factor in winter

  temperature
• what’s the limiting factor when it’s warm and bright

  co2 concentration
• what else can be a limiting factor for photosynthesis

  the amount of chlorophyll
• why does lack of chlorophyll effect photosynthesis

  plants cant absorb as much light
• How does light effect photosynthesis

  Light provides energy needed for photosynthesis

  a the light intensity increases the rate of photosynthesis increases steadily

  it only increases up to a certain pint because something else then becomes a limiting factor
• how does co2 effect the rate of photosynthesis

  co2 is needed for photosynthesis

  the amount of co2 only increases the rate up to a certain point until co2 is no longer a limiting factor
• how does temperature effect the rate of photosynthesis

  if the temperature is too low the enzymes needed for photosynthesis work slower at lower temperatures so the rate is slower

  if the temperature is too high enzymes involved in photosynthesis will denature and the rate will slow down or stop
• What is the most common way to artificially create an ideal environment for plants

  Greenhouses
• what do greenhouses do

  Trap heat from the sun so temperature doesn’t become a limiting factor
• how are lights used in farming

  farmers supply artificial light when the sun goes down so plants photosynthesise more
• how do farmers increase levels of co2

  they use paraffin heaters because when the paraffin burns co2 is produced
• why is keeping plants in a greenhouse good

  They will be free from pests and diseases
• what do fertilisers do

  provide all the minerals needed for healthy growth
• What is respiration


  The process of transferring energy from glucose, which happens in every cell
• what kind of reaction is respiration


  exothermic
• what are 3 ways organisms use energy from respiration


  to build up larger molecules from smaller ones

  so the muscles can contract

  keep body temperature steady in colder surroundings
• what is metabolism

  all the chemical reactions in an organism
• What happens to excess protines 


  Broken down in a reaction to form urea
• what is aerobic respiration


  respiration using oxygen
• what is anaerobic respiration

  respiration without oxygen, incomplete breakdown of glucose
• when is anaerobic respiration used


  when there’s not enough oxygen
• When is anaerobic respiration useful 


  In emergencies

  because it doesn’t transfer as much energy as aerobic respiration

  because glucose isn’t fully oxidised
• what’s the equation for anaerobic respiration

  glucose ————> lactic acid
• what’s the equation for anaerobic respiration in plants and yeast 


  glucose ————> ethanol + carbon dioxide
• what is fermentation


  anaerobic respiration in yeast cells
• what is fermentation used to make

  bread and alcoholic drinks
• what makes bread rise

  carbon dioxide from fermentation