Bio paper 2

• Where does the LDR take place?


  thylakoid membranes of chloroplasts
• Where does the LIR take place?


  stroma
• What is the LDR?

  Light energy and water is used to create ATP and reduced NADP needed for the LIR
• What does this mean?

  The chlorophyll has been ionised by light-as electrons have left
• Photolysis


  two molecules of water are split by light to form oxygen, hydrogen ions, and electrons
• Word equation for photolysis


  H2O->1/2O2+2e-+2H+
• What happens to the oxygen?


  Either used for respiration or diffuses out of the leaf?
• Why is it called chemiosmosis?


  Because the protons move from high to low concentration gradient
• Where does the Calvin cycle occur?


  In the stroma, this fluid contains the enzyme RuBisCo which catalyses the reaction
• What does the calvin cycle use?

  Carbon dioxide, reduced NADP and ATP to form a hexose sugar
• What does RuBP stand for?

  ribulose biphosphate
• What are the limiting factors of photosynthesis?

  light intensity, carbon dioxide concentration and temperature
• What do agricultural practices do to maximise photosynthesis?

  Incorporate techniques to remove limiting factors
• What can these range from?

  Growing plants under artificial lighting to maximise light intensity, heating a greenhouse to increase temperature and burning fuel to release more carbon dioxide
• What does the extent of each technique need to consider?

  Profit. If the extra growth from photosynthesis is minimal it will not be cost effective
• Anaerobic respiration


  Occurs in the absence of oxygen in the cytoplasm
• Stage one of anaerobic respiration

  Glycolysis occurs. The pyruvate produced is reduced to form lactate in animals by gaining the hydrogen from reduced NAD.
• What does this do?

  Oxidises NAD so that it can be reused in glycolysis to ensure more ATP is continued to be produced.
• Why can anaerobic respiration not occur forever?

  As lactate is an acid and will denature enzymes
• How does this occur in plants?

  Pyruvate is reduced to form ethanol and carbon dioxide gaining the hydrogen from reduced NAD. This oxidises NAD so it can be reused in glycolysis and ensure more ATP is continued to be produced.
• What is the total yield of ATP from one glucose molecule in aerobic respiration

  38 molecules of ATP.
• How efficient is aerobic respiration?

  32% efficent. Some protons leak across the mitochondrial memembrane during oxidative phosphorylation. ATP us being used to actively transport pyruvate and NADH into the matrix and because of this some energy is lost as heat
• How efficient is anaerobic respiration

  Even less so only 2 ATP molecules are produced from one glucose molecule
• Process of glycolysis (4)

  1. Phosphorylation of glucose using ATP

  2.Production of triose phosphate

  3. Oxidation of triose phosphate to pyruvate

  4. Net gain of ATP

  5. NAD reduced
• What happens to some energy released during photoionization?

  Conserved in the production of ATP and reduced NADP
• What happens to pyruvate in aerobic respiration?


  Enters the mitochondrial matrix by active transport
• How can biomass be measured?


  In terms of mass of carbon or dry mass of tissue per given area
• Gross primary production GPP


  The chemical energy store in plant biomass in a given area or volume
• Net Primary Production NPP

  Chemical energy store in plant biomass after respiratory losses to the environment have been take into account
• Net production of consumers

  N= I - (F + R)

  I represents the chemical energy store in ingested food

  F represents the chemical energy store lost to the environment in faeces and urine

  R represents respiratory losses to the environment
• Refractory period

  1. Produce discrete impulses
  2. Limit the frequency of impulse transmission
• What does conversion of habitats frequently involve?

  Management of succession
• What do species do within a habitat?

  Occupies a niche governed by adaptation to both abiotic and biotic conditions
• What do totipotent cells do?

  They can divide and produce any type of body cell. They can translate only part of their DNA resulting in cell specialisation
• What are unipotent cells exemplified by?

  The formation of cardiomyocytes
• Describe in vivo cloning?

  • The addition of promoter and terminator regions to the fragments of DNA
  • Use of restriction endonucleases and ligases to insert fragments of DNA into vectors. Transformation of host cells using these vectors
  • Use of marker genes to detect genetically modified cells or organisms
• What does an organism's genome contain?

  Many variable number tandem repeats
• What can VNTR be used to do?

  Determine the genetic variability within a population
• Why are females less likely to get a recessive disease if it's sex-linked?

  1. Allele is on the x chromosome
  2. Females require two alleles males only require one
• Why in gel electrolytes do proteins separate?

  1. Different R groups
  2. Different Charges
  3. Different mass