2023

• Which disease is a non-communicable disease?

  cancer
• give one non-communicable disease that obesity is a risk factor for

  coronary heart disease
• suggest one national policy that could help people to lose weight

  • exercise campaigns
  • Reduce the amount of sugar added to food and drinks
• Describe how the measles virus is transferred from person to person

  • it is spread through cough(spreads virus which is inhaled)
• Athletes foot fungus grows in moist conditions.

  suggest one way a person could reduce their chance of catching athlete's foot

  dry feet after washing
• how to use microscope to estimate the mean length of onion cells on the slideMean:mean real size = mean cell image size/magnification

  • focus on the cells
  • note the magnification
  • take a photo of the image
  • calculate a mean
  • measure the length of one cell
  • calculate the real size
  • repeat for 3 or more other cells
  • calculate mean real size

  yh
• Describe what is meant by double circulatory system

  • The right ventricle pumps blood to the lungs
  • left ventricle pumps blood around the whole body.
• where in the heart is the pacemaker found

  Right atrium
• which blood vessel carries deoxygenated blood

  pulmonary artery
• explain why veins have valves, but arteries do not

  1. Valves prevent backflow because blood in veins is at a lower force than arteries.
• Describe 2 structural differences between vein and an artery

  1-wall of vein(has thinner layer of elastic tissue)

  2-lumen in vein is wider(than in artery)
• explain how the spongy mesophyll is adapted for its function

  has air spaces so gases can diffuse to B layer
• explain one way that xylem is adapted for its function

  has a lignin to hold tubes open
• Describe how an increase in glucose concentration in the guard cells causes the stoma to open

  -water enters guard cells by osmosis

  -cells swell and curve to open the stomata
• Describe the overall change of of carbon dioxide and oxygen at:

  BRIGHT LIGHT

  • the rate of photosynthesis is high due to high light intensity
  • extra carbon dioxide is absorbed from the air
  • carbon dioxide is produced in respiration and is used for photosynthesis so no CO2 is released from the plant or into the air
  • sufficient oxygen for respiration is produced by photosynthesis so no extra oxygen is absorbed from the air
  • the rate of photosynthesis is greater than the rate of respiration


  yh
• Describe the overall change of of carbon dioxide and oxygen at:

  DIM LIGHT

  • there is no overall exchange of CO2 or oxygen in the air
  • because the rate of respiration equals the rate of photosynthesis
  • carbon dioxide produced in respiration is used for photosynthesis and no extra C02 is absorbed from the air
  • oxygen produced by photosynthesis is used in respiration so no extra oxygen is absorbed from the air
• Describe the overall change of of carbon dioxide and oxygen at:

  NO LIGHT

  • no photosynthesis occurs as there is no light
  • so no CO2 is absorbed and oxygen is released
  • the plant respires so it takes in oxygen and releases CO2 into the air
• explain why starch has to be digested

  Starch molecules are large so can't be absorbed into blood.
• • where do mutations happen in a bacterial cell
  • plasmids
  • chromosomes
  • DNA
  • genes
• advantage of using stem cells from fat tissue, rather than from bone marrow

  • easier to obtain
  • less invasive
• A student concluded that stem cell injections with antibiotics should be used for all implant-related infections. Evaluate this conclusion using Figure 10.

  Answer :

  Pros• smallest area of infection• smallest range of results• no overlap with unreactive solution

  Cons• only test on 5 patients• only tested on 1 type of bacterium• only collected results after 7 days