Exam q

• Differences between a red blood cell and plant cell

  • Red blood cell is a biconcave disc and contains haemoglobin
  • Red blood cell has no nucleus
  • Red blood cell has no cell wall
  • Red blood cell has no chloroplasts
  • Red blood cell has no permanent vacuole
  • Red blood cell doesn’t contain chlorophyll
• similarities between red blood cell and plant cell

  • cytoplasm
  • cell membrane
  • pigments
• when placed in water a red blood cell burst but plant cell doesnt, explain why

  water enters via osmosis and plant cell has a cell wall which prevents it from bursting
• name the cells in a leaf that control the rate of water loss

  guard cells
• water is taken in by the roots, transported up the plant and lost from the leaves. what scientific term describes this movement of water

  transpiration stream
• which change would decrease the rate of water loss from a plant's leaves : increased humidity, increased light intensity, increased density of stomata, increased temperature

  increased humidity
• similarities in phloem and vessel cells

  • both made of cells
  • both tubular
  • both transport substances throughout plant
• differences in phloem and vessel cells

  • xylem made of dead cells, phloem made of living
  • xylem transports water and dissolved minerals, phloem transports dissolved sugars
  • xylem is involved in transpiration, phloem involved in translocation
  • xylem doesnt contain cytoplasm, phloem does
• the rate of water loss at midnight was much lower than at 12PM explain why (2m)

  stomata are closed at night because theres no light
• Which organ system is the heart part of?

  Circulatory system
• Valves are found inside some blood vessels. Which type of blood vessel contains valves

  veins
• Explain why a person with a leaking heart valve Will find difficulty exercising

  Blood flows backwards so less blood leaves the heart so less oxygen is supplied to the muscles so less aerobic respiration so less energy released so less efficient muscle contraction. This leads to anaerobic respiration taking place where lactic acid builds up causing muscle fatigue leading to less efficient removal of co2 from blood.
• suggest one reason why an axolotl is a suitable animal for research in the laboratory

  • cheap to keep
  • easy to breed
• an axolotl may not be a suitable animal to study when researching regeneration in human tissue suggest one reason why

  • it's not a mammal
  • body processes are too different to humans
• what is an enzyme

  chemical which speeds up reactions in living organisms and is a protein
• Two advantages of using an electron microscope instead of a light microscope

  higher resolution whereas light is 0.2 micrometers

  Sees more detail

  Higher magnification
• Name a chemical used to test for glucose

  Benedict’s
• New drugs must be tested before they can be used. Give one reasons why drugs should be tested

  To check they’re safe
• Give two ways a person with a mild infection of salmonella can help prevent the spread of the bacteria to other people

  isolation

  washing hands before handling food
• describe how scientists make monoclonal antibodies using the cell created when a mouse lymphocyte and a tumour cell combine

  • cell is cloned
  • identical hybridoma cells are produced
  • antibody is collected and purified
• explain how anabolic steroids could improve an athletes performance

  • athlete is faster/stronger
  • so more stronger muscle contractions
• design an investigation to show the effect of diff types of exercise on the heart rate of athletes (6m)

  • test a group of athletes
  • use at least two different intensities of exercise
  • get each athlete to do all exercises
  • record heart rate for each athlete before and after exercise
  • calculate the mean increase of heart rate for each type of exercise
  • compare mean increases in heart rate for each type of exercise
  • control: same sexes and same age
• antibiotics damage the bacterial cell wall. the bacteria die because the cells burst explain why it bursts

  water enters the bacterial cell by osmosis so damaged cell wall cannot withstand the pressure of the water
• scientists incubate bacteria at 37 degrees but in school its incubated at 25 degrees. explain why scientists incubate at 37 degrees.

  • 37 degrees is body temp
  • bacteria grows best at 37 degrees
  • 25 degrees prevents growth of harmful bacteria
• explain how the immune system of animals respond to a vaccination and the immune response in farm animals prevents an outbreak of food poisoning in humans (salmonella, 4m)

  • white blood cells produce antibodies
  • antibodies bind to antigens on salmonella
  • white blood cells stay in blood stream so correct antibodies are produced quickly which kill the salmonella
  • so fewer salmonella eaten in food
  • fewer toxins produced in humans
• explain the effect of a partly blocked coronary artery on the body (6m)

  • reduced blood flow to heart muscle cells
  • less oxygen to heart muscle cells
  • so less glucose to heart muscle cells
  • so less aerobic respiration in body cells
  • so more anaerobic respiration
  • so less energy released
  • so less muscle contraction
  • resulting in tiredness and lactic acid causes muscle fatigue
• suggest one reason why a report making claims about the effects of chemical A may be biased

  writers/ companies may get financial gain
• what is a tissue

  a group of similar/same cells