questionpaper

• Explain how lifestyle and medical risk factors increase the chance of developing CHD?

  •smoking – high bp / cholesterol / fatty deposition

  • obesity – lack of exercise / high bp / cholesterol / fatty deposition / diabetes

  • exercise – obesity / bp /diabetes

  • diet – obesity / cholesterol / diabetes

  • alcohol – bp / cholesterol

  • high salt intake - high blood pressure

  • genetic factors – bp / cholesterol / diabetes / obesity

  • medication – can affect blood / blood vessels / metabolism
• Explain why the mass of the carrot in the 0.6 mol/dm3 sugar solution changed.

  mass decreased

  (due to) loss of water by osmosis

  through a partially / selectively / semi-permeable membrane (as) concentration of sugar solution is greater than the concentration of sugar (solution) inside cells/carrot
• The student repeated the investigation using boiled pieces of carrot. The pieces of carrot did not change in mass. Suggest why.

  the (partially permeable / cell) membrane was damaged
• Vaccinating a large proportion of the population reduces the spread of the measles virus. Explain why.

  most people are immune so do not become ill (from infection)

  less chance of non-immune / unvaccinated individuals being exposed to pathogen/measles / virus
• Describe what happens in each of the three stages of the cell cycle.

  stage 1 cell growth, DNA replicates

  stage 2 / mitosis one set of chromosomes moves to each end of cell, nucleus divides

  stage 3 cytoplasm / cell membrane divides to form two (genetically) identical cells
• advantages of therapeutic cloning in medical treatments.

  • may be used to cure diseases or cure medical conditions

  • cells / tissues of any type could be produced

  • cells unlikely to be rejected by the patient

  • many cells produced

  • cells produced could be used for research

  • would reduce waiting time for organ transplants
• disadvantages of therapeutic cloning in medical treatments.

  • potential life is killed/destroyed

  • shortage of donors/eggs

  • egg donation/collection has risks

  • do not yet know the risks /side effects of the procedure on the patient

  • may transfer (viral) infection

  • poor success rate to produce viable eggs/embryo
• Where in the heart are ‘pacemaker cells’ found?

  right atrium
• Where does the drug digitalis originate from?

  foxgloves
• effect of exercise:

  • during exercise body needs to transfer (more) energy

  • energy transferred during respiration

  • rate of respiration increases during exercise

  • (so) more oxygen is needed
• effect of beta blockers:

  • beta blockers reduce (the increase in) heart rate (during exercise)

  • beta blockers reduce stroke volume (or described)

  • beta blockers reduce cardiac output

  • (so) heart cannot supply oxygen fast enough / in sufficient quantity to muscle cells
• effect on breathing rate:

  • breathing rate increases to increase the rate/amount of oxygen absorbed

  • breathing rate increases to increase the rate/amount of carbon dioxide removed from the body

  • (but) increased breathing rate cannot fully compensate for changes in heart function
• the enzyme that digests starch?

  amylase
• test for starch: add iodine solution, if starch is present, it will turn blue
• test for sugar: add Benedict's reagent to the sample, and add iodine, if sugar is present, iodine will turn blue
• Explain why narrow tubing was used.

  air bubble moves further (in a given time)

  (so) resolution is improved
• The air bubble would not move if the investigations were done in the dark. Explain why.

  no photosynthesis

  (so) stomata closed (as no carbon dioxide needed)

  (so) no transpiration
• Describe how nitrate ions are used in a plant to help the plant grow:

  nitrate ions are used with glucose

  to form amino acids

  (which are) used to synthesize proteins (needed for growth)
• Explain why the potato in 0.0 mol/dm3 sugar solution increased in mass.?

  gained water

  by osmosis
• Where are most food molecules absorbed? Small intestine
• Give one advantage of using an electron microscope compared with using a light microscope.

  • greater magnification

  • higher resolving power
• Give one use of sugar in the body.

  • respiration

  • to form glycogen

  • to make amino acids/proteins
• Explain how villi are adapted for efficient absorption of sugar molecules.

  • have (many) microvilli

  • (to) increase surface area

  • wall of villus only one cell thick or is thin

  • capillaries are close to surface

  • (so) short pathway

  • good blood supply

  • (to) transport food molecules away or to the body

  • (and) maintain a diffusion gradient

  • cells have many mitochondria

  • (where) respiration takes place

  • (where) energy is transferred

  • (as) active transport requires energy

  • energy is needed to absorb sugar / food / molecules
• Give one disease related to being overweight.

  • (Type 2) diabetes

  • (coronary/ischaemic) heart disease / CHD

  • high blood pressure

  • cancer

  • depression
• Describe how the balance between the mass of food eaten and the amount of exercise a person does controls body mass.

  • increased energy intake if more food eaten

  • if exercise more, more energy is transferred/released

  • if more energy is taken in than is transferred body mass increases
• During exercise:

  • increased breathing rate

  • increased breath volume

  • (to) take in more oxygen for (aerobic) respiration

  • (and) exhale more carbon dioxide

  • increased heart rate

  • (so) increased blood flow (to muscles)

  • (to) transport oxygen/glucose to respiring cells faster

  • (and) increase rate of carbon dioxide removal

  • glycogen converted to glucose
• After exercise:

  • heart rate remains high or heart rate slowly decreases

  • continue to breathe rapidly or the breathing rate slowly decreases

  • (to) pay back oxygen debt

  • oxygen debt is the amount of oxygen needed to break down lactic acid

  • (and to) provide more oxygen to react with the lactic acid and remove it from cells

  • (some) lactic acid transported to the liver

  • (lactic acid) is converted back into glucose
• The number of cases of salmonella food poisoning is usually higher in summer than in winter.

  warmer weather so bacteria reproduce / increase faster
• Suggest one reason why low doses of the drug are used in Phase 1 clinical trials.

  • to reduce any risk

  • to look for side effects
• Suggest two reasons why healthy volunteers are used in Phase 1 clinical trials.

  too great a risk for ill person / patient

  patient might be taking another drug