Exam qs 2022

• The pulmonary artery takes blood to the lungs.
• what can be used to treat people with coronary heart disease?

  • stent
  • statins
• Suggest two risk factors for coronary heart disease.

  • smoking
  • high-fat diet
  • lack of exercise
• HIV (Human Immunodeficiency Virus) is a pathogen. How is HIV spread from one person to another person?

  sexual intercourse
• What could cause a decrease in the number of new HIV cases in the future?

  better education on how to prevent the spread of HIV
• Scientists have been working to produce a vaccine for HIV for many years. How could a vaccine work to prevent a person being infected with HIV?

  1. An inactive form of the virus is injected into the body
  2. White blood cells produce antibodies to the inactive virus.
  3. Antibodies attach to the inactive virus.
  4. Antibodies destroy the inactive virus
  5. If the active virus enters the body, antibodies are produced quickly.
• When scientists produce a vaccine for a disease the vaccine is tested on live animals. What is the next stage in testing the vaccine?

  testing on healthy volunteers
• A vaccine for HIV is important because it is difficult to develop safe drugs to destroy viruses. Why is it difficult to develop safe drugs to destroy viruses?

  drugs that destroy viruses also damage body tissues
• • Drug : Aspirin
  • Plant the drug originated from : Willow
• • Drug : Digitalis
  • Plant the drug originated from : Foxglove
• Before mitosis occurs, the cell grows . The genetic material in the cell doubles when the DNA replicates . After the chromosomes have been pulled to each end of the cell, the cytoplasm divides.
• Stem cells divide by mitosis. Scientists can use stem cells from an embryo to create heart cells in a laboratory. Which organ system contains heart cells?

  Circulatory system
• Name one medical condition that could be treated using heart cells created from an embryo.

  • cardiovascular disease/ CVD
  • (coronary) heart disease / CHD
• Give one reason why a patient may not want to be treated with heart cells created from an embryo.

  • unethical
  • (against) religious / cultural / personal beliefs
  • the method is not (fully) tested
  • risk of infection
  • (heart cells) may be rejected
• • Independent variables – the variable that is being changed during the experiment
• • Dependent variables – the variable being tested or measured during the experiment
• Control variable stays the same
• Carbon dioxide is needed for photosynthesis
• Why was iodine solution added to the layer of onion cells?

  to stain the cells
• Why was a thin layer of onion cells used?

  to allow light to pass through the cells
• How would onion cells look different if they were seen using an electron microscope?

  the cells would look larger the cells would show more internal structures
• carbon dioxide + water → oxygen + glucose
• 1. Cut an onion into pieces using a sharp knife.
  2. Peel off a thin layer of cells from one piece.
  3. Place the layer of cells onto a microscope slide.
  4. Add three drops of iodine solution to the layer of cells.
  5. Cover with a cover slip.
  6. Place the slide on the stage of the microscope.
• Water moves from the roots to the leaves in the xylem . Water is lost from leaves through pores called stomata . Dissolved sugars are transported in the phloem .
• Which environmental change would cause an increase in the rate of transpiration?

  increased temperature
• How will the sharp spines help the gorse plant survive?


  (spines) stop the plant being eaten or (spines) prevent animals damaging the plant
• Hornets are insects that sting other animals and cause pain. Hornet moths do not sting other animals. Explain why animals avoid eating the hornet moth.


  it looks like the hornet (so) animals avoid the risk of being stung
• Name one other substance that enters cells by diffusion

  • carbon dioxide

  glucose / sugar

  water

  ions / minerals / salts
• Suggest two factors that affect the rate of diffusion of oxygen into a jellyfish?

  Surface area, concentration gradient
• Some organisms take in oxygen using a respiratory system. In humans, gas exchange takes place in the lungs. Name the organs where gas exchange takes place in fish.

  gills
• Explain how the human breathing system is adapted to maximise the rate of gas exchange?

  • large number of alveoli
  • large surface
  • capillary are in close proximity
  • capillaries have thin walls or alveoli
  • to reduce diffusion distance
  • has a good blood supply or has a capillary network
  • to maintain concentration gradient
  • to remove oxygen quickly or to deliver carbon dioxide quickly
• Nucleus contains genetic information
• Mitochondria : site of aerobic respiration
• cell membrane : Controls the movement of substances into and out of the cell
• What is the function of Chloroplast?

  Photosynthesis
• Name one type of cell in a potato plant that does not contain chloroplasts

  root (hair)
• 1. Cut three pieces of potato of the same size.
  2. Record the mass of each potato piece.
  3. Add 150 cm3 of 0.4 mol/dm3 salt solution to a beaker.
  4. Place each potato piece into the beaker.
  5. After 30 minutes, remove each potato piece and dry the surface with a paper towel.
  6. Record the mass of each potato piece.
  7. Repeat steps 1 to 6 using different concentrations of salt solution
• What is the independent variable in the investigation? potato practical

  concentration of salt solution
• Why did the student dry the surface of each potato piece with a paper towel in step 5?

  • to make sure only the potato mass was measured
  • if water / solution / liquid was left on (the potato), the mass would be higher / affected
• Which disease is caused by a fungus?

  rose black spot