Exam qs 2021

• Plant cells absorb substances from the soil. Plant cells use osmosis to absorb water . Plant cells use active transport to absorb mineral ions . Active transport moves substances against the concentration gradient and needs energy.
• Describe how root hair cells is adapted to increase the absorption of substances from the soil.

  large surface area
• • Feature of a sperm cell : Contains a nucleus
  • How the feature helps : to provide the chromosomes for fertilisation
• • Feature of a sperm cell : Has a long tail
  • How the feature helps : to help the cell to swim to the egg
• • Name of the cell : nerve cell
  • Feature of the cell : long, has branches, has insulation
• Viruses cause disease. What name is given to microorganisms that cause disease?

  Pathogens
• How do viruses cause the symptoms of disease?

  viruses reproduce inside cells, damaging them
• Suggest one reason why viruses are not classed as cells

  they do not have a cell membrane • they do not have cytoplasm • they do not have a nucleus
• A vaccine can protect humans from a viral disease. What does the vaccine contain?

  a weakened form of a virus
• Tobacco mosaic virus (TMV) causes disease in plants. box TMV affects the rate of photosynthesis in plants. Which part of a plant shows discolouration caused by TMV?


  Leaf
• Explain why a high level of TMV infection reduces growth in a plant.


  less chlorophyll (so) less glucose / starch / protein made
• Give one adaptation that helps to prevent the cactus from being eaten by animals


  (has) spikes / thorns / prickles
• A plant may produce poisons that make animals unwell. What is this type of defence mechanism?

  chemical
• The stem of a cactus is green. What causes the green colour in the stem?

  Chlorophyll
• What is the advantage to the cactus of having a green stem?


  to allow it to photosynthesise or to make sugar / glucose / carbohydrate / starch
• What name is given to a group of tissues working together?

  organ
• Name one substance transported through the xylem in the stem of the cactus.


  Water/ mineral ions
• Name the tissue that transports dissolved sugars through the stem of the cactus

  phloem ( tissue )
• Which type of enzyme breaks down starch?

  carbohydrase
• A high cholesterol concentration in the blood can lead to blockages inside arteries. The coronary arteries supply blood to the heart muscle Why could the blockage cause cells in the heart to die?

  less blood flows through or less blood flows to the heart (muscle / cells / tissue) less oxygen (reaches the heart muscle
• Explain how a stent works as a treatment for a person with a blockage in a coronary artery.

  opens / widens (artery) so (more) blood can flow through
• Patients are given anti-clotting drugs after they have a stent fitted. The drugs help to prevent clots forming in the blood. Which part of the blood starts the blood clotting process

  platelets
• Explain why the man’s breathing rate increased when he was running.

  • to get more oxygen (into the blood)
  • for use in respiration or for releasing energy (for muscle contraction)
  • or to remove more carbon dioxide (1)
  • produced in respiration (1)
• Give one effect that smoking can have on the body

  • (lung) cancer
  • increased blood pressure
  • lung disease
  • low birth weight in babies of mothers who smoke
  • increased risk of heart / cardiovascular disease
• Name two pieces of laboratory equipment the student could have used to prepare cells to view using a microscope

  • (microscope) slide
  • cover slip
  • dye / stain
  • (mounted) needle
  • pipette / dropper
  • scalpel
  • forceps / tweezer
• The student tried to look at the cells using the microscope. Suggest one reason why the student could not see any cells when looking through eyepiece lens.

  • no cells in the field of view
  • slide not in the correct position
  • mirror not in correct position
  • (objective) lens not clicked into place or (objective) lens dirty
  • (student is) looking at a (large) air bubble
  • (the microscope is) not focussed
• Red blood cells are specialised animal cells. Compare the structure of a red blood cell with the structure of a plant cell.

  • Differences: red blood cell has no nucleus or plant cell has a nucleus
  • red blood cell has no cell wall or plant cell has a cell wall
  • red blood cell is a biconcave disc or there are many different shapes of plant cell
  • red blood cell contains haemoglobin or plant cells do not contain haemoglobin
  • Similarities: both have: • cytoplasm • cell membrane • pigments (although they are different
• Explain why the red blood cell bursts but the plant cell does not burst.

  water enters (the cells) by osmosis / diffusion plant cell has a cell wall (which prevents it from bursting)
• Describe two aseptic techniques

  • sterilise equipment / surfaces (before use)
  • (use) sterilised agar
  • secure lid of the Petri dish with (adhesive) tape
  • only lift lid of Petri dish a little (when setting up plate)
• Suggest one way the student could improve the investigation.

  repeat and calculate a mean • repeat and eliminate anomalies
• The number of people who are obese in the UK is increasing. Explain the financial impact on the UK economy of an increasing number of people who are obese.

  • costs the NHS / UK health service / Government / hospitals more money
  • (because need to pay for) additional surgery / medication / hospital stay to treat stroke / diabetes
  • (so) employer / Government have to give financial support
• A person who is obese is more at risk of arthritis. Arthritis is a condition that damages joints. Suggest how arthritis could affect a person’s lifestyle.

  • loss of job / income
  • disability
  • mental health impact of lack of movement
• Name two health conditions that might develop if a person eats a diet high in saturated fat

  • type 2 diabetes CVD / CHD or heart attack / disease