2022

• Similarities between bacterial cell and animal cell

  • both have a cell membanre
  • both have cytoplasm
• • Symptoms of Salmonella
  • fever
  • stomach cramps
  • abdominal pain
  • high temperature
• First antibiotic developed

  penicillin
• • why do doctors not give antibiotics to patients with minor infections
  • to reduce the risk of antibiotic resistant strains developing
  • to prevent resistant bacteria developing
• • platelets startclotting process
• • smallest to largestgene -> chromosome -> nucleus -> cell
• Stage 1 of the Cell Cycle

  • cell growth
  • DNA replicates
  • sub-cellular structures increase
• • Stage 2 of the Cell Cycle
  • one set of chromosomes are pulled to each end of the cell
  • two nuclei form


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• • Stage 3 of the Cell Cycle
  • cytoplasm/membrane divides
  • 2 identical cells are formed


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• • uses of cell division by Mitosis
  • repair of tissues
  • replacement of cells
• where is amylase produced

  • salivary glands, pancreas, small intestine
• • how is the structure of enzyme molecules related to the effect of pH on the activity of amylase
  • enzymes are protein molecules so they have a 3D structure
  • lock and key theory
  • the enzymes have an active site which has a specific shape which will only match the shape of the substrate
  • starch is the substrate for amylase
  • at pH values above or below the optimum temp, the shape of the active site is changed in some molecules
  • so the substrate can no longer fit the active site
  • at extreme pH values the enzyme is denatured, so the shape of the active site is changed
  • so amylase can no longer digest starch, so the rate of digestion decreases
• why is light needed for photosynthesis

  to transfer energy
• what is the equation for photosynthesis

  6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
• Describe the similarities and differences between benign tumours and malignant tumours.

  Answer :• Both benign and malignant tumours are due to changes to the DNA in a cell. In both this genetic change causes uncontrolled division of a cell or group of cells.

  • However, malignant tumours tend to grow faster & be able to spread to other tissues. These can be neighbouring tissues to where the tumours developed or cancer cells can travel in the blood to other parts of the body.

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• • similarities between Benign & Malignant tumours
  • they are a result from changes in the cell/DNA/genes
  • they can form a lump of cells
  • they are made up of abnormal cells
• • Malignant Tumours (only)
  • made of cancer cells
  • grow faster than benign tumours
  • they can invade neighbouring tissues
  • they can spread to other parts of the body
  • they can form secondary tumours
• • Benign Tumours
  • not made of cancer cells
  • made up of cells similar to normal cells
  • do not spread or invade other tissues
  • do not form secondary tumours
• why is the heart described as an organ

  it consists of different tissues & performs a specific function
• Explain what would happen if the valve in Figure 11 had a leak.

  Answer :Some of the blood would flow back into the left ventricle ∴ less oxygenated blood would flow out of the heart to the cells. Cells require oxygen for respiration from the blood. If less oxygenated blood is pumped, less oxygen is supplied, so less respiration can take place. The person hence may feel out of breath and tired.

  4o
• • advantages of a BIOLOGICAL Valve
  • reduces risk of blood clots which could cause a heart attack or stroke
  • reduced risk of bleeding during pregnancy
  • no need to take anti-blood clotting drugs
• • disadvantages of a BIOLOGICAL Valve
  • may be rejected by the body
  • may have to go through surgery more than once
  • may have to take immunosuppressant drugs
  • may have to wait for a suitable doctor
• Describe the advantages and disadvantages for a young woman of having a biological heart valve instead of a mechanical one.

  Answer :Advantages include, not having to remember to take drugs for the rest of her life. Blood thinners would also interfere with the development of a child or cause complications with bleeding at birth. With a biological valve these issues can be avoided.

  However, she might have to undergo a 2ⁿᵈ operation if the biological valve needs replacing. Also for a valve from a donor they may have to wait for a while to find a suitable donor.