Boilogy predicted

• Prokaryotic cells

  Cells without a nucleus
• Eukaryotic cells

  • Larger
  • Have membrane-bound organelles
  • Cells with a nucleus
• Both prokaryotic and eukaryotic cells have a cell membrane, cytoplasm, and ribosomes
• Ribosomes

  Site of protein synthesis
• Sperm cell

  • Have a tail to help them swim
  • Have mitochondria in the middle section for respiration
  • Have a nucleus containing genetic material
  • Have an acrosome which contains digestive enzymes
  • Have a streamlined head to help them manoeuvre faster
• Before a cell undergoes cellular division, its genetic material must be duplicated/doubled
• A human body cell has 46 chromosomes / 23 pairs
• Mitosis

  1. Chromosomes condense

  2. Chromosomes line up at the equator (centre) of the cell

  3. Chromosomes are pulled to opposite poles of the cell by spindle fibres

  4. Chromosomes form two new nuclei to create two genetically identical daughter cells
• Purpose of mitosis

  Growth and repair
• Embryonic stem cells

  • Can differentiate into any cell type
• Adult stem cells

  • Can only differentiate into fewer types of cells
• Embryonic stem cells

  Could be used to treat currently untreatable diseases or growing new organs for transplants
• Adult stem cells

  Have fewer uses, but there are ethical challenges surrounding the use of embryonic stem cells as embryos could begin to be seen as a commodity rather than an embryo that will develop into a person
• Preparing and viewing onion cells under a microscope

  1. Peel a thin layer of onion (the epidermis) off the onion

  2. Place the layer of onion epidermis carefully on the glass slide

  3. Stain the layer of onion with food colouring / dye

  4. Cover the stained onion cells with a cover slip

  5. Place the slide on a stage of a microscope and hold in place with clips

  6. Set the microscope to the lowest objective lens and turn the microscope on

  7. Use the coarse focusing knob and the fine focusing knob to focus on the onion cells

  8. View the cells using the eyepiece
• The drawing must take up at least 50% of the box, must not contain any shading, must be made up of continuous lines (no sketching), labels should not cross over, and labels should only show visible structures
• Xylem

  Transports water and minerals up the plant in a process called transpiration
• Phloem

  Transports sugars up and down the plant in a process called translocation
• The structure in the digestive system which stores bile before it is released into the duodenum is the gallbladder
• Roles of bacteria in the large intestine

  • Break down foods
  • Make vitamins
  • Break down toxins
  • Protect against pathogens
• Effect of temperature on enzyme function

  The higher the temperature, the greater the rate of reaction of enzymes, up to the optimum temperature. Any further than this, the enzyme denatures and the active site will no longer fit with substrate.
• Effect of pH on enzyme function

  Enzymes have an optimum pH too; a pH which is too low or too high denatures enzymes.
• Tests to identify contents of test tubes

  1. Test tube 1 (sugar): Benedict's reagent which goes from blue to red in the presence of sugars when heated

  2. Test tube 2 (starch): Iodine which goes from brown to blue/black

  3. Test tube 3 (protein): Biuret test which goes from blue to purple

  4. Test tube 4 (lipids): Add ethanol - will go from colourless to cloudy white if lipids are present
• Main components of human blood

  • Red blood cells
  • Plasma
• Types of blood vessels in order of smallest lumen to largest lumen

  • Capillary
  • Artery
  • Vein
• Risk factors and associated non-communicable diseases

  • Smoking - lung disease/cancer
  • Obesity - type 2 diabetes
  • Alcohol - liver disease, impaired brain function
• Ways pathogens spread

  Direct contact, sexual contact, droplet infection, vectors
• Principle behind herd immunity

  If a large proportion of the population are vaccinated, it is unlikely that an unvaccinated individual will get infected so the spread of disease is limited
• How vaccinations work

  Introduction of a small amount of dead/inactive form of a pathogen into the body which simulates white blood cells to produce antibodies. Next time the pathogen infects the vaccinated individual, the white blood cells respond more quickly.
• Lack of magnesium in plants

  Fewer chloroplasts, plant becomes more yellow (chlorosis), plant cannot absorb as much light for photosynthesis so it will not be able to grow as much
• Balanced symbol equation for aerobic respiration


  C6H1206 + 6O2 --> 6CO2 + 6H2O
• Word equation for anaerobic respiration in yeast cells

  GLUCOSE --> Ethonal + CARBON DIOXIDE
• Ways the body deals with lactic acid produced during anaerobic respiration

  • Lactic acid can be oxidised (reacted with oxygen) to form carbon dioxide and water
  • Lactic acid can be transported to the liver by the blood where it can be converted back to glucose
• What living organisms require energy for

  • Chemical reactions to build larger molecules from smaller molecules
  • Muscle contraction to allow movement
  • Keeping warm (to maintain a constant temperature suitable for enzyme activity)
• Other ways plants use glucose produced from photosynthesis

  • Converted into insoluble starch for storage
  • Used to produce fat or oil for storage
  • Used to produce cellulose, which strengthens the cell wall
  • Combined with nitrate ions absorbed from the soil to produce amino acids for protein synthesis
• How monoclonal antibodies are made

  1. Stimulate mouse lymphocytes to make a particular antibody by injecting them with an antigen

  2. Combine the lymphocytes with a tumour cell to make a hybridoma cell

  3. Clone the single hybridoma cells, resulting in many divisions and high quantities of identical cells that all produce the same antibody

  4. Collect and purify the antibody
• Advantages and disadvantages of monoclonal antibodies

  • Advantages: Cheaper to develop than conventional drugs, bind to specific diseased or damaged cells, treat a wide range of conditions

  Disadvantages: Expensive, can have many side effects, difficult to get the right antibodies and attach a compound to it
• Uses of nitrates and potassium in plants

  Nitrates - production of amino acids for proteins

  Potassium - production of flowers and fruit
• Ways a farmer can identify plant diseases

  • Use testing kits with monoclonal antibodies

  Check in a gardening manual or online
• How aphid infestation can cause problems for crops

  Aphids have long sharp mouthpieces that pierce the surface of the stem and into the phloem so they can feed on the sugar filled sap, they can infest a plant in large numbers and remove large quantities of the phloem sap which can weaken the plant, aphids can also act as a vector for the transfer of diseases
• Physical and chemical defences plants have against pathogens

  • Physical: Cellulose cell wall, waxy cuticle, bark

  Chemical: Antimicrobial properties of plant extracts