Biology

• What do plant cells have that animal cells don’t?

  ~cell wall

  ~vacuole

  ~chloroplasts filled with chlorophyll
• What does a bacterial cell have?

  ~chromosomal DNA

  ~ribosomes

  ~cell membrane

  ~plasmid DNA

  ~flagellum
• What’s the difference between a light microscope and electron microscope?

  ~electron microscopes use electrons instead of light

  ~electron microscopes have higher magnification and resolution

  ~electron microscopes can’t be used on living structures
• What enzymes break down lipids and what into?

  Lipase breaks down lipids into fatty acids and glycerol.
• What’s the test for sugar?

  Benedict's test
• How is the Benedict’s test preformed?


  Add Benedict's reagent to a sample, heat in a water bath of 75c, if sugar is present the colour will go from blue to green, yellow, orange or brick red
• What’s the test for lipids?

  Emulsion test
• How is the emulsion test preformed?

  ~shake the test substance with ethanol until it dissolves and then pour the solution into water

  ~if there ar any lipids present they will precipitate out of the liquid and show up as a milky emulsion
• What are the risks to stem cell treatments?

  Tumour development

  ~stem cells divide very quickly, if scientists are unable to control the rate of division, a tumour may develop

  Disease transmission

  ~if there’s a virus in the stem cells that wasn’t picked up, this could be transferred to the patient

  Rejection

  ~the body may label the cells as foreign, this will trigger an immune response to try and get rid of them
• What’s the test for starch?

  Iodine
• How is the iodine test preformed?

  ~add iodine solution to the sample

  ~if starch is present the solution will go from a browny-orange to blue—black
• How do you extract DNA from fruit?

  1~ mash some fruit and the put them in a beaker containing a solution of detergent and salt, and mix well.( the detergent will break down the cell membranes to release the DNA, and the salt will make the DNA stick together)

  2~ filter the mixture to get the froth and big, insoluble bite of cell out

  3~ gently add some ice cold alcohol to the filtered mix

  4~ the DNA will start to come out of the solution as it is non-soluble in cold alcohol. It will appear as a stringy white precipitate, that can then be fished out with a glass rod carefully
• How does short sightedness occur?

  occurs when the lens js the wrong shape and bends the light too much or the eyeball is too long, this means that light from the object is brought into focus before the retina
• How do you treat short sightedness?

  Use a concave lens
• How does long sightedness occur?

  When the lens is the wrong shape and doesn’t bend the light enough or the eyeball is too short, this means that the light would focus behind the retina
• How do you treat long sightedness?

  Using a convex lens
• What does the eye do to look at objects that are far away?

  ~the ciliary muscle relaxes, which allows the suspensory ligaments to pull tight, this pulls the lens into a less rounded shape so light is refracted less
• What does the eye do in order to look at objects that are close?

  The ciliary muscle contracts, which slackens the suspensory ligaments, causing the lens to become a more rounded shape so that the light is refracted more
• What does the lens do?

  Refracts light, focusing it on the retina
• What does the retina do?

  The retina is responsible for detecting and converting light into electrical signals that can be interpreted by the brain.
• What are rods and cones?


  Photoreceptor cells in the retina. Rods work well in low light and at night, but can’t sense colour. Cones help us see colour and fine details but don’t work well in low light.
• What does the cornea do?

  The cornea is the transparent outer layer of the eye that helps to focus light onto the retina.
• What does the iris do?

  Controls the size of the pupil and regulates the amount of light entering the eye.
• How do PET scanners work?

  They use radioactive chemicals to show which parts of the brain are active whilst inside the scanner
• Why are PET scanners used?

  To investigate both the structure and function of the brain in real time. A PET scanner can show if parts of the brain are unusually inactive/active, so are useful for studying disorders that can alter the brains activity
• How does a CT scanner work?

  Uses X-rays to produce images of the brain
• What’s the difference between a PET and a CT scan

  ~ a CT scan only shows the main structures of the brain and not the function

  ~ a PET scanner uses chemicals
• Label the parts of the brain

  -

  
• What are the processes for growth and development? (animals and plants)

  Cell differentiation

  ~the process when a cell becomes specialised

  Cell division

  ~when a cell undergoes mitosis
• what enzymes break down proteins and what into?

  Proteases break down proteins into amino acids.
• What enzymes break down carbohydrates and what into?

  Amylase breaks down carbohydrates into sugars.
• How do you figure out the rate of reaction?

  Rate = 1000/time
• What’s resolution?


  How well a microscope distinguishes between two points that are close together
• What’s clomifene therapy?


  Treats infertile women that don’t ovulate regularly or at all
• How clomifene therapy work?

  Works by causing more FSH and LH to be released which stimulates egg maturation and ovulation
• What does the thyroid gland do?

  Produced thyroxine
• What’s osmosis?


  Diffusion of water across a semi-permeable membrane.
• What’s active transport?


  Movement of molecules across a cell membrane requiring energy.
• What’s a potometer?


  Device to measure rate of water uptake by a plant.
• What does the pituitary gland do?

  Produced hormones that act on other glands to direct them to release hormones that bring about change