biology paper 1

• how are the arteries adapted to carry blood away from the heart?

  small lumen, walls can stretch and withstand high pressure, thick, muscular and elastic walls
• how are veins adapted to carry blood to the heart?

  large lumen, thin walls and valves
• how are capillaries adapted to carry blood to cells and connect arteries and veins?

  narrow lumen, one cell thick for short diffusion distance
• what happens to guard cells and stomata when there is high light intensity?

  guard cells swell and change shape, the stomata open and allow carbon dioxide to enter for photosynthesis
• what is the function of xylem?

  carries water and mineral ions from roots to stem and leaves
• what is teh function of phloem?

  transport food substances made in the leaves to rest of the plant for immediate use or storage
• what are the issues with donated hearts?

  there are not enough available and the patients have to take drugs to stop rejection
• what are benign tumours?

  growth of abnormal cells found in one area which are usually contained in a membrane and stay in one place
• what is radon?

  a radioactive gas that increases risk of developing lung cancer due to the ionising radiation whihc damages DNA and causes uncontrolled cell division
• what is measles spread by?

  inhalation of contaminated droplets
• what is HIV spread by?

  sexual contact or exchange of bodily fluids
• The HIV virus attacks the immune system which can lead to AIDS, what is AIDS?

  when the immune system is so damaged it cannoy fight infections or cancers
• how is TMV spread?

  direct contact of plants or soil
• what are symptoms of TMV?

  mosaic pattern of discolouration where chlorophyll is destroyed, it also reduces plants ability to photosynthesise and so affects growth
• why are bacteria harmful?

  they reproduce quickly and produce toxins which damage tissues
• how is gonnorhea spread?

  sexual contact
• what are symptoms of gonnorhea?

  thick yellow or green discharge from penis or vagine and pain when urianting
• how is gonnorhea treated?

  with antibiotics
• how is gonnorhea prevented?

  contraception
• how is rose black spot spread?

  by water and wind
• what are symptoms of rose black spot?

  purple or black spots on leaves that turn yellow and drop early, it also reduces photosynthesis and so affects growth
• how is rose black spot prevented?

  fungicides
• how is rose black spot treated?

  affected leaves removed and destroyed
• how is malaria spread?

  by mosquitos feeding on the blood of infected people and spread protist pathogen when they feed on another person
• why are some bacteria antibiotic resistant?

  antibiotics were overused and the bacteria evolved
• why can antibiotics not treat viruses?

  viruses live and reproduce in human cells, so it would be difficult to develop drugs that kill viruses without also damaging body's tissues
• what is preclinical testing?

  testing of medicine on cells,tissues or on live animals as the drug can be toxic to humans
• what is clinical testing?

  very low doses of the drug are given to healthy volunteers which checks its safe and if it is, optimal dose found
• whats a placebo?

  tablet or injection with no active drug
• what is the double blind trials?

  when test groups receive active group and an placebo group receive dummy drug that looks like test drug but has no active drug. neither patients or doctor knows who has placebo- this stops bias
• what are the uses of glucose in plants?

  respiration, stored as starch, fats or oils and making amino acids
• what is energy needed for?

  movement, keeping warm and chemical reactions to build larger molecules
• why does aerobic respiration release more energy than anaerobic respiration?

  oxidation of glucose is complete in aerobic respiration and incomplete in anaerobic
• how does the body supply the muscles with more oxygenated blood during exercise?


  heart rate, breathing rate and volume increase
• what happens to muscles during long periods of activity?

  muscles become fatigued and stop contracting efficiently
• what is oxgen debt?

  amount of oxygen needed after exercise to react with the accumulated lactic acid and remove it from cells
• how is lactic acid removed from the body?

  lactic acid in muscles, blood transports to the liver, lactic acid converted back to glucose
• what is metabolism?

  sum of all the reactions in a cell or the body
• why are limiting factors important in the economics of growing plants in greenhouses?

  greenhouses need to produce the maximum rate of photosynthesis while making profit