biology section 5/6

• what is the definition of health

  WHO says health is a state of complete physical, mental and social well being and not merley the absence of disease or infirmity
• communicable diseases

  cholera: pathogen bacterium, causes diarrhoea

  tuberculosis: pathogen bacterium, causes coughing & lung damage

  malaria: pathogen protist, causes damage to red blood cells & liver

  chalara ash dieback: pathogen fungus, causes leaf loss & bark lesions
• what is a virus


  arent cells and infect living cells to reproduce e.g HIV human immunodeficiency virus, kills and infects white blood cells
• physical barriers to stop pathogens entering body 


  skin: form sticky clots and seal cuts

  mucus & cilia: mucus catches dust and pathogens, cilia push the mucus to back of throat so it can be swallowed
• chemical barriers to stop pathogens entering body 


  eyes: chemical called lysozyme that kills bacteria

  stomach: produces hydrochloric acid & kills most pathogens that are swallowed
• what is an antibody 


  lymphocyte make antibodies go bind on pathogen to be destroyed by white blood cells
• how does memory lymphocytes make you immune

  in body for long time and remember specific antigens, can recognise pathogens and respond quickly
• how can immunisation stop you from getting infections 


  inject dead or inactive pathogens into the body so antibodies can destroy them, less likely to get disease
• how do antibiotics work

  inhibiting processes in bacterial cells (kill them) e.g stop cell walls from being built

  don’t inhibit in processes in cells of host organisms
• what is preclinical testing 


  first tested on human cells and tissues and then tested on live animals
• what is clinical testing 


  tested on healthy volunteers and if results are good they are tested on people with illnesses and these trials are blind
• BMI 


  25-29.9 - overweight

  BMI over 30 - obese

  BMI below 18.5 - underweight

  18.5–24.9 - healthy weight
• what is cardiovascular disease


  any disease to do with heart & blood vessels, too much cholesterol reduces blood flow and vessels become damaged, can cause blood clots which stop flow of blood leading to heart attack (no flow to heart muscles) or a stroke (no flow to brain)
• what’s drugs can reduce risk of heart attack & stoke

  statins: reduce cholesterol in bloodstream

  anticoagulants: blood clots less likely to form

  antihypertensives: deuce blood pressure but can cause fainting
• how can surgery help with cardiovascular disease 


  stents: tubes to allow blood flow, inserted in arteries

  coronary bypass surgery: healthy blood vessel to allow blood flow around blocked artery

  heart transplant

  risky as it can cause infection & loss of blood
• what is photosynthesis 


  the way plants and algae make their own food

  carbon dioxide + water -> light glucose + oxygen
• what can affect the rate of photosynthesis 


  light intensity: faster as light increases

  carbon dioxide: faster as concentration of co2 increases

  temperature: faster as temp increases but if it’s too hot, rate slows down and can stop
• what do root hairs do in transportation

  mineral ions absorbed by active transport and water absorbed by osmosis
• how to plan tubes transport food in transportation in plants

  living cells and end walls have small holes, leaf contain food substances and the tubes transport these around plant - process is translocation and it uses energy from respiration
• how do xylem tubes take water up in transportation in plants

  made of dead cells with no hole and no end wall, contain lignin to stay strong and carry water from roots to stems to leaves, carry out transpiration stream
• what is transpiration 


  loss of water from plant, caused by evaporation and diffusion of water from plants leaves
• what is stomata

  are tiny pores on mostly the lower surface of leaves, open to allow co2 and oxygen to diffuse in and out and and water vapour can also diffuse out during transpiration
• what affects the rate of transpiration

  light intensity: brighter light, faster transpiration, stomata closes when it’s dark and very little water can escape

  temperature: warmer, faster respiration, water particles have more energy and can move quickly out of stomata

  air flow: more windy, faster transpiration as water vapour is swept away and high concentration inside the leaf
• how can u estimate transpiration rate

  potometre

  record starting position of air bubble

  start stopwatch

  as plant takes up water air bubble gets sucked along tube

  record how far air bubble moves

  estimate transpiration rate = distance bubble moved/time taken