BIO PAPER 1

• Mitosis


  2 genetically identical daughter cells, clones (PMAT) for growth, repair and development
• Diffusion


  • Surface area, concentration gradient, temperature
• Calculate surface area to volume ratio

  1. Total surface area= (length ☓ width) ☓ (amount of faces of the shape)

  2. Volume ratio= length ☓ width ☓ height
• How they are adapted for diffusion

  • Small intestines - villi increase the surface area
  • Alveoli in the lungs - large surface area
  • Fish gills- thin gill for a massive surface area
• Active transport examples

  • Mineral ions in plant
  • Food particles from small intestine
• Enzyme

  Made of long chains of amino acids, affected by temperature, pH
• Digestive system

  Breaks down large insoluble molecules into small soluble molecules
• Digestive enzymes

  • A- amylase for starch in the mouth
  • P- protease for protein in stomach
  • CALP- in pancreas, small intestine
• Blood components

  • Red blood cells- oxygen from lungs to rest of the body, transport carbon dioxide to lungs
  • White blood cells- fights off infections by attacking pathogens
  • Platelets- helps blood stop clotting when cut
• Heart

  Deoxygenated blood on right, Oxygenated blood on left
• How heart rate is controlled by body

  Specialised cells in the right atrium
• Coronary heart disease

  Coronary arteries blocked by layers of fatty build up,

  Stents- opens the lumen, surgery risks,

  Statins- drugs that reduce cholesterol level, side effects
• Arteries

  Carry oxygenated blood away from heart
• Veins

  Carry deoxygenated blood to the heart
• Diseases

  Can cause poor health (physical well being)
• Tumours

  When cell divide uncontrollably (benign or malignant)
• Cancer

  Malignant tumours
• Leaf structure

  • Epidermal- waxy cuticle to prevent water loss
  • Upper epidermis- thin to allow light to pass through
  • Palisade- photosynthesis takes place
  • Lower epidermis- full of stomata that allows gases to diffuse
  • Guard cells- open and close
  • Palisade mesophyll- has lots of chloroplasts
• Phloem

  Glucose and amino acids up and down (flowing up and down)
• Xylem

  Water and minerals up
• Transpiration

  Loss of water from plant surface
• Factors affecting transpiration

  • Temperature- increase
  • Humidity- decrease
  • Air movement- increase
  • Light intensity- increase
• Pathogens

  • Bacteria
  • Virus
  • Fungi
  • Protist
• Bacteria

  Reproduce rapidly, Produce toxins= damage cells + tissue to make you feel ill
• Virus

  Reproduce rapidly, Control the cells to produce viruses, Cell bursts= release new cells, Cell is damaged to make you feel ill
• Protists

  Live in a host organism's body = damage to the body, Transferred by vectors
• Fungi

  Made up of hyphae (thread like structure), Hyphae penetrate human skin/ surface of plants to make them feel ill
• How pathogens spread

  • Water = dirty water
  • Air = coughing and sneezing
  • Direct contact = touching contaminated surface
• Defence system

  • Skin- physical barrier
  • Nose mucus- physical barrier
  • Stomach- chemical barrier
  • Phagocytes- surround any pathogen in blood and engulf them
• If enough people are vaccinated then the spread of disease can be reduced
• Antibiotics

  Slow the growth of bacterial infections
• Painkillers

  Doesn't cure the disease
• Natural sources of drugs

  • Penicillin- came from mould
  • Aspirin- willow
  • Digitalis- foxgloves
• Preclinical testing


  Ensure drug is safe and effective, not given to human
• Clinical testing


  Drugs can tested on real people, double blind trials
• Photosynthesis


  Endothermic reaction
• Factors affecting photosynthesis


  • Light intensity
  • Carbon dioxide concentration
  • Temperature
  • Chlorophyll
• Uses of glucose from photosynthesis

  • Respiration
  • Convert to starch for storage
  • Produce lipids
  • Produce cellulose
  • Make amino acids for photosynthesis
• Respiration

  Exothermic reaction
• Aerobic respiration

  Uses oxygen