Biology

• Blood vessels


  • Arteries
  • Capillaries
  • Veins
• Arteries


  • Carry blood away from the heart
  • Have strong & elastic walls
  • Thick walls compared to lumen
  • Thick layer of muscle and elastic fibres to allow them to stretch
• Capillaries


  • Exchange materials at the tissue
  • Really small and have permeable walls to allow substances to diffuse
  • Carry blood close to every cell
  • One cell thick & Small lumen
  • Supply food and oxygen
• Veins


  • Take blood back to the heart
  • Joined up capillaries
  • Lower blood pressure / thinner walls
  • Bigger lumen to allow blood to flow
  • Valves to help prevent back flow
• Blood components


  • Red blood cells
  • White blood cells
  • Platelets
  • Plasma
• Red blood cells


  • Carry oxygen from lungs to body
  • Biconcave disc shape
  • Large surface area to absorb oxygen
  • No nucleus
  • Red pigment Haemoglobin binds with Oxygen (Oxyhaemoglobin) and releases O
• White blood cells


  • Can gobble up unwelcomed micro-organisms
  • Can produce antibodies that can fight & Antitoxins to neutralise toxins
  • Have a nucleus
  • Fight and defend against any infection
• Platelets


  • Small fragments of cells
  • No nucleus
  • Help blood clot wounds, to stop blood pouring out and micro-organisms getting in
  • Lack of platelets cause excessive bleeding
• Plasma


  • Liquid that carries everything in blood
  • Nutrients: glucose & amino acids
  • Red, white blood cells and platelets
  • Carbon dioxide from organs to lungs
  • Urea from kidney (from liver)
  • Hormones, proteins, antibodies
• Aerobic Respiration


  Needs Plenty of Oxygen
• Aerobic Respiration


  The most efficient way to transfer energy from glucose
• Aerobic Respiration


  1. Glucose + Oxygen

  2. Carbon Dioxide + Water
• Anaerobic Respiration


  Used if There's Not Enough Oxygen
• Anaerobic Respiration in Muscle Cells

  1. Glucose

  2. Lactic Acid
• Anaerobic respiration does not transfer as much energy as aerobic respiration
• Anaerobic respiration is only useful in emergencies, e.g. during exercise when it allows you to keep using your muscles for a while longer
• Anaerobic Respiration in Plants and Yeast

  Produces Ethanol and Carbon Dioxide instead of Lactic Acid
• Anaerobic Respiration in Yeast Cells

  Called Fermentation
• Uses of Fermentation


  • Making bread
  • Making alcoholic drinks like beer and wine
• Fermentation is a really important process because of its use in making alcoholic drinks and bread
• Aerobic Respiration


  Process that uses oxygen to convert glucose into ATP, water, and carbon dioxide
• Carbon Dioxide (CO2)


  Byproduct of aerobic respiration; created when electrons are passed along the electron transport chain and released from the cell as a waste product
• Oxygen (O2)


  Gas needed in large quantities for aerobic respiration; serves as the final electron acceptor in the electron transport chain