biology

• What do all cells have?

  • Nucleus
  • Cytoplasm
  • Cell Membrane
  • Mitochondria
  • Ribosomes
• What do only plant and algal cells have?

  • A Cellulose Cell Wall
  • Chloroplasts
  • A Vacuole
• What do Eukaryotic Cells have?

  • Cell Membrane
  • Cytoplasm
  • Genetic Material enclosed in a nucleus
• Prokaryotic Cells


  Cytoplasm and a cell membrane surrounded by a cell wall. Genetic Material is not in a nucleus, but in a single DNA loop. May also contain plasmids. E.g. Bacteria
• Diffusion


  The spreading out of particles of any substance in a solution or gas, resulting in a net movement from an area of higher concentration to an area of lower concentration
• Examples of dissolved substances which move in and out of cells by diffusion

  • Glucose
  • Urea
  • Oxygen
  • Carbon Dioxide
• Osmosis


  The movement of water from a dilute to a more concentrated solute solution through a partially permeable membrane
• Active Transport


  The movement of substances from a more dilute solution to a more concentrated solution. This uses energy from food in respiration
• Tissue


  A group of cells with a similar structure and function
• Organ


  A collection of tissues performing a specific function
• Benedict's test for sugars


  They turn blue Benedict's solution brick red on heating
• Ethanol test for lipids

  Ethanol will go milky white in the presence of lipids
• Biuret test for Protein

  Biuret turns from blue to purple in the presence of proteins
• Carbohydrases


  Break down carbohydrates to simple sugars
• Proteases


  Break down proteins to amino acids
• Lipases


  Break down lipids to fatty acids and glycerol
• Bile


  Produced by the liver and stored in the gall bladder, neutralises acid and emulsifies fats
• Plasma


  Has blood cells suspended in it and transports proteins and chemicals around the body
• Haemoglobin


  Binds to oxygen to transport it from the lungs to tissues
• White blood cells


  Protect against infection
• Platelets


  Cell fragments that start the clotting process at wounds
• Capillaries


  Substances diffuse in and out of the blood
• Human circulatory system


  A double circulatory system
• Stents


  Keep narrowed or blocked arteries open
• Statins


  Reduce cholesterol levels reducing the risk of coronary heart disease
• Resting heart rate


  Controlled by a group of cells in the right atrium that form a natural pacemaker
• Artificial pacemakers


  Used to correct irregularities in the heart rhythm
• Artificial hearts


  Keep patients alive while they wait for a transplant or to allow their own heart to rest
• Alveoli


  Provide a large surface area and a rich supply of blood capillaries, so gas can diffuse efficiently
• Xylem tissue


  Transports water and mineral ions from the roots to the stems and leaves
• Phloem


  Transports dissolved sugars from the leaves to the rest of the plant
• Transpiration


  Loss of water vapour from the leaves through the stomata (open for carbon dioxide for photosynthesis). Guard cells control this
• Communicable diseases


  Caused by pathogens (microorganisms) which include bacteria, viruses, fungi and protists
• How bacteria make you ill

  Produce toxins
• How viruses make you ill

  Live and reproduce inside your cells, causing cell damage
• Ways in which the spread of disease can be prevented

  • Simple Hygiene
  • Destroying Vectors
  • Vaccination
  • Isolation
• Measles Virus


  Droplet infection. Causes fever and a rash. Isolation and Vaccination
• HIV


  Flu-like illness. Attacks body's immune cells. AIDS occurs when the system become so damaged it can't deal with cancers or infections
• Tobacco Mosaic Virus


  Spread by contact and vectors. Damages leaves, reduces photosynthesis. No treatment. Spread controlled by field hygiene and pest control
• Rose Black Spot


  Spread by wind and water. Damages leaves so they drop off, affecting photosynthesis. Spread controlled by removing affected leaves and chemical sprays