Cells and transport

• Life Processes


  Movement - travelling from place to place

  Reproduction - reproduces a new living organism

  Sensitivity - detecting changes in the surroundings and responding

  Control/homeostasis - keeping a constant internal environment e.g. body temp. in humans

  Growth - increasing in body size

  Respiration - releasing energy from food

  Excretion - removing waste substances

  Nutrition - taking in or making food
• Diagram of Animal Cell

  
• Sperm Cell

  • Male sex cell (gamete)
  • Combines with an egg to make a baby
  • Has a tail to swim to the egg
• Muscle Cell


  • Contracts (shortens) to create movement
  • Branches at each end to provide energy for contraction
• Red Blood Cell


  • Carries oxygen around the body
  • No nucleus so there is more space for haemoglobin which combines with oxygen
• Egg Cell


  • Female sex cell (gamete)
  • Combines with a sperm to make a baby
  • Only half the amount of DNA in its nucleus
  • Contains a food store
• Nerve Cell


  • Carries messages around the body
  • Has insulation to carry messages quickly/to carry messages long distances
• Compare Animal and Plant Cells

  Both cells have:

  mitochondria

  nucleus

  cytoplasm

  cell membrane

  ribosomes

  Plant cells have:

  a vacuole

  chloroplasts

  cell wall

  but animal cells do not
• How a root hair cell differs from a typical plant cell

  it has long projections which increase the surface area that the plant can use to absorb water and minerals: whereas a typically plant cell would usually have its roots to absorb water and minerals.

  
• Fungal Cells


  fungal cells are like animal cells= use complex organic compounds as a source of carbon, rather than fix carbon dioxide from the atmosphere as do some bacteria and most plants.

  However, fungal cells aren't like animal cells= they are different in terms of structure.
• Levels of Organisation


  atom

  molecule

  organelle

  cell

  tissue

  organ

  organ system

  organism
• Levels of Organisation

  
• Diffusion


  it is the movement of particles from an area of high concentration to a low concentration down a concentration gradient
• Variables


  independent variable - what you change

  dependent variable - what you measure

  control variable - keep the same
• CORMMSS - designing an experiment


  Change - independent variable

  Organism - same organism

  Repeats - same organism multiple times: using lots of samples

  Measure x2 - dependent variable: what, how long

  Samex2 - control variable
• Why does temperature affect the rate of diffusion

  temperature affects the rate of diffusion= as you increase the temp. you increase the amount of kinetic energy the particles have, so they have more successful collisions which increases the rate of reaction.
• Osmosis


  is the movement of water across a partially permeable membrane, from a dilute solution to a more concentrated solution down a concentration gradient.
• Following phrases meaning


  Partially permeable membrane - let's small molecules like water through but not large molecules like sugar.

  Dilute solution - contains lots of water in a given volume.

  Concentrated solution - contains little water in a given volume
• Calculating percentages changes


  
• Calculating surface area to volume ratios

  
• Calculating surface area to volume ratios

  
• Active Transport

  
• Active Transport


  Active transport is the movement of particles from an area of low concentration to an area of high concentration, using energy from respiration.
• Methods of transport

  
• Organ systems


  
• What is DNA?


  a store of genetic information in all living organisms
• Diagram of a plant cell