Section 1- Structures and Functions in Living Organisms

Characteristics of Living Organisms
1. M= Movement
2. R= Respiration
3. S= Sensitivity
4. G= Growth
5. R= Reproduction
6. E= Excretion
7. N= Nutrition
Levels of organisation
1. Animal Cells
2. Plant Cells
3. Organelles
  1. Tiny structures within cells.
  2. E.g. the nucleus or chloroplasts
4. Specialised Cells
  1. Cells that are specialised are made to carry out a specific function
  2. (Stem cells are not specialised so can be told to do whatever we want)
  3. E.g. red blood cells are specialised in carrying oxygen
  4. E.g. egg and sperm cells
5. Tissues
  1. A tissue is a group of similar cells that work together to carry out a particular function
  2. E.g. xlyem tissue (for transporting water and mineral salts) and phloem tissue (for transporting sucrose and amino acids).
  3. Tissues can contain more than 1 cell type
6. Organs
  1. These form Organ systems
    1. Organs work together to form organ systems. Each system does a different job.
    2. E.g. the digestive system
  2. An organ ia a group of tissues that work together to perform a function
  3. E.g. Lungs
Plants, Animals and Fungi
1. Plants
  1. Multicellular
  2. Carry out photosynthesis
  3. Have cell walls
  4. Store carbohydrates as sucrose or starch
2. Animals
  1. Multicellular
  2. Cannot photossynthesise due to not having chloroplasts and plant cell structures/organelles
    1. Don't have a cell wall
  3. Most have a nervous system so are able to react and adapt to their surroundings
  4. Can move easily
  5. Can store carbohydrate in form of glucogen
3. Fungi
  1. Some are single-celled
    1. Others have a body called a mycelium made up of hyphae
  2. Can't photosynthesise
  3. Have cell walls made of chittin
  4. Feed off other living things
  5. Store carbohydrates as glucogen
4. All living things are split into 5 kingdoms
  1. The Kingdoms
    1. The Animal Kingdom
    2. The Plant Kingdom
    3. The Bacteria Kingdom
    4. The Fungi Kingdom
    5. The Protist Kingdom
  2. Viruses are NOT part of any kingdoms because they have to live in or on something else and rely on them.
    1. Depend on other living organisms=parasites
Protocists, Bacteria and Viruses
1. Protoctists
  1. Single-celled
  2. Some have chloroplasts like plant cells
    1. Others are like animal cells
  3. Microscopic
2. Bacteria
  1. Single-celled
  2. Microscopic
  3. Don't have a nucleus
  4. Circular chromosome of DNA
  5. Some can photosynthesise
  6. Feed of other living/dead organisms
3. Viruses
  1. Particles rather than cells and are smaller than bacteria
  2. Can only reproduce inside living cells
  4. Infect all types of living organisms
  5. Don't have a structure, they come in many shapes and sizes
Enzymes
1. Enzymes are catalysts produced by living things that speed up the rate of reaction without being changed or used up in the reaction
2. Optimum temperature
  1. Enzymes work best at 37C
  2. Higher= Denatured
    1. Loses active site's shape and cannot function
  3. Lower= slower reaction
  4. Also have optimum Ph
3. 'Lock and key model'
  1. Active site
  2. Substrate
    1. A molecule that is changed in a reaction
  3. Reaction
4. Proteins that are made up of chains of amino acids
Osmosis
1. The movement of water molecules through a partially permeable membrane from an area of higher water concentration to an area of lower water concentration
2. Partially permeable membrane= only small molecules can get through
3. To 'even up' the concentrations on either side of the membrane (reach equilibrium)
4. Cells use osmosis
  1. Short of water
    1. Solution inside becomes concentrated
      1. Water molecules move into the cell to 'even up' the concentration again (osmosis)
  2. Too much water
    1. Solution inside becomes more dilute than that of outside
      1. Water is drawn out of the cell to 'even up' the concentration again (osmosis)
  3. Plant Cells
    1. Too much water/well watered= turgid
      1. Turgor pressure= when the cell is so full it pushes against the cell wall
    2. Not enough water/wilting= Flaccid
      1. Loses turgor pressure
Diffusion
1. The movement of particles from an area or higher concentration to an area of lower concentration
2. Liquids and gasses, not solids as the particles cannot move about freely
3. The bigger the difference in concentration, the faster it happens
  1. Warmer temperature makes diffusion happen faster too
4. Cell membranes use diffusion (and osmosis and active transport) to let small molecules (e.g. glucose, amino acids, water, oxygen) in and out of the cell
Active Transport
1. The movement of particles against a concentration gradient using energy released during respiration
  1. E.g. from an area of lower concentration to an area of higher concentration
2. Used in digestive system when there is a low concentration of nutrients in stomache but a high concentration of nutrients in the blood
3. Main factors that affect the movement of substances
  1. Surface area+volume
    1. Large surface area/volume= faster reaction
  2. Temperature
    1. Warmer= more energy= faster reaction
  3. Concentration gradient
    1. Bigger difference in concentration= faster reaction

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Section 1- Structures and Functions in Living Organisms

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