GCSE BIOLOGY

• Define movement


  An action by an organism or part of an organism causing a change of position or place
• Define respiration


  The chemical reaction that breaks down nutrient molecules in living cells to release energy
• Respiration word equation


  Glucose+oxygen->water+carbon dioxide
• Respiration symbol equation

  
• Define sensitivity


  Ability to detect or sense changes in the environment and to make responses
• Define growth


  A permanent increase in size and mass by an increase in cell number or cell size
• Define reprouction


  Processes that make more of the same kind of organisms
• Define excretion


  Removal from organisms of toxic materials, the waste product of metabolism and substances in excess requirement
• Define nutrition


  Taking in of nutrients which are organic substances and mineral ions, containing raw materials or energy for growth and tissue repair, absorbing and assimilating them
• Define cell


  The smallest structural and functional unit of an aorganism
• State differences between the typical animal and plant cell

  -Only plant cells have chloroplasts and cell walls

  -Shape of plant cell is more regular

  -Animal cells store carbohydrates as glycogen, plant cells store carbohydrates as starch
• Function of nucleus (cell)

  Contains DNA (Genetic material), which controls cell activity
• Function of cytoplasm


  Where chemical reactions take place
• Function of cell membrane


  Partially permeable membrane which controls substances that move in and out of the cell
• Function of cell wall


  Strengthens and protects the cell
• Function of chloroplast


  Contains chlorophyll which absorbs light energy for photosyntheis
• Word equation for photosynthesis

  Carbon dioxide+water->Oxygen+glucose
• Symbol equation fo photosynthesis

  
• Function of vacuole


  Filled with cell sap which helps keep the cell turgid
• Function of red blood cell

  Carries oxygen around the body to all respiring tissues

  (Contains haemoglobin which picks up oxygen)
• How the red blood cell is suitable for its function

  -Biconcave shape (Higher surface area)

  -No nucleus (Can move around more easily and allows the cell to hold more oxygen)
• Function of root hair cell

  To absorb water and mineral ions for the plant (vis osmosis
• How the root hair cell is suitable for its function

  -Elongated section to its main body (Higher surface area)

  -Membrane of the root is semi permeable (only water and minerals can go through)
• Define diffusion


  The net movement of molecules form a region of high concentration to a region of lower concentration down a concentration gradient (Result of random movement/brownian motion)
• Importance of diffusion in gases

  -Necessary for gas exchange in living organisms

  -Necessary for photosynthesis
• Importance of diffusion in water as a solvent

  -Absorption of minerals in plants (minerals salt needs to dissolve in water)

  -Necessary for excretion (pee)
• Define osmosis


  The diffusion of water molecules from a region of high concentration to a region of lower concentration through a semi permeable membrane
• Osmosis in plant cells

  -Water enters the root hair cell through osmosis

  -If vacuoles aren't full of water the cell will become flaccid causing the plant to will
• Osmosis in animal cells

  -If surrounded with high water potential, water will enter the cell, if to much water ends up in the cell it will burst

  -If surrounded with low water potential, water in cytoplasm will diffuse outwards causing the cell to shrink
• Define enzyme


  Proteins that function as biological catalysts (speeds up reaction in living cells)
• Define substrate molecule


  A substance on which enzymes act on
• Define active site


  A region on an enzyme which binds to the substrate during a reaction
• Explain the lock and key mechanism for enzymes

  An enzyme has to be the right shape for the substrate to fit into. An enzyme will only accept 1 substrate (1 specific chemical reaction)
• Temperatures effect on enzymes

  -As temperature increase so does the rate of reaction, up to a certain point. This point is known as the "optimum temperature". If the temperature goes above this enzyme activity will decrease (denature)

  -If the temperature is to low the enzyme will be dormand
• PHs effect on enzymes

  -Different enzymes work best at different PH s

  -If the PH is to low OR to high the enzyme will denature
• Function of protease


  Breaks down protein
• Function of amylase


  Breaks down starch
• Function of lipase


  Breaks down fats and oils
• Denature


  Change in the structure of the enzyme
• What is starch and glycogen made up of

  Glucose