organisation

• Differentiation

  process in which cells become specialized in structure and function - cannot turn back

  
• Muscular Tissue

  Contracts and moves the various parts of the body.

  
• Glandular tissue

  makes and secretes chemicals like enzymes and hormones

  
• Epithelial tissue

  A body tissue that covers the surfaces of the body, inside and out

  
• Organ Systems

  A group of organs working to perform a particular function

  
• Enzymes

  Catalysts for chemical reactions in living things. They have special shapes that fit to exclusive substrates
• Parts of Enzymes

  enzyme, substrate, active site, products
• Describe the Lock and Key model

  1. Substrate collides with the active site of an enzyme

  2. Substrate binds, enzyme-substrate complex forms

  3. Substrate converted to products

  4. Products released from the active site which is now free to bind to another substrate

  
• factors affecting enzyme

  Temperature, pH, enzyme concentration, substrate concentration

  
• Practical - investigating enzyme reactivity

  1 - put a drop of iodine solution into every well of a spotting tile

  2 - Place a bunsen burner on a heat-proof mat, and a tripod and gauze over the bunsen burner. Put a beaker of water on top of the tripod and heat the water until it is 35 degrees celcius. (use thermometer). try to keep the temp of the water constant throughout the experiment.

  3 - Use a syringe to add 1cm^3 of amylase solution and 1cm^3 of a buffer solution with a pH of 5 to a boiling tube. Using test tube holders, put the tube into the beaker of water and wait for five minutes.

  4 - Next, use a different syringe to add 5cm^3 of a starch solution to the boiling tube.

  5 - Immediately mix the contents of the boiling tube and sart a stop clock.

  6 - Use a continuous sampling to record how long it takes for the amylase to break down all of the starch. To do this, use a dropping pipette to take a fresh sample from the boiling tube every 30 seconds and put a drop into a well. When the iodine solution remains browny-orange, starch is no longer present.

  7 - repeat the whole experiment with buffer solutions of different pH values to see how pH affects the time taken for the starch to be broken down.
• rate of reaction

  the change in concentration of a reactant or product per unit time eg) change / time
• types of enzymes

  protease, lipase, carbohydrase, amylase(type of carbohydrase)
• creating samples for food tests

  1 - Break food using a mortar and pestle

  2 - Place into distilled water

  3 - stir using a glass rod until some is dissolved

  4 - filter out the undissolved pieces, and use the leftover solution for food tests

  
  

  For Sudan III, do not filter the solution, leave it slightly dissolved in water.
• practical - Food tests - Protein (Biuret test)

  1 - Add 2cm^3 of Biuret solution to 2cm^3 of food sample

  2 - Gently shake

  3 - If protein is present, the solution will turn form a blue to a pink / purple colour

  
• practical - Food tests - Starch (Iodine test)

  1 - Add a few drops of iodine to 5cm^3 of food sample

  2 - Gently shake

  3 - If starch is present, the solution will change from a brown to a blue /black colour

  
• practical - Food tests - Sugar (Benedict's test)

  1 - Add 10 drops of benedict's solution to 5cm^3 of food sample and gently shake

  2 - Place into a 75 degree Celsius water bath for 5 minutes

  3 - If sugar is present, the solution will turn from a blue to a green, yellow or red colour, depending on how much sugar is present.

  
• practical - Food tests - lipids (Sudan III test)

  1 - Add 3 drops of Sudan III to 5cm^3 of unfiltered food sample

  2 - Gently shake

  3 - If lipids are present, a bright red layer will form at the top

  
• practical - Food tests - lipids (Emulsion test)

  1 - Add 2cm^3 of ethanol to a small amount of food sample

  2 - Shake vigorously until all the sample is dissolved

  3 - Add 2cm^3 of distilled water

  4- If lipids are present, the solution will go a cloudy, whit colour.
• the lungs

  two spongy organs, located in the thoracic cavity enclosed by the diaphragm and rib cage, responsible for respiration

  
• alveoli

  tiny sacs of lung tissue specialized for the movement of gases between air and blood

  
• heart

  A hollow, muscular organ that pumps blood throughout the body.

  
• double circulatory system

  A system in which blood passes twice through the heart on one complete circuit of the body

  
• blood vessel types

  arteries, capillaries, veins

  
• plant cell organisation

  Organs (roots, stems, shoots and leaves) and tissues

  
  

  Plant tissues:

  - Epidermal (covers whole plant)

  - Palisade mesophyll (where photosynthesis happens in the leaf)

  - Xylem and Phloem (transport)

  - Meristem (differentiate to grow)

  - Spongy mesophyll (air spaces in the leaf)

  
• transpiration

  loss of water from a plant through its leaves. This causes more water to be drawn through the roots into the xylem vessels and onto the leaves

  
• Translocation

  the transportation of food substances usually through the phloem. Can travel both ways

  
• factors affecting the rate of transpiration

  Light intensity, temperature, humidity and wind speed.

  
• measuring transpiration

  Potometer:

  A potometer can be used to measure the volume of water absorbed. Usually a leafy shoot is used instead of a single leaf.

  
  

  A simple potometer comprises:

  
  

  -a container of water

  -a capillary tube

  -rubber tubing (to connect the capillary tube to the stem of the leafy shoot)

  -a scale (to measure the distance travelled by a bubble in the capillary tube)

  -A leafy branch (placed in capillary tube and sealed with rubber tubing. Other end is in water. An air bubble is approximately half way up tube.)

  -A ruler (is used to measure volume of water absorbed.)

  
  

  The faster the bubble moves, the greater the rate of water uptake - and so the greater the rate of transpiration. You can vary the conditions to investigate the effect of:

  
  

  changing temperature

  humidity

  wind speed (for example, with a hair dryer)

  light intensity

  
• stomata

  Small openings on the underside of a leaf through which oxygen and carbon dioxide can move