enzymes and digestion- Bioligy

HideShow resource information
  • Created by: holly.567
  • Created on: 21-02-16 13:43


  • Enzymes are a type of (biological) catalyst and protein.
  • They can split/divide a molecule& recycleable
  • Many reactions in cells are catalysed by enzymes including: respiration, digestion, and photosynthesis.
  • Each protein has a unique number and order of amino acids which results in different shaped molecules with different functions.
  • Enzymes increase the rate of reactivity in living orgainisms otherwise the reactions would be too slow.
  • Enzymes have an active site where the reaction that they help to carry out occurs.
  • Enzymes are specific that is to say they only act on one type of molecule.
1 of 8

Enzyme diagrams

Lock and key:



Enzymes(how they work):




2 of 8

Enzymes at different temperatures

  • Enzymes work best at around 40(0c) this is because its the human bodys temperature where they can readily break down the waste as it is the humans amalayse.
  • As the temperature increases the enzymes activity increases up to the optimum temperaturre(40(0c)) and once it reaches this point it decreases until alll enzyme activity has stopped.
  • The increase of activity up to (40(0c)) is because as the temperature rises the particles have more energy, which results in a greater number of succesful reactions. Above (40(0c)) the enzymes begin to loose there shape anf theuy boce denatured.
3 of 8

enzymes at different pH's

  • As the pH increases the enzyme activity increases up to the optimum pH (8) when it then starts to gradually decrease, until enzyme activity stops. The farther away you then get from the optimum pH the less enzyme activity there is as the enzyme looses its shape and becomes dentured as a result it looses reactivity.
4 of 8

Key terms

  • Substrate- what an enzyme acts upon.
  • .....ase- enzyme.
  • Active site- the place where the reaction occurs.
  • Catalyst- a substrate that speeds up a chemical reaction.
  • Optimum- like the limit of proportionality the maximum.
  • Enzymes are specific to their substrate because they are fitted to the shape of the active cell (site) so they are specific to allow enzyme activity to be high.
5 of 8

Digestion in the body- why and where

  • We need to digest food so we can get the nutrients out of the food and increase the surface area so enzymes can "attack" larger surfaces and break down the food quicker and more effectively.
  • The digestive system:
6 of 8

enzymes in your body

  • LipASE is made in your stomach but works in your gut where it breaks down fat molecules into glycerol.
  • AmylASE is made in your salivary glands but works in your mouth (its in your saliva) where it breaks downstarch into glucose via a carbohydrase.
  • ProteASE is made in your stomach but works in your gut where it breaks down protein molecules into amino acids.
  • The acid in your stomach is called hydrochloric acid and is there because stomach ProteASE works best in an acid pH.
  • Bile is produced in your liver where it emulsifies fat- breaking into a larger surface area+ neutralises acid to make the best pH for the enzymes in the small intestine.
7 of 8


  • The small intsetine is adapted to its function by having millions of tiny, finger-like processes called villi(villus). this means that the digested food can pass through the small intestine easily into the blood vessels.
  • The villi increase the amount of surface area in the small intestine. the blood capillarycoming to the villus pick up food molecules and amino acids, sugars, fatty acids, glycerol molecules are all absorbed into the blood capillary. The blood then takes food molecules away to the rest of the body.
  • The lymph coming to the villus collects fatty acids and glycerol are absorbed into a lacteral and the lymph fluid carries fatty acids and glycerol away to the rest of the body.
8 of 8


No comments have yet been made

Similar Biology resources:

See all Biology resources »See all revision resources »