Topic 6 ( enzymes and digestive system ) Flashcards
definition of enzymes
protein molecules that act as a biological catalyst.
what does enzymes speed up
metabolic reactions
definition of catalyst
a substance which increases the speed of a reaction, without being changed or used up in the reaction
definition of substrate
a substance that an enzyme acts on to produce a chemical reaction
definition of active site
A specific region of an enzyme where the substrate binds
definition of enzyme - substrate - complex
The temporary complex formed when the substrate binds to the active site of the enzyme
definition of product
a substance created in a chemical reaction
explain how enzyme works
- substrate binds to the active site
- enzyme - substrate - complex
- substrate broken down into products
how is the active site and substrate shaped
complementary in shape
explain enzyme specificity
- enzyme speeds up 1 reaction
- enzyme specific to substrate
- lock - and - key hypothesis
- substrate fits in to the enzyme
- shape determined by amino acids
what affects enzyme activity
- temperature
- pH levels
how does temperature affect enzyme activity
- low temperature: less energy, less activity
- high temperature: more energy, increases rate of reaction
definition of optimum temperature
the temperature which the enzyme work the fastest at
optimum temperature for enzymes in humans
37 degrees
definition of denaturation
when the shape of the active site changes shape and therefore enzyme can’t react with substrate
how does high temperature denature an enzyme
- breaks the bond holding the enzyme together
- changes shape of active site
how does pH levels affect enzyme activity
too high/low pH level denatures the enzyme
what are the optimum pH levels for enzymes
different for enzymes
how does pH levels denature enzymes
- moving too far away from optimum pH breaks the bond holding the enzyme together
- changes shape of active site
which enzyme to use when investigating the affect of temperature on enzymes
amylase
which enzyme to use when investigating the affect of pH levels on enzymes
amylase
the order of the digestive system
Mouth (salivary glands)
Oesophagus
Stomach
Liver
Gall Bladder
Pancreas
Small intestine ( duodenum then illeum )
(appendix)
Large intestine
Rectum
Anus
definition of ingestion
the taking in of substances
definition of digestion
the breakdown of large, insoluble food molecules into small, soluble molecules using mechanical and chemical processes
definition of absorption
the movement of small food molecules and ions through the wall of intestine to the blood
definition of egestion
the passing out of food that has not been digested or absorbed as faeces
function of the mouth
- where food enters
- site of ingestion
- mastication
function of salivary glands
- site of chemical digestion
- secrete saliva which contains amylase
- lubricates the food
function of oesophagus
- passes down food to the stomach through peristalsis
- site of mechanical digestion
definition of peristalsis
the process of wave-like muscle contractions that move food through the digestive system
function of stomach
- churns food
- produce pepsin
- produce hydrochloric acid
- site of chemical and mechanical digestion
function of Liver
produces bile
function of gall bladder
- stores bile
- releases bile to the duodenum
function of bile
- emulsifies fat molecules
- neutralises stomach acid
- set optimum pH level for enzymes
function of pancreas
release pancreatic juice into duodenum
( contains amylase + protease + lipase )
function of small intestine
- mix food with digestive enzymes
- absorb food molecules into blood
- site of absorption and chemical digestion
function of duodenum
- start of small intestine
- bile and pancreatic juice enters here
function of Ileum
diffuse food molecules into the blood stream
adaptions of the small intestine
- thin walls
- long
- villis
- blood supply
- permeable
adaption of villi
- lacteal: transports fatty acid + glycerol away from small intestine
- microvilli: small projection on the end of lining
- blood capillaries: transports amino acids + glucose away from small intestine
function of appendix
- where small intestine meets large intestine
- stores healthy types of gut bacteria
function of large intestine
absorbs excess water
function of rectum
stores faeces until it’s time to release
function of anus
where faeces leave the body (alimentary canal)
what are Carbohydrase
enzymes that breaks down carbohydrate (starch) into simple sugars
features of Amylase
- type of carbohydrase
- located in salivary glands, pancreas and small intestine
- breaks down starch into maltose
features of Maltase
- type of carbohydrase
- located in salivary glands, pancreas and small intestine
- breaks down maltose into glucose
what are protease
- enzymes that breaks down protein into amino acids
- produced in pancreas and small intestine
features of pepsin
- type of protease
- located in stomach
- optimum pH level of 2
- breaks down protein into smaller polypeptide chains
what are lipase
- enzymes that breaks down lipids into fatty acids and glycerol
- produced in pancreas and small intestine
