digestion and ezymes Flashcards
what do carbohydrates become when they are digested by which enzyme ?
carbohydrase/amylase
sugars eg glucose
what do lipids become when they are digested by which enzyme?
lipase
fatty acids and glycerol
what does protien become when it is digested by which enzyme?
protease
amino acids
what is the function of the mouth in the digestive system?
- where chemical and mechanical digestion begins
- chewing breaks down food to increase surface area
- saliva containing amalyse (starch>glucose)
what is the function of the oesophagus in the digestive system?
moves food to stomach through peristalsis (strong muscle contractions)
what is the function of the stomach in the digestive system?
- muscular walls contract 3x/min to increase surface area of food
- stomach acid kills microbes
- acidic pH perfect for protease
what is the function of the liver in the digestive system?
- produces alkaline bile which neutralises stomach acid
- detoxifies blood
- stores carbohydrates as glycogen
what is the function of the gall bladder in the digestive system?
- small bag-like structure stores bile
- slowly drains bile into small intestine where it is needed
what is the function of the pancreas in the digestive system?
- produces enzymes needed for digestion
- produces isulin to control blood sugar
what is the function of the small intestine in the digestive system?
- large surface area to maximise absorption of soluable food
- produces enzymes
what is absorption?
where the soluable food passes through the small intstine wall into the blood stream
what is the function of the large intestine in the digestive system?
- absorbs water
- solidifies waste
what is the function of the anus in the digestive system?
- strong muscle that releases waste
what are the parts of the digestive system? (10 in order)
- mouth
- oesophagus
- stomach
- liver
- gall bladder
- pancreas
- small intestine
- large intestine
- rectum
- anus
what is the function of the bile in the digestive system?
- bile emulsifies fat into smaller droplets witha larger surface area increasing the rate of digestion
- bile is allkaline which neutralises stomach acid so that there is the optimum pH for the lipase enzyme
why is the small intestine an effective exchange surface? (good at absorption)
- 7m long
- covered in villi (which have very thin permeable membranes , lots of capilleries and good blood flow to mantain high concentratio gradient, increase surface area)
what are amino acids used for?
sythesized into new protiens in the ribosomes
.
what are fatty acids and glycerol used for?
- for energy
- to build cell membranes
- to make hormones
what test and colour change detects the presence of starch?
iodine test
orange > black
what test and colour change detects the presence of lipids?
emulsion test
colourless > milky white
what test and colour change detects the presence of protiens?
biuret test
blue > purple
what test and colour change detects the presence of sugar?
benedicts test
blue > brick red
how do enzymes work? (lock and key theory)
- large protien molecule which has a specific active site (lock) specific to one type of substrate (key)
- once the substrate is attached to the active site it is changed into the product
what factors affect enzyme controlled reactions? (2)
- pH
- temperature
what are optimum pHs and temps?
- a pH or temp where the enzyme works best
- above or below this optimum level, the RoR will slow down
what is denaturation?
- if the pH or temperature is too extreme, the shape of the active site will change irreveribly
- the enzyme will not work because the substrate cannot fit into the active sit, so it is DENATURED
what is an enzyme?
biological catalyst
what is the metabolism?
chemical reactions that convert food ito energy
what are metabolic pathways?
a series of chemical reactions that start with a substrate and finish with an end product.
what is the difference between catabolic and anabolic pathways?
catabolic
- release energy
- break down (degradation)
anabolic
- require energy
- build up (biosythesis)
what is the effect of enzymes of metabolic pathways?
lower activation energy neeeded for reaction to take placee
