Enzymes and digestion Flashcards
what are enzymes
biological catalysts that speed up a chemical reaction without being used up. They are globular proteins- have tertiary structures-3D complex shape, soluble. Have more hydrophyllic groups on outside
What is metabolism
The total of all chemical reactions and organism need to survive.
what is the reaction of metabolism
metabolism= anabolism+catabolism
what is anabolism
the buildup of chemical substances such as photosynthesis and protein synthesis
what is catabolism
the breakdown of substances of chemical substances such as respiration and digestion.
how do enzymes work
enzymes have an active site which has a specific shape which the substrate binds to.The active site shape is determined by the teritiary structure. The enzyme’s active site and substarey must be complimentary or else reaction won’t catalyse.If substrate collides sucessfully with active site it will form an enzyme substrate complex. This binds the reactants together and stresses covalant bonds allowing reaction to occur.
how do we get enzymes with different enzyme shapes
because they have different DNA sequencing- different 3D shape.
what does anabolic result in
2 substrates-1 product
what does catabolic reaction result in
1 substate-2 products
Where is an active site on
ALWAYS ON AN ENZYME.
how does a product form into products
enzyme’s active site and substare must collide sucessfully to form an enzymes substrate complex. active site molds around the substarte- tensiosn on bonds break- products formed.
what is activation energy
A certain amount of energy needs to be supplied to the chemicals before the reaction will start-often provided as heat
what are intracellular enzymes
enzymes that work inside the cells that made them
what extracellular enzymes
made in cell but released outside cell.
what is the lock and theory
suggests that the active site is rigid and therefore the substrates must be complimentary
what is the induced fit theory
suggests that the active site is flexible and can mould around the substarte to fit.
what is the definition of digestion
the process of hydrolysing large insoluble molecules into smaller soluble molecules that can be absorbed and assimilated.
Describe the digestion of starch
starch is made up of many glucose molecules held by glycosidic bonds. Amylase produced by the salivary glands in the mouth and by the deoduem which hydrolyses the starch and breaks it down to maltose. maltose is hydrolysed by the membrane bound enzyme maltase into glucose and water in the illeum which can then be absorbed.
describe the digestion of protein
Protein is hydrolysed by 3 proteases called endopeptidases, exopeptidases and dipeptidases. Endopeptidases hydrolyses the middle of the polypeptide chain to form smaller polypeptide chains which occurs in the stomach e.g pepsin, exopeptidases hydrolyses the peptide bonds between the polypeptide chain to form dipeptides which occyrs in the small intestine e.g trypsin, dipeptidases hydrolyse the peptide bond in a dipeptide to from amino acids.The enzymes are membrane bound enzymes.
describe the digestion of lipids.
in the deodeum the large insoluble fat globules are hydrolysed by lipase with the help of bile salts which are made in the liver and they emulsify the fats into smaller fat droplets called micelles. this is caleed emulsification. The smaller fat globules increase surface area for faster hydrolysis so lipase can act on it quicker. The micelles are products of digestion and they carry fattyu acid and glycerol. The micelles diffuse through the membrane of microvili of small intestine which then the golgi apparatus processes, packages and modifies the triglyceride and the protein from a cylomicron and then it leaves the cell by exocytosis to the lacteal to liver then to the blod.
