3.3.3.1 Proteins - Enzymes and Digestion Flashcards
The 2 stages of digestion humans are…
Physical breakdown by teeth or stomach churning
Chemical digestion by enzymes
What is the function of the pancreas?
Releases pancreatic juice onto food, as it exits the stomach, which contains proteases, lipases and carbohydrases
Give some examples of proteases involved in digestion
Endopeptidase
Exopeptidase
Dipeptidase
What is the function of teeth?
To physically break down food and increase its surface area
What is meant by chemical digestion?
When large food molecules are hydrolysed into smaller molecules by enzymes
Give some examples of carbohydrases involved in digestion
Salivary Amylase Pancreatic Amylase Maltase Sucrase Lactase
Name the cell membrane-bound protease
Dipeptidase
Bile salts are produced by the…
Liver
What is the function of maltase?
To break down maltose into 2 alpha-glucose molecules
What is the function of the stomach?
Produces proteases for protein digestion
Churns food to physically break it down
What is the function of salivary amylase?
To hydrolyse starch into maltose
What is the function of lipase?
To hydrolyse the ester bonds in triglycerides to give fatty acids and monoglycerides
How does the body break down maltose?
The lining of the ileum has maltase enzymes bound to their membranes
What is the function of exopeptidases?
To hydrolyse the peptide bonds at the ends of peptide molecules, which releases amino acids and dipeptides
Name the 3 membrane bound disaccharides…
Maltase
Sucrase
Lactase
What is the function of dipeptidases?
To hydrolyse the peptide bonds between dipeptides.
They are membrane bound enzymes
What is the function of the ileum (small intestine)?
Produces enzymes to digest food
Absorbs the products of digestion into the blood
What is the function of the oesophagus?
To carry food from the mouth to the stomach
What is the function of the large intestine?
To absorb water
What is meant by egestion?
The removal of faeces via the anus
What is the function of bile salts?
To emulsify large lipid molecules into smaller lipid micelles. To increase the surface area that lipase can act on
What is the function of lactase?
To hydrolyse the glycosidic bond in a lactose molecule to give glucose and galactose
What is the function of pancreatic amylase?
To hydrolyse starch in the ileum that was not broken down in the mouth
How does physical breakdown aid digestion?
Creates a larger surface area for enzymes to act on
Makes food easier to ingest (swallow)
Starch is not digested when food enters the stomach. Why?
The salivary amylase enzymes are denatured by the hydrochloric acid in the stomach
What is the function of endopeptidases?
To hydrolyse the central peptide bonds in a large protein molecule to give smaller peptide molecules
Name the 3 categories of enzymes
Carbohydrases
Proteases
Lipases
Which type of bond does amylase break?
Alpha 1-4 glycosidic bonds
What is meant by hydrolysis?
When a water molecule is added to a molecule to break a chemical bond.
What is the function of sucrase?
To hydrolyse the glycosidic bond in a sucrose molecule to give glucose and fructose.
Which enzyme is produced by the salivary glands?
Salivary amylase
Enzymes are secreted by..
Glands
What is the function of the rectum?
The final section of the intestines which stores faeces
What is a monoglyceride
A glycerol molecule with 1 fatty acid attached
Name the 3 proteases (peptidases) that are involved in protein digestion
Endopeptidases
Exopeptidase
Dipeptidase
