3.3 Digestion & Absorption Flashcards
Where does stage 1 of protein digestion occur in the body?
Stomach
What is the first stage of protein breakdown?
Break long polypeptide chains in shorter chains
How do endopeptidases speed up the digestion of proteins?
Hydrolyse bonds in the middle of the chain
Create more ends/greater surface area for exopeptidases
What bonds do peptidases hydrolyse?
Peptide
Where does the second stage of protein breakdown occur?
Duodenum (small intestine)
What enzyme carries out stage 2 of protein breakdown?
Exopeptidases
What is the product in stage 2 of protein breakdown?
Dipeptides
What is a dipeptide?
2 amino acids joined by peptide bond
What enzyme carries out stage 3 of protein breakdown?
Dipeptidases
What is the product in stage 3 of protein breakdown?
Single amino acids
What is the first stage of starch breakdown?
Some starch is hydrolysed to maltose
Where does stage 1 of starch breakdown occur?
Mouth/salivary glands
What kind of biological molecule is starch?
Carbohydrate
What bonds does amylase hydrolyse?
Glycosidic
What reaction does amylase catalyse?
starch -> maltose
What kind of digestion is done by the teeth?
Mechanical
Why is it important to rip and grind food into smaller pieces?
Increase surface area:volume to increase enzyme action
What reaction does lactase catalyse?
lactose -> galactose + glucose
What reaction does sucrase catalyse?
sucrose -> glucose + fructose
What reaction does maltase catalyse?
disaccharides -> glucose
What is found in epithelial cells making up the wall of the ileum (small intestine)?
Dipeptidases
Lactase
Maltase
Sucrase
What problem is there with digestion of hydrophobic fats?
Form large globules in the body that have a small surface area:volume making enzyme action slow
What is bile?
A chemical produced in the liver that increases the surface area:volume of fats
Where is bile secreted?
Small intestine
