Year 1 - Digestion Flashcards
What is mechanical digestion?
Physically breaking down food into smaller particles
Examples of mechanical digestion
Chewing food using teeth in the mouth; muscles contractions of the stomach wall churning food
What is chemical digestion?
Chemically breaking down food using enzymes that perform hydrolysis
What is saliva?
It is a watery secretion, containing mural and salivate amylase and some mineral ions.
What pH is the mouth?
Slightly alkaline - the optimum pH for amylase
What lubricates the oesophagus?
Mucus
What is secreted by the stomach and what is its role?
Mucus and it is there to protect the stomach lining from attack by stomach acid
What is stomach acid made of and what is its role?
It is made of hydrochloric acid and its role is to denature protein to increase surface area, kill pathogens and activate digestive enzymes
What is carbohydrase?
The general term for an enzyme that breaks down carbohydrate.
What are the two polysaccharides of alpha glucose?
Starch (from plants) and glycogen (from animals)
What are starch and glycogen broken down to maltose by?
Salivary amylase in the mouth and the pancreatic amylase
Where is the pancreatic amylase secreted from where is it secreted into?
It is secreted by the pancreas and it is secreted into the small intestine.
What are the three enzymes that the small intestine produces?
Maltase, lactase and sucrose
What does maltase break down and into?
Maltase breaks down maltose to alpha glucose
What does lactase break down and into?
Lactase breaks down lactose to glucose and galactose
What does sucrase break down and into?
Sucrase breaks down sucrose to glucose and fructose
What pH does carbohydrases work the fastest?
At neutral pH
What are the two different types of protease?
Endopeptidase and exopeptidase
What is protease?
They digest proteins
What are endopeptidases?
They hydrolyse peptide bonds within proteins to form short chains of amino acids called peptides
What are exopeptidases?
They hydrolyse peptide bonds at the ends of a proteins to produce either dipeptides or single amino acids
What do exopeptidase produce?
Dipeptides or individual amino acids
What do endopeptidase produce?
Shorter polypeptides
What are the two specific endopeptidase?
Pepsin and trypsin
Where is pepsin secreted?
Gastric glands of the stomach
Where is trypsin secreted?
Pancreas into the small intestine
What is pepsin secreted as?
Inactive pepsinogen
What is trypsin secreted as?
Inactive typsinogen