What are the three main monosaccharides?
glucose, fructose, galactose
What do glands produce?
enzymes
What do enzymes in the digestive system do?
Break down large, insoluble molecules into smaller, soluble ones ready for digestion
Where are the salivary glands and what do they do?
Near the mouth and it secretes salivary amylase via duct into the mouth to break down food
What does salivary amylase break down?
Starch into maltose
What pH does salivary amylase work best at?
a neutral pH of 7
How is neutral environment maintained in the mouth?
Mineral salts in the saliva maintain the neutral pH of 7
What does the oesophagus do in the digestive system?
moves food from the mouth to the stomach via peristalsis
Describe the phyiscal features of the oesphagus and how it is suited its function
Thick muscular wall, lined with flattened epithelial cells and mucus that wears away and is replaced to protect the lining of the oesphagus.
What does the stomach do in the digestive system?
It stores and digests food, especially proteins.
Produces proteases which digests proteins.
HCl which kills microorganisms.
How does the stomach protect itself from self digestion?
the goblet cells in the stomach secrete mucus to protect the stomach from being digested by the HCl and its own enzymes
How does the stomach make digestion of food more efficient?
it churns up food and increase the surface area of the substrate.
Which enzyme breaks down protein?
Pepsin
What is the role of the small intestine in the digestive system?
It digests food using enzymes and the products are absorbed into the bloodstream
What is the process of taking food in called?
Ingestion
What is the process of taking food molecules into the blood called?
Absorption
Molecules released from digestion can be incorporated into body tissue or used within the body, what is this process called?
Assimulation
What is the process of molecules leaving the body as faeces called?
Egestion
Describe how the small intestine is suited to its function
It’s a long muscular tube and its inner walls are folded into villi, giving it a larger surface area.
How is the surface area of the small intestine increased?
The inner walls are folded into villi which give it a larger surface area and this is further increased further by microvilli on the epithelium of each villus
What does the large intestine do?
Absorbs water, most re absorbed water comes from secretions of digestive glands. The food becomes direr and forms faeces
What is the pancreas and where is it situated?
A large gland below the stomach.
What does the pancreas do?
Secretes pancreatic juice which contains
- protease
- amylase
- lipase
What does protease do?
What product does it make?
hydrolyses proteins into amino acids
What does amylase do?
What product does it make?
hydrolyses starch into maltose
What does lipase do?
What products are made?
hydrolyses lipids into fatty acid and glycerol
What are the two different types of digestion?
Mechanical and chemical
What does mechanical digestion consist of?
Ingestion, mastication, peristalsis to increase surface area
What does chemical digestion do?
Uses enzymes to break down large insoluble molecules into smaller soluble molecules
Where is the duodenum in the digestive system?
The 1st part of the small intestine
What does carbohydrase do?
What product is made?
hydrolyses carbohydrates into monosaccharides
What does maltase do?
What product is made?
hydrolyses maltose into a-glucose
Why does it take several enzymes to break down a large molecule into its monomers?
Because enzymes are specific
Where is the enzyme amylase made?
In the mouth and pancreas
What is hydrolysis?
the splitting up of molecules by adding water to break their chemical bonds.
What is the monomer unit of a carbohydrate called?
Monosaccharide
What is the polymer of carbohydrates called?
polysacccharides
What test is used to test for reducing sugars?
Benedicts Test
