Enzymes & Digestion Flashcards
Where are carbohydrases made? Where do they work
Made: Salivary gland, pancreas, small intestine
Work: Mouth, small intestine
Where are proteases made? Where do they work
Made: Stomach, pancreas, small intestine
Work: Stomach, small intestine
Where are lipases made? Where do they work
Made: Pancreas, small intestine
Work: Small intestine
What are the substrates and the product of carbohydrases
Substrates: Carbohydrates and startch
Prodcuct: Glucose
What is the substrate and the product of proteases
Substrate: Proteins
Prodcuct: Amino acid
What is the substrate and the products of lipases
Substrate: Lipids
Prodcucts: Glycerol and fatty acids
What do carbohydrases do
Break down/do lysis of carbohydrates in to monosaccharides
What do proteases do
Break down/do lysis of large, insoluble proteins in to small, soluble amino acids
What do lipases do
Break down/do lysis of large, insoluble lipids into small, soluble fatty acids and glycerol
What organs are in the digestive system
Mouth
Salivary gland
Oesophogus
Liver
Stomach
Gall bladder
Pancreas
Small intestine
Large intestine
Rectum
Anus
Why is it important for enzyme action for the mouth to chew food? (STARCH DIGESTION)
To increase the surface area of the food so more enzymes can act simultaneously and to make it easier to swallow
What does the saliva contain? What does this do? (STARCH DIGESTION)
Amylase and mineral ions
Amylase breaks down starch in to maltose and digests it
Mineral ions help to maintain an optimum pH
What happens to the salivary amylase once it reaches the stomach? Why? (STARCH DIGESTION)
It will become denatured preventing further hydrolysis of starch. This is because conditions are acidic in the stomach
What happens in the small intestine? What does this do (STARCH DIGESTION)
Pancreas releases pancreatic juice (containing pancreatic amylase) in to the small intestine. This hydrolyses any remaining starch in to maltose
Then alkaline salts are produced by the pancreas and intestine wall. This maintains an optimum pH for enzyme action
Where are the disaccharides in the small intestine found? Why is this useful? (STARCH DIGESTION)
The wall of the small intestines
To break down maltose to glucose, using maltose
Is glucose or starch solution present in the boiling tube at the start of the carbohydrate digestion experiment? Explain why
Neither glucose or starch is present because no diffusion has occurred
Is glucose or starch solution present in the visking tube at the start of the carbohydrate digestion experiment
Both are present
Is glucose or starch solution present in the boiling tube at the end of the carbohydrate digestion experiment?
Glucose solution is present but starch solution is not as starch cannot diffuse as it is too large whereas glucose is small enough
Is glucose or starch solution present in the visking tube at the end of the carbohydrate digestion experiment?
Both are present
What does visking tube represent (CARBOHYDRATE DIGESTION)
The gut
What does the solution INside the visking tube represent (CARBOHYDRATE DIGESTION)
The food
What does the solution OUTside the visking tube represent (CARBOHYDRATE DIGESTION)
The blood
How does glucose move through the visking tube in the carbohydrate digestion practical
By diffusion
Why does visking tubing let glucose through but not starch
Because the visking tubing is only semi permeable and starch is too large to be let through
What are the 3 parts of the small intestine
Duodenum, jejunum, ileum
Where does absorption take place in the small intestine
In the ileum - the final section of the small intestine
What do the small intestines have on them? How would you describe them and what do they do?
Villi & microvilli
Finger like protrusions on the small intestine
Increase the surface area of the small intestine
What does the small intestine contain
Membrane bound organelles called disaccharides
Are epithelial cells efficient in absorption of food molecules
Yes
What adaptations do epithelial cells have
Microvilli - Increases the surface area
Lots of mitochondria - Provide energy in the form of ATP in order to carry out active transport
Many proteins - Carrier proteins for active transport, channel/carrier proteins for facilitated diffusion, carrier proteins for co-transport of sodium and glucose ions, membrane bound enzymes digest disaccharides
How does glucose get from the lumen of the small intestine to the blood
A concentration gradient can not always be maintained
Therefore some glucose is able to be taken into the body by active transport. This means all glucose can go to the blood
This process involves active transport
Where does protein digestion start and where is it completed
Starts in the stomach and is completed by the small intestine
Define endopeptidase
Breaks down large polypeptides into smaller ones and hydrolyses internal peptide bonds
Give an example of an endopeptidase
Pepsin in the stomach or chymotrypsin, trypsin in the small intestine
Define exopeptidase
Splits off one amino acid at a time, working from the end of a polypeptide
What are the 2 types of exopeptidase
Aminopeptidase
Carboxypeptidase
What do dipeptidases do
Hydrolyse short peptides which are only 2 or 3 amino acids long
Where are dipeptidases located
On brush border membranes of the small intestine
How do co transport carrier proteins move things in protein absorption? What is it that is moved
In pairs
Di/tripeptides and H+ ions are moved together
Amino acids and Na+ ions are moved together
How do amino acids pass from epithelial cells to capillaries
By facilitated diffusion
What are the characteristics of saturated fats
Long, straight molecules
No more hydrogen can be added to the chain
They are packed closely together with strong intermolecular bonds
Solid at room temp, has a high melting point
Give an example of saturated fats
Meat and dairy products
What can unsaturated fats be
Monosaturated or polysaturated
Give an example of unsaturated fats
Fish and plant products
Where is bile made and stored
Made in the liver
Stored in the gall bladder
What does bile do? What is this called and how can this be an adaptation?
Binds to fat droplets and breaks them down in to smaller fat droplets. This is called emulsification and it increases the surface area for lipase digestion
What are micelles made of
Glycerol, fatty acids, monoglycerides and bile salts
What groups do micelles have? Where
A hydrophobic group on the inside and a hydrophilic group on the outside
Where do micelles fit
Micelles are small enough to fit between microvilli on the epithelial membrane
What is absorbed in protein absorption? What are they
Monoglycerides and fatty acids are absorbed, these are non polar and can diffuse through the membrane.
What is not absorbed during protein absorption
Micelles
What can happen to speed up protein absorption
Facilitated diffusion
What is a chylomicron
An ultra low density lipoprotein. They are a type of water soluble fat droplet
What forms a chylomicron
Longer chain fatty acids, packaged with cholesterol and phospholipids
What type of fatty acids are able to diffuse directly in to the blood
Short chain fatty acids
