Digestion And Absorption Flashcards
What happens during digestion
Large biological molecules are hydrolysed to smaller molecules that can be absorbed across the cell membrane
Test for starch
Iodine
Positive- blue-black
Negative - orange- brown
Test for sugars
Benedict’s
Positive- brick-red
Negative - light blue
Test for proteins
Biuret
Positive- lilac -purple
Negative blue
Function of exopeptidase
Hydrolyse peptide bonds at end of polypeptide
Function of endopeptidase
Hydrolyse internal peptide bonds within polypeptide
Explain the digestion of lipids with in gut (exclude absorption)
Triglycerides decrease because of the action of lipase. They also decrease because of they are hydrolysed into fatty acids which causes the concentration of fatty acids to increases. They also decrease because of the digestion of the ester bonds.
Describe the role of micelles in the absorption of fats into the cells lining the ileum.
Micelles include bile salts and fatty acids
They make fatty acids more soluble in water
They bring the fatty acids to the lining of the ilium and releases it into cell
In calorimeter the higher the absorbency the darker/lighter the colour of the mixture
Darker the mixture
( it’s the absorbency of the substance rather than the absorbable on the other side)
A student did not have a colorimeter describe how a method this student could use to prepare colour standards and use them to give data for the total anthoyancic extracted
Use known concentration of pigment
Prepare dilution series
Compare results with colour standards to give concentration
What does bile do to fats
Emulsification
Where is amylase produced
Salivary glands
Pancreases
Small intestine
How does amylase work
It hydrolyses the polysaccharide into disaccharide by hydrolysing the glycosidic bond
not into monosaccharides because then the specific enzyme does it E,g. Maltase then digests monosaccharides maltose)
Enzyme that break down
Sucrose
Lactose
Maltose
Sucrase
Lactase
Maltase
Where does protein digestion start
Stomach
What are lipids digested by 2
Bile salts
Lipase
Where is lipase produced
Pancreas
How does lipase work
Hydrolyses the ester bond in triglycerides to for glycerol and fatty acids
Where are bile salts made
Liver
How do bile salts work + why is this advantage
The work in the small intestine
Provides a larger surface area for lipas etc act on so faster hydrolysis of lipids. Breaks ester bonds
Which is physical and which is chemical in lipid digestion
Bile salts - physical
Lipase - chemical
Where are bile salts stored
Gall bladder
What are micelles made of
Fatty acids
glycerol
Monoglycerides
Bile salts
What happens when the micelles have released lipid into cell
Reform into triglycerides They are combined with proteins in the Golgi apparatus and form chylomicrons to large to diffuse into blood stream so are released into the lacteal
How is a chylomicron formed
Addition of a protein onto a triglycerides
On which biological molecule do endo and exo peptides work
Proteins
What does the dipeptidase enzyme do
Hydrolyses dipeptides into amino acids by breaking ester bond
Which system is lacteal part of
Lymph
Explain how starch is digested
Starch broken down by amylase into disaccharides ( maltose, sucrose lactose)
The disaccharides are then broken down by membrane-bound disaccharides (sucrase, lactase, maltase)
Role of bile salts
Emulsification of lipids to form micelles to create larger surface area for lipase to work on
Explain the journey of the micelles
1) micelles releases fatty acids and monoglycerides into the ilium
2) the endoplasmic reticulum reforms them into triglycerides
3)the Golgi adds a protein to form chylomicron
4) transported to lacteal via exocytosis
Advantage of lipid droplets and micelle formation x3
Droplets increase surface area for lipase
So after hydrolysis of lipids
Micelles carry fatty acids and glycerol through the membrane to the cell
Role of Golgi apparatus in absorption of lipids
Processes triglycerides
Combines triglyceride with protein to form chylomicron
Packages for releases
