Nutrient Digestion and Absorption 1 - Carbohydrates and Protein Flashcards
Is water a amcro or micro nutrient?
Micronutrient
How many simple sugar molecules are present in monosaccharide?
One
How many simple sugar molecules can an oligosaccharide have?
3-9
What is a short chain of carbohyrdates called?
Oligosaccharide
What is a long chain of carbohydrates called?
Polysaccharide
Describe the difference between a hexose and a pentose.
Hexose is a carbohydrate with six carbons in the backbone while a penthouse has five cabons.
Describe the difference between a aldose and a ketose.
Aldose means the sugar contains aldehyde.
Ketose means the sugar contains ketone.
After the cyclization of glucose, which two forms of glucose can be formed?
Alpha or beta glucose
Describe the structure of beta glucose.
Has the hydroxyl group of the chemical diagram facing up
Describe the structure of alpha glucose.
Has the hydroxyl group of the chemical diagram facing downwards
Name three monosaccharides.
Glucose
Fructose
Galactose
Name three disaccharides
Maltose
Sucrose
Lactose
What is maltose made up from?
Two glucose monosacchwrides
What is sucrose made up from?
One glucose and one fructose
What is lactose made up from?
One glucose and one galactose.
Name the type of bond which connects two monosaccharides in a disaccharide.
Glycosidic bond
How are monosaccharides formed?
They are the breakdown products of complex carbohydrates
Where are monosaccharides absorbed?
Small intestine
How are dissacharides broken down into monomers?
By brush border enzymes in the small intestine
Name three complex carbohydrates/polysaccharides
Starch
Cellulose
Glycogen
What is starch?
Plant storage form of glucose
Describe the starch structure of alpha-amylose
Glucose linked in straight chains
Describe the starch structure of amylopectin
Glucose chain is highly branched
What hydrolyses starch and where can you find it?
Amy.ase, found in saliva and pancreas
Describe the structure of cellulose
Unbranded linear chains
Which type of bond joins in the monomers in starch?
Alpha 1,4 glycosidic bonds
Which type of bond joins in the monomers in cellulose?
Beta 1,4 glycosidic bonds
Which type of bond joins in the monomers in glycogen?
Alpha 1,4 glycosidic bonds
What is cellulose?
Dietary fibre
Constitutes to cell walls
Which polysaccharide can amylase not breakdown?
Cellulose
Which enzyme can degrade cellulose?
Cellulase
What causes lactose intolerance?
An absence or defiency in the enzyme lactase
What happens in those with lactose intolerance?
Lactose is not broken down into glucose and galactose meaning it cannot b3 absorbed by the small intestine.
Bacteria starts to ferment causing acid and gases.
Name the first part of the small intestine.
Duodenum
What is the function of the small finger like projections (villi) in the small intestine?
Increases surface area and allows more absorption
What is meant by transcellular in terms of absorption in the small intestine?
Nutrients can through or inside the cell without a pump or transporter.
What is meant by paracellular in terms of absorption in the small intestine?
Nutrients can go through the tight junctions between the epithelium
What is meant by vectorial transport?
A pump or transporter is required to transfer one molecule from one side to the other.
Which direction does the sodium potassium pump move sodium and potassium?
Pumps sodium out and potassium in
How much sodium and potassium get transported by the pump?
3 sodium out
2 potassium in
Name the transporter found in the epical membrane surface of the small intestine.
Sodium glucose transporter 1
What is meant by the fact that the sodium glucose transporter 1 is a cotransporter?
For glucose to be transported into the cells, sodium needs to be transported at the same time
How does glucose get out of the cell and into the blood?
Via the GLUT2 transporter
How does the movement of sodium help with the absorption of water from the lumen to the blood?
Sodium is a very osmotically active molecule and the movement of sodium will affect the osmotic gradient and force the water to the blood through the tight junctions between the epithelium
How are glucose/galactose absorbed?
Absorbed by the sodium-glucose transporter 1
How is fructose absorbed?
Absorbed by glucose transporter 5
Which type of bond do proteins have?
Peptide bonds
Describe what is meant by secondary active transport of glucose.
The glucose transporters themselves don’t require any energy to move glucose but they need assistance from other pumps which do require energy.
What is meant by a glycoprotein?
When a protein undergoes a post-translational change and there is an addition of a carbohydrate
What is meant by a lipoprotein?
When a protein undergoes a post-translational change and there is an addition of a lipid
What do you call a chain with 3-10 amino acids joined together?
Peptide, it’s a small chain
Name the enzymes which hydrolyse peptide bonds and break them down into amino acids
Proteases/peptidases
Where would you find glucose 1 transporters?
In red blood cells and in the blood brain barrier.
Where would you find glucose 2 transporters?
Epithelial cells
Where would you find glucose 3 transporters?
Brain
Where would you find glucose 4 transporters?
Adipose tissue and straited muscle
->wee tb to AH Bio, they require insulin to work
Where would you find glucose 5 transporters?
Sperm cells
Where do endopepsidases work?
In the middle of a amino acid chain
Where do exopepsidases work?
At the end of an amino acid chain
Which end of the amino acid chain would a aminopepsidase, a type of exopepsidase, work?
At the amino terminal (end)
Which end of the amino acid chain would a carboxypepsidase, a type of exopepsidase, work?
At the carboxylic terminal (end)
Which transporter allows for the transport of amino acids and sodium from the lumen of the small intestine into cells?
Sodium amino acid transporter 1
->similarly to the sodium-glucose transporter 1, it cotransports sodium and amino acids at the same rate.
Describe the function of PepT1
Transporter which cotransports dipeptides or tripeptides with protons
What happens to the pH of the microclimate when protons are released?
The normally neutrally or slightly alkaline pH becomes more acidic, to about pH6 for the microvilli.
What is the difference in pH between the microvilli and the lumen of the small intestine?
Lumen is about pH of 7
Microvilli is about pH of 6
What is the term used to describe the pH of the microvilli?
Acidic microclimate
How do the PepT1 and NHE3 work together?
They work in synchrony as for PepT1 to work, there must be more protons outside the pump so more can go in with the peptides.
NHE3 then pumps the protons back out and this is a continual loop.
Name one type of drug which PepT1 help with absorption of.
Penicillans
Which enzyme in the brush boarder turns lactose into glucose and galactose?
Lactase
Which enzyme in the brush boarder turns sucrose into glucose and fructose?
Sucrase
Which enzyme in the brush boarder turns maltose into glucose and glucose?
Maltase
What level are blood glucose levels maintained at?
5mmol/L of blood
What is the animal equivalent of starch?
Glycogen
Which bonds can alpha amylase break?
Alpha 1,4 glyosidic bonds
How many membranes do epithelial cells have? What are they called?
2- basolateral and apical
What separates the apical and basolateral membranes?
Tight juntions
