Nutrient Digestion 1 & 2 Flashcards
Which sugars are classed as monosaccharides?
Glucose, galactose and fructose
What are disaccharides?
Two monosaccharides linked together by a glycosidic bond
What transported does glucose use to cross the cell membrane into the epithelial cell?
SGLT1
What ion is need to couple glucose to the transporter into the cell?
Na
What transporter removes glucose from the epithelial cell and into the bloodstream?
GLUT-2
What transporter does fructose use to enter the epithelial cell?
GLUT-5
What transporter does fructose use to leave the epithelial cell?
GLUT-2
What is a peptide?
A small protein, 3-10 amino acids in length
What is the name for enzymes that hydrolyse peptide bonds?
Proteases/Peptidases
What is the name given to transporters that move amino acids across the cell membrane?
SAAT1
What transporter moves dipeptides into the epithelial cells?
PepT1
What form is most ingested fat in?
Triacylglycerol
Where is fat digested and by which enzyme?
In the small intestine by pancreatic lipase
What is emulsification?
Dividing large lipid droplets into smaller droplets
What does emulsification require?
Mechanical disruption and an emulsifying agent
What emulsifying agents does the digestive system use to divide large lipid molecules into smaller ones?
Bile salts and phospholipids (secreted in bile)
What components make up a micelle?
Bile salt, monoglycerides, fatty acids and phospholipids
What happens to the fatty acids and monoglycerides after they enter the epithelial cells?
They enter the smooth endoplasmic reticulum where they are turned back into triacylglycerols and coated with amphiphatic protein. They are then transported through the cell in vesicles
Which vitamins are fat soluble?
ADEK
Which vitamins are water soluble and how are they absorbed?
B group, C and folic acid - absorbed by passive diffusion or carrier-mediated transport
How is B12 absorbed?
It is bound to an intrinsic factor in the stomach and is absorbed in the distal ileum
How is Iron transported across the membrane?
Via DMT1
How is iron bound in the cell?
It is bound into ferritin
How is iron bound in blood?
It crosses the serosal membrane and is bound as transferrin
