8.5 Digestion, Absorption & Transport of Macronutrients Flashcards
What is lactose broken into?
Galactose and glucose
What does amylase break polysaccharides into?
- Maltose
- Glucose Oligomers
Describe the action of an SGLT1 transporter
- Na/K pump pumps sodium out of cell, creating concentration gradient
- Two sodium ions transport back into the cell via active transport, and this energy is harnessed to move glucose through the transporter into the cell against its conc gradient
H>ow does water respond to the uptake of monosaccharides?
Follows out of lumen into enterocytes and bloodstream
What is co-lipase?
Protein that binds to and anchors lipase to the surfae of emulsion droplet
Briefly describe lipid digestion
- Bile salts emulsify large lipid droplets
- Pancreatic lipase breaks into monoglycerides and free fatty acids (with co-lipase)
- Packaged into micelles (with bile salts and lecithin)
- Released near cell
- Cross membrane and enter cell, where they are resynthesised to triglycerides
- Coated with lipoprotein to form chylomicrons, which enter central lacteal (too big for capillaries)
What are the two sources of protein in our digestive tract?
- Exogenous: dietary
- Endogenous: digestive enzymes, proteins shed from villi tips
Draw a map of protein digestion
Document
What enzymes in the brush border of the small intestine break down small peptides?
Aminopeptidases
What intracellular enzymes break down peptides?
Intracellular peptidases
Draw a diagram of the movement of ions and sugars into and out of an enterocyte
Document
Which enzyme catalyses fructose phosphorylation?
Ketohexokinase
Describe fructose metabolism
- Fructose is phosphorylated by Khk
- Phosphorylated fructose is cleaved and converted into glucose glycerate and organic acids
Where does the bulk of fructose metabolism occur?
The small intestine
Which can store more glucose: hepatocytes or muscle?
Muscle
