Lecture 16 week 9 Flashcards
What are different types of carbohydrates?
Monosaccharides, disaccharides, polysaccharides
What are some examples of monosaccharides ?
GLucose, fructose, galactose
What are some examples of disaccharides and how are they formed?
Sucrose : glucose+fructose
Maltose : glucose +glucose
Lactose : glucose + galactose
What are some examples of polysaccharides and give explanation
Starches: from plants
Fibers: indigestible from humans
Glycogen: Stored in muscle and liver of animals
In lactose intolerance:
How are glucose and galactose absorbed?
Absorbed by active transport
Lacotse intolerance:
How is fructose absorbed?
Absorbed by facilitated transport
How does lactose intolerance occur?
Deficiency in lactase enzyme results in lactose intolerance.
Peptide and amino transport:
What is step 1 of this process?
Proteins broken down into smaller peptides
Peptide and amino transport:
What is step 2 of this process?
Epithelial cells secrete peptidases to break down larger peptides into individual amino acids
Peptide and amino transport:
What is step 3 of this process?
Transported throughout body in bloodstream to
produce energy or protein synthesis
Peptide and amino acid transport:
What happens in the stomach regarding protein digestion?
- Protein chewed and swallowed into the stomach
- HCL denatures proteins, unfolding their 3D structure, revelaing polypeptide chain
- Enzymatic digestion by pepsin forms shorter polypeptides.
Peptide and amino acid transport:
What happens in the small intestine?
- In small intestine, trypsin, chymotrypsin and proteases continue enzymatic digestion, forming tripeptides, dipeptides and amino acids
- In enterocytes, tripeptides and dipeptides are further broken down into amino acids which are absorbed into the blood
Peptide and amino acid transport:
What happens after proteins broken down by small intestine
Enters bloodstream
How are lipids broken down?
Mouth (lingual lipase) -> Stomach (gastric lipase) -> small intestine (pancreatic lipase)
When can lipases act on lipids
Lipases can only act on lipids when broken down
Where is bile produced and stored
Bile is produced in the liver and stored in the gallbladder
What does bile do?
Aids digestion of lipids through emulsification (large lipid globules broken down and distributed in chyme)
Are bile salts hydrophilic or lipophilic?
How and why is it like this?
Bile salts are amphipathic
Hydrophilic side interfaces with water and hydrophobic side interfaces with lipids
How does lipid absorption and transport occur?
- Absorbed as fatty acids &
monoglycerides - Reassembled into triglycerides &
packaged as chylomicrons (type
of lipoprotein) - Chylomicrons are too large to
cross capillary wall – first
absorbed into lymphatic system - Will re-enter circulation through
thoracic duct near heart
The large intestinal phase of digestion and absorption
What is ileal chyme and what does it do?
comes in from ileum (via ileocecal valve)
* Any unabsorbed nutrients
* Hormones & chemical messengers
* Soluble fibre
* Insoluble fibre
* Microbes
* Cellular debris
* Excretion products from the liver
The Large Intestine (cecum & colon):
What does the colonic epthelium do?
Absorbs water and simple ions (sodium, potassium, magnesium, calcium)
The Large Intestine (cecum & colon):
What do resident microbes digest and absorb? What is produced as the end product?
Digest and absorb what chemicals they can in the process of fermentation. Short chain fatty acid produced as end products
The Large Intestine (cecum & colon):
What do resident microbes produce? What is the end product?
Produces some vitamins as a by product of their metabolism (vitamin K, some B vitamins). Some end products can have hormone like activity.
The Large Intestine (cecum & colon):
What do resident microbes produce during their digestion?
Produce gases during their digestion and consumption of ileal chyme (carbon dioxide, methane, hydrogen sulfide)
