TJ SG Flashcards
Committed Step
The first irreversible step unique to a pathway
Distinguishing features of anabolic and catabolic pathways
Must Be: linked Regulated Enzyme Catalyzed Irreversible
What coenzymes are associated with the following vitamins:
- Riboflavin
- Thiamin
- Vitamin B12
- Niacin
- Folic Acid
- FADH and FADH2
- Thiamin Phosphate
- Cyanobolamine
- NADH
- Tetrahydrofolate
What are the stages in energy extraction from foodstuffs?
- macromolecules broken down to monomers
- Oxidation of monomers to Acetyl CoA with limited ATP formation
- Complete Aerobic Oxidation of acetyle CoA to CO2 and H2O with the formation of ATP in the mitochondria
How does the glucose oxidase assay work?
- HIGHLY specific for Glucose
- forms gluconic acid and H2O2
- H2O2 reacts with an organic chromagen to from a colored product
How does the Hexokinase assay work?
- Gold Standard
- Uses G6 dehydrogenase
- amount of NADPH produced is measured at 340 nm
What accounts for decrease in blood glucose between eating and two hours?
Glucose Uptake
What accounts for stabilization of blood glucose after 2 hours and beyond?
Release of Glucose by the liver
T or F: when you digest food the osmolarity is higher in the lumen, which pulls H2O into the lumen
True
What is the difference between paracellular and transcellular movement of fluid?
Transcellular - through the cell
Paracellular - beside the cell
Does water ever undergo facilitated diffusion?
Yes, through aquaporins
What is the difference between moving in amino acids and di and tripeptides?
both use sodium cotransport, however Di and Tri peptides use an H+ dependent contransport mechanism
What does emulsification do to fats and how does this facilitate their entry into the apical surface of epithelial cells?
- Emulsification by bile salts causes monoglyceride formation from fatty acids.
T or F: Ca2+ has a major passive diffusion paracellular transport pathway in the duodenum and jejunum
True
What type of transport is exemplified by calcium rushing in via voltage dependent calcium channels?
Secondary Active transport
T or F: females have slower GI transit that is subject to hormonal influences.
True
T or F: males have a more acidic stomach than females.
True
What is the importance of drug ionization and ion trapping?
- Unionized is needed to cross biological membranes
- ionized is needed to be soluble inside the aqueous cytosol
- ion trapping happens when drug is ionized before crossing the membrane such as in steroid injections into inflammed areas
What are ABC transports and what are some examples of these?
ABC transporters are a protective mechanism that pumps things out that it senses may be potentially toxic.
T or F: referring to maltase activity may in fact be talking about the activity of multiple enzymes
True
Name 4 tests that may be used to determine if a patient has abnormal digestion of sugars.
Serum/Urine amylase - tests for obstructions in pancreatic ducts etc. (mumps or pancreatitis)
What are precose/acarbose tablets used for?
treat diabetes by inhibiting the alpha-glucosidase activity of the small intestine
In what part of the small intestine are sugars broken down into Tri and oligiosaccharides, maltose and isomaltose, what enzyme is responsible for this activity?
Happens in the small intestine by pancreatic alpha amylase which is active in a slightly more basic environment
Where are sugars broken down into alpha dextrins and what does this?
Salivary amylase in the mouth
