lecture 8 + 9 metabolism Flashcards
catabolism vs anabolism
catabolism: extract biologically useful energy from meals
anabolism: use this energy, and small molecules derived from food breakdown, to sythesize new biomolecules + cells
the three pathways that can synthesize ATP
glycolysis
TCA cycle
electron transport system
hydrolysis goes with (catabolism/anabolism) whereas condensation reactions go with (catabolism/anabolism)
hydrolysis = breaking down: catabolism
condensation = builidng- anabolism
glycosidases
enzymes that break down sugars.
ex: lactase, sucrase
which enzyme breaks down cleaving α-1,4 bonds
α-Amylase
this action initiaties digestion
which enzyme takes over to help break down alpha 1,6 bonds?
α-dextrinase
‘limit dextrin’ when the enzyme has reached its limit of what it can cleave
what happens to these glucose monomers once they are liberated by enzymes from the larger macromolecule
Once the subunits are hydrolyzed to individual sugars they are transported into the gut epithelial cells and out again on the basal surface to diffuse into the blood
what do amino acids, dipeptides, and nitrogenous bases do once liberated from proteins/nucleic acids ?
they are transported into the gut epithelial cells and out again on the basal surface to diffuse into the blood
____reactions require an input of energy either by coupling the + ΔGO synthesis reaction with ATP hydrolysis (-ΔGO) or by using the reducing power of NADPH2 (-ΔGO ) or both.
anabolic
(building things requires energy)
_____reactions have -ΔG values.
catabolic (breaking something down release energy)
T/F: the sum of catabolic and anabolic reactions must add to a - ΔG knot.
true
Intermediary metabolism
integrated network of chemical reactions responsible for catabolism/anabolism
Catabolic and anabolic pathways connect in the “intermediary metabolic pathways” because subunits can change into intermediates at particular steps. Thus, intermediary pathways are amphibolic– can be used to either synthesize needed molecules or break molecules down in order to harvest energy in the form of ATP or store energy as glycogen and triglycerides.
zymogens, and example of a famous one
The digestive enzymes of the pancreas are secreted as in-
active precursors called zymogens
ex: pepsinogen, the stomach digestion pre-enzyme
trypsinogen
pancreatic zymogen trypsinogen is activated to form trypsin,
which in turn activates the remaining pancreatic zymogens necessary for digestion (lipases, etc)
How is the energy released in the oxidation of a carbon compound converted into ATP?
The energy of oxidation is initially trapped as a high-phosphoryl-transfer-potential
compound and then used to form ATP.
___ is a
major electron carrier in the oxidation of fuel molecules
NAD+
the reduced form of electron carrier NAD+ is ___
NADH
The electron donor in most reductive biosyntheses is ___which is different in that is has a phosphate group
NADPH
Glucose is oxidized to pyruvic acid in the ____pathway
glycolytic
Fatty acids and pyruvate are oxidized to CO2 and H2O in the ___
citric acid cycle
As glucose is oxidized, what gets reduced?
NAD+ get reduced to NADH + H+ in glycolysis
____ carries acetic acid or fatty acids in a thioester high energy linkage.
Coenzyme A
All the subunits of the macromolecules (amino acids, sugars, nitrogenous bases, fatty acids, glycerol) can be catabolized to __, __ and __ using fermentation, cictric acid cycle, or ETC
CO2, H20, and NH3
what are the 3 regulatory mechanisms that control which pathways are used?
- Feedback regulation on allosteric enzymes that control a committed step
- Repression or activation of genes to control the amount of new enzyme being synthesized
- Accessibility of substrates (e.g., compartmentalize in an organelle)
