Final Review Flashcards
What is glucokinase?
It is a special form of hexokinase found in the liver
Where is oxaloacetate found/an intermediate of?
gluconeogenesis and citric acid cycle
What is glycogen phosphorylase?
It is the enzyme that cleaves the alpha 1,4 bond in glycogen when you are removing glucose units from the nonreducing end
What is the volume of a HeLa cell?
2 pL
What is the chemical form of glucose’s anomeric carbon?
hemiacetal
Where is the GPI anchor found in the membrane?
Outer leaflet
When is positive cooperatively?
Hill’s coefficient > 1
How do red blood cells use glucose to make ATP?
Because red blood cells don’t have a mitochondria, they can’t do the citric acid cycle nor the oxidative phosphorylation aspect; therefore, they can only make ATP via glycolysis and they can only make 2 ATP
What is the backbone of PI phospholipids?
Glycerol
What is the feedback inhibitor of hexokinase?
G6P
What is the feedback inhibitor of PFK-1
ATP; high energy charge; citrate
What is a phosphoanhydride bond?
the bond between two phosphate groups
What pathways is NADPH used in?
cholesterol synthesis and fatty acid synthesis
Why is citric acid cycle off when ketogenesis is on?
- Citric Acid intermediates have been drained off for biosynthetic reactions (i.e., gluconeogenesis for brain)
- They cannot be replaced by anapleurotic reactions because ketogenesis happens under starvation so you’re not using glucose or carbs and CANNOT make oxaloacetate from pyruvate using pyruvate carboxylase
What is the net reaction catalyzed by the pyruvate dehydrogenase complex?
Pyruvate + NAD+ + CoA —> Acetyl Coa + Co2 + NADH
What does each round of beta oxidation produce?
1 Acetyl CoA, 1 NADH, 1 FADH2
What is the function of Protein disulfide isomerase (PDI)?
The cysteine residues must form disulfide bonds with the correct partner and will block activity if they form a disulfide with the incorrect cysteine
Through which specific mode does Akt/PKB associate with the membrane?
ionic interactions and transient bodning
What is the mechanism of Akt/PKB binding?
PH domains dock proteins at the membrane by coordinating negative charges on PIP3 with basic (Arg, Lys) and polar (Asn) residues
What methods can you use to extract native Akt/PKB?
change pH; treat with phospholipase; extract with detergents
What are the two mechanisms that control Akt/PKB activity?
- Compartmentalization/Subcellular Location (Explanation: when it is not needed, it stays in the cytoplasm however when it is needed it will be recruited to the plasma membrane)
- Covalent modification (phosphorylation)
What is a noncompetitive inhibitor?
It is a special type of mixed inhibitor that has different Vmax (y intercept) but the same Km (x intercept)
Triacylglycerols
(fats) are the major form of energy storage in animals
Bile
Body’s natural detergent used to help solubilize dietary lipids in the gut
NAPDH
A variant of NADH that is used specifically by biosynthetic pathways to reduce metabolites, so that there are separate pools of reducing power for catabolism and anabolism
ketone bodies
hydrophilic derivatives of fatty acids produced by liver as a fuel when carbohydrates are scarce
lipoproteins
come in several types, spherical packages with lipid cores, hydrophilic surfaces, and specific proteins
Beta-oxidation
pathway in the mitochondrial matrix that oxidizes fatty acids to generate energy
Fatty acid Synthase
cytosolic multi-enzyme complex that generates fatty acids
HMG CoA reductase
catalyzes the committed step of cholesterol biosynthesis in the liver. Amount of the enzyme is regulated to control flux through the pathway. Target of drugs used to lower cholesterol levels.
Phosphorolysis
Breaking a bond via attack by a phosphate group
Primer
A short chain of monomers use to initiate synthesis of a longer polymer
glycogenin
the protein that synthesizes the primer for glycogen synthesis, covalently attached to one of its Tyr residues
glycogen synthase
the enzyme that extends the glycogenin-produced primer, polymerizing glucose into a long linear chain
