Question | Answer |
What configuration are amino acids found in (R or L)? | L |
In what cellular compartment does fatty acid, cholesterol and triacylglycerol synthesis take place? | Cytosol |
In what cellular compartment does fatty acid beta-oxidation take place? | mitochondria |
In what cellular compartment does ketone body formation take place? | liver mitochondria |
What are the properties of an enzyme active site? | 1. 3-dimensional cleft 2. Binds substrate with weak attractions 3. Specific for substrate |
What are the factors that influence enzyme reaction rate? | pH, substrate concentration, temperature |
What is a holoenzyme? | an apoenzyme with its coenzyme |
What is the coenzyme required during the synthesis of pyruvate from lactate? | NAD+ is required |
What are the four way regulation of enzymes can be acheived? | 1. Concentration of substrate or products 2. Modulation of enzyme concentration 3. Covalent modification of enzymes 4. Modulation of a metabolic pathway |
Describe enzyme regulation via concentration of substrates/products. | When substrate concentration is low small changes in substrate will affect velocity of reation. Too much product can inhibit enzyme. |
What is an example of enzyme regulation via concentration of substrates/products. | formation of glucose-6-phosphate from glucose. |
How are enzymes regulated by modification of enzyme concentration? | By induction or repression of enzyme synthesis OR regulated enzyme degradation. |
What happens when blood glucose levels falls too low? What type of enzyme regulation is this? | low blood glucose induces glucagon to promote gluconeogenesis enzymes to synthesis glucose |
How is enzyme activity regulated by covalent modification? | phosphorylation/dephosphorylation and proteolytic activation |
What is the function of enteropeptidase? | cleaves the zymogen trypsinogen to trypsin. |
What are the types of modulation of metabolic pathway regulation of enzyme activity? | feedback and feedforward regulation, compartmentation of enzymes/substrates |
What is homotropic allosteric regulation? | when the substrate causes cooperative binding of more substrate. |
What is heterotropic allosteric regulation? | when another molecule binds to the enzyme at a place different than the active site |
what kind of curve to allosteric enzymes show? | sigmoidal curve |
Does feedback/feedforward regulation change K0.5 or Vmax? | K0.5 |
Does competitive inhibition change Km or Vmax? | Km |
Does noncompetitive inhibition change Km or Vmax? | Vmax |
Give an example of competitive inhibition. | the action of statins on HMG-CoA reductase (used for cholesterol synthesis) |
On a Lineweaver-Burk plot where is Vmax? | y-intercept=1/Vmax |
What kind of regulation does DFP exhibit of acetylcholine esterase? | irreversible |
How does aspirin prevent blood clotting? | It inhibits COX which produces thromoxane and prostacyclin. Thromboxane needed by platelets=stimulate blood clotting and prostacyclin needed by endothelial cells=prevent blood clotting. Endothelial produce COX whereas platelets cannot. |