Bio Lecture 23 Metabolism Intro Flashcards
Name the common ways that enzyme reactions are controlled.
Allosteric effectors Product inhibition Substrate concentration Covalent modification Enzyme concentration Compartmentalization
What two things should be considered when looking at metabolism regulation?
Fuel source
Energy level
How are the fuel source and energy level controlled?
Fuel source: hormones such as insulin, glucagon, epinephrine
Energy level: allosteric modifiers, and AMPK
What is AMPK?
It is a protein kinase that phosphorylates other enzymes and is activated by a low amount of energy in the cell that is indicated by a high level of AMP. Its actions are independent of hormone levels. It turns on all enzymes that make energy, and off all those that use energy.
Through what general type of reaction is energy extracted from macromolecules?
Through oxidation reactions.
What kinds of energy carriers are there?
Chemical bond: ATP, GTP
Electron energy: NADH, NADPH
What are the water soluble electron carriers and what is their precurser?
NAD+/NADH and NADP+/NADPH
Niacin (vit B3) precurser
What are the membrane-bound electron carriers and what is their precurser?
FAD/FADH2 and FMN/FMNH2
Riboflavin (vit B2) precurser
Which of the water-soluble electron carriers are used for anabolic vs catabolic pathways?
NAD+/NADH are used in catabolic reactions where the oxidized version is available to accept electrons.
NADP+/NADPH are used for anabolic reactions where the reduced form is available to donate electrons.
What is the hepatocyte sugar trap enzyme in the liver and what is its km?
Glucokinase
km=180 mg/dl
What vessels go to and from the liver?
Hepatic portal vein from the intestines with glucose
Hepatic artery from the heart with oxygen
Hepatic vein from the liver to the heart with lower glucose
What three main states are there?
Fed state: Postprandial/absorptive phase, 0-4 hours
Fasting state: Post-absorptive phase, 5-24 hours
Long-term fasting: >24 hours
Which metabolism pathways are active in the liver during the fed state?
Glycogenesis Glycolysis TCA cycle ETC Fatty Acid synthesis TAG synthesis
Which metabolism pathways are active in the liver during the fasting state?
Glycogenolysis Gluconeogenesis TAG lipolysis Fatty acid oxidation Ketogenesis TCA cycle ETC
Which metabolic pathways are active in the liver during the long term fasting state?
No glycogenolysis because ran out Gluconeogenesis TAG lipolysis Fatty acid oxidation ketogenesis TCA ETC
