F cell energy 1:metabolism, ATP, glycolysis Flashcards
What are catabolic processses?
the breakdown of
complex molecules to release energy
What is anabolic processes?
synthesis of new
molecules from less complex components
What does the oxidation of carbohydrates, fats and proteins produce?
When oxidised they produce water, carbon dioxide and ATP
What are the cofactors central to metabolism used for oxidation/reduction reactions?
NAD and FAD are activated carriers of electrons used for oxidation/reduction reactions
What is the oxidised and reduced form of NAD?
NAD+ –oxidised form
NADH + H+. –reduced form
What is the oxidised and reduced form of FAD?
FAD+ –oxidised form
FADH2 –reduced form
What are major oxidative pathways?
- Glycolysis
- Citric acid cycle
- Electron transport coupled to oxidative
phosphorylation - Fatty acid oxidation
What are the steps involved in glycolysis?
- Glucose(C6) will become G-6-P with the use of ATP
- G-6-P will then become fructose 6 phosphate, which well then convert into fructose 1,6 bisphosphate(C6) using ATP.
- This fructose 1,6 bisphosphate splits into 2 C3 molecules.
- One of the C3 molecules will be converted into phosphoenol pyruvate by phosphorylating NAD+,pi and ADP. This phosphoenol pyruvate then become pyruvate(C3) by phosphorylating ADP. This steps occurs twice for each C3 molecule.
What is the balance sheet for glycolysis?
Reactants:
1 Glucose
2 NAD+
2 ADP
2 Pi
Products:
2 Pyruvate
2 NADH
2 ATP
What are potential sites for regulation in glycolysis?
Enzymes catalysing irreversible reactions are potential sites
for regulation
What can activity of the enzymes involved in glycolysis be regulated by?
- reversible binding of allosteric effectors
- covalent modification
- transcription
What is glycolysis in muscle regulated to meet the need for?
In muscle glycolysis is regulated to meet
the need for ATP
What is the the signal for low energy state in muscles?
AMP
What is the most important control point in glycolysis in muscles?
Phospho-fructokinase
What enzyme does a high concentration of ATP inhibit and how is this done so in muscles?
High concentrations of ATP inhibit PFK
by lowering the affinity for
Fructose 6 phosphate
What other factor inhibits PFK in muscles?
pH
What does the inhibition of PFK lead to the inhibition of in muscles?
Inhibition of PFK leads to inhibition of hexokinase
What does a high concentration of ATP inhibit in the liver?
High concentrations of ATP inhibit PFK
What inhibits PFK in the liver?
PFK is inhibited by citrate
What is PFK stimulated indirectly by in the liver?
PFK is stimulated indirectly by a build up of F6P
What is hexokinase inhibited by in the liver?
Hexokinase is inhibited by G6P
What does galactose do in glycolysis?
Converted into Glucose(C6) to be used in glycolysis to form G-6-P
What does fructose from adipose do in glycolysis?
Converted into fructose-6-phosphate
What does fructose from liver do in glycolysis?
Converted into DHAP and GAP
What does pyruvate convert into in glycolysis in exercising muscles?
-Lactate, NADH–>NAD+ and Acetyl CoA
What is the acetyl CoA in muscles produced, used for?
Oxidative phosphorylation
Why do tumours use the glycolysis pathway?
Their energy needs are met through anaerobic respiration.
What does low oxygen stimulate?
Low oxygen stimulates the expression of
many glycolytic enzymes
