L05 & L06 - METABOLISM Flashcards
What is a catabolic pathway?
Break down complex molecules into simple molecules and release energy
What is an anabolic pathway?
Form a complex molecule from smaller simple molecules. Requires energy usually in the form of ATP
What are the products of glycolysis?
- 2 net ATP
- 2 NADH
What are the products of pyruvate decarboxylation?
- CO2
- NADH
What complex regulates pyruvate decarboxylation and how is the complex regulated?
- PDH complex
- Regulated by feedback which influences kinases
- Has an active and inactive form
- Increase in pyruvate –> increase in the kinase that activates the enzyme
- Increase in acetyl CoA –> increase in the enzyme that deactivates the kinase
What are the products of the TCA cycle?
One molecule of pyruvate:
- 3NADH
- FADH2
- GTP
- 2CO2
What is the energy usage of gluconeogenesis in order to produce 1 glucose molecule
- 4ATP
- 2NADH
- 2 GTP
- 2 Pyruvate
Give two other molecules that are not pyruvate that can be used to form Acetyl CoA
- Fatty acids
- Amino acids
Where does glycolysis occur?
Cytosol
What are the 3 irreversible steps in glycolysis?
1, 3 and 10
What is the enzyme that catalyses step 3 in glycolysis?
Phosphofructokinase
Name the main enzyme in glycolysis and the main enzyme in gluconeogenesis
- Phosphofructokinase
- 1,6 - bisphosphatase
When is phosphofructokinase switched on and when is it switched off?
- Switched on when ATP is low
- Switched off when ATP is abundant
In the TCA cycle, which molecule are the carbon atoms lost from?
Lost from the oxaloacetate molecule
What is NAD derived from and what does it act as?
- Vitamin B3 (Vitamin Niacin)
- acts as a coenzyme
What is FAD derived from?
- Vitamin B2
What are anaplerotic reactions, give 3 examples?
- Reactions that fill in missing metabolites for important metabolic pathways
- Direct conversion of pyruvate to oxaloacetate
- Oxaloacetate/ aspartate conversion which is important for malate/ aspartate shuttle
- Malate to pyruvate conversion
What catalyses the transport of electrons in the ETC and what can it be inhibited by?
- Cytochrome C
- Inhibited by cyanide, carbon monoxide and azide
Explain how new borns generate heat energy.
They use brown adipose tissue - this is more rare compared to white adipose tissue.
The membrane has an uncoupling protein channels. When H+ is transported into the inner membrane, the uncoupling protein transports them back into the cytosol. The energy stored in the electrochemical gradient will be released at heat energy
Which enzyme converts pyruvate to acetyl choline?
pyruvate dehydrogenase
Give 3 ways metabolism is controlled
- Enzyme levels
- Enzyme activities
- Substrate availability
What inhibits the control points of the TCA cycle?
- ATP
- NADH
- Acetyl CoA
