Energetics, Enzymes and Proteins - Midway into first lecture Flashcards
What is the difference between an endergonic reaction and an exergonic reaction?
An endergonic reaction requires energy to take place whereas exergonic reactions release energy.
What is the condition required for endergonic and exergonic reactions to be coupled?
The energy released by the exergonic reaction needs to be greater than the energy required by the endergonic reaction.
Define Gibbs Free Energy
Gibbs Free Energy is the amount of energy available from a particular compound.
The Gibss Free energy of an endergonic reaction is negative/positive.
Select the correct option
The Gibbs Free energy of an endergonic reaction is positive.
The Gibbs Free energy of an exergonic reaction is negative/positive.
The Gibbs Free energy of an exergonic reaction is negative.
What are the components of ATP?
The components of ATP are adenosine (adenine + ribose) + phosphates.
Describe the two methods of ATP hydrolysis.
- ATP → ADP and an inorganic phosphate
- ATP → AMP and pyrophosphate. The pyrophosphate is then split into single phosphates
Describe the energetic differences between the 2 mechanisms of ATP hydrolysis.
The ATP → AMP mechanism releases more energy than the ATP → ADP mechanism. However it requires more energy to reverse.
Give 3 examples of what ATP can be used for.
- chemical work
- Transport
- Movement
Why does the ATP turnover need to be so fast?
The ATP turnover needs to be fast because we need much more ATP per day than what is stored in our body (100-250g stored - need 50-75kg). ATP needs to be turned over around 500 times per day to meet the daily requirement
Describe the energy sources during an 100m sprint, where ATP turnover is not enough to sustain the body.
- Stored ATP - 1 sec
- Creatine phosphate - 4 secs
- Fermentation of glucose - the rest of the race
Why is it sterically difficult to attach a phosphate to ADP?
It is sterically difficult to attach a phosophate to ADP because we need to overcome the repulsive negative charges of the other phosphates.
Because of this a lot of energy is released when a P is released.
Which product of anaerobic metabolism can be very painful?
Lactic acid is the product of anaerobic metabolism which can be painful.
High/low [ATP] inhibits catabolic reactions and stimulates anabolic reactions.
High [ATP] inhibits catabolic reactions and stimulates anabolic reactions.
Give examples of reactions that require phosphate from ATP.
- Fatty acids → Phospholipids
- Synthesis of RNA/DNA - nucleoside monophosphate activation
- Protein synthesis - amino acid activation
- Post translational activation/deactivation by phosphorylation
