Lecture #7- Introduction to Metabolism and Energy

Question 1

what is metabolism? draw the cycle of catabolism and anabolism

Answer 1

• the totality of an organism’s chemical rxns, managing the materials and energy resources of the cell
• ADP + Pi -> Catabolic (energy can be released through nutrient breakdown) -> ATP -> anabolic rxns ( require energy to build the cell)

Question 2

energy: potential and kinetic energy

Answer 2

• capacity to cause change or the capacity to do work, that is the capacity to change or move something
• potential: energy stored due to position or composition
• kinetic: energy due to movement

Question 3

First and second law of thermodynamics

Answer 3

first: energy cannot be created or destroyed, only converted form one form to another
second: entropy of universe e is always increasing, entropy is the measure of randomness/disorder of a system
- heat is the most disordered of energy and therefore a rxn is spontaneous if disorder of a universe increases

Question 4

Draw an exergonic and endergonic graph, label reactants, products and the gibs free energy

Answer 4

exergonic:
- spontaneous
- thermodynamically favourable
- deltaG is negative, the energy released is available to do work and to increase entropy of universe

endergonic:
- thermodynamically unfavourable
- energy requiring
- deltaG is positive, energy is needed

Question 5

What is ATP and draw it out

Answer 5

• Adenosine triphosphate
• energy exists in the 3rd phosphate bond due to charge repulsions and steric hindrance
• the 3rd pi is the guy that everyone hates lol
  do the hydrolysis of the bonds release energy
• ATP ->ADP+ Pi

Question 6

What are enzymes and what’s their function
draw how it influences the graph

Answer 6

• many exergonic rxns are spontaneous but very slow (too slow for cells)
• biological catalysts that provide an alternate energy path for a reaction to process
• highly regulated and names end in -ase

Question 7

how enzymes work

Answer 7

• bind and act on substrates
• are very specific to the substrate
• have an active site (bonding site)
• catalytic site has geometric and chemical compatibility with substrate

Question 8

enzymes lower the Ea of a reaction by:

Answer 8

1. bring reactants closer tgt
2. active site contains a unique chemical envior favourable for rxn
3. physically stress bonds to be broken
4. rare! but convalentl stabilize rxn intermediate
5. place substrates in correct orientation

Question 9

How does enzyme inhibition work: competitive inhibitors and non-competitive inhibitors

Answer 9

• competitive: binds to the active site but doesn’t participate in a rxn, can be out-competed by large [substrate]
• non-competitive inhibitors: binds a site on an enzyme that is not an active site and block the enzyme activity by changing the shape of the active site