Energy, ATP, Enzymes

Question 1

What is metabolism divided into?

Answer 1

• Anabolism: energy input

- Catabolic: release energy

Question 2

What are the two ways that a cell can release free energy/drive chemical reactions?

Answer 2

1) with chemical reaction creating disorder in cell

2) with chemical reaction releasing heat

Question 3

What are the 4 types of reactions?

Answer 3

1) heat released. disorder increased. G=-H-TS
2) heat released. disorder decreased (ex. protein folding) G=-H+TS
3) heat is used. disorder increases. (ex. dissolving NaCl) G=H-TS
4) heat is used. disorder decreases. (most anabolic reactions) G=H+TS

Question 4

What happens to the leftover ATP?

Answer 4

• it gets dispersed to drive the reaction, you don’t get any “change” ATP

Question 5

What happens when reactants (substrate) bind to active site of enzyme?

Answer 5

• it forms enzyme-substrate complex
• enzyme often undergoes small conformational change (shape change) = transition state. Then it goes back to original shape.
• to induce the transition state: bind substrates into correct orientation, this exposes reactions to altered environments that promote catalysis, or induces strain on substrate that facilitates breaking of covalent bond

Question 6

What are cofactors?

Answer 6

• small organic molecules or ions that are not amino acids and are associated more or less tightly w/ enzymes
• many enzymes require cofactors in order to catalyze reaction

Question 7

What are two ways that enzymes can be regulated?

Answer 7

1) competitively w/ regulator binding the active site - need more competitor molecules than substrate molecules
2) allosterically w/ regulator binding somewhere else “other site” on enzyme. This way is much more efficient - less inhibitor molecules are requires - need more allosteric regulators than enzymes