Introduction To Metabolism

Question 1

Metabolism

Answer 1

Totality of rxn in organism

Anabolism: endergonic rxn (require energy)
Catabolism: exergonic rxn (use energy from anabolism to make rxn that release energy).

Question 2

Biochemical pathway

Answer 2

Product of one rxn become reactant of the next

Feedback inhibition

Question 3

Diff. B/w multienzyme complex, biological pathway, and feedback inhibition

Answer 3

Multienzyme complex: Groups of related enzymes- speed up sequential step (multi step rxn)

1) efficient delivery of product to next enzyme
2) prevent unwanted side rxn
3) rxn controlled as one unit

Biological pathway: Product of one rxn become reactant of the next

Feedback inhibition: presence of certain product inhibits further production of said product (product sends signal to change shape of previous enzyme - allosteric inhibition - to inhibit production of product)

Question 4

2 Ways to gather energy

Answer 4

Anabolism:

Autotroph: photosynthesis (energy from sun, convert energy to usable chem energy)

Heterotroph: energy from organic compounds produced by autotroph (glucose)

Catabolism:
Generate ATP (energy currency of cell)
Hydrolysis of ATP: exergonic, releases E (energy used for endergonic cellular processes)

Question 5

To get ATP

Answer 5

Energy converted from nutrients

Glucose:
C6H12O6 + 6O2 ——> 6CO2 + 6 H2O

Energy released:

1) some lost as heat
2) rest transferred & stored as ATP

Question 6

Glucose to ATP (2 mechanisms)

Answer 6

1. Substrate Level Phosphorylation — glycolysis
   1) ADP + phosphate group = ATP
   2) kinase
   3) Catabolism
   Ex: Creatine phosphate: increase amount of substrate level phosphorylation, increase ATP in cell (nutritional supplement)

(But, Anabolism, generally kinase transfer phosphate from ATP to protein - cellular signalling cascades & control of enzymatic activity)

2. Oxidative phosphorylation (majority of ATP from glucose) —- cellular respiration
   1) ATP synthase multi-enzyme complex = ATP
   2) inner membrane of mitochondria
   3) energy from proton gradient catalyze formation of ATP
   4) requires redox rxn

Question 7

Oxidative phosphorylation (Redox rxn)

Answer 7

Gaining & losing H atoms
H- more EN than H element

Oxidation=Dehydrogenation rxn (lose H, lose electron)

Ex: NAD+ = coenzyme, donor & acceptor of H (cellular redox rxn)

Question 8

Electron transport chain (photo)

—> stepwise transfer of e- that produce E for ATP

Answer 8

NAD+ = coenzyme, donor & acceptor of H (cellular redox rxn)

Oxidation: product lose electron to NAD+ = NADH (electron rich, can donate)

Cellular respiration (oxidative phosphorylation):

1) Transfer of e- from high energy molecules to e- acceptors (NAD+)
2) energy released (transfer) = ATP
3) electrons run out of energy (transfer to final acceptor)

NAD+ + 2H+ + 2e- = NADH + H+