Biochemistry And Cellular Respiration

Question 0

Second law of thermodynamics

Answer 0

Disorder or entropy tends to increase

Question 1

First law of thermodynamics

Answer 1

Law of conservation of energy

Question 2

Symbol for entropy

Answer 2

S

Question 3

Symbol for free energy (Gibbs)

Answer 3

G

Question 4

Symbol for enthalpy

Answer 4

H

Question 5

Gibbs free energy - equation

Answer 5

Delta-G = Delta-H - T*Delta-S

Question 6

What are proteases?

Answer 6

Protein cleaving enzymes

Question 7

What are the four main ways enzyme activity is regulated?

Answer 7

• Covalent modification (i.e.- phosphorylation of a site can activate OR deactivate)
• Proteolytic cleavage - synthesized inactive, cleaved by protease to activate
• Association with other polypeptides (i.e.- regulatory subunit slows down activity)
• Allosteric regulation - modification of active site via interactions in the allosteric site

Question 8

Enzyme Cooperativity

Answer 8

The binding of one substrate molecule to the enzyme complex enhances the binding of more substrate molecules to the same complex
(*these enzymes must have more than one active site)

Question 9

Competitive inhibition

Answer 9

Molecular inhibitors compete with substrate at active site

Question 10

Noncompetitive inhibition

Answer 10

Molecular inhibitors bind at allosteric site

Question 11

4 Stages in Cellular Respiration

Answer 11

• Glycolysis
• PDC (pyruvate dehydrogenase complex)
• Krebs Cycle (or citric acid cycle)
• Electron transport chain

Question 12

Basic In’s & Out’s of Glycolysis

Answer 12

Glucose + 2ADP + 2P-i + 2NAD(+)
➡️➡️➡️
2 Pyruvate + 2ATP + 2NADH + 2H2O + 2 H(+)

Question 13

Hexokinase

Answer 13

Enzyme that catalyzes first step in glycolysis (phosphorylation of glucose to G6P)

Question 14

Phosphofructokinase (PFK)

Answer 14

Catalyzes third step in glycolysis - Important bc extremely favorable reaction- practically irreversible (a committed step)

Question 15

Basic in’s & out’s of PDC

Answer 15

Pyruvate + CoA-SH + NAD(+)
➡️➡️➡️(oxidation of pyruvate)
Acetyl-CoA + NADH + H(+) + CO2

Question 16

Coenzyme-A

Answer 16

(CoA-SH) - Coenzyme used in many reactions to pass acetyl units around - Plays major role in PDC

Question 17

Describe what happens in PDC

Answer 17

• Pyruvate transported for. Cytoplasm to inner Mitochondrial matrix
• Here it is oxidative lay decarboxylated by the pyruvate dehydrogenase complex, which is composed of three different enzymes (allows intermediates to be passed from active site to active site)

Question 18

Prosthetic groups vs Co-factors

Answer 18

Prosthetic group - a no protein molecule covalent.y bound to an enzyme at it’s active site
Co-factor - various organic and inorganic substances necessary to enzyme function but which never actually interacts with the enzyme

Question 19

Basic Ins and Outs of the Krebs Cycle

Answer 19

Acetyl-CoA + OAA + 3NAD(+) + FAD + GDP
➡️➡️➡️➡️
2-CO2 + OAA + 3 NADH + FADH2 + GTP

Question 20

Describe what happens in Krebs Cycle

Answer 20

First step: Actyl-CoA (2C) + Oxaloacetate (4C) forms intermediate of citrate (CoA-SH regenerated)
Second step: Citrate further oxidized releasing 2 CO2 molecules and making 2 NADH molecules
Third step: OAA regenerated so cycle can continue - In doing so NADH, FADH2, and GTP is made

Question 21

General description of Electron Transport Chain

Answer 21

• High energy electron carriers (NADH/FADH2) are oxidized by chain of proteins on inner membrane of mitochondria
• Energy produced doing this is used to pump protons out of matrix and lastly reduce O2 to H2O
• Proton gradient is used by ATP synthase, letting protons diffuse down gradient, powering ATP generation

Question 22

Proteins on the Electric Transport Chain

Answer 22

1- NADH dehydrogenase (A)
2 - Ubiquinone, (Q), or CoenzymeQ
3 - Cytochrome C reductase (B)
4 - Cytochrome C
5 - Cytochrome C oxidase (C)

A, B, & C are the only ones that pump protons

Question 23

How many protons pumped per NADH or FADH2?

Answer 23

~10 protons per NADH & ~6 per FADH2

Question 24

How many protons does ATP synthase use to make ATP - AND - what’s the catch

Answer 24

3 protons pumped per ATP generated; caveat is that 1 proton is spent bringing phosphate group into the matrix (total 4 protons pumped in per ATP)

Question 25

Roughly how many ATP are made per Glucose?

Answer 25

~30 ATP synthesized