Wk4 Lecture 1 Ch 9

Question 1

Describe catabolic pathways (breakdown or synthesize, exer/endergonic, energy?)

Answer 1

-Breakdown cellular components
-Exergonic
-Energy can be stored in energy intermediates

Question 2

What is an energy intermediate?

Answer 2

Compounds w/ high energy electrons in bonds

Question 3

Describe anabolic pathways (breakdown or synthesize, exer/endergonic, energy?)

Answer 3

-Synthesis cellular components
-Endergonic
-Must be coupled to exergonic reactions

Question 4

Each step of cellular respiration is coordinated by…

Answer 4

A specific enzyme

Question 5

What is kinase?

Answer 5

An enzyme that catalyzes the transfer of a phosphate group from ATP to another molecule; counterpart of phosphatase

Question 6

What is phosphatase?

Answer 6

An enzyme that catalyzes the removal of a phosphate group from a molecule; counterpart of kinase

Question 7

In order for building and breaking down of molecules to work…

Answer 7

Endergonic reactions must pair w/ exergonic reactions

Question 8

What do all organisms use to build fats, carbohydrates, and other compounds?

Answer 8

Glucose

Question 9

How do cells recover glucose?

Answer 9

By breaking down fats, carbohydrates, and other compounds

Question 10

What is glucose used for?

Answer 10

Glucose is used to make ATP through CELLULAR RESPIRATION or FERMENTATION

Question 11

How does cellular respiration produce ATP?

Answer 11

Produces ATP from a molecule w/ high potential energy (usually glucose)

Question 12

How long is ATP used and why?

Answer 12

ATP is only used from 30 seconds to a minute b/c it is highly unstable (3 phosphates adjacent spontaneously separate in water) => ATP is not used for energy storage

Question 13

Cellular respiration formula; what is oxidized, what is reduced?

Answer 13

C6H12O6 + 6O2 -> 6CO2 + 6H2O + energy

Glucose is oxidized (loses electrons and hydrogens)
Oxygen is reduced (gains electrons and hydrogens)

Question 14

Where does glycolysis occur, and why?

Answer 14

Glycolysis occurs OUTSIDE the mitochondria (in cytosol) because enzymes for glycolysis are not found within the mitochondria

Question 15

What are the 2 methods of producing ATP

Answer 15

1. Substrate-level phosphorylation
2. Oxidative phosphorylation

Question 16

When does substrate-level phosphorylation occur?

Answer 16

1. ATP is produced by the enzyme catalyzed transfer of a phosphate group from an intermediate substrate to ADP
2. ATP is produced in GLYCOLYSIS and the CITRIC ACID CYCLE

Question 17

When does oxidative phosphorylation occur?

Answer 17

1. In an ELECTRON TRANSPORT CHAIN
   -a proton gradient provides energy for ATP production
   -Membrane protein ATP SYNTHASE uses this energy to phosphorylate ADP to form ATP

Question 18

What are the 4 metabolic pathways of cellular respiration?

Answer 18

1. Glycolysis
2. Pyruvate processing/breakdown of pyruvate (into acetyl CoA)
3. Citric acid/Krebs cycle
4. Electron Transport Chain and Oxidative Phosphorylation

Question 19

What is the advantage of a stepwise pathway?

Answer 19

A series of small steps allows free energy to be transferred in conveniently sized packets to carrier molecules–most often ATP and NADH; directly burning sugar would release all free energy as heat

Question 20

Stage 1 of Cellular Respiration is…

Answer 20

Glycolysis

Question 21

Does glycolysis need oxygen to occur? What about cellular respiration as a whole?

Answer 21

Glycolysis can occur w/ or w/o oxygen, but cellular respiration overall needs oxygen

Question 22

What are the 3 phases of glycolysis’ 10 steps?

Answer 22

1. Energy investment (pay some to make some)
2. Cleavage (break things down)
3. Energy payoff

Question 23

What is the final outcome of glycolysis?

Answer 23

Make 2 pyruvate (and 2 NADH and 2 ATP)

Question 24

Which steps of glycolysis are assigned to each phase?

Answer 24

Energy investment => steps 1-3
Cleavage => steps 4-5
Energy payoff/liberation => steps 6-10

Question 25

Give overview of energy investment phase

Answer 25

Steps 1-3 needs 2 ATP to... -Phosphorylate and create a symmetric molecule Fructose 1,6 bisphosphate (F1, 6BP)

Question 26

Give overview of cleavage phase

Answer 26

Steps 4-5 -cleave F1, 6BP to get two molecules of Glyceraldehyde-3-phosphate (G3P)

Question 27

Give overview of energy payoff/liberation phase

Answer 27

Steps 6-10 -Step 6: convert G3P to high energy 1,3-Bisphosphylglycerate (BPG) -Steps 7-10: harvest energy from BPG, end with 2 PYRUVATE, 2 NADH, and 2 ATP

Question 28

What is the net ATP and NADH produced during glycolysis?

Answer 28

2 ATP; 2 NADH

Question 29

Where is (2) pyruvate produced during glycolysis transported?

Answer 29

To the mitochondria

Question 30

Why is the mitochondria considered the "powerhouse" of the cell?

Answer 30

Due to the amount of ATP it produces as a result of cellular respiration