INTRO TO METABOLISM

Question 1

Catabolic pathways

Answer 1

breakdown
* extract H/e- to be delivered to ETC

Question 2

Anabolic pathways

Answer 2

build larger molecules from smaller substrates
* requires ATP/ reducing power (NADPH, NADH)

Question 3

Chemical “work”

Answer 3

• Build big molecules
• Protien
• Fat to store in adipose

Question 4

Transport “work”

Answer 4

• Move across membrane
• Against diffusion

Question 5

Mechanical “work”

Answer 5

• Muscles moving
• Heart pumping
• Movement

Question 6

“____” is required to do work

Answer 6

energy

Question 7

Reactions that require free energy can be coupled to ____ to make them thermodynamically ____

Answer 7

1. ATP hydrolysis
2. favourable
   ATP -> ADP or AMP

Question 8

Kinases

Answer 8

catalyse a phosphorylation reaction

Question 9

Phosphatases

Answer 9

catalyse dephosphorylation reactions

Question 10

Phosphorylases

Answer 10

catalyse a phosphorolysis reaction

Question 11

Synthases

Answer 11

do NOT require nucleotide triphospate

Question 12

Synthetases

Answer 12

do require nucleotide triphosphate

Question 13

Synthases & synthetases
both…

Answer 13

catalyses condensation reaction

Question 14

Dehydrogenase

Answer 14

• Catalyse oxidation-reduction reactions
• Usually involved NAD+/FAD as cofactors
• Named for the substrate that is oxidised by NAD+/FAD

Question 15

NAD+

Answer 15

Nicotinamide adenine dinucleotide
* oxidises -CH2-CHOH-
* becomes NADH

Question 16

Coenzyme A

Answer 16

• Carrier of acyl groups
• Trapping metabolites in cell
• Won’t diffuse across membrane

Question 16

FAD

Answer 16

Flavin adenine dinucleotide
* accepts 2 protons and 2 electons
* oxidises -CH2-CH2- to -CH=CH-
* FADH2

Question 17

Fuel oxidation: Stage 1

Answer 17

• Rip hydrogen/electrons out of fuels
• Fuels break up into two carbon chunks

Question 18

Fuel oxidation: Stage 2

Answer 18

• Rip hydrogens/electrons out of acetate
• Complete oxidation of carbon → CO2
• Kreb’s

Question 19

H/e- carriers…

Answer 19

Are in limited supply
* Once they are carrying, cannot do anymore stripping

Question 20

Making ATP with the H+ gradient

Answer 20

• protons flow (under pressure) into inner mito membrane
• cause another protein to rotate
• interacts with subunits of the ATP synthase
• generate ATP from ADP + P

Question 21

ADP is in ____ supply

Answer 21

short

Question 22

ATP is very ___

Answer 22

stable

Question 23

inner mitochondrial membrane is ____ to protons

Answer 23

impermeable

Question 24

Protons will only flow into the matrix if...

Answer 24

*ATP* is being made

Question 25

The proton pumps dont work if the proton gradient is very ____

Answer 25

high

Question 26

If there is no proton pumping...

Answer 26

no **H/e-** movement down **ETC**

Question 27

Fuels: Fatty Acid

Answer 27

* nearly all **C** atoms *reduced* * stored as **triglyceride** * **hydrophobic** * **energy** dense * **CANNOT** be used by **brain**

Question 28

Beta-oxidation

Answer 28

1. **Fatty acids** trapped in cytoplasm as **fatty acyl-CoA** 2. *Transported* into mitochondria by **carnitine** 3. **H/e-** *ripped* out by **FAD** and **NAD+** 4. Fatty acid part *loses* an **acetate chunk**

Question 29

Fuels: Glucose

Answer 29

* Reasonably **charged** * Stored as **glycogen** (low) * Hydro**philic** * **Inefficient** * Can be used by *all* tissue * Brain has an **obligatory requirement**

Question 30

Glucose oxidation (glycolysis)

Answer 30

* All tissues * **Wholly cytosolic** * *No* requirement for **oxygen** * Fast *but* inefficient - ATP generation almost irrelevant compared to oxidative phosphorylation * **Pyruvate** must be transported into mitochondria for full oxidation

Question 31

Fuels: Protein

Answer 31

* We *dont* store protein - it all has **function** * Making proteins **costs** lost of energy * Protein is **last ditch** fuel store - starving

Question 32

Does the rate of ATP synthesis exactly match the rate of ATP use?

Answer 32

Yes * **Turnover** is huge * Cells *can't* burn fuel without doing work * **Catabolism** is controlled by *demand*

Question 33

DNP

Answer 33

**Uncoupler** * “Dont need to do any exercise or work” * Rapidly use **oxygens**