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)
• Hydrophilic
• 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