slides 8-13 - physiology

Question 1

what are enzymatic cofactors and coenzymes?

Answer 1

a non protein substance required for catalytic activity of some enzymes

Question 2

examples of cofactors or coenzymes

Answer 2

Mg2+, Zn2+, Mn2+ . . . and
NAD+, FAD

Question 3

study of metab. in vitro advantages and disadvantages:

Answer 3

isolated , defined and modifiable conditions, quantative results

loss of compartmentation
- doesn’t reflect the actual cell (eg running out of Pi

Question 4

study of metab. in vivo advantages and disadvantages:

Answer 4

in cell - realistic

hard to quantify (many variables)

Question 5

why do we need metabolic pathways?

Answer 5

multistep pathway that allows control

Question 6

what is a metabolic crossroad?

Answer 6

most pathways lead to the same common intermediates eg (Glucose - 6 - P)

Question 7

what are some key cofactor carriers?

Answer 7

ATP, NAD+, FAD, NADPH , CoA

Question 8

outline the two stages of glycolysis:

Answer 8

invstment and pay out
uses: 2 ATP
then produces: 4 ATP & 2 NADH
NET=2ATP

Question 9

What happens if cofactors run out?

Answer 9

glycolysis stops

Question 10

outline how NAD+ is regenerated in aerobic vs anaerobic:

Answer 10

pyruvate is oxidised and NADH gives e- to O2 forming H2O and NAD+

anaerobic : Glucose oxides to pyruvate and Pyruvate is reduced to ethanol or lactic acid

Question 11

what makes glycolysis central to carbohydrate breakdown?

Answer 11

it is the original way of making energy and leads to many other pathways essential for modern organisms

Question 12

outline the main stages of control and why of glycolysis:

Answer 12

1 stage –> not main regulation step as glucose is needed in other pathways

3 stage : main regulatory point

10 step : not main but needed as metabolic branch point.

Question 13

name the enzymes in the control stages:

Answer 13

Hexokinase - feedback inhibition
Phosphofructo Kinase - energy levels (AMP/ATP) + Metabolic intermediates

Pyruvate Kinase - feed forward activation

Question 14

what happens when there is a high level vs low level of ATP in glycolysis?

Answer 14

high = PFK inactivated
Low = PFK activated

Question 15

liver control in glycolysis?

Answer 15

yes - liver regulates blood glucose
Fructose - 2, 6-P increases when blood glucose is high
makes a feed forward and reduces inhibition by ATP

Question 16

sources for metabolism:

Answer 16

Galactose, Fructose

Question 17

Outline gluconeogenesis:

Answer 17

pyruvate –> glucose
liver and kidney
uses: ATP and GTP
shares steps with glycolysis but not all because it is Anabolic pathway

Question 18

what is generated from the hydrolysis of fructose -1, 6 bisP and glucose - 6- Pi?

Answer 18

not ATP (not regenerated) –> futile cycle
therefore tight regulation occurs –> PFK and Fructose -1, 6- bisphosphatase = oppositely regulates

Question 19

what are the starting materials for gluconogenesis?

Answer 19

Lactate , amino acids, and glycerol –> pyruvate oxaloacitate dihydroxyacetone

– triacylglycerides (fat) –> glycerol but only one not considered a source

Question 20

what is the pentose phosphate pathway?

Answer 20

converts glucose to pentoses releasing NADPH
also produces ribose - 5 P

Question 21

key stages of PPP:

Answer 21

oxidative stage (2 NADPH) and non oxidative stage( ribose -5-P+ glycolytic intermediates)

Question 22

how is PPP controlled?

Answer 22

by NADP+ availability (the substrate)

Question 23

steps for PPP:

Answer 23

step 1 : glucose 6 P
step 2 :gluconolactonase
step 3 : 6-P gluconate DH

Question 24

what kind of pathway is the PPP?

Answer 24

cyclic - completely oxidises glucose to CO2

Question 25

how many different modes does the PPP cycle have?

Answer 25

1. No NADPH (ribose) 2. (NADPH + ribose) 3. NO Ribose (NADPH) 4 NADPH and ATP

Question 26

what is the ^G of glucose --> co2 and h20?

Answer 26

-2.9x10^3

Question 27

what was the sparker effect?

Answer 27

the effect is that of an organic acid on the use of O2. the more O2, the more

Question 28

inhibitors of the Krebs cycle?

Answer 28

malonate (competitive)

Question 29

conversion of pyruvate to acetal CoA steps

Answer 29

irreversible pyruvate + coenzyme a + NAD+

Question 30

what are the components of the pyruvatedehydrogenase complex and function

Answer 30

E1, decarboxylates pyruvate E2, transfers to CoA E3, regenerates lipoamide

Question 31

what are multi enzyme complexes?

Answer 31

non covalent bonded enzymes that catalyse 2+ sequential steps

Question 32

citric acid cycle regulation points:

Answer 32

1. pyruvate to acetal Coa 2. acetal Coa to citrate 3. isocitrate to alpha ketoglutarate 4. alpha ketoglutarate to succinyl CoA

Question 33

what reaction occurs to replenish oxaloacitate if it is pulled out of citric acid cycle?

Answer 33

carboxylation of pyruvate

Question 34

explain the electron transport chain in oxidative phosphorylation:

Answer 34

free energy release

Question 35

role of the complex 1, 3, and 4

Answer 35

1, 2 ,3 4 complexes and function of each should be on paper

Question 36

proton motive force:

Answer 36

delta p --> each proton moving back = -22kj/mol 3 H+ are needed for 1 ATP

Question 37

what does complex V do and why is it coupled?

Answer 37

F0 = proton pump F1 = ATP synthesis (condensation?) not coupled= F0 pumps H+ but does not make ATP and if just F1, it hydrolyses ATP

Question 38

how does ATP synthase work?

Answer 38

F0 rotates, Y rotates ADP and P are trapped and T site

Question 39

what are the components of beta

Answer 39

O: binds and release of ADP and P Y rotates L: ADP and P bound y rotates T: ATP formed y rotates O: atp leaves

Question 40

what moves the electrons from NADH into the mitochondria from glycolysis?

Answer 40

glycerol phosphate shuttle = carried by FADH2 into complex 2 therefore only 6 H+ pumped total malate shuttle =complex and goes to complex 1

Question 41

how are the nucleotide carriers used? / how does the ADP and P end up in the matrix where they are needed?

Answer 41

P-OH antiporter ATP-ADP antiporter

Question 42

equation to calculate the energy of a photon?

Answer 42

e=HC/lamda

Question 43

what was the hill reaction?

Answer 43

isolated chloroplast was illuminated - primary event in photosynthesis occurred

Question 44

explain the light harvesting complex:

Answer 44

photons hit chlorophylls and auxiliary pigments electron gets excited transfered to reaction centre

Question 45

explain the reaction centre:

Answer 45

photons end up at reaction centre chlorophylls energy used for charge separation the resulting e- can be given to other molecules

Question 46

how is light energy converted?

Answer 46

by photosystem 1 and 2