German 3

Front 1

How does cAMP affect so many different signaling pathways?

Back 1

cAMP is formed by the activation of adenylate cyclase and the change of ?? +[cAMP] => activation of PKA which is an enzyme that can activat or ???? other enzymes (of different pathways) by phosphorylation.

Front 2

Why is it necessary that second messengers are short living?

Back 2

Because the signal not only is transduced, it is amplified and it is important to stop its effect at the right time.

Front 3

Describe in general terms the IP3 (inositol 1,4,5 triphosphate) cascade.

Back 3

PIP2 ->(phosphorylase C)-> IP3 + diacylglycerol
IP3 will activate the Ca++ channel, raising the Ca++ concentration in the cytosol. Different cellular processes happen. Muscle contraction. IP3 is dephosphorylated -> inositol cease the signal

Front 4

Signaling pathways use proteins with specific adaptor modules. Describe one of those. Why is the use of modules such a powerful mechanism?

Back 4

??IRS (insulin substrate proteins) bind lipid kinase and take it to the membrane where it can act on substrate a membrane lipid.

Front 5

Suppose you have discovered a new yeast strain that contains a new enzyme in the glycolytic pathway and catalyzes the following reaction:
Glyceraldehys 3-P + NAD+ +H2 ---> 3-phosphoglycerate + NADH + H+
This shortens the pathway but would it benefit the cell? Explain.

Back 5

The cell will not benefit because
PGA --> P 1,3 bisphosphoglycerate (using Pi +NAD+--> NADH + H+) --> 3-phosphoglycerate (using ADP -> ATP)
So the cell will lose the opportunity to yield ATP during glycolysis

Front 6

In 1906 Harden & Young performed experiments using yeast extracts and glucose.
They found that fermentation stopped when the assay mixture had exhausted the supply of phosphate. Explain.

Back 6

PGA -->1,3 bisphosphoglycerate (via Pi+NAD+). Exhausted the supply of phosphate would stop glycolysis at this step

Front 7

In 1906 Harden & Young performed experiments using yeast extracts and glucose.
Ethanol and CO2 accumulated, why was pyruvate converted to these molecules?

Back 7

To regenerate NA+, to keep the redox ?? ???? balance
Pyruvate --> ethanol +CO2 via (NADH + H+ --> NAD+)

Front 8

In 1906 Harden & Young performed experiments using yeast extracts and glucose.
They noticed that when fermentation ceased a hexose-bisphosphate had accumulated, which bisphosphate is this and why did it accumulate?

Back 8

Fructose 1,6 bisphosphate, because all other reactions are reversible.
Fructose 6-P + ATP --> Fructose 1,6-bisphosphate + ADP + H+

Front 9

In 1906 Harden & Young performed experiments using yeast extracts and glucose.
When they added arsenate to the mixture instead of phosphate they noticed that the hexose-bisphosphate did not accumulate and that the fermentation to ethanol and CO2 went to completion. Explain.

Back 9

Arsenate bound to the PGA and ?IG? glycolysis will continue to pyruvate --> ethanoly + CO2 (via NADH + NAD+), but the cell will not yield ATP during glycolysis.

Front 10

Proteins, Polysacchardies and lipids all yield the same two carbon metabolite.
What is this metabolite?

Back 10

Acetyl - SCoA

Front 11

Proteins, Polysacchardies and lipids all yield the same two carbon metabolite.
What is the major carbon containing compoun produced from this metabolite?

Back 11

CO2

Front 12

2-Phosphoglycerate --> _____ + H2O

Back 12

2-Phosphoglycerate --> PEP (phosphoenolpyruvate) + H2O
Glycolysis Step #9
Enolase performs dehydration

Front 13

Glucose + ATP --> _________ + _________

What enzyme is used in this reaction?

Back 13

Glucose + ATP --> Glucose 6-phosphate + ADP + H+
Step #1 in glycolysis
Hexokinase does a phosphoryl transfer

Front 14

Oxaloacetate + acetyl-CoA ⇒ ________

Back 14

Citrate
(citric acid cycle)

Front 15

Oxaloacetate + acetyl-CoA ⇒ Citrate
uses what enzyme?

Back 15

Citrate synthase
(citric acid cycle)

Front 16

SuccinylSCoA + ___ ⇒ Succinyl-P ⇒ Succinate

Back 16

Pi
(citric acid cycle)

Front 17

SuccinylSCoA + Pi ⇒ Succinyl-P ⇒ Succinate
This reaction is called?

Back 17

Substrate level phosphorylation
The reaction proceeds through a phosphorylated enzyme intermediate

Front 18

Malate + ____ ⇒ (Malate dehydrogenase) ⇒ ___ + NADH + H+

Back 18

NAD+ ⇒ OAA
(citric acid cycle)

Front 19

What is the precursor for citrate?

Back 19

Acetyl-CoA + OAA

Front 20

What is the precursor for succinate?

Back 20

Succinyl-SCoA

Front 21

What is the structure of oxaloacetate?

Back 21

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