Final exam Flashcards by forrest V

What is the net yield of ATP after glycolysis?

2 ATP

How well did you know this?

Not at all

Perfectly

What enzymes catalyzes the transfer of a phosphoryl group from ATP to glucose

hexinose

How well did you know this?

Not at all

Perfectly

Phosphofructokinase (PFK) is allosterically activated by _____

AMP

How well did you know this?

Not at all

Perfectly

Phosphofructokinase (PFK) is _ inhibited by __

ATP and citrate

How well did you know this?

Not at all

Perfectly

What is glucose converted to in the skeletal muscle under anerobic conditions?

lactate

How well did you know this?

Not at all

Perfectly

What is the purpose of co-factors chemical teeth?

broaden the range of enzymes’ catalytic properties

How well did you know this?

Not at all

Perfectly

What are the two cofactor

metal ions and coenzymes

How well did you know this?

Not at all

Perfectly

What are the different types of coenzymes

cosubtrates and Prosthetic groups

How well did you know this?

Not at all

Perfectly

Define cosubstrates

loosely bound, cycle on & off

How well did you know this?

Not at all

Perfectly

Define prosthetic

tightly/covalently bound

How well did you know this?

Not at all

Perfectly

What are some examples of Metabolite coenzymes:

ATP, UDP-glucose, S-adenosylmethionine

How well did you know this?

Not at all

Perfectly

What are some examples of Vitamin-derived coenzymes (water soluble)

Vitamins B and C

How well did you know this?

Not at all

Perfectly

What are some examples of lipid soluble vitamin-derived coenzymes

vitamins` A, D, E, and K (

How well did you know this?

Not at all

Perfectly

Acid-base catalysis

Partial proton donation (general acid catalysis) or abstraction (general base catalysis)

How well did you know this?

Not at all

Perfectly

What amino acids participate in acid-base catalysis

Asp, Glu, Lys, Arg, and His

How well did you know this?

Not at all

Perfectly

What makes a good catalyst

Good leaving group, reversibiliy of the bond, (how mobile electrons are).

How well did you know this?

Not at all

Perfectly

How does covalent catalyst form

Via transient formation of covalent E-S intermediate

How well did you know this?

Not at all

Perfectly

What is a covelent catalysis

a nucleophile attacks an electrophile and forms covalent bond with it

How well did you know this?

Not at all

Perfectly

There are 2 classes of metal ion catalysis, what are those two classes?

Metalloenzymes and Metal-activated enzymes

How well did you know this?

Not at all

Perfectly

What are the differences between Metal-activated enzymes and Metalloenzymes

Metalloenzymes are tightly bound and are transition metals. Metal-activated enzymes are loosely bound and are alkaine

How well did you know this?

Not at all

Perfectly

What are the 3 ways that metal ion catalysis act

Bind to substrates (orient properly for reaction).
2. Transiently change redox state (mediate redox reaction).
3. Stabilize/shield negative charges.

How well did you know this?

Not at all

Perfectly

What is the proximity and oreintation effects?

Binding to E forces substrate orient in a certain way  Rotational, translational motions cease
 active groups face each other  reaction

How well did you know this?

Not at all

Perfectly

Is there a prefential binding for ES

yes, there’s an affinity for E in ES because there’s a higher chance to form product

How well did you know this?

Not at all

Perfectly

What is Km ((Michealis constant)

enzyme binding affinity (higher Km=weaker affinity)

How well did you know this?

Not at all

Perfectly

What is Vmax

maximum rate of the reaction

Vmax relates

Kcat and [Et] by Vmax = kcat[Et]

What is Kcat

(turnover number or catalytic constant) and the Speed of catalysis

Define kcat/KM

measure of catalytic efficiency of enzyme

What does Kcat measure

product formation, substrate turnover

What is the Michaelis-Menten equation

V = Vmax[S]/(KM+[S])`

When would the Michaelis-Menten equation be haf-maximal

[S] = KM

what is the slope of Lineweaver-Burk plot or double reciprocal plot

Km/Vmax

What is the y-intercept of the Lineweaver -Burk plot

1/vmax

What is the x-intercept of the Lineweaver

-1/Km

What is the purpose of Lineweaver -Burk

Can determine KM and Vmax graphically

What is competitive inhibition

the inhibtition is structurally similar to the substrate and competes with the substrate for active site binding

What is competitve inhibtion impact on the reaction

reduces the steady state of ES, increases the Km, and no reaction happens if the inhibition binds to the active site

How can the competitve inhibition be overcommed

increase the amount of substrate

What is uncompetitve inhibitor

binds only to ES but not to any free enzyme

What is the impact uncometitve inhibitor has on the reaction

Both KM and Vmax change,Does not change the slope (KM/Vmax), no reaction happens at ESI

Defines Noncompetitive (mixed) inhibition

Binds both E and ES (somewhere, not in the active site)

Non competitve inhibition impact on the reaction

slope becomes steeper Y-intercept moves up, but X-intercept stays the same. o Apparent Vmax ↓ but KM stays the same.

What is an example of product inhibition

hexokinase by glucose-6-P

Define feedback inhibition

cellular control mechanism in which an enzyme's activity is inhibited by the enzyme's end product.

Where does glycolysis take place?

in the cytosal

What are the products of glycolysis

2 ATP, 2 Pyr, 2 NADH, 4 H+, 2 H20

Pyruvate kinase (step 10) is inhibitied by

ATP and acetyl-CoA

Pyruvate kinase (step 10) is activated by

AMP and fructose-1,6-bisphosphate.

What is the purpose of glycolysis?

provides precursor for aerobic catabolism (TCA cycle

What are the 2 stages of glycolysis

Investment and activation

What is the product from the stage 1: investment

2 glyceraldehyde-3-phosphate (GAP)

Stage 1 in glycolysis spends how many ATP

2 ATP for glucose activation

What steps consume ATP in glycolysis?

are consumed in steps 1 and 3 by hexokinase (HK) and phosphofructokinase (PFK)

What steps are ATP synthesized in during glycolysis

steps 7&10 by phosphoglycerate kinase (PGK) and pyruvate kinase (PK) via substrate-level phosphorylation

What were the 3 irreversible control points in glycolysis

Hexokinase (step 1), Phosphofructokinase (step 3), Pyruvate kinase (step 10)

Step 1 of Glycolysis results in

glucose-6-P

In step 3 what catalyzes fructose-6-phosphate?

phosphofructokinase (PFK )

Where does the TCA cycle take place

in the mitochondrial matrix

define reduction potential

tendency of a given reacting species to gain e - when paired with a standard

Positive reduction potential

tendency to attract/accept e- (reduced)

Negative reduction potential

tendency to give up e- (oxidized

What happens in a 2 half cell

e- always spontaneously flow from the half-rxn with more negative E o (donor) to more positive E o (acceptor)

Mechanims of ATP sysnthese

3 αβ protomers, 3 distinct sites, in 3 different conformations (states)

O state of ATP sysnthase

open, inactive, cannot bind ADP

L State of ATP synthase

loose binding, inactive, can bind ADP & Pi

T state of ATP synthase

tight binding, active,can synthesize ATP

What is the Michaelis-Menten equation

V = Vmax[S]/(KM+[S]

Pyruvate kinase is inhibited by

ATP and acetyl-CoA

Pyruvate kinase is activated

AMP and fructose-1,6-bisphosphate

What steps in glycolysis go through

substrate-level phosphorylation

What is substrate-level phosphorylation

the formation of ATP from ADP and a phosphorylated intermediate,

What activates step 4 of the citric acid cycle?

AMP

What inhibits step 4 of the TCA cycle

NADH and succinyl-CoA

What is being oxidized in step 6 of the Kreb's cycle

succinate

What is being reduced in step 6 of the citric acid cycle ?

FAD to FADH2

What process is succinate dehydrogenase is apart of besides the TCA cycle

electron transport chain

Where does o

Final exam Flashcards

(77 cards)