Cell Metabolism Equilibrium and Flow

FALSE

A reaction in a test tube is the same as a reaction within a cell T/F

True

A unidirectional reaction can possible be a rate limiting step T/F

If A increases, the reaction would move to the right to produce more C and D

By Le Chatelier's Principle: A + B <--> C + D What happens when A increases?

If B decreases, A will increase, then C and D will increase

By Le Chatelier's Principle: A + B <--> C + D What happens when b decreases?

steady state

Cell do not achieve equilibrium as opposed to reaction in lab. Instead, they perform ______ equilibrium.

False

Cellular pathways are not at equilibrium, this is why Le Chatlier's Principle applies to metabolism. True False

TRUE

Cellular pathways are trying to achieve equilibrium but never achieve it T/F

lysosome

Cholesterol ester and fatty acid catabolism is central to cellular health and is conducted in the _______

If D is elevated, then that will cause it to move forward to make more E and F and also to move backwards to make more A and B. While this is happening, C decreases because it is being used to make those products b. E and F increase e. A and B increase a. C decreases

Consider the following cellular pathway: A + B <----> C + D <----> E + F If D is supplied from an outside pathway what is the effect? (Select all that apply.) a. C decreases b. E and F increase. c. A and B decrease d. E and F decrease e. A and B increase

b. possible rate limiting step d. likely point of regulation e. increasing D may decrease C

Examining a pathway inside a cell, you determine the following: A+ B --> C + D Which of the follow statements is / are true. (Select all that apply) a. Step is in equilibrium. b. Possible rate limiting step. c. Step does not require energy. d. Likely point of regulation. e. Increasing D may decrease C.

b. the Keq is 3.33

Given the following: A + B <----> C + D at equilibrium the measured concentrations are: A = 3 M B = 2 M C = 5 M D = 4 M Select the statements that is / are true. (Select all that apply) a. The reaction is not at equilibrium because the concentrations vary dramatically. b. The Keq is 3.33 c. The reaction releases energy. d. The reaction has a negative delta G.

([C][D]) / ([A][B])

Given the following: A + B <--> C + D What is Keq?

If C is diverted, A and B will move forward and E and F will move backward to restore C

If C is diverted to a secondary reaction, what happens?

Since D is elevated, enzyme 2 will produce more E and F, enzyme 1 will make more A and B

If D is supplied by an accelerated secondary reaction, what happens?

If F is being consumed, it is being depleted. C and D will move forward to restore F (and E). As C and D decrease, A and B will move forward to make more C and D

If F is consumed by a follow up reaction that is accelerated, what happens?

Increase of D would result in an increase of E and an increase of R", then since 11 is now reversible, and increase in H and an increase in R'

If enzyme 11 was freely reversible, what would happen due to an increase in D?

F and G would go back and forth with no where else to go

If enzyme 8 was mutated to inactivity, which substrates would build up?

If C increases, it will make more D and E. An increase in E inhibits the first enzyme which will slow down the production of C and restore the system. a. A and B increase b. The rate of the enzyme that makes C slows down c. D and E increase e. The rate of the enzyme that makes D and E speeds up

If the concentration of "C" increases what happens? (Select all that apply, assume no other connections to other pathways, assume cellular behavior.) a. A and B increase. b. The rate of the enzyme that makes C slows down. c. D and E increase. d. A and B decrease. e. The rate of the enzyme that makes D and E speeds up.

If enzyme 2 is inhibited: A and B will convert to C and D, but C and D do not convert efficiently to E and F. C and D will accumulated and back flow to make A and B

If the enzyme that converts C + D to E + F is inhibited, what happens?

C and D increase

In a closed system: A + B <--> C + D What happens if A and B increases?

B decreases, C and D increase

In a closed system: A + B <--> C + D What happens if A increases?

A increases, C and D increase

In a closed system: A + B <--> C + D What happens if B decreases?

D decreases, A and B increase

In a closed system: A + B <--> C + D What happens if C increases?

C increases, A and B decrease

In a closed system: A + B <--> C + D What happens if D decreases?

True

In a freely reversible reaction, intermediates can be restores and regulation is limited T/F

The conversion is freely reversible If B depletes, C and D deplete If B depletes, the system attempts to restore B

In a steady-state system: A + B <----> C + D Which of the statements are true? (Select all that apply). If B depletes, the system attempts to restore B. The conversion is at equilibrium. If B depletes, C and D also deplete. The conversion is freely reversible. If C depletes, A and B increase.

If A increases, B decreases and C and D increase. (that's it)

Le Chatelier's Principle: What happens when A increases?

pentose phosphate shunt

Metabolism can divert glucose from the energy pathway (glycolysis) into the _________

weak (hydrogen, van der waals, hydrophobic, electrostatic

Protein functions are driven by _____ bonds

If A increases, B decreases If A increases, more B reacts with A If A increases, C and D increase

Standard equilibrium: A + B <--> C + D Which of the following statements are correct? As the system is in equilibrium changes will have no effect. If A increases, C and D decrease If A increases, B decreases If A increases, more B reacts with A If A increases, C and D increase If A increases, B increases

All of Them

The following are assumptions of Le Chatelier's rules: 1. Closed System 2. Equilibrium 3. Reaction is fully reversible 4. No loss of material Which assumptions does metabolism violate (select all that apply. If none apply select "Metabolic Systems do not violate the assumptions").

A & B would decrease by forming C and D Now, C and D are abundant and can either backflow to make A and B or move forward to make E and F

What actually happens when A is increases?

Notice the loop bypasses enzymes 4 and 5. Perhaps reactions 4 and 5 are highly energetic or it uses rare substances that need to be kept abundant

What are some reasons of introducing a loop within a pathway?

1. When pathways are depleted cells try to replenish those pathways 2. All pathways are connected to other pathways 3. Loops exist to maneuver around energy or material intensive portions of pathways

What are the exceptions to Le Chatelier's Principle?

- metabolism has large interconnected pathways - "irreversible" reactions that cannot achieve ebb. - ebb. cannot be achieved with reversible reactions

What are the problems with metabolism and Le Chatelier's Principle?

None

What are the units of Keq?

B, C, D, E, and R" will increase. Increase of enzyme E will result in the slowing down of enzyme 2 (inhibited by enzyme 5), which will slow the production of A to B. Will also see and increase in F, G, H, R' (but less of an increase)

What happens if A is increased?

Since enzyme 4 is strong in the forward direction, we will get a strong forward pull on C to D will continues to make E..... We will also see a loss of enzyme 6 activity.

What happens if D in decreased?

If E is increased, we will see a slow down of A to B, B to C, C to D, D to E, and E to R" until the block is removed and the system goes back to normal

What happens if E is increased?

If G is increased, it will make more H and R'

What happens if G is increased?

Any that are unidirectional (1, 2, 5, 10, 8, 9, 11)

Which enzymes are likely to be highly regulated?

weak

_____ bonds can be affected by changes in pH