Lec 17 - Regulation Metabolic Pathways

explain the importance of feedback inhibition in regulating metabolic pathways

not to waste glucose for unecesary energy

define allosteric enzyme

binds to some place other than active site to stabilize either its active or inactive form.

define allosteric inhibitor and an example

binds to some place on enzyme other than active site to stabilize the inactive form (ie. ATP coming from citric acid cycle or oxidative phosphorylation to PFK) (decreases enzyme activity)

define allosteric activator and an example

binds to some place on enzyme other than the active site to stabilize the active form (ie. AMP to PFK) (Increases enzyme activity)

Which steps in glycolysis are irreversible in glycolysis and why?

1, 3, and 10 because they are highly exergonic and it would take to much energy to get deltaG back up

describe what happens in step 3 of glycolysis

F-6-P gets another phosphate (ATP required)

what is the reactant, product, and enzyme used in step 3 of glycolysis?

reactant: fructose 6 phosphate. product: fructose 1-6 biphosphate. enzyme: PFK

what does "-kinase" mean?

an enzyme that phosphorylates something (adds a phosphate group)

what is "dephosphorylase"

an enzyme that takes phosphates off of things

define an enzyme being downregulated

enzyme's activity is reduced

define an enzyme being upregulated

the enzyme's activity increases

define feedback inhibitor

an inhibitor is feeding back into glycolysis to down regulate an enzyme

define metabolic rate

sum of all energy an animal uses in a time interval (calories per day) or speed at which your body uses energy

When there is a noncompetitive inhibitor present, it doesn't matter if you …; the Vmax will still be reduced.

you increase substrate concentration

What are all the ways enzymes can be regulated?

allosteric/feedback regulation, DNA transcription alteration,

Define DNA transcription alteration.

Increasing or decreasing the number of copies of mRNA that are transcribed from a gene, changes the"expression" of the enzyme

define catabolism

the part of metabolism that breaks down larger molecules into smaller ones

What macromolecules does glycolysis use for catabolism?

proteins, fats, and carbs

First law of thermodynamics

Energy can be transferred and transformed, but it cannot be created or destroyed

Second law of thermodynamics

every energy transfer or transformation increases the entropy of the universe

what is Lactic acid fermentation

after glycolysis when glucose is turned into pyruvate, pyruvate then gets turned into lactic acid

explain how the enzyme phosphofructokinase (PFK) is

under both positive and negative allosteric regulation.

PFK is activated by AMP (when low energy) and inhibited by ATP and citrate (when high energy) — allowing the cell to match glycolysis to its energy needs.

Define deamination

the removing of amino groups from from proteins before they go into glycolysis

Define Beta Oxidation

breaking fatty acids down into two carbon fragments which enter citric acid cycle as acetyl CoA

Define Biosynthetic Pathways

anabolic pathways that require ATP

Define PFK

step 3 and pacemaker of cellular respiration (inhibited by ATP and activated by ADP)

define allosteric effector

a molecule that attaches to an enzyme to effect its behavior