biochem exam 3

1. fuel for molecules (stored as triacyglycerol)
2. target molecules (attach to proteins to target membrane location)
3. hormones/intracellular messengers
4. fatty acids are building blocks- phospholipids/glycolipis

what are the roles of fatty acid metabolism

fatty acids

long hydrocarbon chains of unsaturated and saturated degrees and C02- on one end

octadecadienoic acid

what is the name of a C18 with 2 double bonds?

there is a cis double bond between carbon 9 and 10

what does a cis(triangle)-9 mean?

cytosol and peroxisomes

where are the two places that fatty acid synthesis occur?

triacyglycerols

how are fatty acids stored?

-reduced
-nonpolar
-stored in anhydrous form

what are the three characteristics that make fatty acids have a high caloric yield?

condensation
reduction
dehydration
reduction

what are the 4 steps of fatty acid synthesis?

lipases

what is the enzyme that degrades triacylglycerol into fatty acid and monoacylglycerol

False

T/F: TAG are soluble in water

micelle

In the intestine, TAG are packaged as ___________ composed of bile salts due to their insolubility in water

ester bond

what structure is rendered on top of the micelle so lipase can digest it in soluble solution

chylomicrons

how are TAG transported in the mucosal cell?

TAG
apolipoprotein
fat-soluble vitamins
cholesterol

what are chylomicrons composed of?

lymph nodes and bloodstream

where are the 2 places that chylomicrons are transported to?

fatty acid and monoacylglycerols

on the lumen side triacylglycerol are digested into?

True

T/F: triacylglycerides are resynthesized in the mucosal cell and transpored as chylomicrons

-mobilization
-FA activation and transported into the mitochondria
-FA broken down into aetyl coA and then used in citric acid cycle.

what are the 3 steps of utilizing fatty acid as fuel required?

TAG is degraded into fatty acid and glycerol

what happens during the mobilization ?

glycerol gets shipped to the liver and converted to GAP and DHAP

what happens to glycerol from the mobilization step?

1. 7TM receptor
2. adenylate cyclase
3. ATP
4. PKA
5. perilipin A
6. restructures fat droplets so that the hormone lipase can be accessible to hormone sensitive lipase.

Fill in the blank: the entire mechanism of how TAG is degraded.
Glucagon/Epinephrine binds to ________receptor, then GTP binds to __________. _________ increases cyclic AMP then cyclic AMP activates ___________. PKA phosphorylates triacylglycerol lipase a

liver

what organ functions to maintain a nearly constant level of glucose in the blood?

Glucose 6 phosphatase

a hydrolytic enzyme that cleaves phosphoryl group to form free glucose and orthophosphate which allows glucose to leave the liver

glucose+ Pi

what are the products of this reaction?
glucose 6 phosphate + H20------->

glycogen phosphorylase

an enzyme that is composed as a dimer which cleaves glycogen, water is excluded from the active site and involves the PLP coenzyme

pyridoxal phosphate

the coenzyme that bound to glycogen phosphorylase?

allosteric regulation and reversible phosphorylation

what are the 2 ways that glycogen phosphorylase is regulated/

glycogen phosphorylase

what enzyme catalyzes this reaction
glycogen---->glucose 1P

False

T/F: During glycogen breakdown ATP is expended

transferase
alpha- 1,6 glucosidase

what two debranching enzymes catalyze the degradation of branch points?

phosphorolysis

the cleavage of a bond by the addition of orthophosphate.

glycogen and Pi

the reactant to this reaction
______________------------> glucose 1P + glycogen (n-1)

phosphoglucomutase

the enzyme that catalyzes the rearragement
glucose 1P---------->glucose 6P

Ca 2++
phosphorylation

what are the two ways phosphorylase kinase is regulated?

glycogen phosophorylase a

what form is glycogen phosporylase in its active form?

inactive

the T state of glycogen phosphorylase b?
-inactive or active

high levels of AMP

what is a factor that renders glycogen phosphorylase b in its relaxed phase?

ATP
glucose 6 phosphate

what two factors causes glycogen phosphorylase b to remain in its tense state?

phosphorylated

glycogen phosphorylase a is active when _______?

glycogen phosphorylase a

in what form is glycogen phosphorylase predominant in the liver to make more glucose.

True

T/F: glucose deactivates glycogen phosphorylase a

False

T/F: liver phosphorylase is sensitive to AMP

epinephrine
glucagon

what two hormones are needed as signals during glycogen breakdown?

protein kinase

what enzyme activates phosphorylase kinase?

phosphorylase kinase

what enzyme activates glycogen/liver phosphorylase a?

epinephrine

what hormone elicit glycogen degradation in the liver?

epinephrine (muscle) glucagon (liver)
adenylate cyclase
ATP
Phosphorylase kinase
phosphorylase a

__________________ binds the 7TM receptors then GDP is formed to GTP, _____________ is then activated because GTP binds onto it. ________ increases cylic AMP , cAMP activates PKA which in turn activates_________. Phosphorylase kinase then activates ______

phosphorylase kinase and glycogen phosphorylase

what two enzymes are deactivated during the shutting off of glycogen?

protein kinase

what enzyme adds an additional phosphate to phosphorylase kinase?

protein phosphatase 1

what is the enzyme that removes 2 phosphate group from phosphorylase kinase and deactivates it?

glycogen phosphorylase

Protein phosphatase 1 dephosphorylates what enzyme after deactivating phosphorylase kinase?

glycogen (n+1) + UDP

what is the product of this reaction?
glycogen (n) + UDP-glucose----->

UTP + glucose 1P

what is the reactant of this reaction?
__________________ ------> UDP-glucose+ PPi

UDP pyrophosphorylase

what enzyme catalyzes the formation of UDP-glucose

UDP-glucose

what is the name of an activated glucose?

glycogen synthase

what enzyme catalyzes the synthesis of glycogen

glycogenin

what is the primer that glycogen synthase uses to add polysaccharide chains already containing more than 4 residues?

branching enzyme

the enzyme that catalyzes branches forming alpha 1,6 linkages

inactive

when glycogen phosphorylase is dephosphorylated it is :
inactive or inactive

active

when glycogen synthase b is dephoshorylated it is:
inactive or active

inactive

when phosphorylase kinase is dephosphorylated ?
inactive or active

inactivate

what happens to glycogen synthase when protein kinase phosphorylates it

GM
less active
phosphorylated

epinephrine binds to Protein kinase A and protein kinase phosphorylates GM(glycogen binding site in muscle) and dissociates PP1 and __________. PP1 is (less/more active), then an inhibitor is (phosphorylated, dephosphorylated) and inhibitor deactivates PP

tyrosine
PKA
deactivates

Insulin regulation
insulin binds to ______receptors, signal transduction, ________ inactivates glycogen synthase kinase then phosphorylates glycogen synthase which is then (activated, deactivated). PP1 dephosphorylates it and glycogen reserves are synthes

Pompe disease

the disease that is caused by lack of alpha glucosidase. which causes a build up of glycogen in the blood

Gierke disease

loss glucose 6 phosphatase. which causes glucose to remain in the blood and glycogen increases and cannot enter cell and cannot enter blood.

They are emulsified in the small intestine by bile salts.

How are fats absorbed by the body during digestion?
A. They are hydrolyzed by amylase in the mouth.
B. They are emulsified in the small intestine by bile salts.
C. They are digested in the stomach by stomach acids.

D. They keep triacylglycerols in a soluble form.

Once fats are digested, they are transported by lipoproteins in the blood to the peripheral tissues. What is the role of lipoproteins?
A. They act as detergents.
B. They degrade triacylglycerols into fatty acids and glycerol.
C. They raise cAMP levels.
D.

C. Diffusion

How do triacylglycerols go through the cell membrane of adipocytes or muscle cells?
A. Active transport
B. Through the action of a permease
C. Diffusion

A. Acetyl CoA goes on to further oxidation in the citric acid

b oxidation of fatty acids occurs on activated fatty acids (fatty acyl CoA). After each set of reactions, the fatty acid chain is reduced by two carbons. These leave in the form of acetyl CoA. Why is this important?
A. Acetyl CoA goes on to further oxidat