Biochemistry

Front 1

What does Insulin do to Glyocogen Synthase?

Back 1

It dephosphorylates it, because the phosphorylated state means we are POOPED of our glucose levels--> we need to make glucoses

so glycogen synthase is DEphosphorylated by the activated protein phosphatases to tell the cell to START making glycogen, we are no longer POOPED

Front 2

What does Insulin do to Fructose 1,6 Bisphosphonate?

Back 2

F16BP is also dephosphorylated because now we have glucose around. I

Remember, it is Phosphorylated when we are POOPED of our stores, so we need to ACTIVATE it to undergo gluconeogenesis

Front 3

When is pyruvate dehydrogenase activated?

Back 3

When we are in anaerobic states where pyruvate isn't going to go through the TCA cycle, because we don't have oxygen, but it will turn into lactate to generate NAD+ to permit G3P to move to 13BPG

Front 4

What are the universal electron acceptors?

Back 4

NAD+
NADP+
FAD+

NAD+ is used in catabolic processes to carry reducing equivalents away as NADH

NADPH is used in anabolic processes as a supply of reducing equivalants (used in fatty acid and steroid synthesis)

Front 5

NADPH

Back 5

is a reducing equivalent in anabolic processes

used in fatty acid synthesis
steroid synthesis

also used in the respiratory burst
used in P-450

Front 6

What is the difference between hexokinase and glucokinase?

Back 6

hexokinase is UBIQUITOUS, it is in every tissue. High affinity (low Km) and low capacity (low Vmax). It is NOT induced by insulin

GLucokinase: has LOW affinity, and a high Km--only insulin can induce the expression of glucokinase and it has a high capacity

Glucokinase (liver and beta cells of the pancreas)

l=low
I=insulin induced

Front 7

glucokinase

Back 7

sequesters excess glucose after a meal in the liver and allows glucose to serve as a blood glucose buffer

Front 8

HMP shunt

Back 8

generates NADPH and ribose 5 phosphate for nucleotide synthesis

Front 9

Pyruvate Dehydrogenase Deficiency

Back 9

Causes backup of substrate (pyruvate and alanine) resulting in lactic acidosis. Can be congenital or acquired.

Generally acquired with Alcoholics and Vit B1 deficiency)

Treatment: ketogenic amino acid diet (high fat content or high in lysine and leucine)

Front 10

Where would you see pyruvate and alanine build up?

Back 10

pyruvate dehydrogenase deficiency

Front 11

What is the Cori Cycle?

Back 11

Allows lactate generated in the anaerobic metabolism to undergo hepatic gluconeogenesis and provide glucose for the body

Comes at a net loss of 4ATP per cycle

Front 12

rate limiting step for gluconeogenesis?

Back 12

Fructose 1, 6 bisphosphate

Front 13

rate limiting step for glycolysis?

Back 13

PFK-1

Front 14

Site of Metabolism for Heme Synthesis?

Back 14

BOTH mitochondria and cytoplasm

HUGs take two

heme synthesis
urea cycle
Gluconeogenesis

Front 15

Reactions occuring in the cytoplasm?

Back 15

glycolysis, fatty acid synthesis, HMP shunt, protein synthesis (RER) steroid synthesis (SER)

Front 16

What reactions occur in the mitochondria?

Back 16

Fatty acid oxidation (beta oxidation) acetyl CoA production, TCA cycle, oxidative phosphorylation

Front 17

What is the rate limiting step in the TCA cycle?

Back 17

isocitrate dehydrogenase

Front 18

What is the rate limiting step in glyocogen synthesis?

Back 18

glycogen synthase

Front 19

what is the rate limiting step in glycogenolysis?

Back 19

glycogen phosphorylase

Front 20

What is NADPH used for?

Back 20

Fatty acid and steroid biosynthesis and for glutathione reduction inside RBCs

Front 21

Where does HMP shunt occur? in What tissues?

Back 21

Cytoplasm

lactating mammary glands (FA synthesis) liver, adrenal cortex (steroid synthesis) and RBCs

Front 22

what are the two phases of the HMP shunt?

Back 22

oxidative: the rate limiting step is glucose 6 phosphate dehydrogenase (IRREVERSIBLE)

the oxidative pathway produces NADPH (for FA, Steroid synthesis, glutathione reduction and cytochrome p450)

Non-Oxidative:

nonoxidative

Front 23

What is the non-oxidative part of the HMP?

Back 23

this is reversible, and the key enzyme is transketolase (which requires thiamine) this produces ridose 5 phosphate (for nucleotide synthesis) G3P and F6P

Front 24

What are the irreversible enzymes in gluconeogenesis?

Back 24

Pyruvate Carboxylase
PEPCK
F16BP
G6P

Pathway Produces Fresh Glucose

Front 25

What amino acids are required during peroids of growth?

Back 25

Arginine and Histidine

Front 26

What amino acids are present in histone proteins?

Back 26

Arginine and Lysine, which bind the negative charged DNA

arg is the most basic
His has no charge at body pH

Front 27

What are the acidic amino acids, negatively charged at body pH?

Back 27

Aspartate and Glutamate

Front 28

What are the ketogenic amino acids? how about the glucogenic?

Back 28

Ketogenic: Leucine and Lysine

Glucogenic: Met, Val, Arg and HIs

Front 29

What is essential fructosuria?

Back 29

Defect in Fructokinase; this is benign and asymptomatic

fructose is in the blood and the urine--> you get a build up of Fructose (can't convert it into F1P)

Front 30

What is Fructose Intolerance?

Back 30

Hereditary deficiency of aldolase B. buildup of Fructose 1 Phosphate--> which causes a decrease in available phosphate, causing inhibition of glycogenolysis and gluconeogenesis

Front 31

what are the signs and symptoms of fructose intolerance?

Back 31

hypoglycemia, vomitting, cirrhosis, jaundice

tx: don't take in fructose or sucrose (glucose + fructose)

Front 32

hyperammonemia

Back 32

may be acquired (liver disease) or hereditary (urea cycle enzyme deficiencies)

results in excess NH4+ which depletes alpha ketoglutarate leading to inhibition of the TCA cycle

tx: benzoate or phenylbutyrate to lower the serum ammonia levels

Front 33

OTC deficiency

Back 33

X linked recessive (other urea cycle deficiencies are autosomal recessive)

this is the most common urea cycle disorder. OTC deficiency is often evident in the first few days of life, but may presents with late onset. The body can't eliminate ammonia, and the excess carbamoyl phosphate is converted to orotic acid

Findings: orotic acid in the blood and urin, decreased BUN and symptoms of hyperammoniemia (tremor, slurred speech, somnolence, vomitting, cerebral edema and blurred vision)

Front 34

Alkaptonuria

Back 34

congenital deficiency of homogetisic acid oxidase

in the degradative pathway of tyrosine. Autosomal recessive and benign

pigmented sclera and ears--> may have debilitating arthralgias

Front 35

PKU

Back 35

decreased phenylalanine hydroxylase or decreased Tetrahydrobiopterin cofactor

Tyrosine becomes ESSENTIAL

the increased phenylalanine leads to excess phenylketones in urine

Mental Retardation, growth retardation, seizures, fair skin, mousy body odor

Front 36

Disorder of aromatic amino acid metabolism

Back 36

PKU--> you get a musty body odor

how do you treat PKU? you decrease phenylalanine (contained in nutrasweet) and you increase tyrosine in the diet

Front 37

What are the byproducts of tryptophan?

Back 37

serotonin ---> melatonin

niacin-->leads to NAD+/NADP+

Front 38

What amino acid does Heme derive from?

Back 38

Glycine

glycine--> porphyrin --> heme