Midterm 1 Content Flashcards
catabolism
breakdown of precursor into smaller, simpler products.. release energy (convergent)
anabolism
small, simple precursors built into larger products .. requires energy (divergent)
Is ATP a storage molecule?
No. Broken down at high rates
The use of ATP is has a delta G of ?
-30.5 kJ/mol
zymogen
precursor to enzyme
trypsinogen
zymogen that activates trypsin
secretin
releases sodium bicarb which neutralizes stomach acid
cholecystokinin (CCK)
stimulates release of digestive enzymes from pancreas and secretion of bile salts from gallbladder
How can GERD be treated?
inhibitors of H+-K+ ATPase , omeprazole
What specific proteins are in gluten that are resistant to digestion in Celiac?
proline and glutamine
What breaks alpha 1,4 bonds on starch?
alpha- Amylase
lipoprotein transport particles
chylomicrons
Where are chylomicrons formed?
intestinal cells
The more reduced a carbon atom is, the more free energy is released upon oxidation T/F?
true
Biological reactions of reduction and oxidation are ___?
coupled
What vitamin is apart of CoA structure?
Vitamin B5, pantothenic acid
What vitamin is apart of FAD structure?
B2, riboflavin
What vitamin is apart of NAD+ structure?
B3, nicotinic acid
What vitamin is also known as biotin?
B7
Glycolysis delta G
-77 kJ/mol, will never go backwards
What do kinases in glycolysis require?
Mg2+
Why is step 1 in glycolysis irreversible?
glucose can leave a cell but glucose 6-phosphate cannot, so trapped in the cell
How many GAPs are formed from 1 F-1,6-BP?
2
What are the 3 fates of pyruvate?
ethanol, lactate, further oxidation
Warburg effect
cancer cells carry out anaerobic glycolysis even if O2 levels are abundant. Cancer cells uptake FDG more rapidly than non-cancer cells bc rate of anaerobic glycolysis is so rapid. FDG is phosphorylated by hexokinase to 6-phospho-FDG
What is PFK inhibited by in the liver?
excess citrate
What is PFK activated by in the liver?
F2,6 BP (F2,6BP is generated by PFK2 in excess of F-6P)
PFK directly inhibits hexokinase when there is an accumulation of F-6P
False, INDIRECTLY inhibits
GLUT2 function
found in liver, pancreatic islet cells, intestine, kidneys. Removes excess glucose and regulates insulin release. Has high Kt value of 17mM and is never saturated
GLUT4 function
found in muscle, adipose, and heart. In fed state responds to insulin to stimulate glucose uptake. In fasted state, increases lipolysis. Kt value of 5mM and works at Vmax
GLUT5 function
found in intestine, testis, and kidney. Regulates fructose transport Kt is 6mM
Insulin independent?
GLUT2
Insulin dependent?
GLUT4
Gluconeogenesis
non-carbohydrate precursors to carbohydrates. important during fasting or starvation
2 sites of gluconeogenesis in mammals
- liver
- kidney cortex
Where does conversion of pyruvate to lactate occur?
liver
1st step of gluconeogenesis
pyruvate –> oxaloacetate –> PEP
- oxaloacetate –> malate (mitochondria)
- malate –> oxaloacetate (cytosol)
What coenzyme does pyruvate carboxylase use?
biotin
Where does gluconeogenesis occur?
cytoplasm
Irreversible enzymes of gluconeogenesis
- pyruvate carboxylase
- fructose 1,6- bisphosphatase
- glucose 6-phosphatase
Where does conversion of glucose 6-phosphate –> glucose occur?
lumen of ER of liver bc glucose 6-phosphatase on inner surface of ER
F-2,6- BP is high in fasted state T/F?
False
F-2,6- BP stimulates and inhibits ..?
stimulates: PFK-1
inhibits: F-1,6- BP
Cori cycle
conversion of lactate into glucose in liver after heavy muscle work
What is core of glycogen?
glycogenin
glycogen phosphorlyase
degrades glycogen from alpha-1,4 (nonreducing ends)
debranching enzyme
cleaves alpha-1,6 bond at branch point
allosteric factors regulating glycogen phosphorylase
epinephrine, glucagon, insulin
Diff between liver and muscle for glycogen degradation
liver maintains glucose homeostasis for entire body while muscle uses glucose to produce energy for itself
It is clear that glycogen depletion is an actual cause of fatigue T/F?
False
What is the monomer that is used to extend glycogen chain in synthesis?
UDP-glucose= activated form of glucose bc will donate glucose
Key regulatory enzyme in glycogen synthesis
glycogen synthase= transfers glucose from UDP glucose to form alpha-1,4 bond
What forms alpha-1,6 linkages?
branching enzyme. Takes block of 7 glucoses and synthesizes an alpha-1,6 linkage
How many molecules of ATP are required to incorporate dietary glucose into glycogen?
2 ATP. Yields 31 molecules of ATP
What inhibits glycogen synthesis?
glucagon and epinephrine
What stimulates glycogen synthesis?
insulin. By transduction pathway and increase GLUT4 transporters
Pyruvate transport is a symporter T/F?
true. transports pyruvate and H+ into mitochondrial matrix
E1 of PDH complex
thiamine pyrophosphate (TPP)
E2 of PDH complex
lipoic acid
E3 of PDH complex
FAD
What does PDH complex produce?
CoA, NADH + H+, CO2
How do arsenic and mercury act?
target reduced lypollysine in E2 by associating with its sulfhydryl groups
Arsenite comes from?
natural mineral in mines and chemotherapeutic agent
Mercury comes from?
thermometers, soften and shape fur for hats
