metabolism A Flashcards
which enzyme is found only in the liver
phosphatase
why is phosphatase found only in the liver
glycogen in the liver must provide glucose for the entire body
what does phosphatase do
convert glucose-6-phosphate to glucose
when glucagon affects a liver cell, a phosphate is attached to both glycogen synthetase and glycogen phosphorylase.
which enzyme is activated?
glycogen phosphorylase
glucagon is trying to raise blood sugar
what compounds can be converted to glucose in gluconeogenesis
lactic acid
glycerol
some amino acids
which cells need insulin for glucose entry
muscle cells
liver
adipose
if glycogen synthetase were allosteric, what effect would ATP have on it
active
excess ATP means that there is no need for glycolysis
glucose should be stored as glycogen
what happens to MOST of the glucose-6-phosphate in liver versus muscle tissue
- In muscle it is used for energy, in liver it is converted to glucose to be transported by the blood to other cells
- they can both be converted to glycogen if not needed
Liver uses fatty acids for most of its energy needs
Exothermic reactions
- oxidation glucose to CO2 H2O
- succinyl-CoA–> succinic acid & coenzyme A
- GTP –> GDP & Pi
- hydrolysis of acetyl-CoA
- hydrolysis of glucose-6-phosphate to glucose
- CH3CH2OH to CH3CH=O
cannot be converted back to glucose-1-phosphate
fructose-1,6-biphosphate
step # 3 in glycolysis is irreversible
the purpose of the cori cycle is
move lactic acid out of the muscle
have the liver provide the muscle with “new” glucose
oxidation reactions
are always exothermic
oxidation of glucose to CO2 H2O
exothermic
glycogen synthesis
endothermic
ADP & Pi –> ATP
endothermic
Conversion of glucose-1-phosphate to glucose-6-phosphate
endothermic
succinyl-CoA –> sussinic acid & coenzyme A
exothermic
GTP –> GDP & Pi
exothermic
all anabolic reactions
endothermic
photosynthesis
endothermic
hydrolysis of acetyl CoA
exothermic
formation of glucose-6-phosphate from glucose
endothermic
hydrolysis of glycogen to glucose
exothermic
hydrolysis of glucose-6-phosphate to glucose
exothermic
CH3CH2OH to CH3CH=O
exothermic
does NOT occur in “fight or flight”
epinephrine crosses cell membrane to stimulate glycogenolysis
epinephrine cannot enter the cell
which occurs during “fight or flight”
- glycogen is converted to glucose-1-phosphate in the muscles
- epinphrine stimulate the production of cyclic-AMP in muscle cells
- cAMP causes the glycogen synthetase to be deactivated
- glycogenolysis is stimulated
proteins (polypeptides)
Glucagon
Insulin
Lactic acid dehydrogenase
polysaccharides
glycogen
can move through a cell membrane
glucose
cortisol
can stimulate fatty acid synthesis from acetyl CoA
insulin
stimulate the immediate conversion of glycogen to glucose-1-phosphate in the liver
Glucagon
stimulate the conversion of certain amino acids to glucose in gluconeogenesis
cortisol
Glucagon
Reverse of the other
- anabolism & catabolism
- glycogenolysis & glycogenesis
- photosynthesis & complete oxidation of glucose
produces the most ATP in glycolysis
fructose-1,6-biphosphate
there are already 2 phosphates on the molecule
produces the least ATP in glycolysis
glucose
in anaerobic exercise the pH of the muscle will
decrease
acidosis
which processes needs alot of ATP
muscle activity
synthesizing protein from amino acid
active transport
all anabolic reactions
reactions can be coupled so
one reaction drives the other
hydrolysis of glucose-1-phosphate to glucose give 5 kcal/mole
fructose-6-phosphate to fructose give 3.8
glucose-6-phosphate to glucose 3.8
creatine phosphate to creatine give 10.3
ATP to ADP and Pi gives 7.5 kcal/mol
which reactions would be exothermic or favorable
creatine phosphate & ADP to creatine & ATP
get 3.8 from fructose-1-P to fructose need 7.5 for ADP & Pi to ATP
total needed 3.7
get 10.3 from creatine-phosphate to creatine need 7.5
ADP & Pi to ATP
total get 2.8
get 3.8 from glucose-6-P to glucose need 10.3 for creatine to creatine-phosphate
total need 6.5
inhibits glycogenesis in the liver
hormone
Glucagon
stimulates glycogenolysis in the muscle
hormone
Epinephrine
stimulates entry of glucose into a muscle cell
hormone
insulin
inhibits gluconeogenesis
hormone
Insulin
stimulates entry of glucose into brain cells
hormone
none
Glycogen to glucose-1-phosphate
enzyme catalyzes
Phosphorylase
Glucose-1-phosphate to glucose-6-phosphate
enzyme catalyzes
mutase
GLucose & ATP to glucose-6-phosphate & ADP
enzyme catalyzes
kinase
Glucose-6-phosphate to glucose
phosphatase
if glycolysis is taking place in a red blood cell, where is the starting point
glucose
the purpose of converting pyruvic acid to lactic acid is to regenerate
NAD
which cannot move through a cell membrane
glycogen glucose-1-phosphate protein hormones epinephrine polypeptides
can move through cell
glucose CO2 galactose steroid hormones fatty acids glycerol amino acids
glycogen
cannot move through cell
polysaccharide
glucose-1-phosphate
cannot move through cell
phosphate prevents moving through membrane
protein hormones
cannot move through cell
epinephrine
cannot move through cell
polypeptides
cannot move through cell
true of insulin
inhibits glycogenolysis
stimulates entry of glucose into muscle tissue & liver tissue
FALSE of insulin
- too much insulin will result in hyper glycemia
- stimulates entry of glucose into brain cells
- it stimulates gluconeogenesis
the cAMP system is used for
mainly protein hormones
digestion is mainly a process of
hydrolysis
which process is MOST important in the maintenance of a constant blood glucose concentration
synthesis and breakdown of glycogen in the liver
TRUE diabetes
- it will occur when there are not enough insulin receptor sites
- it will occur when not enough insulin is secreted (released) by the pancreas
- kidneys will excrete large amounts of water in order to remove excess sugar from the blood
FALSE of diabetes
- occur when not enough insulin is produced by the liver
- can cause hyperglycemia
3.
when a phosphate is added to an enzyme to either activate it or deactivate it
covalent modification
what is called the “famine” hormone
famine= glucagon
“feast” hormone
feast=insulin
where is galactose converted to glucose
liver
the breakdown of food molecules into simpler chemical substances that can be absorbed by the body is called
digestion
what substance is secreted from the adrenal glands in response to low blood sugar levels, strenuous exercise or stress
epinephrine
adrenaline
what type of enzyme is needed to convert pyruvic acid to acetalaldehyde in fermentation
decarboxylase
starting with glucose, which steps in glycolysis are using up ATP
#3 #1
where does digestion start for proteins
stomach
where does digestion start for carbohydrates
mouth
where does digestion start for lipids [not metabolism]
small intestines
when epinephrine reaches the receptor cell on
muscle cells
when empinphrine reaches the receptor cell on muscle cells, it stimulates the process called
glycogenolysis
what happens when glucagon affects a liver cell
glucagon turns on adenyl cyclase which stimulates the reaction ATP to cAMP
kinase enzymes are turned on so phosphate can be put on glycogen synthetase and glycogen phosphorylase
what are the effects of glucagon
- glucose is converted to glycogen in the liver
b. glycogenolysis is stimulated in the liver and muscle
c. gluconeogenesis is inhibited
d. none
none
conversion of glucose-6-phophate to fructose-6-phosphate needs an isomerase enzyme and ATP for energy
false
no ATP is needed
RBCs do not have mitochondria so they must get all their energy from glycolysis
true
in a reaction that is energetically unfavorable, the energy of the products is more than the energy of the reactants
true
oral anti-diabetic drugs are similar to insulin in their structure
false
they are not proteins
proteins would be digested in the stomach
oral anti-diabetic drugs help with only some types of diabetes
they help increase the release of insulin from the pancreas
but no the original amount of insulin produced
Glucose 1-phosphate
Mutase
Isomers see
Glucose6-phosphate—> liver only
Phosphatase
Glucose–> to blood
Glucose 6-phosphate–ATP/ADP–> glucose.
Kinase
ATP–>ADP
Blood
Glucose 6-phosphate fructose 6-phosphate
Isomerase
Fructose 6-phosphate –ATP ADP–> fructose 1,6-biphosphate
Allosteric
Inhibited by ATP
Kinase
NAD
NADH
Dehydrogenase
-CO2
Decarboxylase
ATP
ADP
Kinase
Steps 7+ 10
Substrate level phosphorylation
Oxidative pathways
Kreb cycle
Aerobic
Muscle..
Anaerobic
Yeast
Anaerobic
Fermentation
Allosteric
Inhibited ATP
Using up ATP
Putting P on
Against gradient
Step 6
Glyceraldehyde 3-phosphate -P. NAD NADH-> 1,3 biphosphoglyceric acid
Coupling
Endothermic
Putting P on