Both glycogenesis and glycogenolysis are controlled primarily by the interplay between the two hormones insulin and ______?
glucagon
Hexokinase D is found in the ____?
Liver, pancreas, intestine, brain
An enzyme family called the _____ catalyzes the phosphorylation of hexoses in the body.
hexokinases
The conversion of glucose-1-phosphate to UDP-glucose has a ?G0' near zero. Which of the following reactions is coupled with the above reaction to drive it to completion?
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Which of the following is required for the conversion of UDP-glucose to glycogen?
Two enzymes required.
1. Glycogen synthase
2. Amylo-alpha-(1,4 ? 1,6)-glucosyl transferase
Also requires pre-existing tetrasacharide composed of 4 alpha linked glucosyl residues.
A glycogen molecule that has been degraded to its branch points is called a?
limit dextrin
Regulation of glycolysis involves all of the following except?
Hexokinase (I,II,III,IV)
PFK-1
Private kinase
Feedback inhibition by ATP
Allosteric inhibition by ATP
Allosteric stimulation by ADP
The binding of insulin to receptors on the surface of muscle cells stimulates which of the following processes?
1. Activates kinase function of PFK2
2. Promotes the translocation of glucose transporters to the cell surface
3. Receptor protein undergoes several autophosphorylation reactions triggering phosphorylation/dephosphorylation of target enzymes and transcrip
Under stressful conditions epinephrine is released from the adrenal medulla. THe release of epinephrine has which of the following effects on glucose metabolism?
1. Activates glycogenolysis
2. Inhibits glycogenesis
3. When released in large quantities, massive production of glucose provides energy required to manage the situation (fight or flight response)
4. Activate adenylate cyclase in liver and muscle cells
Phosphorylase kinase
Converts the inactive form of glycogen phosphorylase to the active form called phosphorylase A, by the phosphorylation of a specific serine residue.
Cori's disease is cased by a deficiency of?
glycogen debrancher enzyme deficiency in liver
Which of the following activates phosphoprotein phosphatase?
Insulin
Glucose 6 phosphate is a substrate in which of the following processes?
The conversion fructose 6 phosphate by enzyme phosphoglucoisomerase
Fructose 2, 6 biphosphate is?
an allosteric regulator of glycolysis and gluconeogenesis. F-2,6 BP activates PFK1 (glycolysis) and inhibits F-1,6-BPase (gluconeognsis)
The Embden-Myerhof pathway is also referred to as?
The glycolytic pathway or glycolysis
In glycolysis ___ moles of ATP are produced per mole of glucose consumed.
2
In glycolysis ___ moles of NADH are produced per mole of glucose consumed.
2
The presence of which of the following molecules indicate that the cell has sufficient energy reserves?
FIND ANSWER
Which of the following enzymes is an oxidoreductase?
Alcohol dehydrogenase
Ribonucelotide reductase
oxygenases
oxidases
peroxidases
The first reaction in the oxidative phase of the pentose phosphate pathway is catalyzed by?
oxidation of G6P by G6P dehydrogenase
Which of the following enzymes catalyzes an irreversible process?
Hexokinase, PFK1, pyruvate kinase
In anaerobic organisms, pyruvate is used to regenerate ___?
NAD+
Allosteric regulation of which of the following enzymes is important in the regulation of glycolysis?
Hexokinases 1, 2, 3
PFK1
Pyruvate Kinase
Gluconeogenesis occurs primarily in the ___?
Liver
Which of the following molecules can be used to synthesize glucose via gluconeogenesis?
Lactate
pyruvate
glycerol
certain alpha keto acids
Which of the following is the most important glycogenic amino acid?
Alanine
Gluconeogenesis is stimulated by high concentrations of which of the following compounds?
Lactate
glycerol
amino acids
Which of the following is an oxidizing agent in fermentation?
NAD+
IN addition to glucose which of the following sugars are important in the human diet?
Fructose, galactose, and mannose
Intermediates in the nonoxidative phase of the pentose phosphate pathway include all of the following except?
ribose- 5- phosphate
fructose- 6- phosphate
glyceraldehyde- 3- phosphate.
The use of a highly exergonic reaction in the beginning of a catabolic pathway is referred to as?
activation" or "turbo design" (found on page 260 under Metabolism and Jet engines)
Aldol cleavage of which of the following sugars will prduce on mole each of dihydroxyacteone and glyceraldehyde?
Fructose 1-6 bisphosphate
Which of the following is a second messenger in glycogeneolysis?
Cyclic Amp (CAMP)
In animals excess glucose is converted into its storage form ___?
glycogen
The major carbohydrate fuel for most organisms is?
glucose
Which of the following enzymes is not required in gluconeogenesis?
Pyruvate carboxylase (Biotin)
PEP carboxykinase
Malate dehydrogenase
fructose 1-6 bisphophatase
The final product of glycolysis is?
Pyruvate
The principal products of the pentose phosphate pathway include?
NADPH (reducing agent)
Ribose 5 phosphate
Flux of which of the following sugars into the glycolytic pathway is essentially unregulated?
Fructose
Conversion of fructose 6 phosphate to fructose 1,6 bisphosphate has two purposes. One is the commitment of the molecule to glycolysis, the second is?
to prevent any later product from diffusing out of the cell because charged molecules cannot easily cross membranes
Which of the following enzymes will catalyze the first committed step in glycolysis?
Phosphofructokinase 1 (PFK1)
The crabtree effect in yeast is?
When glucose represses aerobic
The Pasteur effect is when?
glucose represses aerobic metabolism
A diauxic shift is?
when there is a significant change in gene expression once glucose levles are depleted and oxygen is avilable, which alters yeast energy metabolism
The phosphorylation of glucose when it enters a cell accomplishes which of the following?
1. Prevents transport of glucose out of the cell
2. increases the reactivity of the oxygen in the resulting phosphate ester
Which of the following compounds is an end product of anaerobic respiration?
Ethanol, lactic acid, acetic acid waste products
or Pyruvate, 2ATP, 2NADH, 2 H+, 2 H20