Metabolic Biochemistry 2023

Question 1 of 36

Which of the following modification is NOT correctly associated with the other part?

Phosphorylation — kinase cascade
γ-carboxylation — blood clotting factors
ADP-ribosylation — proteases
Acetylation — histones

Question 2 of 36

Which of the following statements about Protein Kinase A is NOT true?

It inhibits glycogen synthase.
It activates gluconeogenesis.
It favors fatty acid synthesis.
It stimulates FBPase2 to be active.

Question 3 of 36

Under hypoxia conditions, a cell synthesizes a transcription factor. What is it called?

HIF-1
GLUT1
Two transcription factors, called GLUT1 and GLUT3.
HIF-2
GLUT2

Question 4 of 36

Which of the following is NOT true regarding fat metabolism in the body?

Insulin and adrenaline together participate in the breakdown of proteins inside the cell by regulating the phosphorylation of proteases.
Insulin works against the adrenalin hormone and stimulates fat synthesis in the body.
The binding of epinephrine or glucagon to the cell receptors stimulates the breakdown of fats by activating the triacylglycerol lipase enzyme.
The phosphorylated triacylglycerol lipase works in conjugation with perilipin protein and removes the first fatty acid from the triacylglycerol molecule.
The attachment of insulin to the cell membrane receptor activates the enzyme phosphoprotein phosphatase and stimulates the removal of phosphate from the activated triacylglycerol lipase and perilipin protein.

Question 5 of 36

Which of the following mechanisms is NOT involved in metabolic control?

Ribozyme catalysis
Regulation of gene expression
Zymogen activation
Allosterism

Question 6 of 36

Which of the following statements is NOT correct?

Under hypoxia conditions, the regular cells, as well as cancer cells, synthesize the transcription factor called HIF-1.
The HIF-1 factor helps the cell to combat toxic conditions that originated due to higher oxygen levels.
HIF-1 factor favors elevated levels of expression of the seven enzymes of the glycolysis pathway during hypoxia condition.
The transcription factor HIF-1 helps in the movement of glucose to the interior of the cell by favoring the formation of GLUT1 and GLUT3 proteins.
HIF-1 factor binds to the particular class of genes in the DNA which helps in the survival of cells at low oxygen concentrations.

Question 7 of 36

Acetyl-CoA-carboxylase
Glycogen synthase
Perilipin
Triacylglycerol lipase
Phosphoglucomutase

Question 8 of 36

Which is true of allosteric control?

It acts to positively regulate enzymes, but not negatively.
It involves the addition or removal of phosphates.
It is basically an on/off switch.
It involves the binding of a small molecule to the enzyme.

Question 9 of 36

Which of the following enable anabolic reactions to operate in a cell?

Ample amounts of energy in the form of ATP.
Plentiful water concentration for enzyme activities.
The needed amount of DNA in the cell.
Sufficiently low amounts of CO2 in the surroundings.
Ample amount of oxygen dissolved in the aqueous surroundings.

Question 10 of 36

Which of the following function is NOT associated with insulin?

Stimulating glycogen synthesis.
Deactivating the enzyme triacylglycerol lipase via dephosphorylation.
Helping the adrenaline in stimulating the liver cells to release glucose-1-phosphate.
Lowering of blood glucose levels.
Stimulating fat synthesis and storage.

Question 11 of 36

Which is true of aspartate transcarbamoylase?

It is feedback inhibited by ATP.
It is activated by CTP.
it is activated by aspartate.
It is allosterically regulated by its substrate, CTP.

Question 12 of 36

What do you mean by the control of gene expression?

Controlling the amounts of rRNA and tRNA to regulate.
Controlling the process of transcription and hence synthesis of specific mRNA and protein molecules.
Controlling the permeabilities of the cell membrane and mitochondrial membrane for water.
Controlling the amounts of energy in the form of ATP and GTP.
Controlling the fluidity of cell membrane by regulating ion movement.

Question 13 of 36

Which of the following enzymes are NOT deactivated under the effect of the activated protein kinase A enzyme?

PFK2
Acetyl CoA carboxylase
Glycogen synthase
Phosphorylase kinase
FBPase2

Question 14 of 36

Aspartate transcarbamoylase does which of the following?

Flips into the T state when CTP binds into the catalytic site.
Flips into the T state when aspartate binds to the regulatory site.
Flips into the R state when ATP binds to the catalytic site.
Flips into the T state when CTP binds to the regulatory site.

Question 15 of 36

Which of the following occurs in the Cori cycle?

Gluconeogenesis in muscle cells provides them with glucose for energy.
The muscles release lactate in response to a low oxygen environment.
Glycolysis is going on mostly in liver cells to make ATP.
The liver has excess lactate.

Question 16 of 36

Insulin favors glycolysis, glycogen, and fat synthesis by the activation of which enzyme?

Phosphorylase kinase
FBPase2
PFK2
Phosphoprotein phosphatase
Acetyl CoA carboxylase

Question 17 of 36

Feedback inhibition occurs when which of these happens?

An end product of a pathway inhibits the first enzyme of the pathway.
A regulator binds to a catalytic site of an enzyme.
The first product of a pathway inhibits the last enzyme of the pathway.
A substrate inhibits an enzyme from catalyzing a reaction.
The correct answer is A) An end product of a pathway inhibits the first enzyme of the pathway. Feedback inhibition is a regulatory mechanism that helps maintain homeostasis in the body by controlling the rate of metabolic pathways. In this mechanism, the end product of a pathway acts as an inhibitor and binds to the active site or allosteric site of the first enzyme in the pathway. This binding prevents the enzyme from catalyzing the reaction and slows down the production of the end product. By inhibiting the first enzyme, the end product prevents the pathway from producing more of itself when it is not needed. This helps to prevent an excessive accumulation of the end product and maintains a balance in the metabolic processes of the body.

Question 18 of 36

What occurs in the hormonal regulation of sugar metabolism?

Insulin stimulates muscles to produce glucose when needed.
Adrenaline and insulin work together to reduce blood glucose levels.
Adrenaline stimulates the liver to absorb glucose from the bloodstream.
Adrenaline and insulin have opposite effects on the liver.

Question 19 of 36

Which of the following is true of zymogens?

They are activated by the cleaving of peptide bonds.
They are inactivated by phosphorylation.
They are inactivated by the cleaving of peptide bonds.
They are created by phosphorylation.

Question 20 of 36

Which of the following statements about fructose 2,6-bisphosphate (F2,6BP) is NOT true?

Insulin stimulates its production.
It is made by PFK1.
It is broken down by FBPase-2.
It favors glycolysis by activating phosphofructokinase (PFK).

Question 21 of 36

Which of the following regarding chymotrypsinogen is true?

It is activated by trypsin.
It is an active form and is inactivated by enteropeptidase.
π chymotrypsin seals back sulfide bonds to form chymotrypsinogen.
π chymotrypsin is a final active form of chymotrypsinogen.
α chymotrypsin is a partially active form of chymotrypsinogen.

Question 22 of 36

Which of the following statement is NOT true?

The insulin hormone stimulates the body cells to take up the glucose from the bloodstream.
The liver senses the blood glucose levels and controls the release of glucose accordingly.
The Cori cycle is an important source of substrate for gluconeogenesis and helps in the prevention of lactic acidosis in the muscles under anaerobic conditions.
In the lactic acid cycle or Cori cycle, the lactate produced during anaerobic glycolysis in the muscle cells is moved to the liver and converted to glucose.
The Cori cycle acts as a major source of ATP during muscle contraction in anaerobic conditions.

Question 23 of 36

Why is it important to maintain the proper balance of nucleotides in the cell?

To avoid mutations during DNA replication.
To maintain the proper amount of lipoproteins in the extracellular surface of the cell membrane.
To maintain the proper amount of proteins associated with the cell membrane.
To maintain the optimum amounts of tRNA in the cell.
To maintain the proper amount of a particular mRNA in the cytoplasm of the cell.

Question 24 of 36

Which of the following hormones do NOT play a role in maintaining the blood glucose levels in the body of multicellular organisms?

Glucagon
Glucagon
Inhibin
Insulin
Epinephrine
Androgen

Question 25 of 36

Which of the following do not control the activities of the ATCase enzyme?

ATP
TTP
CTP
GTP
Aspartate

Question 26 of 36

Which of the following hormones counteracts the effect of epinephrine?

Glucagon
Insulin
Inhibin
Hepcidin
Androgen

Question 27 of 36

Which of the following enzyme is NOT activated by the action of trypsin?

Proelastase
Enteropeptidase
Prolipase
Chymotrypsinogen
Procarboxypeptidase

Question 28 of 36

Which of the following is true of fructose-2,6-bisphosphate?

It stimulates the production of insulin by the pancreas.
It allosterically affects the activities of the adenyl cyclase enzyme.
It allosterically affects the activities of phosphofructokinase-1 (PFK-1) and fructose-1,6-bisphosphatase enzymes.
It allosterically affects the function of insulin hormones.
It stimulates the production of glucagon and epinephrine hormones.

Question 29 of 36

Which of the following is true of prothrombin?

It gains the ability to bind calcium in a reaction requiring vitamin E.
It is inactivated by the addition of an extra carboxyl group.
It can have carboxylation blocked by warfarin.
It must lose its extra carboxyl group to be active.

Question 30 of 36

Which of the following statements is NOT true regarding the hormonal regulation of glucose in the body?

In response to the high levels of insulin, the G-protein gets inactivated, and then the insulin-stimulated phosphatase enzyme converts FBPase to PFK-2 form and starts the glycolysis pathway.
Insulin and epinephrine hormones directly bind to the catalytic sites of the FBPase enzyme and regulate the simultaneous working of gluconeogenesis and glycolysis.
The activated FBPase-2 activates gluconeogenesis by synthesis of fructose-6-phosphate from fructose-2,6-bisphosphate.
The activated protein kinase A enzyme causes the phosphorylation of PFK-2 and activates the FBPase-2 activity.
The enzyme protein kinase A gets activated by the hormones epinephrine and glucagon.

Question 31 of 36

Which of the control mechanisms below is NOT a means of controlling gene expression in eukaryotes?

Transcriptional
RNA stability
Nucleotide
Translational

Question 32 of 36

Which of the following statements is NOT true regarding glycogen metabolism?

The conversion of glucose-1-phosphate to glucose-6-phosphate occurs via enzyme phosphoglucomutase.
At high glucose levels in the blood, insulin stimulates the excretion of glucose-1-phosphate from the liver cells.
The insulin binding to body cells stimulates the uptake of glucose from the blood and the synthesis of glycogen.
Phosphorylated protein kinase A enzyme activates phosphorylase kinase enzyme, whereas it has an inhibitory effect on the activity of glycogen synthase.
The insulin binding to liver cell receptors stops the release of glucose from liver cells by stopping the breakdown of glycogen due to the deactivation of the phosphorylase-a enzyme.

Question 33 of 36

Which of the following is true of catabolic pathways?

They require NADH, FADH2, or NADPH.
They generate energy.
They make big molecules from smaller ones.
They include gluconeogenesis and glycogen breakdown.

Question 34 of 36

Which of the following is NOT an endocrine gland?

Brunner's glands
Pituitary gland
Adrenal glands
Thyroid gland
Pineal gland

Question 35 of 36

Which of the following is true of reciprocal regulation?

It is a way to reverse processes in cells.
It has opposite effects on catabolic and anabolic pathways.
It is controlled by regulating gene expression.
It is prevented with ATP.

Question 36 of 36

Phosphoprotein phosphatase is stimulated by which of the following?

Glucagon
F2,6BP
Adrenaline
Insulin

Metabolic Biochemistry 2023

Metabolic Biochemistry 2023

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Which of the following enzyme participates in fat synthesis under the effect of the insulin hormone?

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