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Biochemistry

Metabolic Regulation Practice Questions

20 free Metabolic Regulation practice questions for the Zoology. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.

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Question 1 of 20 Medium

Metabolic regulation primarily ensures that cellular pathways operate to:

  1. A Maximize energy loss
  2. B Maintain metabolic balance
  3. C Stop all catabolic reactions
  4. D Eliminate enzyme activity

Correct answer: Maintain metabolic balance

Metabolic regulation maintains homeostasis by balancing anabolic and catabolic pathways. It ensures efficient use of nutrients according to cellular needs.

Question 2 of 20 Medium

Which molecule acts as a key indicator of the energy status of the cell?

  1. A Glucose
  2. B ATP
  3. C NADH
  4. D Acetyl-CoA

Correct answer: ATP

ATP levels reflect the energy status of the cell. High ATP indicates energy sufficiency, while low ATP signals the need for energy production.

Question 3 of 20 Medium

Allosteric regulation of enzymes involves:

  1. A Covalent modification such as phosphorylation
  2. B Effector binding at non-active sites
  3. C Irreversible enzyme inhibition
  4. D Degradation of substrates

Correct answer: Effector binding at non-active sites

Allosteric regulation occurs when molecules bind to sites other than the active site. This binding alters enzyme activity by changing its conformation.

Question 4 of 20 Medium

Which pathway is primarily active during the fed state?

  1. A Gluconeogenesis
  2. B Glycogen synthesis
  3. C Fatty acid oxidation
  4. D Ketogenesis

Correct answer: Glycogen synthesis

In the fed state, excess glucose is stored as glycogen. Glycogen synthesis is therefore upregulated after meals.

Question 5 of 20 Medium

The hormone insulin mainly promotes:

  1. A Catabolic pathways
  2. B Breakdown of glycogen
  3. C Anabolic pathways
  4. D Ketone body formation

Correct answer: Anabolic pathways

Insulin promotes anabolic processes such as glycogen synthesis, lipogenesis, and protein synthesis. It lowers blood glucose levels.

Question 6 of 20 Medium

Which hormone stimulates glycogen breakdown during fasting?

  1. A Insulin
  2. B Glucagon
  3. C Estrogen
  4. D Thyroxine

Correct answer: Glucagon

Glucagon is released during fasting and stimulates glycogenolysis. This helps maintain blood glucose levels.

Question 7 of 20 Medium

Reciprocal regulation refers to:

  1. A Simultaneous activation of both opposing pathways at once
  2. B Independent regulation of pathways
  3. C Opposite control of anabolic and catabolic paths
  4. D Random control of metabolism

Correct answer: Opposite control of anabolic and catabolic paths

Reciprocal regulation ensures that opposing pathways do not occur simultaneously. For example, glycolysis and gluconeogenesis are inversely regulated.

Question 8 of 20 Medium

Which enzyme is a major regulatory point in glycolysis?

  1. A Hexokinase and glucokinase
  2. B Phosphofructokinase-1
  3. C Aldolase
  4. D Enolase

Correct answer: Phosphofructokinase-1

Phosphofructokinase-1 is the rate-limiting enzyme of glycolysis. It is tightly regulated by energy signals such as ATP and AMP.

Question 9 of 20 Medium

Covalent modification of enzymes commonly involves:

  1. A Non-covalent binding of substrate molecules
  2. B Protein degradation
  3. C Phosphorylation and dephosphorylation
  4. D Allosteric inhibition

Correct answer: Phosphorylation and dephosphorylation

Covalent modification usually involves phosphorylation or dephosphorylation of enzymes. This alters enzyme activity rapidly in response to signals.

Question 10 of 20 Medium

Which pathway supplies reducing power for biosynthetic reactions?

  1. A Glycolysis
  2. B Citric acid cycle in mitochondria
  3. C Pentose phosphate pathway
  4. D Electron transport chain

Correct answer: Pentose phosphate pathway

The pentose phosphate pathway generates NADPH. NADPH is essential for reductive biosynthesis and antioxidant defense.

Question 11 of 20 Medium

High levels of ATP generally inhibit:

  1. A Anabolic biosynthetic pathways
  2. B Energy-producing pathways
  3. C Protein synthesis
  4. D Fat storage

Correct answer: Energy-producing pathways

When ATP levels are high, the cell suppresses energy-producing pathways. This prevents unnecessary breakdown of nutrients.

Question 12 of 20 Medium

Which metabolic pathway operates in both anabolic and catabolic roles?

  1. A Glycolysis
  2. B Citric acid cycle
  3. C Beta-oxidation of fatty acids
  4. D Ketogenesis

Correct answer: Citric acid cycle

The citric acid cycle is amphibolic. It provides energy while also supplying intermediates for biosynthesis.

Question 13 of 20 Medium

Which molecule activates phosphofructokinase-1 during low energy conditions?

  1. A ATP
  2. B Citrate
  3. C AMP
  4. D NADH

Correct answer: AMP

AMP accumulates when energy levels are low. It activates phosphofructokinase-1 to enhance glycolysis.

Question 14 of 20 Medium

Hormonal regulation of metabolism usually involves:

  1. A Direct DNA binding
  2. B Signal transduction pathways
  3. C Enzyme degradation only
  4. D Permanent inhibition of enzymes

Correct answer: Signal transduction pathways

Hormones act through signal transduction pathways to alter enzyme activity. These effects are often rapid and reversible.

Question 15 of 20 Medium

Which pathway is dominant during prolonged fasting?

  1. A Glycogen synthesis
  2. B Glycolysis
  3. C Gluconeogenesis
  4. D Lipogenesis

Correct answer: Gluconeogenesis

During prolonged fasting, gluconeogenesis maintains blood glucose levels. It synthesizes glucose from non-carbohydrate sources.

Question 16 of 20 Medium

The regulation of enzyme synthesis at the gene level is known as:

  1. A Short-term regulation
  2. B Allosteric regulation
  3. C Covalent modification
  4. D Long-term regulation

Correct answer: Long-term regulation

Long-term regulation involves changes in gene expression. It adjusts enzyme levels according to metabolic demands.

Question 17 of 20 Medium

Which molecule links carbohydrate and lipid metabolism?

  1. A Pyruvate
  2. B Glucose-6-phosphate
  3. C Acetyl-CoA
  4. D Lactate

Correct answer: Acetyl-CoA

Acetyl-CoA is a central metabolic intermediate. It connects carbohydrate metabolism with lipid synthesis and oxidation.

Question 18 of 20 Medium

Feedback inhibition occurs when:

  1. A A substrate molecule directly inhibits the enzyme
  2. B The end product inhibits an early enzyme
  3. C An enzyme inhibits itself
  4. D Hormones block enzyme synthesis

Correct answer: The end product inhibits an early enzyme

In feedback inhibition, the end product of a pathway inhibits an enzyme earlier in the pathway. This prevents overproduction.

Question 19 of 20 Medium

Which organ plays a central role in metabolic regulation of the body?

  1. A Kidney
  2. B Liver
  3. C Heart
  4. D Lung

Correct answer: Liver

The liver integrates carbohydrate, lipid, and protein metabolism. It plays a key role in maintaining blood nutrient levels.

Question 20 of 20 Medium

Which regulatory mechanism provides the fastest response to metabolic changes?

  1. A Gene expression control
  2. B Enzyme synthesis
  3. C Allosteric regulation
  4. D Cell division

Correct answer: Allosteric regulation

Allosteric regulation alters enzyme activity almost instantly. It allows rapid metabolic responses without changing enzyme concentration.

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