MCQs on Chemical Coordination and Integration – Class 11 Biology

MCQs on Chemical Coordination and Integration – CBSE Class 11 Biology (Unit V | NCERT-Based)

CBSE Class 11 Biology – MCQs with Answers and Explanations

Unit V: Human Physiology

Topic: Chemical Coordination and Integration

Section A: Endocrine System – Basics & Hormones (Q1–Q10)

Q1. Chemical coordination in humans is achieved through:

A. Nervous system only
B. Muscular system
C. Endocrine system
D. Skeletal system

Answer: C
Explanation: Chemical coordination is carried out by hormones secreted by endocrine glands.

Q2. Hormones are:

A. Enzymes
B. Nutrients
C. Chemical messengers
D. Antibodies

Answer: C
Explanation: Hormones act as chemical messengers transported via blood.

Q3. Endocrine glands are also called ductless glands because they:

A. Have no blood supply
B. Secrete enzymes
C. Release hormones directly into blood
D. Store secretions

Answer: C
Explanation: Endocrine glands lack ducts and secrete hormones directly into bloodstream.

Q4. Which gland is known as the “master gland”?

A. Thyroid
B. Adrenal
C. Pituitary
D. Pineal

Answer: C
Explanation: Pituitary controls activity of other endocrine glands.

Q5. Hormones generally act in:

A. Large amounts
B. Small quantities
C. Solid form
D. Local tissues only

Answer: B
Explanation: Hormones are effective in minute concentrations.

Q6. Which hormone is NOT a protein hormone?

A. Insulin
B. Growth hormone
C. Adrenaline
D. Prolactin

Answer: C
Explanation: Adrenaline is an amine hormone, not protein.

Q7. Target cells respond to hormones due to presence of:

A. Nucleus
B. Enzymes
C. Receptors
D. Mitochondria

Answer: C
Explanation: Hormone action depends on specific receptors.

Q8. Hormones that act on nearby cells are called:

A. Endocrine
B. Autocrine
C. Paracrine
D. Exocrine

Answer: C
Explanation: Paracrine hormones act on neighboring cells.

Q9. Which hormone acts faster?

A. Steroid hormone
B. Protein hormone
C. Thyroxine
D. Cortisol

Answer: B
Explanation: Protein hormones act through cell surface receptors, producing quick effects.

Q10. Chemical coordination is generally:

A. Very fast and short-lived
B. Slow and long-lasting
C. Instantaneous
D. Voluntary

Answer: B
Explanation: Hormonal effects are slow but prolonged.

Section B: Hypothalamus & Pituitary Gland (Q11–Q20)

Q11. Hypothalamus links:

A. Nervous and muscular systems
B. Nervous and endocrine systems
C. Digestive and circulatory systems
D. Respiratory and endocrine systems

Answer: B
Explanation: Hypothalamus connects neural control with hormonal control.

Q12. Releasing hormones are secreted by:

A. Pituitary
B. Hypothalamus
C. Thyroid
D. Adrenal

Answer: B
Explanation: Hypothalamus secretes RH and IH to regulate pituitary.

Q13. Anterior pituitary is also called:

A. Neurohypophysis
B. Adenohypophysis
C. Epiphysis
D. Pars nervosa

Answer: B
Explanation: Adenohypophysis secretes tropic hormones.

Q14. Which hormone stimulates growth of bones and muscles?

A. TSH
B. ACTH
C. Growth hormone
D. Prolactin

Answer: C
Explanation: Growth hormone promotes overall body growth.

Q15. Deficiency of growth hormone in childhood leads to:

A. Gigantism
B. Acromegaly
C. Dwarfism
D. Goitre

Answer: C
Explanation: GH deficiency causes pituitary dwarfism.

Q16. Excess GH secretion in adults causes:

A. Dwarfism
B. Gigantism
C. Acromegaly
D. Goitre

Answer: C
Explanation: Excess GH after growth phase causes acromegaly.

Q17. Which hormone stimulates milk production?

A. Oxytocin
B. Prolactin
C. Estrogen
D. Progesterone

Answer: B
Explanation: Prolactin stimulates milk synthesis.

Q18. Oxytocin is responsible for:

A. Milk secretion
B. Milk ejection and uterine contraction
C. Ovulation
D. Spermatogenesis

Answer: B
Explanation: Oxytocin aids parturition and milk ejection.

Q19. ADH deficiency leads to:

A. Diabetes mellitus
B. Diabetes insipidus
C. Goitre
D. Addison’s disease

Answer: B
Explanation: Lack of ADH causes excessive urination.

Q20. ADH is synthesized in hypothalamus and released from:

A. Anterior pituitary
B. Thyroid
C. Posterior pituitary
D. Adrenal

Answer: C
Explanation: ADH is stored and released from neurohypophysis.

Section C: Thyroid, Parathyroid & Adrenal Glands (Q21–Q35)

Q21. Thyroid hormone regulates:

A. Blood pressure
B. Metabolic rate
C. Growth only
D. Reproduction

Answer: B
Explanation: Thyroxine controls basal metabolic rate (BMR).

Q22. Deficiency of iodine leads to:

A. Cretinism
B. Myxedema
C. Goitre
D. Diabetes

Answer: C
Explanation: Iodine deficiency causes thyroid enlargement.

Q23. Hypothyroidism in children causes:

A. Goitre
B. Cretinism
C. Myxedema
D. Acromegaly

Answer: B
Explanation: Cretinism leads to stunted physical and mental growth.

Q24. Parathyroid hormone regulates metabolism of:

A. Sodium
B. Calcium
C. Iodine
D. Iron

Answer: B
Explanation: PTH maintains calcium balance.

Q25. Hyposecretion of parathyroid hormone causes:

A. Bone softening
B. Tetany
C. Rickets
D. Goitre

Answer: B
Explanation: Low calcium levels lead to muscle spasms (tetany).

Q26. Adrenal glands are located:

A. Below kidneys
B. Above kidneys
C. Near pancreas
D. In neck

Answer: B
Explanation: Adrenals sit on top of each kidney.

Q27. Adrenal medulla secretes:

A. Cortisol
B. Aldosterone
C. Adrenaline
D. Thyroxine

Answer: C
Explanation: Adrenaline prepares body for emergency situations.

Q28. Adrenaline is also known as:

A. Stress hormone
B. Emergency hormone
C. Growth hormone
D. Lactation hormone

Answer: B
Explanation: It prepares body for fight or flight.

Q29. Adrenal cortex secretes:

A. Adrenaline
B. Noradrenaline
C. Corticosteroids
D. Insulin

Answer: C
Explanation: Cortex produces mineralocorticoids and glucocorticoids.

Q30. Addison’s disease is caused by deficiency of:

A. Thyroxine
B. Insulin
C. Adrenal cortical hormones
D. Parathyroid hormone

Answer: C
Explanation: Adrenal insufficiency leads to Addison’s disease.

Q31. Aldosterone regulates balance of:

A. Calcium and phosphate
B. Sodium and potassium
C. Glucose
D. Iodine

Answer: B
Explanation: Aldosterone controls electrolyte balance.

Q32. Cortisol helps in:

A. Stress adaptation
B. Bone formation
C. Milk secretion
D. Ovulation

Answer: A
Explanation: Cortisol helps body cope with stress.

Q33. Hormones acting on cell surface receptors include:

A. Steroid hormones
B. Thyroid hormones
C. Protein hormones
D. Sex hormones

Answer: C
Explanation: Protein hormones cannot enter cell membrane.

Q34. Steroid hormones act by:

A. Activating membrane enzymes
B. Binding to nuclear receptors
C. Blocking ion channels
D. Destroying enzymes

Answer: B
Explanation: Steroids regulate gene expression.

Q35. Hormones are inactivated mainly in:

A. Kidney
B. Liver
C. Brain
D. Lungs

Answer: B
Explanation: Liver metabolizes excess hormones.

Section D: Pancreas, Gonads & Disorders (Q36–Q50)

Q36. Pancreas is a:

A. Endocrine gland
B. Exocrine gland
C. Mixed gland
D. Duct gland

Answer: C
Explanation: Pancreas has both endocrine and exocrine functions.

Q37. Insulin is secreted by:

A. Alpha cells
B. Beta cells
C. Delta cells
D. Acinar cells

Answer: B
Explanation: Beta cells of islets of Langerhans secrete insulin.

Q38. Insulin deficiency leads to:

A. Hypoglycemia
B. Diabetes mellitus
C. Goitre
D. Cretinism

Answer: B
Explanation: Insulin regulates blood glucose levels.

Q39. Glucagon increases blood glucose by:

A. Glycogenesis
B. Glycolysis
C. Glycogenolysis
D. Lipogenesis

Answer: C
Explanation: Glucagon breaks glycogen into glucose.

Q40. Testes secrete:

A. Estrogen
B. Progesterone
C. Testosterone
D. Prolactin

Answer: C
Explanation: Testosterone controls male secondary sexual characters.

Q41. Ovaries secrete:

A. Testosterone
B. Thyroxine
C. Estrogen and progesterone
D. Insulin

Answer: C
Explanation: Ovarian hormones regulate female reproductive cycle.

Q42. Estrogen is responsible for:

A. Spermatogenesis
B. Secondary male characters
C. Secondary female characters
D. Milk ejection

Answer: C
Explanation: Estrogen develops female secondary sexual traits.

Q43. Progesterone helps in:

A. Ovulation
B. Maintenance of pregnancy
C. Lactation
D. Menstruation

Answer: B
Explanation: Progesterone prepares uterus for pregnancy.

Q44. Pineal gland secretes:

A. Melatonin
B. Thyroxine
C. Oxytocin
D. Cortisol

Answer: A
Explanation: Melatonin regulates biological rhythms.

Q45. Hormonal imbalance causing early puberty is called:

A. Delayed puberty
B. Precocious puberty
C. Menopause
D. Andropause

Answer: B
Explanation: Early sexual maturity is precocious puberty.

Q46. Negative feedback mechanism means:

A. Hormone increases its own secretion
B. Hormone inhibits its own secretion
C. Hormone has no effect
D. Hormone destroys gland

Answer: B
Explanation: Feedback maintains hormonal balance.

Q47. Hormones are transported in blood:

A. Freely dissolved
B. Bound to proteins
C. Both A and B
D. As enzymes

Answer: C
Explanation: Transport depends on chemical nature.

Q48. Endocrine disorders are usually:

A. Infectious
B. Genetic and metabolic
C. Contagious
D. Temporary

Answer: B
Explanation: Hormonal disorders affect metabolism and growth.

Q49. Chemical coordination is slower than neural control because:

A. Hormones are destroyed quickly
B. Hormones travel through blood
C. Hormones are proteins
D. Hormones act locally

Answer: B
Explanation: Blood transport makes hormonal action slower.

Q50. Chemical coordination and integration are essential because they:

A. Produce energy
B. Control voluntary movements
C. Regulate metabolism, growth, and reproduction
D. Aid digestion only

Answer: C
Explanation: Hormones maintain long-term regulation and homeostasis.