Category: Class 11 Biology Objective Questions

250+ TOP MCQs on Mineral Requirements of a Plant-1 and Answers

Biology Multiple Choice Questions on “Mineral Requirements of a Plant-1”.

1. Which of the following is not a function of chlorine?
a) Water splitting reaction
b) Anion-cation balance
c) Pollen germination
d) Determination of solute concentration
Answer: c
Clarification: Chlorine is an essential micronutrient. It is absorbed by plants in form of Cl-. Its functions include maintaining anion-cation balance of cell, determination of solute concentration in cell and oxygen evolution in water splitting reaction. Boron is responsible for pollen germination.

2. Boron is required for the synthesis of Auxin hormone.
a) True
b) False
Answer: b
Clarification: Zinc is required for the synthesis of Auxin hormone. Zinc is absorbed in form of divalent form. It activates various enzymes such as alcohol dehydrogenase and carboxylases. Deficiency symptoms.

3. Which of the following elements will not cause delay flowering due to its less concentration?
a) K
b) Mo
c) S
d) N
Answer: a
Clarification: Deficiency symptoms are morphological changes are indicative of certain element deficiencies. Due to less concentration of N, S and Mo, there is delay in flowering.

4. Which of the following vitamins contain Sulphur?
a) Ascorbic acid
b) Biotin
c) Cobalamin
d) Retinol
Answer: b
Clarification: Biotin is the sulphur-containing vitamin. Ascorbic acid is vitamin C. Retinol is vitamin A. Cobalamin is vitamin B12.

5. Which of the following element activates enzyme catalase?
a) Na
b) Co
c) Fe
d) Si
Answer: c
Clarification: Fe is the element that activates enzyme catalase. Plants obtain iron in the form of ferric ions. Na is responsible for C4 metabolism. Co is essential for nitrogen fixation by the nitrogen-fixing bacteria associated with legumes and other plants. Si improves the health of plants.

6. Which of the following elements is the binding component of ribosomes?
a) Cu
b) Mn
c) Cl
d) Mg
Answer: d
Clarification: Mg is absorbed by plants in the form of divalent. It is a constituent of structure of ribosome and acts as a binding component. Cu is involved in electron transport chain of photosynthesis. Mn is the component of oxygen evolving complex. Cl is responsible for anion-cation balance in cells.

7. Which of the following micronutrients is used in metabolism of urea?
a) Ni
b) Cu
c) Mn
d) Mo
Answer: a
Clarification: Ni is the micronutrient is used in metabolism of urea and ureides. Mo participates in nitrogen metabolism. Cu is involved in electron transport chain of photosynthesis. Mn is the component of oxygen evolving complex.

8. Which of the following element’s deficiency leads to grey speck of oats?
a) Mn
b) Mo
c) B
d) Zn
Answer: a
Clarification: Mn deficiency that leads to grey speck of oats. Zn deficiency leads to sickle disease of cocoa. B deficiency leads to brown heart of turnip. Mo deficiency leads to whiptail of cauliflower.

9. Which of the following element’s deficiency leads to Exanthema in Citrus?
a) P
b) Cu
c) B
d) Zn
Answer: b
Clarification: Cu deficiency leads to Exanthema in Citrus. P deficiency leads to poor growth of leaves. B deficiency leads to heart rot of beets. Zn deficiency leads to Khaira disease of rice.

10. Which of the following element’s deficiency leads to rosette growth of plant?
a) P
b) Mo
c) B
d) Zn
Answer: d
Clarification: Deficiency of Zn leads to rosette growth of plant. P is present in cell membranes. Mo participates in nitrogen metabolism. B is responsible for carbohydrate translocation.

250+ TOP MCQs on Factors Affecting Photosynthesis and Answers

Botany Online Quiz on “Factors Affecting Photosynthesis”.

1. Which of these is not an internal factor affecting photosynthesis?
a) Size
b) Age
c) Number
d) Water
Answer: d
Clarification: Various internal and external factors affect the rate of photosynthesis, which in turn affects the overall productivity and yield of the plant. Size, age and number are internal factors while water is an external factor.

2. What do the internal factors affecting photosynthesis dependent on?
a) External factors
b) Geographical area
c) Genetic predisposition
d) Species and sub-species
Answer: c
Clarification: The genetic predisposition or the genetic make up of a plant is an internal factor that affects the rate of photosynthesis. The arrangement of genes present in the plant is expressed in a certain way in different plants.

3. Which of these is not an external factor affecting photosynthesis?
a) Sunlight
b) Temperature
c) Leaf orientation
d) CO2 concentration
Answer: c
Clarification: Various internal and external factors affect the rate of photosynthesis, which in turn affects the overall productivity and yield of the plant. Sunlight, temperature and CO2 concentration are external factors.

4. Which of these statements is false regarding the factors affecting photosynthesis?
a) The leaf orientation of a plant affects photosynthesis
b) Both internal and external factors affect photosynthesis
c) Photosynthetic rate is determined by a factor at sub-optimal level
d) Both CO2 concentration in the environment and inside the plant affect photosynthesis
Answer: a
Clarification: The rate of photosynthesis is affected by both external and internal factors. The photosynthetic rate is determined by a factor at sub-optimal level which is known as the limiting factor.

5. Which scientist gave the Law of Limiting Factors?
a) Hooke
b) Blackman
c) Fleming
d) Mendel
Answer: b
Clarification: Blackman gave the Law of Limiting Factors in 1905. It states that if multiple factors affect a process, then the rate of the process is determined by the factor which is the closest to its minimal value.

6. At what percentage of sunlight does light saturation occur?
a) 30
b) 20
c) 10
d) 15
Answer: c
Clarification: Light is an external factor that affects the rate of photosynthesis. Light saturation occurs at 10% of full sunlight. At high light intensities, the rate of photosynthesis does not increase linearly.

7. A portion of the graph ‘Rate of photosynthesis vs. Light intensity’ is labelled ‘A’. What causes ‘A’?

a) Increase in light intensity
b) Decrease in light intensity
c) Opening of stomata
d) Closing of stomata
Answer: a
Clarification: In the graph ‘Rate of photosynthesis vs. Light intensity’, the portion labelled ‘A’ implies that with an increase in the light intensity, the rate remains constant after some time and does not increase.

8. What happens when the incident light on a plant is excessive?
a) RuBP undergoes oxidation
b) Vascular bundles lose functionality
c) Mesophyll cells are destroyed
d) Chlorophyll breaks down
Answer: d
Clarification: Light is rarely a limiting factor for photosynthesis, but excess amount of light reaching the photosynthetic parts of plant causes the breakdown of chlorophyll and hence, reduces the rate of photosynthesis.

9. What is the atmospheric concentration of carbon dioxide?
a) 0.3 – 0.4%
b) 3 – 4%
c) 0.03 – 0.04%
d) 0.003 – 0.004%
Answer: c
Clarification: The atmospheric concentration of carbon dioxide is 0.03 – 0.04%. Carbon dioxide concentration is an important external factor that affects the rate of photosynthesis in all plants.

10. Increase in CO2 concentration up to 0.5% causes an increase in photosynthesis. True or false?
a) True
b) False
Answer: b
Clarification: Increase in CO2 concentration up to 0.05% causes an increase in photosynthesis. If the carbon dioxide concentration increases beyond this level, it can become damaging for the plant over long periods.

11. At what concentration do C4 plants show saturation?
a) 430 μlL-1
b) 450 μlL-1
c) 340 μlL-1
d) 360 μlL-1
Answer: d
Clarification: C3 plants and C4 plants show different carbon dioxide concentration saturations. At high intensities of light, C4 plants show carbon dioxide saturation at 360 μlL-1 while C3 plants show saturation at 450 μlL-1.

12. Which of these plants are grown in carbon dioxide enriched atmosphere?
a) Maize
b) Sugarcane
c) Tomato
d) Millets
Answer: c
Clarification: Maize, sugarcane and millets are C4 plants. Since C3 plants reach saturation at higher carbon dioxide concentrations, plants such as tomatoes and bell peppers are grown in carbon dioxide enriched atmosphere.

13. Which of these plants have the highest optimum temperature?
a) Tropical C3
b) Temperate C3
c) Tropical C4
d) Temperate C4
Answer: c
Clarification: Tropical plants have a higher optimum temperature than temperate plants. C4 plants show a higher rate of photosynthesis at higher temperatures than C3 plants. Hence, tropical C4 plants have the highest optimum temperature.

14. Why do stomata close during water shortage?
a) To reduce CO2 availability
b) To trap water
c) To increase metabolic activity
d) To increase the surface area of leaves
Answer: a
Clarification: During water shortage in plants, the stomata close in order to reduce the availability of carbon dioxide for carbon dioxide fixation, which is the first part of the Calvin cycle of photosynthesis.

15. Which of these is not an effect of water stress?
a) Closing of stomata
b) Increase in metabolism
c) Wilting of leaves
d) Reduction in surface area of leaves
Answer: b
Clarification: When there is a water stress, its effects can be seen on the plant. Water stress closes stomata hence carbon dioxide availability reduces. The leaves wilt to reduce surface area and metabolism.

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250+ TOP MCQs on Digestion of Food-1 and Answers

Biology Multiple Choice Questions on “Digestion of Food-1”.

1. The stomach is divided into how many major portions?
a) One
b) Two
c) Three
d) Four
Answer: d
Clarification: The stomach is divided into four major portions namely-Fundus, Cardiac, Body, and Pyloric. The given figure represents the anatomical regions of the human stomach:

2. Which of the following is incorrect regarding the shapes of the three portions of the small intestine?
a) Duodenum-C shape
b) Duodenum-J shape
c) Ileum-highly coiled
d) Jejunum-long coiled
Answer: b
Clarification: Small intestine is distinguishable into three regions, a ‘C’ shaped duodenum, a long coiled middle portion jejunum, and highly coiled ileum.

3. Vermiform appendix arises from which part of the large intestine?
a) Transverse colon
b) Sigmoid colon
c) Caecum
d) Rectum
Answer: c
Clarification: Vermiform appendix is a narrow finger-like tubular projection that arises from the caecum of the large intestine. The vermiform appendix is a vestigial organ in the human body.

4. Which type of micro-organisms does caecum hosts?
a) Symbiotic
b) Saprophytic
c) Detrivorous
d) Parasitic
Answer: a
Clarification: Large intestine consists of the caecum, colon, and rectum. The ileum is a part of the small intestine which opens into the large intestine. The caecum is a blind sac which hosts some symbiotic micro-organisms.

5. The colon is divided into how many parts?
a) One
b) Three
c) Four
d) Five
Answer: c
Clarification: Colon is divided into four parts- an ascending, a transverse, descending part, and a sigmoid colon. The descending part opens into the rectum which opens out through the anus.

6. The mucosa is the outermost layer of the alimentary canal.
a) True
b) False
Answer: b
Clarification: The serosa is the outermost layer of the alimentary canal. The alimentary canal is made up of four different layers namely-serosa, muscularis, sub-mucosa and mucosa. Mucosa is the innermost layer of the alimentary canal.

7. In which layer of the alimentary canal, goblet cells are present?
a) Serosa
b) Mucosa
c) Muscularis
d) Sub-mucosa
Answer: b
Clarification: Mucosal epithelium has goblet cells which secrete mucus that helps in lubrication. All four layers show modifications in different parts of the alimentary canal.

8. Muscularis layer is made up of which of the following?
a) Cardiac muscles
b) Skeletal muscles
c) Smooth muscles
d) Connective tissue sheath
Answer: c
Clarification: Muscularis layer is formed by smooth muscles which are usually arranged into an inner circular and an outer longitudinal layer. An oblique muscle layer may be present in some regions.

9. In which layer of the alimentary canal, the glands are present in duodenum?
a) Sub-mucosa
b) Muscularis
c) Mucosa
d) Serosa
Answer: a
Clarification: In the duodenum, glands are present in the sub-mucosa. The sub-mucosal layer is formed of loose connective tissue containing nerves, blood, and lymph vessels.

10. What does the question mark represents in the given diagram?

a) Inner circular mucosa layer
b) Outer circular mucosa layer
c) Inner circular muscularis layer
d) The outer longitudinal mucosal layer
Answer: c
Clarification: The correct labelling of the given diagram is as follows:

Muscularis layer is further made up Inner circular layer and outer longitudinal layer.

11. Innermost layer mucosa forms rugae in the stomach.
a) True
b) False
Answer: a
Clarification: The mucosal layer of the alimentary forms irregular folds or rugae in the stomach and small finger-like projections-villi in the small intestine. The cells lining the villi produce numerous microscopic projections called microvilli giving a brush bordered appearance.

12. Which layer of the alimentary canal forms gastric glands?
a) Sub-mucosa
b) Mucosa
c) Muscularis
d) Serosa
Answer: b
Clarification: The mucosa layer of the alimentary canal forms gastric glands in the stomach and crypts in between the bases of villi in the intestine which are also known as Crypts of Lieberkuhn.

13. Which of the following is not a digestive gland?
a) Salivary gland
b) Testis
c) Liver
d) Pancreas
Answer: b
Clarification: The digestive glands associated with the alimentary canal include the salivary glands, the liver, and the pancreas. The testis is not a digestive gland.

14. Saliva is produced by how many salivary glands?
a) Three
b) Four
c) Five
d) Six
Answer: d
Clarification: Saliva is mainly produced by three pairs of salivary glands which are the parotids, the sub-maxillary or sub-mandibular, and the sub-lingual.

15. What is the weight of the largest gland of the human body?
a) 1.2-1.3 kg
b) 1.3-1.4 kg
c) 1.0-1.5 kg
d) 1.2-1.5 kg
Answer: d
Clarification: The liver is the largest gland of the human body and weighs about 1.2-1.4 kg in an adult human. It is situated in the abdominal cavity, just below the diaphragm, and has two lobes.

250+ TOP MCQs on Human Circulatory System and Answers

Biology Multiple Choice Questions on “Human Circulatory System – 1”.

1. Which of these is not included in the vascular system?
a) Heart
b) Blood vessels
c) Blood
d) Lungs
Answer: d
Clarification: The vascular system or the human circulatory system consists of the heart, the blood vessels-the arteries, the veins and the capillaries, and the specialized fluid connective tissue, blood. The lungs are a part of the respiratory system.

2. Which of these organs are situated in the thoracic cavity?
a) Stomach
b) Kidney
c) Heart
d) Ovaries
Answer: c
Clarification: The muscular heart is located in the thoracic cavity of the body. It is located on the ventral side of the body. The stomach, the kidneys and the ovaries are located below the heart and the lungs.

3. What is the covering of the heart known as?
a) Meninges
b) Pleura
c) Pericardium
d) Peritoneum
Answer: c
Clarification: The heart is a part of the circulatory system along with the blood vessels and blood. The covering of the heart is a double layered structure known as pericardium which contains pericardial fluid.

4. Which of these structures separate the atria of the heart?
a) Septum
b) Ventricle
c) Purkinje fibers
d) Bundle of His
Answer: a
Clarification: The human heart is divided into four chambers-two atria and two ventricles. The septum separates the two atria of the heart. Another septum also separates the two ventricles of the heart.

5. What is the atrio-ventricular septum made of?
a) Cartilage
b) Fibrous tissue
c) Osteocytes
d) Mucous membrane
Answer: b
Clarification: The human heart is divided into four chambers- two atria and two ventricles. They pump blood to different parts of the body. The atrio-ventricular septum separates the atria and the ventricles. It is made of fibrous tissue.

6. What is the opening between the right auricle and the right ventricle called?
a) Aortic valve
b) Bicuspid valve
c) Tricuspid valve
d) Pulmonary valve
Answer: c
Clarification: The atrio-ventricular septum separates the atria and the ventricles. However, to permit the flow of blood from the right atrium to the right ventricle, there is an opening known as the tricuspid valve.

7. What is the opening between the left atrium and the left ventricle known as?
a) Mitral valve
b) Tricuspid valve
c) Aortic valve
d) Pulmonary valve
Answer: a
Clarification: A septum separates the atria and the ventricles. There is an opening between the left atrium and the left ventricle to permit the flow of blood. This is called the mitral valve or the bicuspid valve.

8. What is the location of the SAN?
a) Left upper corner of right ventricle
b) Right upper corner of right ventricle
c) Right upper corner of left atrium
d) Right upper corner of right atrium
Answer: d
Clarification: The SAN or the sinoatrial node is located in the upper right corner of the right atrium. It has the ability to generate 70-75 action potentials per minute. It is hence known as the pacemaker of the heart.

9. Which of these structures is close to the AVN?
a) SAN
b) Left ventricle
c) Atrio-ventricular septum
d) Aorta
Answer: c
Clarification: The AVN or the atrio-ventricular node is located in the lower left corner of the right atrium. It is situated close to the atrio-ventricular septum which separates the atria and the ventricles.

10. The nodal musculature of the heart is auto excitable. True or false?
a) True
b) False
Answer: a
Clarification: The nodal musculature of the heart possesses the ability to produce action potentials on their own, without receiving inputs from nerve cells. Hence, the nodal musculature of the heart is auto excitable.

11. How many action potentials can the SAN generate per minute?
a) 40-60
b) 80-120
c) 12-16
d) 70-75
Answer: d
Clarification: The SAN or the sinoatrial node possesses the ability to generate action potentials without receiving any external stimuli. It is auto excitable and can generate 70-75 action potentials per minute.

12. Which of these is known as the pacemaker of the heart?
a) Purkinje fibers
b) AVN
c) SAN
d) Bundle of His
Answer: c
Clarification: The sinoatrial node, abbreviated SAN, is known as the pacemaker of the heart. It has the ability to generate 70-75 action potentials per minute, which initiates the contractility of the heart muscles.

13. How many times does the heart beat in one minute?
a) 40-60
b) 80-120
c) 70-75
d) 12-15
Answer: c
Clarification: The heart beats 70-75 times in one minute. 72 times is the average number of heart beats for an adult per minute. It is influenced by the activity of the sinoatrial node or the pacemaker of the heart.

14. Identify the part of the heart.

a) Aorta
b) Inferior vena cava
c) Superior vena cava
d) Pulmonary vein
Answer: a
Clarification: The diagram given is that of the cross section of the heart. The structure of the heart indicated is identified to be the aorta. It is the largest blood vessel that transports blood to all parts of the body.

15. Identify the part of the heart.

a) Aorta
b) Inferior vena cava
c) Superior vena cava
d) Pulmonary vein
Answer: b
Clarification: In the diagram of the cross section of the heart, the indicated structure is identified to be the inferior vena cava. Its function is to carry blood from the lower parts of the body to the right atrium.

250+ TOP MCQs on Locomotion & Movement – Muscle and Answers

Biology Multiple Choice Questions on “Locomotion & Movement – Muscle – 1”.

1. Which of these do not involve flagellar movement?
a) Swimming of spermatozoa
b) Maintenance of water current in sponges
c) Locomotion of some protozoans
d) Movement of macrophages in blood
Answer: d
Clarification: The movement of macrophages in blood does not involve the use of flagella. Macrophages are phagocytic in nature and are a part of the immune system. They show amoeboid movement.

2. What percentage of body weight of an adult human is contributed by muscles?
a) 20-30%
b) 10-20%
c) 40-50%
d) 30-40%
Answer: c
Clarification: 40-50% of the total body weight of an adult human is contributed by muscles. Muscles are required for numerous processes of the body in order to survive and locomote. They are of mesodermal origin.

3. Which of these is not a property of muscles?
a) Extensibility
b) Excitability
c) Degradability
d) Elasticity
Answer: c
Clarification: 40-50% of the total body weight of an adult human is contributed by muscles. Muscles have several properties such as elasticity, extensibility, excitability and contractibility. Degradability is not a property.

4. Which of these is not a basis of classification for muscles?
a) Excitability
b) Appearance
c) Location
d) Regulation of activities
Answer: a
Clarification: Muscles have several properties such as elasticity, extensibility, excitability and contractibility. Muscles can be classified on the basis of appearance, location and regulation of activities.

5. Which of these statements is not true regarding skeletal muscles?
a) They are also called voluntary muscles
b) They help in the movement of food through the oesophagus
c) They have striations
d) They are involved in changing of body posture
Answer: b
Clarification: Skeletal muscles are also known as voluntary muscles. They have striations and are also known as striated muscles. They are involved in changing of body posture but not in the movement of food through the oesophagus.

6. Which of these is not a characteristic of cardiac muscles?
a) They work continuously
b) They are branched
c) They are not striated
d) They are involuntary
Answer: c
Clarification: Cardiac muscles are the muscles of the heart. Cardiac muscles are involuntary muscles that work continuously to pump blood throughout the body. They are branched and are striated in appearance.

7. What is fascia made of?
a) Collagen
b) Keratin
c) Microtubules
d) Muscle fibres
Answer: a
Clarification: Fascia is a layer of connective tissue that surrounds the fascicles or muscle bundles in a muscle. It is made out of collagen. Each muscle bundle contains a number of muscle fibres or muscle cells.

8. Identify the structure shown in the figure.

a) Fascia
b) Muscle fibre
c) Sarcolemma
d) Fascicle
Answer: d
Clarification: The diagram given is that of the cross-sectional view of a muscle. The structure shown is a fascicle or a muscle bundle. A number of fascicles or muscle bundles are surrounded by a collagenous fascia.

9. Identify the structure shown in the figure.

a) Fascicle
b) Muscle bundles
c) Muscle fibres
d) Fascia
Answer: c
Clarification: The diagram given is that of the cross-sectional view of a muscle. The structures shown are muscle fibres or muscle cells. A number of muscle fibres are grouped together into a muscle bundle.

10. A muscle fibre is a syncytium. True or false?
a) True
b) False
Answer: a
Clarification: A muscle fibre or a muscle cell possesses many nuclei or is multinucleated. Hence, it is a syncytium. A number of muscle fibres or muscle cells are grouped together into a muscle bundle or fascicle.

11. Which of these ions are abundant in the sarcoplasmic reticulum?
a) Magnesium
b) Sodium
c) Potassium
d) Calcium
Answer: d
Clarification: The sarcoplasmic reticulum is the endoplasmic reticulum present in the sarcoplasm of the muscle cell or the muscle fibre. The sarcoplasmic reticulum contains a large number of calcium ions.

12. Which of these structures has alternate dark and light bands on it?
a) Fascicles
b) Sarcolemma
c) Myofibrils
d) Fascia
Answer: c
Clarification: Each muscle cell or muscle fibre contains filaments in its sarcoplasm which are arranged in a parallel manner. These filaments are known as myofibrils and they have alternate dark and light bands.

13. What does the A band of a myofibril contain?
a) Troponin
b) Actin
c) Myosin
d) Tropomyosin
Answer: c
Clarification: The A band or anisotropic band contains the protein myosin. The A band is also known as the dark band. The light bands, also called the I bands or the isotropic bands contain the protein actin.

14. Which of these statements is false regarding myofibrils?
a) The A band is also known as the light band
b) Myosin is parallel to the longitudinal axis of myofibril
c) Light bands contain actin
d) Anisotropic bands contain myosin
Answer: a
Clarification: Actin and myosin lie parallel to the longitudinal axis of the myofibril and also to each other. The A band or the anisotropic band or the dark band contains myosin while the light band contains actin.

15. Actin filaments are thicker than myosin filaments. True or false?
a) True
b) False
Answer: b
Clarification: Actin and myosin lie parallel to the longitudinal axis of the myofibril and also to each other. The A band contains myosin while the light band contains actin. Actin filaments are thinner than myosin filaments.

250+ TOP MCQs on Chemical Control and Coordination – Endocrine Glands and Hormones and Answers

Biology Multiple Choice Questions on “Chemical Control and Coordination – Endocrine Glands and Hormones”.

1. Which of the following is incorrect regarding the endocrine glands?
a) They are known as ductless glands
b) Their secretions are called hormones
c) Hormones are secreted through ducts in the bloodstream
d) These glands lack ducts
Answer: c
Clarification: Endocrine glands lack ducts and are hence, known as ductless glands. Their secretions are called hormones. As these glands do not have ducts, therefore they release their secretions directly into the bloodstream.

2. Which of the following is not an endocrine gland?
a) Pituitary gland
b) Sebaceous gland
c) Pineal gland
d) Adrenal gland
Answer: b
Clarification: Pituitary, pineal, thyroid, adrenal, pancreas, parathyroid, thymus, and gonads are the organised endocrine bodies in our body. The endocrine glands and their hormones constitute the endocrine system.

3. Hypothalamus is the basal part of which of the following?
a) Forebrain
b) Midbrain
c) Hindbrain
d) Mesencephalon
Answer: a
Clarification: The hypothalamus is the basal part of the diencephalon, forebrain and it regulates a wide spectrum of body functions. It contains several groups of neurosecretory cells called nuclei which produce hormones.

4. How many types of hormones are released by the pituitary?
a) One
b) Two
c) Three
d) Four
Answer: b
Clarification: The hormones produced by the hypothalamus are of two types:
i. Releasing hormones-which stimulate the secretion of pituitary hormones
ii. Inhibiting hormones-which inhibit the secretion of pituitary hormones.

5. Where do the hypothalamic hormones originate?
a) Nerve endings
b) Synaptic vesicles
c) Hypothalamic neurons
d) Axons
Answer: c
Clarification: The hypothalamic hormones originate in the hypothalamic neurons, pass through axons, and are released from their nerve endings. These hormones reach the pituitary gland through a portal circulatory system and regulate the function of the anterior pituitary.

6. Gonadotrophins inhibits the release of growth hormones from the pituitary gland.
a) True
b) False
Answer: b
Clarification: Somatostatin from the hypothalamus inhibits the release of growth hormones from the pituitary gland. Gonadotrophin releasing hormones stimulate the pituitary synthesis and release of gonadotrophins.

7. Which part of the pituitary is under the direct control of the hypothalamus?
a) Posterior part
b) Anterior part
c) Dorsal part
d) Ventral part
Answer: a
Clarification: The posterior pituitary is under the direct neural regulation of the hypothalamus. The pituitary gland is located in a bony cavity called Sella turcica and is attached to the hypothalamus by a stalk.

8. In how many parts, the pituitary is divided?
a) One
b) Two
c) Four
d) Five
Answer: b
Clarification: The pituitary is anatomically divided into two major portions known as adenohypophysis and neurohypophysis. Adenohypophysis consists of two portions, pars distalis, and pars intermedia.

9. Which of the following hormone is not secreted by the pars distalis region of the pituitary?
a) Prolactin
b) Growth hormone
c) Follicle-stimulating hormone
d) Oxytocin
Answer: d
Clarification: The pars distalis region of pituitary produces growth hormone, prolactin, thyroid-stimulating hormone, adrenocorticotrophic hormone, luteinizing hormone, and follicle-stimulating hormone.

10. Oxytocin and vasopressin are synthesised by the pituitary.
a) True
b) False
Answer: b
Clarification: Posterior pituitary stores and releases two hormones called oxytocin and vasopressin, which are actually synthesised by the hypothalamus and are transported axonally to the neurohypophysis.

11. Low secretion of the growth hormone causes which of the following diseases?
a) Acromegaly
b) Gigantism
c) Dwarfism
d) Thyroid
Answer: c
Clarification: Low secretion of growth hormone results in stunted growth and which is known as dwarfism while the over secretion of the growth hormone causes the abnormal growth of the body leading to gigantism.

12. Which of the following diseases is hard to diagnose?
a) Gigantism
b) Goitre
c) Dwarfism
d) Acromegaly
Answer: d
Clarification: Excess secretion of growth hormones in adults especially in middle age can result in severe disfigurement which is known as Acromegaly, which may lead to serious complications. The disease is hard to diagnose in the early stages and often goes undetected for many years.

13. Which of the following hormones regulate the growth of mammary glands?
a) Prolactin
b) TSH
c) FSH
d) ACTH
Answer: a
Clarification: Prolactin regulates the growth of the mammary glands and the formation of milk in them. ACTH stimulates the synthesis and steroid hormones called glucocorticoids from the adrenal cortex.

14. Which of the following hormones are known as gonadotrophins?
a) LH and Oxytocin
b) LH and vasopressin
c) LH and FSH
d) FSH and Oxytocin
Answer: c
Clarification: LH and FSH stimulate the gonadal activity and are therefore referred to as gonadotrophins. In males, LH stimulates the synthesis and secretion of hormones called androgens from the testis.

15. Which of the following is not a function of LH and FSH in females?
a) Induces ovulation
b) Secretion of androgens
c) Maintaining corpus luteum
d) Stimulates the growth of follicles
Answer: b
Clarification: FSH stimulates the growth and development of the ovarian follicles in females. LH induces ovulation of fully mature follicles and maintains the corpus luteum, formed from the remnants of Graafian follicles after ovulation in females.