Category: Class 11 Biology Objective Questions

250+ TOP MCQs on ECG and Answers Pdf Online Quiz [Updated]

Biology Multiple Choice Questions on “ECG”.

1. What is the full form of ECG?
a) Electricity cardiac group
b) Electrocardio group
c) Electrocardium granules
d) Electrocardiogram

Answer: d
Clarification: ECG stands for Electrocardiogram. ECG is a graphical representation of the electrical activity of the heart during a cardiac cycle. It is measured with the help of a machine called an electrocardiograph.

2. To measure ECG, usually how many electrodes are connected to a patient?
a) One
b) Two
c) Three
d) Four

Answer: c
Clarification: To measure a standard ECG, a patient is connected to the machine with three electrical leads-one to each wrist and one to the left ankle. It continuously monitors heart activity.

3. What is the full form of CAD?
a) Coronary artery disease
b) Carotid artery disorder
c) Carotid artery disease
d) Coronary angina disorder

Answer: a
Clarification: CAD refers to coronary artery disease which is caused by atherosclerosis and arteriosclerosis. Atherosclerosis refers to the deposition of cholesterol, fat, calcium on the walls of coronary arteries while arteriosclerosis refers to the deposition of calcium which leads to the hardening of the arteries.

4. Which of the following waves represent the excitation of the atria?
a) P-wave
b) QRS complex
c) T-wave
d) ST-segment

Answer: a
Clarification: The P-wave represents the electrical excitation of depolarisation of the atria which leads to the contraction of both the atria. The T-wave represents the repolarisation of the ventricles.

5. Which of the following represents the depolarisation of the ventricles?
a) P-wave
b) T-wave
c) QRS complex
d) PQ interval

Answer: c
Clarification: The QRS complex represents the depolarisation of the ventricles, which initiate the ventricular contraction. The contraction starts shortly after Q and marks the beginning of the systole.

6. The end of the T-wave marks the end of the systole.
a) True
b) False

Answer: a
Clarification: The end of the T-wave marks the end of the systole. The T-wave represents the return of the ventricles from excited to normal state which is also known as repolarisation of the ventricles.

7. By counting the number of which of the following waves, the heartbeat of a person can be determined?
a) P-wave
b) QRS complex
c) ST-segment
d) PQ interval

Answer: b
Clarification: By counting the number of QRS complexes that occur in a given period, one can determine the heartbeat rate of an individual. Any deviation from the shapes of the curve indicates a possible abnormality or a disease. Hence, it is of great clinical significance.

8. Which of the following represents the enlargement of auricles?
a) Enlargement of P-wave
b) Enlargement of QR segment
c) Depression of ST segment
d) Elevation of ST segment

Answer: a
Clarification: Enlargement of auricles is represented by the enlargement of P-wave or sometimes the lengthening of PQ interval also represents the enlargement of auricles by rheumatic fever.

9. What does the depression of ST-segment depict?
a) Ischemia
b) Hypokalemia
c) Myocardial infarction
d) Acute heart attack

Answer: a
Clarification: The depression of ST-segment shows Ischemia which means there is an insufficient supply of blood to the heart muscles or the weakening of the heart muscles.

10. Which of the following muscles have the longest refractive period?
a) Skeletal muscles
b) Smooth muscles
c) Cardiac muscles
d) Facial muscles

Answer: c
Clarification: Cardiac muscles never show the property of summation or tetanus spasm as the muscles have the longest refractory period. Cardiac muscles also have the least latent period.

11. Angina pectoris is a symptom of myocardial infarction.
a) True
b) False

Answer: a
Clarification: Angina pectoris is a symptom of myocardial infarction. Due to the weakening of heart muscles, the heart is not able to supply enough blood which causes severe pain called angina pectoris. If left untreated, tissues would be dead and that will cause myocardial infarction or acute heart attack.

12. What is meant by iso-volumetric systole?
a) The time duration between the closing and opening of AV valves
b) The time duration between the closing and opening of semilunar valves
c) The time duration between the closing of AV valves and opening of semilunar valves
d) The time duration between the closing of semilunar valves and the opening of AV valves

Answer: c
Clarification: The time duration between the closing of AV valves and the opening of semilunar valves is known as iso-volumetric systole. The time duration between the closing of semilunar valves and the opening of AV valves is known as iso-volumetric diastole.

13. What is meant by AV block?
a) Impulse not reaching SA node
b) Impulse not reaching the AV node
c) Impulse not reaching Purkinje fibers
d) Impulse not generating in the heart

Answer: b
Clarification: When the impulse is not reaching the AV node then this is known as AV block. When the impulse is not reaching the Purkinje fibers then it is called a Purkinje block.

14. What is the main symptom of heart failure?
a) Lung congestion
b) Vomiting
c) Yellowing of eyes
d) Pain in the chest

Answer: a
Clarification: When the heart is not pumping sufficient blood according to the needs of the body organs then it leads to heart failure. Lung congestion is the main symptom of heart failure.

250+ TOP MCQs on Locomotion & Movement – Skeletal System and Answers

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

1. Which of these is not a function of the skeletal system?
a) Mineral storage
b) Protection of organs
c) Movement
d) Metabolism
Answer: d
Clarification: The skeletal system is made of bones and cartilages. The skeletal system has several important functions, which include storage of minerals, protection of vital organs, support and movement.

2. What type of tissue is cartilage?
a) Muscular
b) Epithelial
c) Connective
d) Nervous
Answer: c
Clarification: The skeletal system is made of bones and cartilages. Both bones and cartilages are specialised connective tissues. Cartilages have a slightly pliable matrix, unlike bones, which possess a hard matrix.

3. The presence of what makes the matrix of bones hard?
a) Phosphate salts
b) Chondroitin salts
c) Calcium salts
d) Sodium salts
Answer: c
Clarification: The bones and cartilages that make up our skeletal system are specialised connective tissues. The matrix of bones is hard due to the presence of calcium salts, while that of cartilage is slightly pliable.

4. The presence of what makes the matrix of cartilages slightly pliable?
a) Chondroitin salts
b) Phosphate salts
c) Calcium salts
d) Sodium salts
Answer: a
Clarification: The bones and cartilages that make up our skeletal system are specialised connective tissues. The presence of chondroitin salts in the matrix of cartilages is what makes the matrix slightly pliable.

5. How many bones do we have?
a) 273
b) 270
c) 206
d) 201
Answer: b
Clarification: The human body has 206 bones. However, at birth, the human body possesses 270 bones. As we grow up, some of the bones fuse together and hence the number of bones decreases from 270 to 206.

6. How many bones are present in the axial skeleton?
a) 126
b) 65
c) 80
d) 106
Answer: c
Clarification: The bones of the skeletal system are divided into two parts-the axial skeleton and the appendicular skeleton. The axial skeleton consists of 80 bones. These bones are present along the main axis of the body.

7. Which of these bones are not a part of the axial skeleton?
a) Clavicle
b) Skull
c) Sternum
d) Ribs
Answer: a
Clarification: The bones of the skeletal system are divided into two parts- the axial skeleton and the appendicular skeleton. The skull, sternum, vertebral column and ribs make up the axial skeleton of the body.

8. How many facial bones does the skull possess?
a) 22
b) 8
c) 12
d) 14
Answer: d
Clarification: The skull is made up of 22 bones. These bones are classified into two categories- the cranial bones and the facial bones. There are 8 cranial bones and 22 facial bones. The facial bones form the front part of the skull.

9. What is the shape of the hyoid bone?
a) S – shape
b) L – shape
c) U – shape
d) C – shape
Answer: c
Clarification: The hyoid bone is a U – shaped bone which is located at the base of the buccal cavity. It is a single bone and is included along with the bones of the skull. The skull possesses a total of 22 bones.

10. The inner ear contains three bones-Malleus, Incus and Stapes. True or false?
a) True
b) False
Answer: b
Clarification: The middle ear consists of the three bones- Malleus, Incus and Stapes. They are also called the hammer, anvil and stirrup, respectively. The Malleus, Incus and Stapes are collectively called the ear ossicles.

11. How many occipital condyles do humans possess?
a) 4
b) 1
c) 3
d) 2
Answer: d
Clarification: Humans possess two occipital condyles. Hence, humans have a dicondylic skull. The function of the occipital condyles is to articulate the skull region with the superior region of the vertebral column.

12. How many vertebrae do humans possess?
a) 33
b) 30
c) 26
d) 22
Answer: c
Clarification: Humans possess 26 vertebrae in the vertebral column. These vertebrae are divided into five different regions, namely the cervical (7), thoracic (12), lumbar (5), sacral (1-fused) and coccygeal (1-fused) regions.

13. What is the central hollow portion of each vertebra known as?
a) Spinal canal
b) Vertebral canal
c) Neural canal
d) Axial canal
Answer: c
Clarification: Humans possess 26 vertebrae in the vertebral column. The central hollow portion of each vertebra of the vertebral column is known as the neural canal. The spinal cord passes through the neural canal.

14. Which vertebra articulates with the occipital condyles?
a) Atlas
b) Axis
c) Sacral vertebra
d) Coccygeal vertebra
Answer: a
Clarification: Humans possess two occipital condyles. The function of the occipital condyles is to articulate the skull region with the first vertebra of the vertebral column, which is known as the atlas.

15. How many regions is the vertebral column divided into?
a) 6
b) 5
c) 7
d) 4
Answer: b
Clarification: Humans possess 26 vertebrae in the vertebral column. These vertebrae are divided into five different regions, namely the cervical (7), thoracic (12), lumbar (5), sacral (1-fused) and coccygeal (1-fused) regions.

250+ TOP MCQs on Chemical Control and Coordination – Human Endocrine System and Answers

Biology Assessment Questions for AIIMS Exam on “Chemical Control and Coordination – Human Endocrine System – 2”.

1. What is the function of FSH in males?
a) Fight or flight response
b) Secretion of androgens
c) Synthesis of androgens
d) Regulation of spermatogenesis
Answer: d
Clarification: FSH or follicle stimulating hormone regulates spermatogenesis. Luteinizing hormone or LH is responsible for the synthesis and secretion of androgens, while catecholamines are responsible for the fight or flight response.

2. Which of these is not a function of gonadotropins in females?
a) Induction of ovulation
b) Maintenance of corpus luteum
c) Breakdown of corpus luteum
d) Development of ovarian follicles
Answer: c
Clarification: The gonadotropins are luteinizing hormone (LH) and follicle stimulating hormone (FSH). In females, they are responsible for inducing ovulation, maintaining the corpus luteum and developing ovarian follicles.

3. What is the function of MSH?
a) Formation of milk in females
b) Growth of mammary glands
c) Regulation of pigmentation
d) Stimulation of smooth muscle contraction
Answer: c
Clarification: MSH or melanocyte stimulating hormone is responsible for regulating the pigmentation of the body. It does so by acting on melanin containing cells or melanocytes. MSH is secreted by the pineal gland.

4. Which of these is not a function of oxytocin?
a) Stimulation of breastmilk production
b) Stimulation of smooth muscle contraction
c) Stimulation of uterine contraction at childbirth
d) Ejection of milk
Answer: a
Clarification: Oxytocin is secreted by the posterior pituitary gland. Its functions include stimulating the contraction of smooth muscles as well as contractions of the uterus during childbirth and ejection of milk. Prolactin is responsible for the production of breastmilk.

5. Where does vasopressin act on in the kidneys?
a) Afferent arteriole
b) DCT
c) PCT
d) Efferent arteriole
Answer: b
Clarification: Vasopressin or anti-diuretic hormone is secreted by the posterior pituitary gland. It acts on the DCT or distal convoluted tubule of the nephrons of the kidney for the reabsorption of water and electrolytes.

6. An abnormality in the functioning of which of these hormones can lead to diabetes insipidus?
a) Insulin
b) Glucagon
c) Vasopressin
d) Growth hormone
Answer: c
Clarification: An abnormality in the synthesis or secretion of anti-diuretic hormone (ADH) or vasopressin leads to diabetes insipidus. This disorder is characterized by dehydration due to excess water loss.

7. What is the location of the pineal gland?
a) Dorsal side of forebrain
b) Ventral side of forebrain
c) Dorsal side of midbrain
d) Ventral side of midbrain
Answer: a
Clarification: The pineal gland is located on the dorsal side of the forebrain. It secretes melatonin, which is an important hormone that regulates the diurnal cycle of the body as well as body temperature.

8. Which of these is not a function of melatonin?
a) Regulation of the diurnal cycle
b) Regulation of body temperature
c) Regulation of menstrual cycle
d) Regulation of bowel movements
Answer: d
Clarification: Melatonin is secreted by the pineal gland. It is responsible for the regulation of the sleep-wake or diurnal cycle, body temperature as well as menstrual cycle, but not bowel movements.

9. Identify the structure shown below.

a) Pineal gland
b) Adrenal gland
c) Thyroid gland
d) Ovaries
Answer: c
Clarification: The thyroid gland is an endocrine gland located below the vocal cords on either side of the trachea. It consists of two lobes joined by the isthmus, which is a thin stretch of connective tissue.

10. Melatonin influences our defense capabilities. True or false?
a) True
b) False
Answer: a
Clarification: Melatonin is a hormone secreted by the pineal gland. It is responsible for various functions such as the sleep-wake or diurnal cycle and body temperature. It also affects our defense capabilities.

11. Thyroid gland contains ______
a) granules, collagen fibers
b) goblet cells, plasma
c) mast cells, matrix
d) follicles, stromal tissue
Answer: d
Clarification: The thyroid gland is made up of follicles and stromal tissue. The follicular cells are responsible for the production of hormones thyroxine or tetraiodothyronine as well as triiodothyronine.

12. Which element is crucial for the normal functioning of the thyroid gland?
a) Potassium
b) Sulphur
c) Iodine
d) Calcium
Answer: c
Clarification: Iodine is responsible for the normal functioning of the thyroid gland. It is used for the production of the thyroid hormones thyroxine or tetraiodothyronine (T4) as well as triiodothyronine(T3).

13. Goiter is caused by ______
a) deficiency of calcium
b) surplus of iodine
c) deficiency of iodine
d) surplus of calcium
Answer: c
Clarification: Goiter is caused due to the deficiency of iodine in the diet. The element iodine is important for the proper functioning of the thyroid gland and its deficiency leads to the enlargement of the gland.

14. Hypothyroidism causes _____
a) goiter
b) Addison’s disease
c) Graves’ disease
d) dwarfism
Answer: a
Clarification: Hypothyroidism is the decreased synthesis and secretion of thyroid hormones. It is caused due to the deficiency of iodine and leads to the enlargement of the thyroid gland which is called goiter.

15. Graves’ disease is caused by ______
a) hypothyroidism
b) hyperthyroidism
c) deficiency of vasopressin
d) deficiency of adrenaline
Answer: b
Clarification: Graves’ disease is caused due to hyperthyroidism or excess production of thyroid hormones. It is characterized by enlargement of the thyroid gland, protruding eyeballs and weight loss.

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