NEET SECTION - A [ZOOLOGY - MCQ]

C. An RNA virus that can synthesise DNA during infection
Explanation:
A retrovirus is RNA virus which is capable to synthesize DNA during infection.

D. Disulphide bridges
Explanation:
Human insulin is made up of 51 amino acids arranged in two polypeptide chains. Chain A has 21 amino acids and chain B has 30 amino acids. The two polypeptide chains are interconnected by disulphide bridges or S - S - linkages.

B. A - (iv), B - (i), C - (ii), D - (iii)
Explanation:
Transformation is a procedure through which a piece of DNA is introduced in a host bacterium, the DNA fragments resulting from digestion of DNA by restriction endonucleases can be separated by a technique known as gel electrophoresis, each restriction endonuclease recognises a specific palindromic nucleotide sequence in the DNA called recognition site, and recombinant DNA is composed of DNA from two different sources or organisms.

D

D

A. Precavals and postcavals
Explanation:
The superior and inferior vena cavas (pre and post caval) are the great veins which empty blood in the right auricle.
Superior Vena Cava is the veins of the head, neck, upper extremities, and chest all drain into the superior vena cava, which goes to the heart. It is formed by the union of the right and left brachiocephalic veins, which drain the head, neck, and upper extremities. The azygos vein drains the veins of the chest wall and empties into the superior vena cava just before the latter empties into the heart.
Inferior Vena Cava is much longer than the superior vena cava and returns the blood from the parts of the body below the diaphragm. It begins in the lower abdomen with the union of the two common iliac veins. It then ascends along the back wall of the abdomen, through a groove in the posterior part of the liver, through the diaphragm, and finally through the lower thorax to empty into the right atrium of the heart.

D. Complex QRS - One complete pulse
Explanation:
The QRS complex shows one complete pulse. It represents the depolarisation of the ventricles, which initiates the ventricular contraction. The contraction starts shortly after Q and marks the beginning of the systole.

D

B. presence of thyroxine.
Explanation:
Growth hormone of pituitary is more effective in presence of thyroxine hormone.

A

B

C. Lateral part of frontal lobe
Explanation:
Broca's area is located in a region called the inferior frontal gyrus, found in the frontal lobe.

D. Medulla
Explanation:
The choroid plexus is located in the posterior medullary velum which partially forms the roof of the fourth ventricle.

D

B. Neuromuscular junction
Explanation:
The junction between a motor neuron and the sarcolemma of a muscle fiber is called a neuromuscular junction.

B. Muscular dystrophy, lack of a protein called dystrophin.
Explanation:
Muscular dystrophy (MD) is a group of muscle diseases that results in increasing weakening and breakdown of skeletal muscles over time. This damage and weakness is due to the lack of a protein called dystrophin, which is necessary for normal muscle function. The absence of this protein can cause problems with walking, swallowing, and muscle coordination. The disorders differ in which muscles are primarily affected, the degree of weakness, how fast they worsen, how and when symptoms begin.

C

C. Green gland
Explanation:
Green gland are the excretory organ of crustaceans.

D. Marine teleost
Explanation:
Certain marine molluscs, crustaceans, and teleost fishes first form trimethylamine from their ammonia by a process known as methylation. Then, the trimethylamine is oxidized to trimethylamine oxide for excretion. This oxide is soluble in water, but non-toxic.

B

B

C. Evidences from biogeographical distribution.
Explanation:
Galapagos Islands are a chain of 14 islands in the Pacific Ocean on the west coast of South America. Charles Darwin visited these islands during his famous voyage on HMS Beagle (name of his ship) in 1835. The flora and fauna of these islands resemble with those of the South American mainland with which the Galapagos Islands were once connected. However, Darwin's finches (birds of Galapagos Islands) influenced Darwin to think about the evolutionary change. These birds designated as Darwins' finches by Dr. David Lack (1947) do not resemble the birds of the South American species. These finches were the first to reach the Galapagos Islands as migrants from the mainland (South America). When they reached the islands, they faced many problems for obtaining food. They had to change their feeding habits.

B. Gonorrhoea
Explanation:
Gonorrhoea is a sexually transmitted disease caused by a bacterium whereas AIDS, hepatitis-B, and genital herpes are caused by viruses.

C. Only (ii)
Explanation:
Intra uterine devices like copper-Tare effective contraceptives.

B

B. fructose, calcium, and certain enzymes.
Explanation:
Secretions of male accessory glands such as seminal vesicles, prostate, and bulbourethral glands constitute the seminal plasma which is rich in fructose, calcium, and certain enzymes.

A. A - Degeneration of endometrium, B - Regeneration of endometrium, C - Endometrium thickness increases and becomes vascularised to receive and implant embryo
Explanation:
During menstrual phase (A), endometrium degenerates. The menstrual phase is followed by the follicular phase (B). During this phase, oestrogen made by the maturing ovarian follicle causes the glands to grow and the endometrium regenerates. Follicular phase is followed by luteal phase during which corpus luteum secretes large amounts of progesterone which is essential for maintenance of the endometrium.

C. collection of the ovum after ovulation
Explanation:
The edges of the infundibulum possess finger-like projections called fimbriae, which help in collection of the ovum after ovulation.

C. (iii) and (iv)
Explanation:
Silicosis and asbestosis are known as occupational disorders as they occur due to one's occupation. Workers working in industries where silica and asbestos are used can suffer from these respiratory disorders.

A

B. Lungs
Explanation:
Residual volume (RV) is the volume of air remaining in the lungs after maximum forceful expiration. In other words, it is the volume of air that cannot be expelled, thus causing the alveoli to remain open at all times. The residual volume remains unchanged regardless of the lung volume at which expiration was started.

D

B. Dense fibrous connective tissue
Explanation:
A tendon is composed of dense fibrous connective tissue made up primarily of collagenous fibres.

D. (A) - (i), (vi), (viii); (B) - (ii), (vii), (ix); (C) - (iii), (iv), (v)
Explanation:
Image A is a unicellular gland consisting of isolated glandular cells or goblet cells of the alimentary canal.
Image B is a multicellular gland consisting of a cluster of cells such as the salivary gland.
Image C represents a compound epithelium made of more than one layer (multi-layered) of cells. Their main function is to provide protection against chemical and mechanical stresses. They cover the dry surface of the skin, the moist surface of the buccal cavity, pharynx, the inner lining of ducts of salivary glands, and of pancreatic ducts.
Hence, the correct match is (A) - (i), (vi), (viii); (B) - (ii), (vii), (ix); (C) - (iii), (iv), (v).

A. All of these
Explanation:
Obelia, Aurelia, and Hydra are aquatic, sessile, or free-swimming, radially symmetrical animals belonging to phylum Cnidaria, and hence all are cnidarians.

D. It is absent throughout life in humans from the very beginning
Explanation:
Humans are vertebrates belonging to Class Mammals in which the notochord is replaced by a cartilaginous or bony vertebral column in the adult.

B. Notochord is replaced by vertebral column in adult of some chordates.
Explanation:
All chordates have a notochord but only in adult of some chordates or vertebrates, the notochord is replaced by a cartilaginous or bony vertebral column. So, all chordates are not vertebrates. All vertebrates are chordates as they have notochord during the embryonic stage.

D. Archaeocytes
Explanation:
Archaeocytes may be converted into other types of cells and are also called as undifferentiated totipotent cells.

A. Lampreys and hagfishes
Explanation:
Lamprey and, Hagfish are Cyclostomes which are jawless fishes.