Zoology
- Analogous structures are a result of : Answer: 2. Convergent evolution Analogous structures have different origins but similar function because unrelated organisms face similar en... 1
- Following are the two statements regarding the origin of life :(a) The earliest organisms that appeared on the earth were non-green and presumably anaerobes.(b) The first autotrophic organisms were the chemoautotrophs that never released oxygen.Of th… Answer: 3. Both (a) and (b) are correct. Both statements are correct. Life began in an oxygen-free atmosphere, so the first cells were non-g... 1
- Reduction in pH of blood will : Answer: 3. decrease the affinity of hemoglobin with oxygen. A fall in blood pH (more H⁺, higher CO₂) shifts the oxygen dissociation curve to... 1
- Blood pressure in the pulmonary artery is : Answer: 3. more than that in the pulmonary vein. The pulmonary artery carries blood from the right ventricle at a pressure much higher than... 1
- Identify the correct statement on 'inhibin' : Answer: 2. Is produced by granulose cells in ovary and inhibits the secretion of FSH. Key idea: Inhibin is made by the granulosa cells of th... 1
- The amino acid Tryptophan is the precursor for the synthesis of : Answer: 1. Melatonin and Serotonin Tryptophan is the precursor of melatonin and serotonin. Thyroid hormones (thyroxine, T₃) are made from ty... 1
- Lack of relaxation between successive stimuli in sustained muscle contraction is known as : Answer: 3. Tetanus Sustained contraction caused by rapid successive stimuli, with no time to relax between them, is tetanus. Spasm: sudden i... 1
- Which type of tissue correctly matches with its location ?Tissue | Location(1) Smooth muscle | Wall of intestine(2) Areolar tissue | Tendons(3) Transitional epithelium | Tip of nose(4) Cuboidal epithelium | Lining of stomach Answer: 1. Smooth muscle - Wall of intestine Smooth (visceral) muscle forms the walls of hollow organs such as the intestine. 2: Areolar tis... 1
- In higher vertebrates, the immune system can distinguish self-cells and non-self. If this property is lost due to genetic abnormality and it attacks self-cells, then it leads to : Answer: 3. Auto-immune disease Key idea: When the immune system attacks the body's own cells, it is an auto-immune disease. Examples are rhe... 1
- The taq polymerase enzyme is obtained from : Answer: 1. *Thermus aquaticus* Key idea: Taq polymerase comes from the thermophilic bacterium Thermus aquaticus. It is stable at the high te... 1
- Which of the following is not a feature of the plasmids ? Answer: 4. Single - stranded Key idea: Plasmids are double-stranded, circular, extra-chromosomal DNA. They replicate independently of the ch... 1
- Which of the following features is not present in *Periplaneta americana* ? Answer: 2. Indeterminate and radial cleavage during embryonic development Key idea: Cockroach (Periplaneta) is a protostome arthropod, so it... 1
- Asthma may be attributed to : Answer: 2. allergic reaction of the mast cells in the lungs Key idea: Asthma is an allergic reaction that inflames the bronchi and bronchiol... 1
- Which of the following pairs of hormones are not antagonistic (having opposite effects) to each other ? Answer: 4. Relaxin - Inhibin Key idea: Antagonistic hormones have opposite effects. Parathormone raises blood calcium; calcitonin lowers it.... 1
- Photosensitive compound in human eye is made up of : Answer: 2. Opsin and Retinal Key idea: The photosensitive pigment of the eye, rhodopsin (visual purple), is made of opsin (a protein) and re... 1
- Which of the following approaches does not give the defined action of contraceptive ? Answer: 4. Vasectomy - prevents spermatogenesis Key idea: Vasectomy blocks the transport of sperms; it does not stop spermatogenesis. In vas... 1
- Fertilization in humans is practically feasible only if : Answer: 2. the ovum and sperms are transported simultaneously to ampullary - isthmic junction of the fallopian tube. Key idea: Fertilization... 1
- Select the incorrect statement : Answer: 3. LH and FSH decrease gradually during the follicular phase. Key idea: LH and FSH rise, not fall, during the follicular phase. FSH... 1
- Changes in GnRH pulse frequency in females is controlled by circulating levels of : Answer: 1. estrogen and progesterone Key idea: GnRH pulse frequency in females is controlled by the circulating levels of oestrogen and prog... 1
- Which of the following features is not present in the Phylum - Arthropoda ? Answer: 3. Parapodia Key idea: Arthropods have a chitinous exoskeleton, a metamerically segmented body and jointed appendages. Parapodia are... 1
- Name the chronic respiratory disorder caused mainly by cigarette smoking : Answer: 1. Emphysema Key idea: Cigarette smoking mainly causes emphysema. Smoke damages the alveolar walls, so the surface area for gas exch... 1
- In context of Amniocentesis, which of the following statement is incorrect ? Answer: 4. It can be used for detection of Cleft palate. Key idea: Amniocentesis tests fluid-borne foetal cells for chromosomal and metaboli... 1