Zoology
- The part of nephron involved in active reabsorption of sodium is Answer: 1. proximal convoluted tubule The proximal convoluted tubule (PCT) reabsorbs about 70 to 80 percent of the filtered Na⁺ (with water,... 1
- Graves' disease is caused due to Answer: 1. hypersecretion of thyroid gland Graves' disease is a form of hyperthyroidism, an autoimmune disease in which antibodies stimulate... 1
- Name the ion responsible for unmasking of active sites for myosin for cross-bridge activity during muscle contraction. Answer: 4. Calcium When a nerve signal reaches the muscle, Ca²⁺ is released from the sarcoplasmic reticulum. Ca²⁺ binds to troponin on the t... 1
- Choose the correct statement. Answer: 2. Photoreceptors in the human eye are depolarized during darkness and become hyperpolarized in response to the light stimulus. Go t... 1
- Osteoporosis, an age-related disease of skeletal system, may occur due to Answer: 2. decreased level of estrogen Osteoporosis is a loss of bone mass that makes bones fragile. It is common after menopause or in old... 1
- Embryo with more than 16 blastomeres formed due to in vitro fertilization is transferred into Answer: 4. uterus In IVF-ET, an embryo with up to 8 blastomeres is transferred into the fallopian tube (ZIFT). An embryo with more than 8 bl... 1
- Which of the following is hormone-releasing IUD? Answer: 4. LNG-20 IUDs are of three kinds: non-medicated (Lippes loop), copper releasing (Cu7, Multiload 375, CuT) and hormone releasing (Pr... 1
- Which of the following is incorrect regarding vasectomy? Answer: 1. No sperm occurs in epididymis In vasectomy the vasa deferentia are cut and tied, so sperm cannot reach the seminal fluid. The ste... 1
- Which kind of therapy was given in 1990 to a four-year-old girl with adenosine deaminase (ADA) deficiency? Answer: 4. Gene therapy In 1990 a four-year-old girl with ADA deficiency received the first clinical gene therapy: lymphocytes were taken, a... 1
- Stirred-tank bioreactors have been designed for Answer: 2. availability of oxygen throughout the process A stirred-tank bioreactor has an agitator and a sparger. Stirring mixes the content... 1
- A foreign DNA and plasmid cut by the same restriction endonuclease can be joined to form a recombinant plasmid using Answer: 3. ligase The same restriction enzyme gives matching sticky ends on the foreign DNA and plasmid. These ends anneal, and DNA ligase s... 1
- Which of the following is not a component of downstream processing? Answer: 3. Expression Downstream processing includes separation, purification and preservation of the product after the biosynthesis stage.... 1
- Which of the following restriction enzymes produces blunt ends? Answer: 1. *Eco* RV EcoRV cuts in the middle of its recognition site (GAT^ATC) and gives blunt ends. XhoI, HindIII and SalI cut with a stagg... 1
- In mammals, which blood vessel would normally carry largest amount of urea ? Answer: 3. Hepatic Vein Urea is made in the liver, so the blood leaving the liver through the hepatic vein carries the largest amount of ure... 1
- It is much easier for a small animal to run uphill than for a large animal, because : Answer: 2. Smaller animals have a higher metabolic rate. Smaller animals have a larger surface area to volume ratio and so a higher metaboli... 1
- In the stomach, gastric acid is secreted by the : Answer: 2. parietal cells The parietal (oxyntic) cells of the gastric glands secrete HCl and intrinsic factor. Peptic (chief) cells secrete... 1
- Which of the following guards the opening of hepatopancreatic duct into the duodenum ? Answer: 4. Sphincter of Oddi The sphincter of Oddi guards the opening of the hepatopancreatic duct into the duodenum. The pyloric sphincter... 1
- Which of the following statements is not true for cancer cells in relation to mutations ? Answer: 4. Mutations inhibit production of telomerase. Cancer cells show reactivation of telomerase, which keeps telomeres from shortening a... 1
- Antivenom injection contains preformed antibodies while polio drops that are administered into the body contain : Answer: 4. Attenuated pathogens Key idea: Antivenom gives readymade antibodies (passive immunity), while polio drops contain attenuated (wea... 1
- Which part of the tobacco plant is infected by *Meloidogyne incognita* ? Answer: 4. Root Key idea: The nematode Meloidogyne incognita infects the roots of tobacco. It causes root-knot galls and reduces yield. In b... 1
- Which of the following is a restriction endonuclease ? Answer: 1. Hind II Hind II is a restriction endonuclease, an enzyme from bacteria that cuts DNA at specific recognition sequences. Protease... 1
- Which one of the following characteristics is not shared by birds and mammals ? Answer: 3. Viviparity Both birds and mammals have a bony endoskeleton, breathe with lungs and are warm blooded. Viviparity (giving birth to... 1
- Which of the following characteristic features always holds true for the corresponding group of animals ?(1) Cartilaginous endoskeleton | Chondrichthyes(2) Viviparous | Mammalia(3) Possess a mouth with an upper and a lower jaw | Chordata(4) 3 - chamb… Answer: 1. Cartilaginous endoskeleton - Chondrichthyes Class Chondrichthyes (sharks, rays) always has a cartilaginous endoskeleton. 2: Not a... 1
- Which of the following structures is homologus to the wing of a bird ? Answer: 4. Flipper of Whale Homologous organs share the same basic anatomical plan (here the forelimb bones) but may differ in function. A b... 1