Students Biology Questions solved

Student’s QuestionsSolved : Student’s QuestionsSolved Dr Subroto Biswas & Dr Aman Biswas

1..What is ecotone : 1..What is ecotone A transition area between two adjacent ecological communities (ecosystems).

2.What is edge effect ? : 2.What is edge effect ? Contrasting environment on an ecosystem = boundary between natural habitats, especially forests, and disturbed or developed land. Pronounced in small habitat fragments where they may extend throughout the patch.

Edge effect : Edge effect When an edge is created to any natural ecosystem, and the area outside the boundary is a disturbed or unnatural system, the natural ecosystem is seriously affected for some distance in from the edge. In the case of a forest where the adjacent land has been cut, creating an open/forest boundary, sunlight and wind penetrate to a much greater extent, drying out the interior of the forest close to the edge and encouraging growth of opportunistic species at the edge.

3. What do you mean by Edge species ? : 3. What do you mean by Edge species ? Evolutionarily Distinct and Globally Endangered (EDGE) Species represent a disproportionate amount of unique evolutionary history. They have few close relatives and are often extremely unusual in the way they look, live and behave. Some EDGE species, such as elephants and pandas, are well known and already receive considerable conservation attention, Many others, such as the Yangtze River dolphin (the world’s rarest cetacean), The bumblebee bat (arguably the world’s smallest mammal) Egg-laying long-beaked echidnas are highly threatened

4. What are Keystone species ? : 4. What are Keystone species ? A species that has a disproportionate effect on its environment relative to its abundance Such species affect many other organisms in an ecosystem and help to determine the types and numbers of various others species in a community.

Slide 7 : Such an organism plays a role in its ecosystem that is analogous to the role of a keystone in an arch. While the keystone feels the least pressure of any of the stones in an arch, the arch still collapses without it. Similarly, an ecosystem may experience a dramatic shift if a keystone species is removed, even though that species was a small part of the ecosystem by measures of biomass or productivity. It has become a very popular concept in conservation biology

Slide 8 : A keystone species is a species that plays a critical role in maintaining the structure of an ecological community and whose impact on the community is greater than would be expected based on its relative abundance or total biomass.

5. What are critically endangered species? : 5. What are critically endangered species? Organisms with a conservation status of critically endangered have an extremely high risk of becoming extinct in the wild in the immediate future

6. Which Immunoglobin (Ig) is responsible for primary response? : 6. Which Immunoglobin (Ig) is responsible for primary response? (a) IgA (b) IgE (c) IgG (d) IgM

7. FAD is electron acceptor during oxidation of : 7. FAD is electron acceptor during oxidation of alpha-ketogulatarate to Succinyl CoA Succinic acid to fumaric acid (c) Succinyl CoA to Succinic acid (d) Fumaric acid to malic acid

8. The chemical nature of hormones secreted by alpha and delta cells of pancreas is : 8. The chemical nature of hormones secreted by alpha and delta cells of pancreas is Glycolipid Glycoprotein Steroid Polypeptide

9. The genetic material of Rabies virus is : 9. The genetic material of Rabies virus is (a) ss RNA (b) dsRNA (c) ssDNA (d) dsDNA

11. The length of DNA having 23 base pair is : 11. The length of DNA having 23 base pair is 78 Ao 78.4 Ao 74.8 Ao 78.2 Ao

12. T-lymphocyte is produced in : 12. T-lymphocyte is produced in bone marrow Spleen pancreas thymus

13. The average diameter of Red Blood Corpuscles of man is : 13. The average diameter of Red Blood Corpuscles of man is 7.2 um 8.1 um 9.2 um 10.3 um

14. How many ATP molecules are obtained from fermentation of 1 molecule of glucose? : 14. How many ATP molecules are obtained from fermentation of 1 molecule of glucose? 4 2 5 5

15. Number of nitrogenous bases in a codon is : 15. Number of nitrogenous bases in a codon is 3 2 1 5

16. A character which is expressed in a hybrid is called : 16. A character which is expressed in a hybrid is called dominant Recessive co-dominant epistatic

17. DNA in the nucleus of rabbit egg is 1.8 picograms its liver cell will have mass of …picograms of DNA : 17. DNA in the nucleus of rabbit egg is 1.8 picograms its liver cell will have mass of …picograms of DNA 7.2 0.9 1.8 3.6

18. In a double stranded DNA which has 15% adenine,there will be…….. : 18. In a double stranded DNA which has 15% adenine,there will be…….. 15% cytosine 35% cytosine 85% cytosine 30% cytosine

19. In yeast alanyl t-RNA nucleotides are…….in number? : 19. In yeast alanyl t-RNA nucleotides are…….in number? 77 77 pairs 88 33800

20. Unit of distance between genes on the chromosome is……? : 20. Unit of distance between genes on the chromosome is……? cDNA Morgan Centimorgan Chi-square

21. Dr Khorana and his collegues synthesized an RNA molecule with repeating sequence of UG and bases (UG UG UG UG UG UG) . It produced a tetrapeptide with alternating sequence of cysteine and valine and options are? : 21. Dr Khorana and his collegues synthesized an RNA molecule with repeating sequence of UG and bases (UG UG UG UG UG UG) . It produced a tetrapeptide with alternating sequence of cysteine and valine and options are? 1. UGU AND GUU 2. UGU AND GUG 3. UUG AND GGU 4. GUG AND UGU 5. GUU AND UGU

Slide 25 : H.G. Khorana identified the rest of the code, and shortly thereafter R.W. Holley determined the structure of tRNA, the adapter molecule that facilitates translation. This work was based upon earlier studies by S.Ochoa, who received the Nobel prize in 1959 for his work on the enzymology of RNA synthesis. In 1968, Khorana, Holley and Nirenberg received the Nobel prize in Physiology or Medicine for their work. UGU and GUU represent cysteine and valine respectively.

22. If we take food rich in lime juice , then action of ptyalin on starch : 22. If we take food rich in lime juice , then action of ptyalin on starch is enhanced is reduced is unaffected stops

Slide 27 : Normal pH in healthy mouth is about 6.5-7, so slightly acidic to neutral. Lime juice contains a mild organic acid (citric acid), so consuming food with lime juice will cause a lowering of pH in your mouth. As a consequence, the activity of ptyalin (salivary a-amylase, an enzyme which breaks starch down into maltose and dextrin, making digestion to glucose easier - and your body really needs glucose as a source of energy!) will be inhibited if pH drops below the optimum range of 5.6-6.9. In extreme case, if enough acidic food is consumed together with food containing starch, probably the effect would be a slower digestion of starch since ptyalin is not much helping anymore (by starting breaking the starch from the mouth).

23. People recovering from long illness are often advised to include alga, Spirulina in their diet because it : 23. People recovering from long illness are often advised to include alga, Spirulina in their diet because it makes food easy to digest is rich in proteins has antibiotic properties restores intestinal microflora

24. An oocyte is released from the ovary under the influence of LH after : 24. An oocyte is released from the ovary under the influence of LH after completing meiosis and before polar bodies are released completing meiosis I and before release of polar bodies completing meiosis completing meiosis I and after release of polar bodies

25 .The 3 subfamilies of leguminosae are distinguished mainly on the basis of : 25 .The 3 subfamilies of leguminosae are distinguished mainly on the basis of a) nature and habit of plants b) inflorescence and flower characters c) nature of gynoecium d) nature of fruit and its germination

26. Which of these pesticides is an acetylcholinesterase inhibitor? : 26. Which of these pesticides is an acetylcholinesterase inhibitor? Aldrin BHC Endosulfan malathion

27. The first case of polyembryony was reportd in certain…. : 27. The first case of polyembryony was reportd in certain…. grape seed orange seed pulse seed mango seed

28. Which of these is incorrect ? : 28. Which of these is incorrect ? Afflatoxin - Aspergillus parasiticus Red rust of tea – Melanospora Black rust of wheat – Puccinia Plant parasite - Meladogyne

Slide 34 : Red rust of tea – Cephalouros

29. Match the following1. Endarch and closed vascular bundle a. pericycle2. outermost layer of stele b. monocot stem3. dorsiventral leaf c. monocot root4. conjunctive tissue are sclerenchymatous d. dicot leaf : 29. Match the following1. Endarch and closed vascular bundle a. pericycle2. outermost layer of stele b. monocot stem3. dorsiventral leaf c. monocot root4. conjunctive tissue are sclerenchymatous d. dicot leaf a) 1-b 2-a 3-d 4-c b) 1-a 2-b 3-c 4-d c) 1-d 2-c 3-a 4-b d) 1-c 2-d 3-b 4-a

30. Which of the following is not a variety of Oryza sativa? : 30. Which of the following is not a variety of Oryza sativa? CO15 TMV2 APT19 ADT16

Slide 37 : TMV2 is variety of groundnut

31. Choose the incorrect statement/s1. The most important phagocytes are macrophages and basophils2. The process of production of lympphocytes in bone marrow is called haematopoiesis3. Thymus develops at about 7th week of gestation4. The mucosa is endowed with secretory IgA : 31. Choose the incorrect statement/s1. The most important phagocytes are macrophages and basophils2. The process of production of lympphocytes in bone marrow is called haematopoiesis3. Thymus develops at about 7th week of gestation4. The mucosa is endowed with secretory IgA 1 only 3 only 4 only 2 and 3 only

32. The genome of retroviruses contain : 32. The genome of retroviruses contain only 1 double stranded DNA 2 single strand DNA 2 identical single strand RNAs 2 identical single strand DNAs

33. For every carbon fixation during dark reaction_____ATP and _____ NADPH2 are consumed : 33. For every carbon fixation during dark reaction_____ATP and _____ NADPH2 are consumed a) 2 ATP and 2 NADPH2 b) 3 ATP and 3 NADPH2 c) 3 ATP and 2 NADPH2 d) 2 ATP and 3 NADPH2

34. Which of the following statements is/ are not true ? : 34. Which of the following statements is/ are not true ? a) In Abelomoschus esculentus the fruit is schizocarp b) The leaves of Nicotiana tabaccum contain anabasine c) The tepals are gamophyllous in Riccinus communis d) Ovary superior trilocular ovules on axile placentation in musaceae

Slide 42 : Abelmeschos (bhindi) is loculicidal capsule, i.e. dry dehiscent fruit not schizocarp Anabasine is present in trace amounts in tobacco smoke, and can be used as an indicator of a person's exposure to tobacco smoke Trilocular ovary of Musa

35. Bundle sheath of the leaf is made up of ________ : 35. Bundle sheath of the leaf is made up of ________ sclerenchyma collenchyma parenchyma stellate parenchyma

36. __________ fowl is the oldest and most popular breed of America : 36. __________ fowl is the oldest and most popular breed of America New hampshire Plymouth rock Wyandotte Rhode island red

Slide 45 : Coming from America where it was standardised in 1883, the Wyandotte is every inch the traditional farmyard fowl. The cock bird is particularly attractive and like the Welsummer has a multi coloured feather pattern. The Wyandotte has a rose comb. Very docile and friendly.

37. Pick out the trace elements from the following : 37. Pick out the trace elements from the following Co & S Mg & K Cu & Zn Mn & P

38 Gastric HCl secretion is decreased by __________ : 38 Gastric HCl secretion is decreased by __________ a) enterogasterone b) Mineralocorticoids c) aldosterone d) calcitonin

39. In which of the following fruits the edible part is the aril ? : 39. In which of the following fruits the edible part is the aril ? 1. Apple 2. Pomegranate 3. Orange 4. Litchi A true nut

40. Coconut milk is widely used in tissue culture because it contains….. : 40. Coconut milk is widely used in tissue culture because it contains….. auxins cytokinin giberellin ethylene Role of cytokinin

41. Which one is not essential for plants ? : 41. Which one is not essential for plants ? Fe Zn Iodine Potassium

42. What is the full form of BOD ? : 42. What is the full form of BOD ? 1.Biochemical Oxygen Demand 2.Biological Oxygen Demand 3.Biotic Oxygen Demand 4.None of the above

Slide 52 :

43. When is World Aids day celebrated ? : 43. When is World Aids day celebrated ? Dec 1 Jan 2 Feb 12 Jan 30

44. Minamata disease is caused by ? : 44. Minamata disease is caused by ? Cadmium toxicity Mercury toxicity Lack of iron Lead toxicity

Slide 55 : Minamata- is a neurological syndrome caused by severe mercury poisoning. Symptoms : ataxia, numbness in the hands and feet, general muscle weakness, narrowing of vision and damage to hearing & speech. In extreme cases, insanity, paralysis, coma and death follow within weeks of the onset of symptoms

45. BCG vaccine is used against which disease? : 45. BCG vaccine is used against which disease? Typhoid Tuberculosis Cholera Leprosy ExplanationBacillus Calmette-Guérin (or BCG) is a vaccine against tuberculosis. It is prepared from attenuated (weakened) live Mycobacterium bovis, a bovine tuberculosis bacillus. The strain is not virulent in humans

46. What causes Pellegra ? : 46. What causes Pellegra ? Retinol Folic acid Niacin Riboflavin

47. Which of the following is used in genetic engineering? : 47. Which of the following is used in genetic engineering? Ligase Gyrase Restriction endonuclease DNA polymerase

Slide 59 : Among the first of these "restriction enzymes" to be purified were Eco RI  and EcoRII from Escherichia coli, and HindII and Hind III from Haemophilus influenzae. This was done by Arber and Nathans.

Slide 60 : Bacteria prevent their own DNA from being degraded in this manner by disguising their recognition sequences. Enzymes called methylases add (—CH3) methyl groups to adenine or cytosine bases within the recognition sequence, which is thus modified and protected from the endonuclease. The restriction enzyme and its corresponding methylase constitute the restriction-modification system of a bacterial species.

48. Aedes agypti is the vector of which disease? : 48. Aedes agypti is the vector of which disease? Dengue Plague Malaria Kala azar

49 . What is the location and function of gerlach’s valve? : 49 . What is the location and function of gerlach’s valve?

Elaters : Elaters What is elater mechanism of spore dispersal ?

50. Who are the amphibians of plant kingdom ? : 50. Who are the amphibians of plant kingdom ? bryophytes pteridophytes algae fungi

Zoooidogamy requires water in all bryophytes : Zoooidogamy requires water in all bryophytes

Slide 66 : Hit us at ….. bisbio.in