Bihar Board 12th Biology Important Questions Short Answer Type Part 1

Bihar Board 12th Biology Important Questions Short Answer Type Part 1

BSEB 12th Biology Important Questions Short Answer Type Part 1

Question 1. Draw a well labelled diagram of a typical flower.
Answer:

Question 2. Draw a well labelled diagram of a pollen grain.
Answer:

Question 3. In algae and fungi which structure help in asexual reproduction.
Answer: Thallus in algae and spores in fungi help in asexual reproduction.

Question 4. What is double fertilization?
Answer: One male gamete fuses with egg to form zygote and another male nucleus fuses with polar nuclei. Hence male nuclei fuse double is called double fertilization.

Question 5. What is pollination by Bat?
Answer: Chiropterophily e.g. Kadam

Question 6. Describe different parts of Seed.
Answer: Seed Coat, embryo, endosperm and cotyledon.

Question 7. Which type of fruit develops from hypanthodium?
Answer: Syconus eg. Fig. Peepal.

Question 8. Why vegetative reproduction is also considered as a asexual reproduction?
Answer: Reproduction occurs by any part of body other than flower in plant is called asexual reproduction.

Question 9. What is law of Mendel?
Answer:

• Mendel took only those trait which did not show linkage interaction.
• Plan pea is ideal for controlled breeding.

Question 10. Name any two reasons for Mendel’s success.
Answer:

1. Mendel selected only pure breeding varieties of pea for his experiments.
2. Mendel took one or two characters at one time for his breeding experiments.

Question 11. What is genotypic and phenotypic ratio of monohybrid and dihybrid corss?
Answer:
Monohybrid cross:

• Phenotypic Ratio 3 : 1
• Genotypic Ratio 1 : 2 : 1

Dihybrid Cross:

• Phenotypic Ratio 9 : 3 : 3 : 1
• Genotypic Ratio 1 : 2 : 1 : 2 : 4 : 2 : 1 : 2 : 1

Question 12. What is Polyploidy?
Answer: Increase in number of chromosome or set of chromosomes is called polyploidy.

Question 13. What is multiple alleles?
Answer: It is present more than two alleles of a gene.

Question 14. What is difference between DNA and RNA.
Answer:

Character	DNA	RNA
1. Nitrogen Base	Thymine and cytosine Adenine & Guanine	Uracil and Cytosine Adenine and Guanine
2. Sugar	Deoxyribose Sugar	Ribose Sugar

Question 15. What are Okazaki fragments and what enzymes join them?
Answer: A small fragment of lagging strand of DNA that contains numerous nucleotides.
-DNA ligase join them.

Question 16. Define operon?
Answer: A group of genes making up a regulatory or control unit.

Question 17. What is reverse transcription?
Answer: RNA → DNA → RNA → Protein.

Question 18. Major function of gene.
Answer:

• Genetic information
• Replication

Question 19. AUGCCG is base sequence in mRNA write base sequence in DNA?
Answer: TACGGC

Question 20. What is Peptide Bond?
Answer: A bond between two amino acid is called peptide bond.

Question 21. What is main source of variation in gene pool?
Answer:

• Genetic drift
• gene migration.

Question 22. How the gene expression is carried out at translocation level.
Answer: Gene expression occurs by Repressible regulation/control or negative control and by positive control or inducible control processes.

Question 23. What are the terms given by Benzor for genes.
Answer: Cistron was given by Benzer.

Question 24. What is tissue culture?
Answer: It is a technique of maintaining and growing plant cells, tissue or organs especially on artificial medium in suitable containers under control environmental conditions.

Question 25. Name some genetically engineered crop plants.
Answer:

• Bt Cotton
• Golden rice
• Transgenic Tobacco
• Flaur Saure

Question 26. What is Apiculture and Sericulture.
Answer:
Apiculture – It is rearing of honey bees for obtaining honey and bee wax.
Sericulture – It is an art for breeding of Silk Worm to produce Silk.

Question 27. What is Special about Bacillus Thuringiensis?
Answer: Bacillus thuringiensis is a soil bacterium that produces cry protein which kill certain insects.

Question 28. What do you mean by Biopiracy?
Answer: Some organizations and multinational companies exploit and patent biological resources of other nation without proper authorisation is called Biopiracy.

Question 29. What is role of Bacillus thuringiensis?
Answer: Bacillus thuringiensis produces cry protein which is lethal to pest.

Question 30. What is gene therapy?
Answer: Technique of genetic engineering to replace a family gene by a normal healthy functional gene.

Question 31. What is Vaccines?
Answer: Vaccines are preparation of extract of dead which on evoculation into a healthy person provide temporary or permanent active or passive immunity by inducing antibody formation.

Question 32. Name same antibiotics produced by Microorganisms?
Answer: Penicillin, Neomycin, Streptomycin, Tetracyclines. Terramycin, Erythromycin etc.

Question 33. What is isolation of genetic material?
Answer: Finding out of DNA molecule from the desired cells with Lysozyme or Cellulase or Chitinase.

Question 34. What is difference between transformation and transduction?
Answer:

• Transformation – Change in the genetic constitution of an organism by picking up genes present in the medium.
• Transduction – Change in genetic constitution of an organism through reproduction with Virus.

Question 35. What is function of Restriction endonuclease and Ligase?
Answer:

• Restriction Endonuclease – It cleave DNA duplex at any point except end.
• Ligase – Bind Vector DNA segment with the DNA of desired cells.

Question 36. Give the name of same antibiotics.
Answer: Penicillin, Neomycin, Streptomycin, Tetracyclines, Terramycin.

Question 37. Give the name of four antibiotics producing organisms.
Answer:

1. Penicillium notatum
2. Penicillium chrysogenum
3. Streptomyces noursei
4. Streptomyces griseus.

Question 38. What is difference between Cybrid and Hybrid?
Answer:
Cybrid – One nucleus of one cells persist and cytoplasm of both cell fused.
Hybrid – Nucleus of both cells with cytoplasm fused.

Question 39. What is retrovirus?
Answer: It is RNA Containing virus showing reverse transcription, i.e. HIV Virus.

Question 40. What is DNA Probe?
Answer: It is single stranded piece of DNA.

Question 41. What do you mean by the term in Vitro and in Vivo experiments?
Answer:
In Vitro – Experiment conducted in lab.
In Vivo – Experiment conducted in natural condition.

Question 42. How a recombinant DNA is formed by the help of genetic engineering?
Answer: It is formed by recombinant DNA technology.

Question 43. What is DNA Primer?
Answer: It is the synthetic small segment of DNA which is complementary to the specific segment of a DNA.

Question 44. Give the name of natural polymer which is extracted from seaweed (Sea Algae).
Answer: Agar.

Question 45. DNA and proteins are macromolecules which among the two is bigger and how?
Answer: DNA is bigger than proteins because protein is produced by coding strand of DNA.

Question 46. What is Symbiosis? Name two types of Symbiosis.
Answer:
It is relationship between two living individuals of different species in which either both species are benefitted.

• Mutualism – Both benefitted
• Commensalism – One benefitted but other neither benefitted nor harmed.

Question 47. Name the types of ecological pyramid.
Answer:

1. Pyramid of number
2. Pyramid of Biomass
3. Pyramid of Energy

Question 48. What is biotic component of Ecosystem?
Answer:
(a) Producer
(b) Consumers
(c) Decomposer.

Question 49. Why are the testes of human male considered extra abdominal?
Answer: The human testes lie in scrotum out side the body cavity.

Question 50. Define ovulation? On which day it occur in a menstrual cycle?
Answer: Ovulation is expulsion of ovum from ovary. It takes place on 14th day of mensuration.

Question 51. What is difference between spermatogenesis and Oogenesis?
Answer: Spermatogenesis – It gives rise to sperm.
Oogenesis – It is polar bodies formed which are not formed during spermatogenesis.

Question 52. Name the Chemicals released by the acrosome during fertilization.
Answer: Spenrtlysin is secreated by acrosome during fertilization.

Question 53. Differentiate between trophectoderm and ectoderm.
Answer: Trophoecotoderm – It is outer cellular envelop of Blasto Cyst where an ectoderm is the outermost cellular type of gastrula.

Question 54. Name the hormone secreted by human placenta.
Answer: (a) Oestrogen, HCG, Human Chorionic gonadotropin.

Question 55. What is Colostrum?
Answer: It is the first milk that comes from the mammary glands of the mother just after childbirth for 2 – 3 days.

Question 56. Difference between Vasectomy and tubectomy.
Answer:
Vasectomy – Sterilization procedure in the male in called Vasectomy.
Tubectomy – Sterilization procedure in the female is called tubectomy.

Question 57. Name the devices which are used under the barrier method of contraception.
Answer:

• Condom
• Diaphragm
• Cervicalcap and
• Vaults.

Question 58. Name any four STD’s disease with their causal agents.
Answer:

Disesase	Causative agent
1. Syphilis	Treponema Pattidum
2. AIDS	HIV
3. Hepatitis	Hepatitis B virus (HBV)
4. Gonorrhoea	Neisseria gonorrhoea

Question 59. Comment upon genetic equilibrium.
Answer: Total genes and their alleles in a population (Gene pool) remain constant called genetic equilibrium.

Question 60. Write main points of Lamarckism.
Answer:

• Due to internal force, living things continuously increased.
• Effect of environment results new needs that produce new structure.
• Inheritance of acquired characters.

Question 61. Differentiate between homology and analogy.
Answer:
Homology – It is study of entier relationship of homologous structure.
Analogy – It is study of analogous structure.

Question 62. Name four living fossils.
Answer:

1. Limulus
2. Latimeria
3. Gingko biloba
4. Cycas.

Question 63. Name Two features of Australopithecus.
Answer: It was about 1.5 meter in height. It was with bipedal locomotion, omnivorous diet and had erect posture. It had human like teeth and had erect posture.

Question 64. Comment upon H.M.S. Beagle.
Answer: In 1831 Darwin got an opportunity to travel on H.M.S. Beagle ship in which Charles Darvin sailed around the world.

Question 65. Differenciate between convergent and divergent evolution.
Answer: Divergent Evolution – Development of different functional structural from a common form.
Convergent Evolution – Development of similar adaptive functional structure in unrelated group of organism.

Question 66. Mention two evidences of organic evolution.
Answer: The evidence of organic evolution comes from the study of homology and analogy of organs and palaeontology.

Question 67. Which is responsible for sex determination in chick-sperm or ovum.
Answer: Ovum is responsible for sex determination in chick because female produces two types of gamete where one male produces same type of sperm.

Question 68. What is Sickle-Cell anaemia.
Answer: Sickle Cell anaemia is an autosomal hereditary disorder in which erythrocytes become sickle shaped under oxygen deficiency.

Question 69. What is bioinformatics?
Answer: It is the science concerned with development and application of computer hardware and software to the analysis.

Question 70. What is repetitive DNA?
Answer: It is the DNA having multiple copies of identical sequence of nitrogen base.

Question 71. Explain Chiru?
Answer: Antilope is called Chiru.

Question 72. Name four indigenous Cow.
Answer:

1. Sahiwal
2. Red Sindhi and
3. Gir.

Question 73. What is neurosis?
Answer: It is a kind of mental disease of Maladaptive state.

Question 74. Enumerate the symptoms of syphilis.
Answer:

• Initially a red painless ulcer appears at the site of infection (eg. Penis, Vagena and Cervix).
• In late, fever, lymph node, pink skin all over the body and joint pain.

Question 75. What is opsonization?
Answer: It is process of identifying pathogen by phagocyte.

Question 76. What do you mean by cellular immunity?
Answer: The immunity obtained by lymphocyte is called cell immunity.

Question 77. Name four Indian Common Carp.
Answer:

1. Rohu (Labeo rohita)
2. Catla (Catla Catla)
3. Mangur (Clarias batrachus)
4. Calbasu (Labeo Calbasu).

Question 78. Name four types of Silk.
Answer:

1. Mulberry Silk
2. Tasar Silk
3. Moonga Silk
4. Arandi Silk.

Question 79. What is artificial insemination?
Answer: It is the technique of transfer of siemens of male into the reproductive tract of female invitro.

Question 80. What is inbreeding?
Answer: It is the process of reproduction among similar animals of a species for obtaining pure line.

Question 81. What birds are use for poultry farming.
Answer:

• Chicken
• Sturkeys
• Ducks
• Gees Swans
• Fowls
• Pigeons.

Question 82. Name four carcinogens.
Answer:
(A) Radiation i.e.

• X-ray
• U. V. rays
• Cosmic rays

(B) Tumour Viruses
(C) Mustard gas.

Question 83. Differentiate between population and community.
Answer:
Population – It is a group of individuals of a single species found in an area.
Community – It is a group of different species found in an area.

Question 84. Enumerate any four characteristics of population.
Answer:

1. Birth rate
2. Death rate
3. Age distribution
4. Population Size.

Question 85. Discuss about Sarcoma?
Answer: These cancers are located in connective and muscular tissues derived from mesoderm.

Question 86. Differentiate between hibernation and aestivation. Give one example of each.
Answer:
(A) Hibernation – It is winter sleep in which animal passes the winter period in dormant condition.
(B) Aestivation – It is summer sleep.

Question 87. Mention any two adaptation found in organisms of desert.
Answer:

• Devices developed to reduce water loss so that leaves modified into Spines and Stem becomes succulent.
• C₄ Photosynthesis mechanism develops.

Question 88. Construct grazing food chain.
Answer: Grass → Grasshopper → Frog → Snake → Hawk.

Question 89. Distinguish between primary and Secondary productivity.
Answer:
Primary productivity – Rate of synthesis of organic matter by producer.
Secondary productivity – Rate of synthesis by organic matter by consumers.

Question 90. Constant pyramid of number of grassland ecosystem.
Answer: Pyramid of number of grassland Ecosystem

Question 91. Distinguish between primary succession and secondary succession.
Answer:
Primary succession – It occurs in an area which has been bare where soil is absent.
Secondary succession – It occurs in an area which have developed recently where soil is present on substratum.

Question 92. Describe two factors for loss of biodiversity.
Answer:

1. Habit fragmentation or loss.
2. Overexploitation of biodiversity.

Question 93. What is red data Book.
Answer: Red data Book in a catalogue at taxa facing risk of extinction.

Question 94. Differentiate between the following:
(i) Asexual and sexual reproduction.
(ii) Binary fission and multiple fission.
(iii) Primary and secondary sex organs.
Answer:
(i) Asexual and sexual reproduction:

Asexual reproduction	Sexual reproduction
1. Always uniparental.	1. Generally biparental except Taenia, Fasciola.
2. No gametes are involved.	2. Male and female gametes are involved.
3. Only mitotic divisions takes place.	3. Meiosis occurs at gametogenesis. Mitosis occurs after fertilization.
4. Somatic cells are involved.	4. Germ cells are involved.
5. Offsprings are genetically identical to the parent.	5. Offsprings are genetically different from the parent.

(ii) Binary fission and multiple fission:

(iii) Primary and secondary sex organs:

Primary sex organs	Secondary sex organs
1. These form the gametes.	1. These help in conduction of gametes
2. They secrete sex hormones.	2. They do not secrete sex hormones.
3. Their growth, maintenance and functions are controlled by gonad tropins of anterior pituitary.	3.  Their growth, maintenance and functions are controlled by sex hormones secreted by gonads.

Question 95. How is polyspermy prevented?
Answer: During the process of egg sperm binding, the egg becomes activated and undergoes depolarization of its membrane. The egg exhibits cortical reaction and shows zona reaction, which makes the egg impervious to any second sperm. This is how polyspermy, the entry of more than one sperm into the ovum is prevented.

Question 96. How does the transmission of malaria and Pneumonia take places?
Answer:
Malaria is transmitted by female Anopheles mosquito.
Pneumonia is transmitted thourgh deplophatical Pneumonia bacteria.

Question 97. How is milk production hormonally regulated?
Answer: Colostrum is rich in calories and protein. Its synthesis is stimulated by the pituitary hormone prolactin (PRL). Its release is stimulated by a rise in the level of oxytocin when baby begins nursing. Milk contains an inhibitory peptide. If the breasts are not fully emptied, the peptide accumulates and inhibits milk production. This autrorine action, thus, matches supply with demand.

Question 98. What is the significance of crossing over?
Answer: Crossing over provides a proof for the linear arrangement of genes. New gene combinations are produced due to change in coursing over. It has led to the construction of linkage maps or genetic maps of the chromosomes.

Question 99. Mention three advantages of sexual reproduction.
Answer: Sexual reproduction is the process of union of male and female gametes mostly morphologically and physiologically distinct the process is advantageous in the aspect that:

• The haploid gametes unite and the chromosome number of the species is restored.
• Variations are produced in the off-springs.
• Off-springs are better adapted to environmental conditions.

Question 100. Give an account of accessory or secondary glands in a mammalian male reproductive system.
Answer: Secondary glands include a prostate two seminal vesicles and two Cowper’s gland. The prostate is located around the first part of the urethra and secretes its fluid into the urethra walls. These secretion enters the vas deferens through their ducts. Cowper’s gland are situated below the bladder are behind the urethra. Their secretion enters the urethra through their ducts.

Question 101. What was Darwin view on his visit to Galapagos Islands.
Answer: In Galapagos Islands, Darwin observed amazing diversity of creatures. A small black bird called finches amazed him. He realised that there were many varieties of finches within the same island. All the varieties, he conjectured, evolved on the island itself. From the original seed eating features, many other forms with altered beaks arose, enabling then to become insectivorous and vegetarian finches. This process of revolution is regarded as adaptive radiation.

Question 102. What was the contribution of Lamarch for the evolution of life forms?
Answer: Lamarch a French naturalist has said that evolution of life forms had occurred but driven by use and disuse of organs. For example, giraffes who in an attempt to forage leaves on tall trees had to adopt by elongation of their necks. As time passed, this acquired character of elongated neck passed to succeeding generations. Giraffes slowly, over the years, came to acquire long necks!

Question 103. Define cleaning. What are its advantages?
Answer: The production of one individual organism or a group of organisms of identical genotype or cells that have been derived from a single parental organism or cell. Cloning is of two types: gene cloning and organism cloning.

Cloning is very beneficial in DNA fingerprinting. DNA-probe, gene therapy and genetic engineering.

Question 104. What is therapeutic cloning? Write its some uses?
Answer: Therapeutic cloning is used to repair damaged tissues and diseased organs. Its uses are:

• In the production of cloned embryos and harvesting of their stem cells to repair damaged or defective tissue in the DNA donor.
• Human embryonic cells can be transformed into insulin producing cells
• Mature nerve cells can be created from human embryonic stem cells
• Human embryos can be created from stem cells through cloning.

Question 105. What is genetic engineering?
Answer: Genetic engineering is the science which deals with the synthesis of artificial genes, repair of genes, combining of genes from two organisms (recombinant DNA) and manipulation of the artificial genes for improvement of living beings.

Question 106. What is difference between the nucleoside and nucleotides?
Answer:
Nucleoside – A purine or pyrimidine base that is attached to a deoxyribose sugar.
Nucleotide – A phosphoric ester of nucleoside.

Question 107. How antibiotics are produced? What are their properties?
Answer: Antibiotics are produced by lichens, fungi, actinomycetes and eubacteria. According to their effect they may be specific antibiotics or broad spectrum antibiotics. They have following properties:

• The antibiotic should be able to destroy all the strains of the parasite,
• It should not produce any allergic reactions or toxic to the host,
• The antibiotic should not be harmful to natural and useful microbial flora of the host.
• Is should have broad spectrum application beside being specific for a particular pathogen.
• Antibiotics kill the pathogen by breaking a vital link in the metabolism of the pathogen.

Question 108. Which steps are involved in genetic engineering?
Answer: Genetic engineering process has several steps:

• Gene isolation – The desired gene is cut with restriction enzymes and joined by ligases to host DNA.
• Synthesis of gene – The nucleotides are synthesized chemically.
• Transformation – The DNA is incorporated into genome of a cell.
• Transduction – The DNA is carried from a donor bacterium to a recipient bacterium with the help of bacteriophages. It results in changing the recipient’s genotype.
• Gene cloning – It is a technique for producing new combination of genetic material in bacterial cells. The DNA is inserted in the vector, where it produces copies of itself.

Question 109. Define biotechnology.
Answer: According to EFB (European Federation of Biotechnology) “Biotechnology is the integrated use of biochemistry, microbiology and engineering sciences in order to achieve technological application of the capabilities of micro-organisms, cultured tissues/cells and parts their of.”