An anther with malfunctioning tapetum often fails to produce viable male gametophytes. Give one reason.
The tapetum is the innermost layer of a microsporangium. It is found in a cluster of two in each lobe of the anther. It nourishes the pollen grains. If it malfunctions, then the pollen grains are provided with adequate nutrition. Hence, the anther is not able to produce mature viable male gametes.
RNAi is considered as an important technique of Biotechnology because:
1. This technique can be used to trace the function of a gene.
2. It can be used to discover new drugs which can suppress or enhance the expression of a gene or set of genes.
Diseases | Causal Organisms | Medium of transfer | Symptoms |
Ascariasis | Ascaris | Through contaminated waters, vegetables and fruits. | d |
Amoebiasis | a | House fly | Constipation, abdominal pain, cramps, stool with excess mucous and blood. |
Common Cold | b | Droplets from sneezing of infected persons. | Affect nose and respiratory passage, sore throat |
Pneumonia | Streptococcus- pneumoniae | c | Fever, chills, cough and headache. |
(c) By inhaling droplets released by an infected person or by sharing glasses and utensils with an infected person.
(d) Internal bleeding, muscular pain, fever, anemia and blockage of the passage intestinal.
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(a) Bone marrow
(b) B-lymphocytes migrate to the secondary lymphoid organs like spleen, lymph nodes, etc. T-lymphocytes migrate to thymus for their maturation.
B-lymphocytes produce antibodies and T-lymphocytes help B-cells in production of antibodies. Hence lymphocytes are involved in providing immunity to the body. | | |
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A species that has been introduced from another geographic region to an area outside its natural range is known as exotic species.
Their introduction into a particular geographical area leads to invasion by them. They spread very fast as there are no natural predators of the exotic species in the invaded area.For example the prickly pear cactus introduced into Australia caused havoc by rapidly spreading into vast areas of rangeland.
'Terror of Bengal' or water hyacinth introduced in Bengal has spread vastly choking most of the waterways.
In the adjacent figure of a typical dicot embryo, label the parts (1), (2) and (3). State the function of each of the labelled part.
(1) Plumule - The portion of an embryo that gives rise to the shoot system (as distinct from the root system) of a plants.
(2) Cotyledons - It involves in either storage or absorption of food reserves.
(3) Radicle – The portion of an embryo that gives rise to the root system of a plant.
(a) Mention the specific geographical region where these organisms are found.
(b) Name and explain the phenomenon that has resulted in the evolution of such diverse species in the region.
(c) Explain giving reasons the existence of placental wolf and Tasmanian wolf sharing the same habitat.
Below given are the process of manufacturing of two commercial products ‘X’ and ‘Y’ as directed by FAO from soy.
Examine the two flow charts (I and II) and answer the following questions:
Emma’s mother got eye bags around her eyes. She thought that harmful UV rays have affected her mother’s skin and this might symptomise skin cancer.
When she took her to the doctor, the doctor prescribed her a drug which was extracted from yeast strain.
Based on the given information, answer the following questions:
(i) Name the organism in which the vector shown is inserted to get the copies of the desired gene.
(ii) Mention the area labelled in the vector responsible for controlling the copy number of the inserted gene.
(iii) Name and explain the role of selectable marker in the vector shown.
Second amendment of the Indian Patents Bill will help Indian bio-resources as follows:
• It is in the area of genetically modified plants and seeds. Methods of agriculture and plants were excluded from patentability in the Indian patent act to ensure that seed can be held as a common property resource in the public domain and hence there will not be any violation of farmers' right to save, exchange and improve seed.
• It takes into consideration issues like exploitation of bio-resources and traditional knowledge related to bio-resources including patent terms, emergency provisions and research and development initiative.
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Study the population growth curve shown above.
(i) Identify curve 'a' and 'b'.
(ii) mention the conditions responsible for the curve 'a' and 'b' respectively.
(iii) Give the necessary equation for the curve 'b'.
How does radioactive pollution harm living organisms? Suggest ways to control radioactive pollution.
Radioactive substances can cause deleterious mutations in genes, impairment of various biological functions. In higher doses, these can cause immediate death of the organism.
Ways for controlling radioactive pollution:
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ª Banning the use of nuclear weapons.
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(a) A colour blind man marries a woman with normal vision whose father was colour blind. Work out a cross to demonstrate the genotype of the new couple and their future sons?(b) Answer the following questions with reference to the given pedigree.
i) Is the trait autosomal dominant, autosomal recessive or sex-linked? Justify your answer.
ii) Give the genotypes of the parents (individual 1 and 2).
iii) Give the genotype of the daughter in the first generation and the son and the daughters in the second generation.
(a) Since the father of the normal women is colour blind, her genotype will be XcX (carrier)
Colour blind man X Normal woman
XcY XcX
Gamete: Xc, Y Xc, X
Progeny: | Xc | Y |
X | XcX Normal (carrier)female | XY Normal male |
Xc | XcXc Colour Blind female | XcY Colour blind male |
50% of their sons will be colour blind.
(b) (i) The trait is sex linked (recessive) as it has appeared in male child in the first generation pointing at the possibility that the female parent is a carrier as his father is normal.
(ii) Genotype of individual 1 => Male => XY
Genotype of individual 2 => Female => XcX (Carrier)
(iii)
Genotype of individual 3 in generation I => XcY
Genotype of individual 4 in generation I => XcX
Genotype of individual 6 in generation II => XcX Genotype of individual 7 in generation II => XcXc
Study the following flow chart. Name the hormones involved at each stage. Explain their function.
Gonadotropin releasing hormone secreted by hypothalamus causes release of follicle stimulating hormone (FSH) and luteinizing hormone (LH) from pituitary.
• Luteinising hormone (LH) acts on the Leydig cells and stimulates synthesis and secretion of androgens.
• FSH acts on the sertoli cells and stimulates secretion of some factors which help in the process of spermiogenesis.
• Androgens(Testosterone) stimulate the process of spermatogenesis.
At oogonia- 46 chromosomes per cell
At primary oocyte- 23 chromosomes per cell
At secondary oocyte- 23 chromosomes per cell
The flow diagram above shows the correlation between the life phases of the individual with the states of the process.
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