Biology:2012:CBSE:[Delhi ]:Set-III
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Q1
Mention the difference between spermiogenesis and spermiation.
Marks:1View AnswerAnswer:
Spermiogenesis
Spermiation
It is the process of maturation of spermatids into motile spermatozoa
It is the process of releasing spermatozoa from sertoli cells of seminiferous tubules.
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Q2
A garden pea plant (A) produced inflated yellow pod, and another plant (B) of the same species produced constricted green pods. Identify the dominant trait.
Marks:1View AnswerAnswer:
Dominant
Recessive
Pod Colour
Green
Yellow
Pod Shape
Inflated
Constricted
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Q3
What is an interaction called when an orchid grows on a mango plant?
Marks:1View AnswerAnswer:
When an orchid grows on a mango plant the interaction is called commensalism.
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Q4
Write the names of two semi-dwarf and high yielding rice varieties developed in India after 1966.
Marks:1View AnswerAnswer:
Jaya and Ratna are the two semi-dwarf and high yield rice varieties developed in India after 1966.
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Q5
Write what do phytophagous insects feed on.
Marks:1View AnswerAnswer:
Phytophagous insects feed on plant sap and parts of plants.
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Q6
Mention the unique feature with respect to flowering and fruiting in bamboo species.
Marks:1View AnswerAnswer:
Bamboo species flower only once in their life time and die after producing large number of fruits.
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Q7
How does smoking tobacco in human lead to oxygen deficiency in their body?
Marks:1View AnswerAnswer:
Smoking tobacco increases carbon monoxide content in blood that bind to haemoglobin and reduces concentration of haembound oxygen. This causes oxygen deficiency in the body.
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Q8
State the significance of biochemical similarities amongst diverse organism in evolution.
Marks:1View AnswerAnswer:
Biochemicals are molecules such as DNA, RNA, proteins, etc. found in living organisms. Similarities in biochemical molecules such as DNA, help in deriving the line of evolution. Organisms with similar DNA sequences are considered close relatives or have evolved from the common ancestor.
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Q9
Explain the work carried out by Cohen and Boyer that contributed immensely in biotechnology.
Marks:2View AnswerAnswer:
Cohen and Boyer carried out one of the first genetic engineering experiments. They invented the technique of DNA cloning. Cohen developed a method of removing plasmids from the cell and then reintroducing them in other cells. Merging this process with that of DNA splicing enabled Boyer and Cohen to recombine segments of DNA in desired configurations and insert the DNA in bacterial cells, which could then act as manufacturing plants for specific proteins.
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Q10
(a) State the difference between meiocyte and gamete with respect to chromosome number.
(b) Why is a whiptail lizard referred to as parthenogenetic?Marks:2View AnswerAnswer:
(a) The gamete contains haploid(n) set of chromosomes while the meiocyte contains a diploid(2n) set.
(b) The process of reproduction without fertilisation is called parthenogenesis. Whiptail lizard is parthenogenetic because its unfertilised eggs develop into a new individuals.
