There are several types of enzyme catalysed reactions. In one type of enzyme catalysed reaction, in addition to the catalytic site to which the substrate (X) binds, the enzyme also has a site to which some other substance (Y) can bind. When Y binds to such an enzyme, the enzyme can still bind to the substrate but cannot convert it to the product. Which of the following will occur in such a case?

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There are several types of enzyme catalysed reactions. In
one type of enzyme catalysed reaction, in addition to the
catalytic site to which the substrate (X) binds, the enzyme
also has a site to which some other substance (Y) can bind.
When Y binds to such an enzyme, the enzyme can still bind
to the substrate but cannot convert it to the product. Which
of the following will occur in such a case?

Anonymous User tag : Biology 18 Apr, 2020 1 Answer 63 views



During the growth of marine fish, initially, yolk sac and skin are the principal sites where transport protein ‘x’ is located. Later, skin and gills become principal sites and finally ‘x’ becomes localised to gills. The protein ‘x’ is

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During the growth of marine fish, initially, yolk sac and skin are the principal sites where transport protein ‘x’ is located. Later, skin and gills become principal sites and finally ‘x’ becomes localised to gills. The protein ‘x’ is

Anonymous User tag : Biology 18 Apr, 2020 1 Answer 58 views















































































































































Select the statement which explains best parasitism. (a) One organism is benefited. (b) Both the organisms are benefited. (c) One organism is benefited, other is not affected. (d) One organism is benefited, other is affected.

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 Select the statement which explains best parasitism.
(a) One organism is benefited.
(b) Both the organisms are benefited.
(c) One organism is benefited, other is not affected.
(d) One organism is benefited, other is affected.

Anonymous User tag : Biology Organisms and Populations 16 Mar, 2020 1 Answer 59 views






Write a short note on (a) Adaptations of desert plants and animals (b) Adaptations of plants to water scarcity (c) Behavioural adaptations in animals (d) Importance of light to plants (e) Effect of temperature or water scarcity and the adaptations of animals.

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Write a short note on
(a) Adaptations of desert plants and animals
(b) Adaptations of plants to water scarcity
(c) Behavioural adaptations in animals
(d) Importance of light to plants
(e) Effect of temperature or water scarcity and the adaptations of animals.

Anonymous User tag : Biology Organisms and Populations 16 Mar, 2020 1 Answer 65 views





















Crystals of Bt toxin produced by some bacteria do not kill the bacteria themselves because − (a) bacteria are resistant to the toxin (b) toxin is immature: (c) toxin is inactive: (d) bacteria encloses toxin in a special sac.

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Crystals of Bt toxin produced by some bacteria do not kill the bacteria themselves because −
(a) bacteria are resistant to the toxin
(b) toxin is immature:
(c) toxin is inactive:
(d) bacteria encloses toxin in a special sac.

Anonymous User tag : Biology Biotechnology and its Applications 15 Mar, 2020 1 Answer 62 views




Three water samples namely river water, untreated sewage water and secondary effluent discharged from a sewage treatment plant were subjected to BOD test. The samples were labelled A, B and C; but the laboratory attendant did not note which was which. The BOD values of the three samples A, B and C were recorded as 20mg/L, 8mg/L and 400mg/L, respectively. Which sample of the water is most polluted? Can you assign the correct label to each assuming the river water is relatively clean?

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Three water samples namely river water, untreated sewage water and secondary effluent discharged from a sewage treatment plant were subjected to BOD test. The samples were labelled A, B and C; but the laboratory attendant did not note which was which. The BOD values of the three samples A, B and C were recorded as 20mg/L, 8mg/L and 400mg/L, respectively. Which sample of the water is most polluted? Can you assign the correct label to each assuming the river water is relatively clean?

Anonymous User tag : Biology Microbes in Human Welfare 14 Mar, 2020 1 Answer 57 views










Bacteria cannot be seen with the naked eyes, but these can be seen with the help of a microscope. If you have to carry a sample from your home to your biology laboratory to demonstrate the presence of microbes under a microscope, which sample would you carry and why?

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 Bacteria cannot be seen with the naked eyes, but these can be seen with the help of a microscope. If you have to carry a sample from your home to your biology laboratory to demonstrate the presence of microbes under a microscope, which sample would you carry and why?

Anonymous User tag : Biology Microbes in Human Welfare 14 Mar, 2020 1 Answer 54 views



















AIDS (Acquired Immuno Deficiency Syndrome) is caused by the human immunodeficiency virus (HIV) via sexual or blood-blood contact. After entering the human body, the HIV virus attacks and enters the macrophages. Inside the macrophages, the RNA of the virus replicates with the help of enzyme reverse transcriptase and gives rise to viral DNA. Then, this viral DNA incorporates into the host DNA and directs the synthesis of virus particles. At the same time, HIV enters helper T- lymphocytes. It replicates and produces viral progeny there. These newly formed progeny viruses get released into the blood, attacking other healthy helper T- lymphocytes in the body. As a result, the number of T-lymphocytes in the body of an infected person decreases progressively, thereby decreasing the immunity of a person.

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AIDS (Acquired Immuno Deficiency Syndrome) is caused by the human immunodeficiency virus (HIV) via sexual or blood-blood contact. After entering the human body, the HIV virus attacks and enters the macrophages. Inside the macrophages, the RNA of the virus replicates with the help of enzyme reverse transcriptase and gives rise to viral DNA. Then, this viral DNA incorporates into the host DNA and directs the synthesis of virus particles. At the same time, HIV enters helper T- lymphocytes. It replicates and produces viral progeny there. These newly formed progeny viruses get released into the blood, attacking other healthy helper T- lymphocytes in the body. As a result, the number of T-lymphocytes in the body of an infected person decreases progressively, thereby decreasing the immunity of a person.

Anonymous User tag : Biology Human Health and Disease 07 Mar, 2020 0 Answer 57 views













































When a cross in made between tall plants with yellow seeds (TtYy) and tall plant with green seed (TtYy), what proportions of phenotype in the offspring could be expected to be (a) Tall and green. (b) Dwarf and green.

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When a cross in made between tall plants with yellow seeds (TtYy) and tall plant with
green seed (TtYy), what proportions of phenotype in the offspring could be expected to be
(a) Tall and green.
(b) Dwarf and green.

Anonymous User tag : Biology Principles of Inheritance and Variation 01 Mar, 2020 1 Answer 56 views







Correct the following statements: (a) Surgical methods of contraception prevent gamete formation. (b) All sexually transmitted diseases are completely curable. (c) Oral pills are very popular contraceptives among the rural women. (d) In E. T. techniques, embryos are always transferred into the uterus.

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Correct the following statements:
(a) Surgical methods of contraception prevent gamete formation.
(b) All sexually transmitted diseases are completely curable.
(c) Oral pills are very popular contraceptives among the rural women.
(d) In E. T. techniques, embryos are always transferred into the uterus.

Anonymous User tag : Biology Human Reproduction 29 Feb, 2020 1 Answer 58 views

State True/False with explanation

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(a) Abortions could happen spontaneously too. (True/False)
(b) Infertility is defined as the inability to produce a viable offspring and is always due to abnormalities/defects in the female partner. (True/False)
(c) Complete lactation could help as a natural method of contraception. (True/False)
(d) Creating awareness about sex related aspects is an effective method to improve reproductive health of the people. (True/False)

Anonymous User tag : Biology Reproductive Health 29 Feb, 2020 1 Answer 54 views












How many eggs are released by a human ovary in a month? How many eggs do you think would have been released if the mother gave birth to identical twins? Would your answer change if the twins born were fraternal?

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How many eggs are released by a human ovary in a month? How many eggs do you think would have been released if the mother gave birth to identical twins? Would your answer change if the twins born were fraternal?

Anonymous User tag : Biology Human Reproduction 27 Feb, 2020 1 Answer 78 views




Identify True/False statements. Correct each false statement to make it true

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 Identify True/False statements. Correct each false statement to make it true.
(a) Androgens are produced by Sertoli cells. (True/False)
(b) Spermatozoa get nutrition from Sertoli cells. (True/False)
(c) Leydig cells are found in ovary. (True/False)
(d) Leydig cells synthesise androgens. (True/False)
(e) Oogenesis takes place in corpus luteum. (True/False)
(f) Menstrual cycle ceases during pregnancy. (True/False)
(g) Presence or absence of hymen is not a reliable indicator of virginity or sexual experience. (True/False)

Anonymous User tag : Biology Human Reproduction 27 Feb, 2020 1 Answer 56 views

















































yellow dust appears on the fingers, whenever we touch the middle of a flower. These tiny yellow grains are one of the most precious substances in nature because they contain the secret of plant life. What is this dust called?

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yellow dust appears on the fingers, whenever we touch the middle of a flower. These tiny yellow grains are one of the most precious substances in nature because they contain the secret of plant life.  What is this dust called?

Anonymous User tag : Biology 09 Feb, 2020 1 Answer 70 views