Subject

Biology

Class

NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

21.

Assertion : Persons suffering from haemophilia fail to produce blood clotting factor VIII.

Reason : Prothrombin producing platelets in such persons are found in very low concentration

  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion

  • If both Assertion and Reason are true but the Reason is not the correct explanation of the assertion

  • If Assertion is true but Reason is false

  • If both Assertion and Reason are false


22.

Assertion : Mitochondria and chloroplasts are semi-autonomous organelles.

Reason : They are formed by division of pre-existing organelles as well as contain DNA but lack protein synthesizing machinery.

  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion

  • If both Assertion and Reason are true but the Reason is not the correct explanation of the assertion

  • If Assertion is true but Reason is false

  • If both Assertion and Reason are false


23.

Assertion : The fungi are widespread in distribution and they even live on or inside other plants and animals.

Reason : Fungi are able to grow anywhere on land, water or on other organisms because they have a variety of pigments, including chlorophyll, carotenoids, fucooxanthin and phycoerythrin.

  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion

  • If both Assertion and Reason are true but the Reason is not the correct explanation of the assertion

  • If Assertion is true but Reason is false

  • If both Assertion and Reason are false


24.

Assertion : C4 photosynthetic pathway is more efficient than the C3 pathway.

Reason : Photorespiration is suppressed in Cplants.

  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion

  • If both Assertion and Reason are true but the Reason is not the correct explanation of the assertion

  • If Assertion is true but Reason is false

  • If both Assertion and Reason are false


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25.

Assertion : The atmospheric concentration of CO2 at which photosynthesis just compensates for respiration is referred to as CO2 compensation point. 

Reason : The CO2 compensation point is reached when the amount of CO2 uptake is less than that generated through respiration because the level of CO, in the atmosphere is more than that required for achieving CO2 compensation point.

  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion

  • If both Assertion and Reason are true but the Reason is not the correct explanation of the assertion

  • If Assertion is true but Reason is false

  • If both Assertion and Reason are false


26.

Assertion : The duck-billed Platypus and the spiny ant-eater, both are egg-laying animals yet they are grouped under mammals.

Reason : Both of them have seven cervical vertebrae and 12 pairs of cranial nerves.

  • If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion

  • If both Assertion and Reason are true but the Reason is not the correct explanation of the assertion

  • If Assertion is true but Reason is false

  • If both Assertion and Reason are false


27.

Given below is a pedigree chart showing the inheritance ofa certain sex-linked trait in humans

The trait traced in the above pedigree chart is

  • dominant X- linked

  • recessive X- linked

  • dominant Y- linked

  • recessive Y- linked


28.

A cross section at the midpoint of the middle piece of a human sperm will show

  • centriole, mitochondria and 9 + 2 arrangement of microtubules

  • centriole and mitochondria

  • mitochondria and 9 + 2 arrangement of microtubules

  • 9 + 2 arrangement of microtubules only


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29.

Which one of the following is a correct statement?

  • "Bt" in "Bt-cotton" indicates that it is a genetically modified organism produced through biotechnology

  • Somatic hybridization involves fusion of two complete plant cells carrying desired genes.

  • The anticoagulant hirudin is being produced from transgenic Brassica napus seeds.

  • "Flavr Savr" variety of tomato has enhanced the production of ethylene which improves its taste.


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30.

An insect bite may result in inflammation of that spot. This is triggered by the alarm chemicals such as

  • histamine and dopamine

  • histamine and kinins

  • interferons and opsonin

  • interferons and histones


B.

histamine and kinins

Inflammation is a process by which body's immune system malfunctions. It is common to almost all diseases that involve microbiologic, chemical or physical injury to living tissues. Acute inflammation is a short term process occuring in response to tissue injury. Heat, Redness, Pain, swelling and loss of function are the cardinal signs. 

Histamine is stored in mast cell granules and basophils. It is released by inflammatory and immunologic stimuli. It plays an important role in acute inflammation, exerting a dilator action on arterioles, increasing the permeability of small venules to plasma proteins and causing pain by stimulating nociceptors. 

Plasma kinins such as bradykinin are not stored but are released by the action of kininogenase on plasma a,­ globulin. Bradykinin is a potent vasodilator, increasing small vein permeability and causing pain by stimulating peripheral nociceptors, but it has a short half-life.


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