NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

21. All tissues consist of cells sentence was said by
  • Wallace

  • Virchow

  • Schleiden

  • None of these



Schleiden (1838) proposed cell theory and said, "all tissues consist of cell".


Which one of the following elements is almost non-essential for plants?

  • Ca

  • Mo

  • Zn

  • Na



Sodium and Iodine  are not required by most of the plants.

Sodium (Na) is required by very limited plants as it helps to concentrate carbon- dioxide, but mostly plants use a trace amount to produce metabolism.


In C4 plants, CO2 combines with

  • phosphoglyceric acid

  • ribulose diphosphate

  • phosphoenol pyruvate

  • phosphoglyceraldehyde


phosphoenol pyruvate

In C4 plants, CO2 is picked up by a 3-carbon compound Phosphoenol pyruvate (PEP) to form 4-carbon compound Oxaloacetic acid. This reaction is catalysed by PEP carboxylase and it takes place in the cytoplasm of mesophyll cells.


The red colour of 'red sea' is due to which of the following blue-green algae?

  • Chlamydomonas nivalis

  • Anabaena

  • Microcystis

  • Trichodesmium



Trichodesmium is a diazotroph, ie, it fixes atmospheric nitrogen into ammonium, a nutrient used by other organisms.

Red Sea looks reddish because of the presence of cyanobacteria Trichodesmium erythraeum which turns the normaly blue- green water a reddish- brown water.


Which is a typical example of 'feedback inhibition'?

  • Allosteric inhibition of hexokinase by glucose-6-phosphate

  • Reaction between succinic dehydrogenase and succinic acid

  • Cyanide and cytochrome reaction

  • Sulpha drugs and folic acid synthesizer bacteria


Allosteric inhibition of hexokinase by glucose-6-phosphate

Feedback inhibition is a form of enzyme regulation whereby products prevent product formation by binding to an allosteric site and inhibiting enzyme activity.


Mycorrhiza is correctly described as

  • symbiosis of algae and fungi

  • relation of ants with the stem of some trees

  • parasitic association between roots and some fungi

  • symbiotic relationship between fungi and roots of some higher plants


symbiotic relationship between fungi and roots of some higher plants

Mycorrhiza is a symbiotic association between a fungus and the roots of a vascular host plant (higher plants). It mainly refers to the role of the fungi in the plants rhizosphere, its root system.


Pneumatophores (respiratory roots) are found in

  • Pistia

  • Calobranchia

  • Rhizophora

  • All of these



Pneumatophores are the aerial roots that grow vertically upwards in swampy plants like rhizophora to obtain oxygen as swampy plants are constantly submerged under water. Their main function is respiration, hence, they are also called as respiratory roots.


Now-a-days cornea transplantation is very popular. The reason is that it

  • is easy to preserve

  • transplanted very easily

  • can be easily obtained

  • does not link with blood supply and immune system


does not link with blood supply and immune system

Cornea transplantation is very popular these days because the cornea has no blood supply, so it is away from the immune system of the body.


The part of mushroom comes out from soil is called

  • basidiocarp

  • ascogonium

  • ascocarp

  • pericarp



Basidiocarp is the part of mushroom that comes out from soil.

Ascogonium is a female reproductive body in some ascomycetous fungi from which asci are produced.

Ascocarp is the fruiting body (sporocarp) of an ascomycete Phylum fungus. It consists of very tightly interwoven hyphae and may contain millions of asci, each of which typically contains four to eight ascospores.

Pericarp is the part of a fruit formed from the wall of the ripened ovary.


Maximum absorption of light occurs in the region of

  • 400 - 700 nm

  • 700 - 900 nm

  • 1000 - 1200 nm

  • 1500 - 2000 nm


400 - 700 nm

Wavelengths shorter than 380 nm have too much energy which can disrupt the molecular organisation of cell; wavelength longer than 750 nm do not have energy to raise an electron to a higher orbital.