Subject

Biology

Class

NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

1.

Fruit ripening is promoted by the hormone that also

  • promotes thinning of fruits in cherry and walnut

  • induce parthenocarpy in tomato

  • promote flowering in lemma

  • induce dormancy


A.

promotes thinning of fruits in cherry and walnut

Ethylene is the hormone that promotes fruit ripening. It also promoted thinning of fruits in cherry, cotton and walnut. It is a gaseous hormones, i.e. a gas that forms through the breakdown of methionine, which is in all cells. It is produced at a faster rate in rapidly growing and dividing cells, especially in darkness.


2.

All given statements regarding cymose inflorescence are correct except

  • main axis terminate in a flower

  • development of flowers is basipetal

  • opening of flowers is centrifugal

  • unlimited growth of axis


D.

unlimited growth of axis

Cymose inflorescence is a definite inflorescence. In this a type of flowering shoot in wichh the first- formed flower develops from the growing region at the top of the flower stalk. The main axis terminates in a flower, hence is limited in growth. The development of flowers is basipetal and opening of flowers is centrifugal, e.g. Datura, Atropa, etc.


3.

A plant cell is placed in a solution whose solute concentration is twice as great as the concentration of the cell cytoplasm. The plasma membrance is selectively permeable, allowing water but not solutes to pass through. What will happen to the cell?

  • The cell will swell because of endosmosis

  • The cell will shrivel because of exosmosis

  • The cell will shrivel because of active transport of water

  • No change will occur because of hard impervious cell wall present


B.

The cell will shrivel because of exosmosis

The cell will shrivel because of exosmosis. Exosmosis will occur as the concentration inside the cell is half than outside, hence, water will move from the cytoplasm to the surrounding medium causing the cell to shrivel.


4.

The leaves of some plants contain crystals of calcium carbonate in epidermal cells, giving appearance that of bunch of grapes are called

  • cystoliths

  • sphaeraphides

  • raphides

  • otoliths


A.

cystoliths

Cystoliths are the clusters of crystal of calcium carbonate found in leaves of member belonging to families such as Acanthaceae, Cucurbitaceae, Urticaceae, Banyan leaf, etc. They give an appearence of grapes hanging from a stalk, attached to cell wall.

Sphaeraphides is the aggregation of crystals of calcium oxalate.

Raphides are needle shaped crystals of calcium oxalate occurring in bundles.

Otoliths is granule of calcium carbonate in vertebrates's inner ear.


5.

Statement I:- α-ketoglutarate dehydrogenase catalyses the conversion of oxalosuccinic acid to α-ketoglutarate.

Statement II:- This reaction is accompained with release of CO2.

Choose the correct option.

  • Statement I is correct and statement II is incorrect

  • Statement II is correct and statement I is incorrect

  • Both statements correct

  • Both statements incorrect


B.

Statement II is correct and statement I is incorrect

α- ketoglutarate dehydrogenase catalyses conversion of α-ketoglutarate acid, i.e. a 5C compound to 4C Succinyl Co-A. The reaction is as follows


6.

Match the following electron transport chain (ETC) inhibitors with their mode of action.

Column I Column II
A. Dinitrophenol (2,4- DNP) 1. Electron flow from cyt a3 to O2
B. Cyanide 2. Direct electrons from Co-Q to O2
C. Antimycin-A 3. Electron flow from NADH/FADH2 to Co- Q
D. Rotenone 4. Electron flow from Cyt- b to Cyt- c

  • A - 2; B - 4; C - 1; D - 3

  • A - 2; B - 1; C - 4; D - 3

  • A - 3; B - 4; C - 1; D - 2

  • A - 1; B - 2; C - 3; D - 4


A.

A - 2; B - 4; C - 1; D - 3

Column I Column II
A. Dinitrophenol (2,4- DNP) 2. Direct electrons from Co-Q to O2
B. Cyanide 4. Electron flow from Cyt- b to Cyt- c
C. Antimycin-A 1. Electron flow from cyt a3 to O2
D. Rotenone 3.  Electron flow from NADH/FADH2 to Co- Q

7.

The name of this class is based on sexual structure as the site of karyogamy and meiosis in

  • Phycomyctes and Actinomycetes

  • Deuteromycetes and Zygomycetes

  • Ascomycetes and Basidiomycetes

  • Basidiomycetes and Actinomycetes


C.

Ascomycetes and Basidiomycetes

Ascomycetes and Basidiomycetes is based on sexual structure as the site of karyogamy and meiosis. Together they form the sub-kingdom - Dikarya.

Ascomycetes (sac-fungi) e.g. morels, truffles, brewer's yeast, etc.

Basidiomycetes (club-fungi) e.g. mushroom, etc.


8.

Which of the following pair of characters distinguish Gnetum from Cycas and Pinus?

  • Abscence of resin duct and leaf venation

  • Prasence of vessel elements and absence of archegonia

  • Perianth and two integuments

  • Embryo development and apical meristem


B.

Prasence of vessel elements and absence of archegonia

Gnetum is a genus of gymonosperms, the sole genus in the family-Gnetaceae. They are tropical evergreen trees, shrubs and lianas. Unlike other gymnosperms like Cycas and Pinus, they possess vessel elements in the xylem and absence of archegonia. Some species are found to be insect pollinated also. Thus, show affinities with angiosperms.


9.

Which of the following feature cannot be considered to distinguish underground stem from a root?

  • Presence of nodes and internodes

  • Presence of axillary and terminal buds

  • Absence of scale leaves and adventitious roots arising from nodes

  • Presence of exogenous branches


C.

Absence of scale leaves and adventitious roots arising from nodes

The underground stem can be differentiated from root in presence of nodes and internodes, presence of axillary and terminal buds, presence of exogenous branches, presence of scale leaves and adventitious roots arising from nodes and absence of root cap and root hair (which are present exclusively on roots).


10.

As compared to sun plants, the plants, which are adopted to low light intensity possess

  • more extended root system

  • very high rate of CO2 fixation

  • larger photosynthetic units

  • more extended shoot system


C.

larger photosynthetic units

As compare to sun plants the plants, which are adapted to low light intensity possess larger photosynthetic units.