NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions


Thermococcus, Methanococcus and Methanobacterium are groups of

  • Bacteria containing a cytoskeleton and all membrane-bound organelles

  • Archaebacteria with peptidoglycan in their cell wall

  • Archaebacteria that consists of protein homologous to eukaryotic core histones

  • Most advanced type of bacteria


Archaebacteria that consists of protein homologous to eukaryotic core histones

Archaebacteria are the most primitive and ancient bacterial species.

Key characteristic features are:

(i) Lack of peptidoglycan in the cell wall instead pseudomurein is present.

(ii) Lipids in cell membrane have a different structure than in all other organisms.

(iii) They lack membrane-bound organelles.


If the free energy change of a reaction is greater than zero, then the reaction is

  • Spontaneous

  • Non-spontaneous

  • At equilibrium

  • Endothermic



An endergonic reaction (also called a non-spontaneous reaction) is a chemical reaction in which the standard change in free energy is positive and energy is absorbed.


The mitotic cell cycle is divided typically into four phases; G1, S, G2 and M. Considering a mitotic cycle time of 18 hrs; the distribution of period of time (in hrs) for each of these phases will be

  • G1 S G2 M
    1 3 5 9
  • G1 S G2 M
    9 1 3 5
  • G1 S G2 M
    9 5 3 1
  • G1 S G2 M
    3 5 9 1


G1 S G2 M
9 5 3 1

The longest phase of cell cycle in G1 where these rapid growths and metabolic activity, followed by S phase for DNA synthesis and replication then G2 phase for preparation of cell division and lastly mitotic phase.

therefore, Ratio is 9:5:3:1


The non-disjunction, in meiosis may result is extra copy of a chromosome in a sperm cell. During which phase the above phenomenon may occur?

  • Prophase-I, prophase-II

  • Prophase-I, prophase-II

  • Anaphase-I, anaphase-II

  • Anaphase-I, telophase-II


Anaphase-I, anaphase-II

In anaphase-I and II chromosomes become shorter and thicker and migrate towards opposite poles of the cell. In case of non-disjunction of chromosomes, an extra copy of a chromosome will be present in the cell.


 A connecting link between plant and animal kingdom is

  • Paramecium

  • Chlamydomonas

  • Chlorella

  • Euglena



Euglena can be considered as both plants as well as an animal. It can perform photosynthesis in presence of light. But in the absence of light, it opts holozoic mode nutrition which is the feature of animals. Thus, Euglena is considered as connecting link between plant and animal kingdom.


The enzyme hexokinase which catalysis glucose to a glucose-6-phosphate in glycolysis is inhibited by glucose-6-phosphate. This is an example of

I. Competitive inhibition

II. non-competitive inhibition

III. feedback allosteric inhibition

Which of the above statements is/are correct?

  • I and II

  • I and III

  • Only III

  • All of these


Only III

Hexokinase catalyses the phosphorylation of hexose in general and is found in all cells that metabolise glucose. It has low Km (high affinity, strong bonding) with glucose in such a way that it is active at low glucose concentration. It shows allosteric feed beat inhibition by to product glucose-6-phosphate.


Organisms who are able to freely interbreed producing fertile off-springs and having a similar blueprint for making these organisms are referred to as

  • Species

  • Tribe

  • Genus

  • Sub-genus



The term species was given by John Ray and are the lowest category of classification. A species is a group of closely related individuals having similar morphological, anatomical, biochemical and cytological characteristics. It consists of naturally interbreeding population with the ability to produce fertile offsprings. This group is reproductively isolated and genetically closed.


Independent assortment of gene occurs due to the orientation of chromosomes at

  • Metaphase-I of mitosis

  • Metaphase-I of meiosis

  • Metaphase-II of meiosis

  • Any phase of the cell division


Metaphase-I of meiosis

The independent assortment of the gene occurs due to the orientation of chromosomes at late metaphase - I of meiotic cell division at the time of gamete formation.


Which of the following is the most primitive ancestor of man?

  • Ramapithecus

  • Homo habilis

  • Australopithecus

  •  Homo sapiens neanderthalensis



Ramapithecus was the most primitive hominid. It is fossils were obtained from Asia and Africa. Its features suggested that they were the beginning of the linkages leading to human.


Which of the following sequences represent a possible pathway in the production of a secretory protein?

  • Rough ER → Secretory vesicle → Ribosome → Golgi apparatus

  • Ribosome → Rough ER → Golgi apparatus → Secretory vesicle

  • Secretory vesicle → Golgi apparatus → Ribosomes → Rough ER

  • Rough ER → Ribosomes → Secretory vesicles → Golgi appratus


Rough ER → Ribosomes → Secretory vesicles → Golgi appratus

Ribosome is the place where protein synthesis takes place →rough ER produces proteins and helps them fold property → Golgi bodies does packaging of proteins → secretory vesicles does the transport of proteins.