Subject

Biology

Class

NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions

91.

Which one of the following is the correct matching of the events occurring during menstrual cycle?

  • Ovulation - LH and FSH attain peak level and sharp fall in the secretion of progesterone

  • Proliferative - Rapid regeneration of myometrium and maturation of Graafian follicle

  • Development of corpus - luteum - Secretory phase and increased secretion of progesterone

  • Development of corpus - luteum - Secretory phase and increased secretion of progesterone


C.

Development of corpus - luteum - Secretory phase and increased secretion of progesterone

In secretory phase during ovulation, the follicle breaks and collapses under the continuous influence of Luteinizing Hormone (LH). It begins to enlarge and forms a yellowish structure, called the corpus luteum. The corpus luteum plays an important role in the preparation of the endometrium for the implantation of the fertilised egg by secreting oestrogens and progesterone.

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92.

Transgenic plants are

  • produced by a somatic embryo in an artificial medium

  • generated by introducing foreign DNA into a cell and regenerating a plant from that cell

  • Produced by protoplast fusion in the artificial medium

  • Produced by protoplast fusion in the artificial medium


B.

generated by introducing foreign DNA into a cell and regenerating a plant from that cell

The plants obtained through genetic engineering contain a gene or genes usually from an unrelated organism, such genes are called transgenes and the plants containing transgenes are known as transgenic plants. These plants are often called as genetically modified or GM crops, eg, Flavor saur transgenic for identification, expressing the gene activity in time to produced several chemicals likes fatty acids sugars cellulose, rubber, etc.

301 Views

93.

Which one of the following statements is correct?

  • Patients, who had undergone surgery are given cannabinoids to relieve pain

  • Benign tumours show the property of metastasis

  • Heroin accelerates body functions

  • Heroin accelerates body functions


D.

Heroin accelerates body functions

Malignant tumour first grows slowly. No symptoms are noticed. This stage is called the latent stage. The tumour later grows quickly. The cancer cells go beyond adjacent tissue and enter the blood and lymph. Once this happens, they migrate to many other sites in the body, where the cancer cells continue to divide. It is metasis. Only maligant tumours are properly designated as cancer.

300 Views

94.

What is not true for genetic code?

  • A condon in mRNA is read in a non-contiguous fashion

  • It is nearly universal 

  • It is degenerate

  • It is degenerate


A.

A condon in mRNA is read in a non-contiguous fashion

The general features of genetic code are:

(i) The genetic code is written in linear form, using the ribonuclotide bases that compose mRNA molecule as letters.

(ii) Each word of codon consists of three letters, ie, the codon triplet.

(iii) The genetic code inside the cell medium is said to be non-ambiguous.

(iv) The code is degenerate, ie, a given amino acid can be specified by more than one codons.
(v) The codon contains start and stops signals.

(vi) The code is said to be commaless.

(vii) The code is said to be commaless.

361 Views

95.

An example of a seed with endosperm, perisperm and caruncle is 

  • Cotton

  • coffee

  • lily

  • lily


D.

lily

The seeds of castor (Ricinus communis, family -Euphorbiaceae) are endospermic dicot seeds. They possess  endosperm which acts at the food storgage tissue of seed. They also possess perisperm and cruncle.

527 Views

96.

Global agreement on specific control strategies to reduce the release of ozone depleting substance was adopted by

  • Rio de Janerio Conference

  • The Montreal protocol

  • The koyoto protocol

  • The koyoto protocol


B.

The Montreal protocol

The Montreal protocol on substances that deplete the ozone layer is a landmark international agreement designed to protect the stratospheric ozone layer.  The treaty was originally signed in 1987 and substantially amended in 1990 and 1992. The Montreal protocol stipulates that the production and consumption of compounds that deplete ozone in the stratosphere-chlorofluorocarbons (CFCs) halons, carbon tetrachloride, and methyl chloroform are to be phased out 2000 (2005 for methyl chloroform).

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97.

Biochemical Oxygen Demand (BOD) in a river water

  • remains unchanged when algal bloom occurs

  • has no relationship with the concentration of oxygen in the water

  • gives a measure of Salmonella in the water

  • gives a measure of Salmonella in the water


D.

gives a measure of Salmonella in the water

Biochemical Oxygen Demand (BOD) is the amount of oxygen used for biochemical oxidation by micro-organisms in a unit volume of water. Polluted water has high BOD. Thus, when sewage gets mixed with river water, BOD will increase.

585 Views

98.

The letter T in T-lymphocyte refer to 

  • thyroid

  • thalamus

  • tonsil

  • tonsil


D.

tonsil

Tonsil is a mass of lymphoid tissue, several of which are situated at the back of the mouth and throat in higher vertebrates.


The thymus is haemopoietic as well as an endocrine gland.The thymus is the seedbed of thymic lymphocytes (T-lymphocytes). Certain stem cells, originating in yolk sac and liver in the early embryo, migrate into the thymus and proliferate to form a large number of lymphocytes.

The thyroid is an endocrine gland.

Thalamus is the part forebrain in vertebrate lies above the hypothalamus.

337 Views

99.

A young infant may be feeding entirely on mother's milk, which is white in colour but the stools, which the infant passes out is quite yellowish. What is the yellow colour due to?

  • Intestinal Juice

  • Bile pigements passed through bile juice

  • Undigested milk protein casein

  • Undigested milk protein casein


B.

Bile pigements passed through bile juice

The stools, which the infant passes out is quite yellowish due to bile pigments passed through bile juice.

788 Views

100.

Semiconservative replication of DNA was first demonstrated in

  • Drosophila melanogaster

  • Escherichia Coli

  • Streptococcus pneumoniae

  • Streptococcus pneumoniae


B.

Escherichia Coli

Semiconservative replication of DNA was first demonstrated in E.coil. According to the semiconservative mode proposed by Waston and Crick, each strand of the two double helices formed would have one old and one new strand. The semiconservative nature of DNA of replication was proved by the experiment of Meselson and Stahl (1958).

885 Views