AIIMS Biology Class 12 Questions

Which of the following are homosporous pteridophytes? I. Selaginella II. Lycopodium III. Salvinia IV. Equisetum

Which of the following statements is correct regarding menstrual cycle?

Match column I with column II and select the correct option from the codes given below.

Which of the following is used as bioinsecticide?

Identify the given structure.

If both parents are carriers for thalassaemia, which is an autosomal recessive disorder, what are the chances of pregnancy resulting in an affected child?

The correct sequence of stages in the evolution of modern man (Homo sapiens), is

Identify the parts labeled A, B, C, and D in the diagram.

Match column I with column II and select the correct option from the given codes.

In a 3.2 Kbp long pieces of DNA, 820 adenine bases were found. What would be the number of cytosine bases?

Some of the steps of DNA fingerprinting are given below. Identify their correct sequence from the options given. A. Electrophoresis of DNA fragments B. Hybridization with DNA probe C. Digestion of DNA by restriction endonucleases D. Autoradiography E. Blotting of DNA fragments nitrocellulose membrane

One of the following statements is incorrect with reference of biodiversity. Identify it.

If the sequence of bases in the coding strand of a double stranded DNA is 5’-GTTCGAGTC^{-3}’, the sequence of bases in its transcript will be

If ‘A’ represents the dominant gene and ‘a’ represents its recessive allele, which of the following would be the most likely result in the first generation offspring when Aa is crossed with aa?

Assertion : Hardy-Weinberg principle states that in the absence of disturbing influences, gene frequencies of large populations of sexually reproducing organisms do not change, provided that matings, occur at random. Reason : The disturbing influences include mutation, gene flow, genetic drift, genetic recombination and natural selection.

Assertion: Endothecium layer of anther wall plays an important role in dehiscence of anther. Reason: The presence of fibrous bands and differential expansion of inner and outer tangential walls of endothecial cells cause dehiscence of anther.

Assertion: Foetal disorders can be diagnosed by chorionic villi sampling. Reason: Karyotyping can be done for mitotically dividing cells of chorionic villi.

Assertion: The technique of micropropagation has been used to introduce variations in the offspring. Reason: It is not possible to generate virus-free plants by micropropagation.

Assertion: IgM is a type of immunoglobulin which cannot cross the placenta. Reason: IgM is pentamer immunoglobulin, joined by J⁻chain.

Assertion: Pili are tubular structures present in bacteria which help in conjugation. Reason: Formation of pili is controlled by F⁺ or fertility factor.

Assertion: XX⁻XY type of sex determination mechanism is an example of male heterogametry. Reason: In birds, male heterogamety is seen as males produce two different types of gametes.

Assertion: Curdling is required in the manufacture of cheese. Reason: Lactic acid bacteria are used for the purpose.

Assertion: Atmospheric nitrogen gas is always fixed by nitrogen-fixing micro-organisms. Reason: Decomposers release nitrogen gas from dead bodies of plants and animals.

Assertion: Number of chromosomes in one genome is equal to number of linkage groups. Reason: Linkage groups give important information about the location of genes in the chromosomes.