Which stage of meiosis is shown in the diagram given below?
1. | Metaphase I | 2. | Metaphase II |
3. | Anaphase I | 4. | Anaphase II |
In meiosis:
1. | A single round of DNA replication is followed by two sequential divisions with chromosome number and DNA content getting reduced twice |
2. | A single round of DNA replication is followed by two sequential divisions with chromosome number getting reduced twice and DNA content getting reduced once |
3. | A single round of DNA replication is followed by two sequential divisions with chromosome number getting reduced once and DNA content getting reduced twice |
4. | A single round of DNA replication is followed by two sequential divisions with chromosome number and DNA content getting reduced once |
The mechanisms that contribute to the genetic variation arising from sexual reproduction include:
I: | Independent assortment of chromosomes |
II: | Crossing over |
III: | Random fertilization |
1. | I and II only | 2. | I and III only |
3. | II and III only | 4. | I, II and III |
Consider the following functions:
I: | Replication of DNA along with the synthesis of nuclear proteins such as histones |
II: | Duplication of centriole |
III: | Synthesis of energy rich compounds and proteins |
Which of the above functions are carried out by a plant cell before it divides?
1. | I only | 2. | I, and II |
3. | I and III | 4. | I, II and III |
A ribbon-like structure consisting of three protein components and extending across the region of synapsed chromosomes during the prophase of meiosis, is called:
1. | Phragmoplast | 2. | Phragmosome |
3. | Synaptonemal complex | 4. | Recombination nodule |
The point of contact between paired chromatids during meiosis, resulting in a cross-shaped configuration and representing the cytological manifestation of crossing over is called:
1. | Centromere | 2. | Centrosome |
3. | Chiasmata | 4. | Tetrad |
Organisms prefer sexual mode of reproduction in adverse conditions because:
1. | It leads to a rapid proliferation of numbers |
2. | It requires two individuals that can support the progeny |
3. | It is less energy consuming than the asexual mode of reproduction |
4. | It provides protection and increases variations that may help progeny to survive |
With respect to meiosis, when does DNA replication occur?
1. | Before meiosis I only | 2. | After meiosis I only |
3. | Before and after meiosis I | 4. | After meiosis II |
The most important significance of meiosis is that:
1. | It increases variations in the gene pool of the species that helps in evolution of that species. |
2. | It causes growth in the multicellular organisms. |
3. | It conserves specific number of chromosomes in each species across generations. |
4. | It is vital for repair and regeneration functions in the living organisms. |
Consider the following statements regarding meiosis:
I: | At metaphase I, the microtubules from the opposite poles of the spindle attach to the pair of homologous chromosomes. |
II: | At anaphase I, the homologous chromosomes separate, while sister chromatids remain associated with each other. |
Of the two statements:
1. Only I is correct
2. Only II is correct
3. Both I and II are correct
4. Both I and II are incorrect