Match each item in Column I with one in Column II and select the correct answer from the codes given below:
Column I |
|
Column II |
|
A |
Zygotene |
a |
Pairing of homologous chromosomes |
B |
Pachytene |
b |
Appearance of chiasma |
C |
Diplotene |
c |
Terminalization of chiasma |
D |
Diakinesis |
d |
Crossing over |
Codes:
A | B | C | D | |
1. | a | c | b | d |
2. | a | d | b | c |
3. | a | b | c | d |
4. | b | c | d | a |
Identify the correct statement amongst the following:
1. | Crossing over occurs in prophase I of meiosis and metaphase of mitosis. |
2. | DNA replication occurs once prior to mitosis and twice prior to meiosis. |
3. | Both mitosis and meiosis result in daughter cells identical to the parent cells. |
4. | Karyokinesis occurs once in mitosis and twice in meiosis. |
Which of the following is not a feature of diakinesis stage of prophase I of meiosis I?
1. | Terminalization of chiasmata |
2. | Meiotic spindle assembling to prepare separation of homologues |
3. | Decondensation of the chromatin |
4. | NEBD and disappearance of nucleolus |
Crossing over or recombination can be defined as:
1. | exchange of segments between sister chromatids of homologous chromosomes |
2. | exchange of segments between non sister chromatids of homologous chromosomes |
3. | exchange of segments between sister chromatids of heterologous chromosomes |
4. | exchange of segments between non sister chromatids of heterologous chromosomes |
Which stage of meiosis is shown in the diagram given below?
1. | Metaphase I | 2. | Metaphase II |
3. | Anaphase I | 4. | Anaphase II |
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 |
Consider the following key events:
I: | Chromosomes cluster at opposite spindle poles and their identity is lost as discrete elements. |
II: | Nucleolus, Golgi complex and ER reform. |
The stage of mitosis characterized by these key events is:
1. | Prophase | 2. | Metaphase |
3. | Anaphase | 4. | Telophase |
Identify the correct statement regarding meiosis amongst the following:
I: | Meiosis involves two sequential cycles of nuclear and cell divisions but only a single cycle of DNA replication. |
II: | Meiosis II is initiated after the parental chromosomes have replicated to produce identical sister chromatids at the S phase. |
III: | Meiosis involves pairing of bivalents and recombinations between them. |
1. | I only | 2. | I and II only |
3. | I and III only | 4. | I, II and III |
Consider the following two statements:
I: | Plant cells undergo cytokinesis in a different manner than the animal cells. |
II: | Plant cells are enclosed by a relatively inextensible cell wall. |
Of the two statements:
1. Both I and II are correct and II explains I
2. Both I and II are correct but II does not explain I
3. I is correct but II is incorrect
4. I is incorrect but II is correct