During meiosis, the bivalent chromosomes clearly appear as tetrads first at:
1. Zygotene of prophase I
2. Pachytene of Prophase I
3. Metaphase I
4. Anaphase I
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
During diakinesis of prophase I:
I. Terminalisation of chiasmata takes place
II. Meiotic spindle is assembled.
III. Nucleolus disappears and the nuclear membrane breaks down.
The correct statements are:
1. I, II and III
2. I and II only
3. I and III only
4. II and III only
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
The enzymes that catalyse removal of groups from substrates by mechanisms other than hydrolysis leaving double bonds are called as:
1. Oxidoreductases
2. Hydrolases
3. Ligases
4. Lyases
Consider the following two statements:
I. The growth of multi-cellular organisms is due to mitosis.
II. Mitosis results in the production of diploid daughter cells with identical genetic complement usually.
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
Consider the following two statements:
III. Plant cells undergo cytokinesis in a different manner than the animal cells
IV. 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
Consider the following enzymes:
I. Catalase
II. Peroxidase
III. Carboxypeptidase
Which of these enzymes require haem as a cofactor for their activity?
1. I only
2. I and II only
3. II and III only
4. I, II and III
Cells at the end of prophase of mitosis, when viewed under the microscope, do not show:
I. Golgi complexes
II. Endoplasmic reticulum
III. Nucleolus
IV. Nuclear envelope
1. Only I and II are correct
2. Only III and IV are correct
3. Only II, III and IV are correct
4. I, II, III and IV are correct
The stage of mitosis at which morphology of chromosomes is most easily studied is the:
1. Prophase
2. Metaphase
3. Anaphase
4. Telophase