A point in the animal cell cycle, at which the cell becomes "committed" to the cell cycle, occurs in:
1. | G1 phase | 2. | S phase |
3. | G2 phase | 4. | M phase |
During what phase in the cell cycle would you find the most DNA per cell?
1. G1 | 2. G2 |
3. S | 4. Prophase II |
The phase of the cell cycle that is expected to be the most variable in duration in different types of cells in an animal will be:
1. G1 | 2. S |
3. G2 | 4. M |
Onion root tip has 16 chromosomes in each cell. How many chromosomes will the cell respectively have at G1 phase, after S phase and after M phase?
1. | 16, 32, 16 | 2. | 16, 32, 8 |
3. | 16, 16, 8 | 4. | 16, 16, 16 |
Destruction of both centrosomes with a laser beam in an animal cell:
1. will prevent both mitosis and cytokinesis
2. prevents cytokinesis even if mitosis has been completed normally
3. permits cytokinesis but the daughter cells fail to enter a new S phase
4. prevents mitosis but permits cytokinesis
Which of the following statements is not true for cancer cells in relation to mutations?
1. Mutations in proto-oncogenes accelerate the cell cycle.
2. Mutations destroy telomerase inhibitor.
3. Mutations inactivate the cell control.
4. Mutations inhibit production of telomerase.
Telomerase is an enzyme which is a:
1. Ribonucleoprotein
2. Simple protein
3. RNA
4. Repetitive DNA
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 |