In bacteria the cell cycle is divided into:
1. Only 1 phase
2. Two stages
3. Three periods
4. Four classes
The G0 stage of the cell cycle is irreversible in:
I. Quiscent cells
II. Senescent cells
III. Terminally differentiated cells
1. I and II only
2. I and III only
3. II and III only
4. I, II and III
If a cell in S phase is fused with a cell in G1:
1. The G1 nucleus immediately enters the S phase
2. The S nucleus stops DNA replication
3. The G1 nucleus directly enters G2 phase
4. Both nuclei enter the M phase immediately
A point in the animal cell cycle at which the cell becomes "committed" to the cell cycle occurs in:
1. G1
2. S
3. G2
4. M
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 stage phase of the cell cycle that is expected to be 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 cell 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 two chromosome number and DNA content getting reduced twice
2. A single round of DNA replication is followed by two sequential divisions with two 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 two 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 two 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
At which stage of mitosis are chromosomes usually photographed in the preparation of a karyotype?
1. Prophase
2. Metaphase
3. Anaphase
4. Telophase
A prolonged resting phase in oogenesis as seen in many vertebrate occytes is called as:
1. Intekinesis
2. Diakinesis
3. Dictyotene
4. Prometaphase II