The Mitotic Cell Cycle
305 questions· page 1 of 31
A nucleus in a body cell of a species of fruit fly has 8 chromosomes.
How many strands of DNA are present in the nucleus at the end of interphase?
Options
A 8
B 16
C 32
D 64
The photomicrograph shows plant cells in different stages of the mitotic cell cycle. Four of the cells are labelled with a number to identify them.
One of the numbered cells is within the main stage of mitosis in which the spindle begins to form.
A second numbered cell is within the main stage of mitosis in which the spindle fibres shorten.
Which row correctly identifies the two cells that are in these stages of mitosis?
Options
| stage in which spindle begins to form | stage in which spindle fibres shorten | |
|---|---|---|
| A | 1 | 2 |
| B | 2 | 1 |
| C | 3 | 1 |
| D | 4 | 2 |
Which percentage of the chromosomal DNA present in a cell during is present in the same cell later in the same mitotic cell cycle during prophase and during telophase?
Options
| prophase | telophase | |
|---|---|---|
| A | 50% | 25% |
| B | 50% | 50% |
| C | 100% | 50% |
| D | 100% | 100% |
The statements are about two genes and their protein products that can have a role in tumour formation.
● The protein coded for by the PTEN gene prevents cells from growing and dividing too rapidly.
● The protein coded for by the p53 gene prevents cells progressing through the mitotic cell cycle if the cells have damaged DNA.
Which combination of mutations of these two genes in an individual is most likely to result in the formation of a tumour?
Options
| PTEN gene | p53 gene | |
|---|---|---|
| A | mutation present | mutation present |
| B | no mutation | mutation present |
| C | mutation present | no mutation |
| D | no mutation | no mutation |
Telomerase is an enzyme that prevents the shortening of telomeres. It is not present in most normal cells, but is active in an estimated 85% to 95% of human tumour cells.
Which statement explains the effect of telomerase on human tumour cells?
Options
A Telomerase triggers a self-destruct process, known as apoptosis, ending the life of the cell.
B Telomerase damages the chromosomes so they become genetically unstable and are unable to replicate and divide.
C Telomerase helps human tumour cells avoid senescence, or cell death, which is usually the expected consequence of repeated cell division.
D Telomerase enables the human tumour cells to divide more rapidly by reducing the time taken for a complete mitotic cell cycle.
A sample of 500 cells dividing by mitosis was examined to identify the stage of mitosis for each cell.
The table shows the results.
| stage of mitosis | percentage of cells in the stage |
|---|---|
| late prophase | 23 |
| end of metaphase | 45 |
| between the start of anaphase and the end of telophase | 24 |
Which row is correct?
Options
| number of cells with chromosomes at the equator of the cell | number of cells with separated chromatids | |
|---|---|---|
| A | 225 | 120 |
| B | 225 | 345 |
| C | 380 | 120 |
| D | 380 | 345 |
The diagram shows a chromosome.
What are structures P and Q?
Options
| P | Q | |
|---|---|---|
| A | centriole | chromatid |
| B | centromere | telomere |
| C | centromere | centriole |
| D | centriole | telomere |
Which processes are used by stem cells during tissue repair?
1 cytokinesis
2 DNA replication
3 transcription
Options
A 1, 2 and 3
B 1 and 2 only
C 1 and 3 only
D 2 and 3 only
The enzyme telomerase prevents loss of telomeres after many mitotic cell cycles.
Which cells transcribe a high concentration of telomerase?
1 neutrophils
2 mature red blood cells
3 activated memory T-lymphocytes
Options
A 1 and 2
B 1 and 3
C 1 only
D 3 only
The diagram shows the arrangement of chromosomes with attached spindle fibres during a stage of mitosis.
Which row correctly identifies the stage of mitosis and describes what is happening?
Options
| stage of mitosis | description | |
|---|---|---|
| A | anaphase | chromosomes are being pulled towards the centromeres |
| B | metaphase | sister chromatids are replicating prior to separation |
| C | metaphase | chromosomes are being positioned along the equator of the cell |
| D | anaphase | sister chromatids are being pulled towards the poles of the cell |