The Cell Cycle including Mitosis ( Required Practical Questions Flashcards
Place stages A to E in the correct order.
Start with D.
- DCBEA
Complete the table below to give one reason why each of these steps was necessary.
- Where mitosis occurs
- To allow light through
Explain how the behaviour of chromosomes causes these changes in the amount of DNA per cell between F and G.
- DNA replicates
- Homologous chromosomes separate
- Sister chromatids separate
What would happen to the amount of DNA per cell at fertilisation of cell G?
- Double
The doctors compared median survival times for patients in each group.
How would you find the median survival time for a group of patients?
- Rank all ST’s in ascending order
- Find the value with the same numbers of people above and below
In many trials of new drugs, a control group of patients is given a placebo that does not contain any drug.
The control group in this investigation had been treated with dacarbazine.
Suggest why they had not been given a placebo.
- Not ethical to fail to treat cancer
A journalist who read this investigation concluded that ipilimumab improved the treatment of MM.
Do the data in the table support this conclusion?
Give reasons for your answer.
- Yes as the median ST increased by 2.1 months
- Percentage of patients showing reduction in tumours increased from 10.3% to 15.2%
- However improvement might only be evident in some patients
- Quality of time alive isn’t recorded
MM is caused by a faulty receptor protein in cell-surface membranes.
Cells in MM tumours can be destroyed by the immune system.
Suggest why they can be destroyed by the immune system.
- Faulty protein is recognised as a foreign protein
- T cells will bind to faulty protein
- T cells will stimulate clonal selection of B cells
- Results in the release of antibodies against faulty protein
Water treatment was the independent variable in this investigation.
Explain what is meant by the independent variable
- Variable that is changed
The same variety of barley was used in all the plots.
why was this important?
- So that they’re genetically similar
- So have similar yield of seeds
When barley plants are growing, the number of cells increases.
Name the process that increases the number of cells.
- Mitosis
What do the data in the table above show about the effect of watering barley with a mixture of fresh water and seawater?
- Watering with sea and fresh water increased the yield compared to A
- Yield was lower when sea water and fresh water was used compared with just using fresh water
The scientist suggested that watering barley with diluted seawater might not be sustainable if repeated every year.
Do these data support this suggestion?
- Watering with sea water increases concentration of salt in the soil
- Lower water potential in the soil linked to reduced uptake of water
- Might decrease plant growth in the future
