AQA Bio A Level Unit 2 Flashcards
How does the cell prepare for nuclear division after DNA replication? (3)
1 Replicating organelles;
2 Increasing/synthesising protein;
3 ATP synthesis;
In the cell cycle, in which phase does DNA replication occur?
Interphase
What term is used to describe the mass of uncondensed DNA in a nucleus during interphase?
Chromatin
What determines how long a cell spends in interphase as a proportion of its cell cycle? (2)
- How rapidly that type of cell divides;
- Rapidly dividing cells spend much less time in interphase;
Does DNA replication change the chromosome number? Explain your answer. (2)
- No
- Chromosomes are replicated to give two chromatids – but each pair of chromatids is still just one chromosome. (count the centromeres…)
What happens to the mass of DNA in DNA replication?
It doubles
In which phase of mitosis do chromosomes condense?
Prophase
In which phase of mitosis do chromosomes line up on the equator?
Metaphase
Which organelle produces the spindle fibres?
Centrioles
How many chromatids would there be in a human cell at metaphase of mitosis? Explain your answer (2)
- 92;
- Each of the 46 chromosomes consists of two sister chromatids
In which phase does the nuclear membrane break down?
Prophase
What do spindle fibres attach to in mitosis?
Centromeres
In which phase of mitosis do chromatids separate?
Anaphase
What is the consequence of uncontrolled cell division?
Formation of tumours – which may be cancerous.
Suggest likely targets of anti-cancer drugs.
- Prevention of DNA replication – e.g. modified nucleotides that cannot be joined together, or inhibition of DNA polymerase
- Prevention of cell division, often by inhibiting spindle-fibre formation.