Mitosis Flashcards
What happens in mitosis?
Cell division to produce 2 genetically identical daughter cells, no genetic variation. Maintain haploid/diploid number
Can you describe the behaviour of chromosomes during interphase, prophase, metaphase, anaphase and telophase of mitosis?
G1 Transcription and translator of proteins organelles replicate
S Semi conservative replication
G2 Cell volume increases to cope with replication
Pro Chromatin condenses into chromosomes, centrioles move to opposite poles and spindles develop.
Meta Chromosomes line up at equator and spindle connects centrioles at poles to centromeres.
Ana Chromatids separate at centromere spindled shorten and contract.
Telo DNA Decondenses, nuclear envelop reforms and spindles break down.
Cytokinesis cell pinched from out to in producing 2 daughter cells.
What can uncontrolled cell division lead to?
Faulty proto-onco/ tumour suppressor genes at checkpoints during interphase and throughout the cells cycle
Rapid division leads to tumour and cancer.
Can you explain the role of spindle fibres?
Separates chromosomes by attaching during metaphase, pull chromatids to opposite rules during anaphase.
Why is mitosis important?
Cell number increase
Replace tissues, organs, cells
Genetically identical cells.
Asexual reproduction
Checkpoints prevent tumours leading to cell apoptosis.
Describe the three stages of the cell cycle:
Interphase: G1 S G2
Mitosis: pro, meta,ana,telo
Cytokinesis: 2 daughter cells diploid maintained.
Explain why. Some cancer treatments are directed at controlling the rate of cell division. How might they disrupt the cell cycle? What is the problem with these types of drugs?
Drugs may stop DNA Replication (S)
Spindle Formation (Meta)
Cytokinesis
Usually cytotoxic and aren’t targeted to cancer cells killing healthy cells also.
How do prokaryotic cells divide?
Binary fission
Dna replicated (including plasmids)
Cell elongates from centre separating DNA
New cell wall formed down middle
Mitochondria and chloroplast replicate like this also.
How do viruses replicate?
inside host cells, attaches to cell, injects DNA/RNA into cell, viral nucleic acid replicates using host machinery, packaged into viral particles and exoctyosed.
