Cell Replication Flashcards
Function of mitosis
Growth, repair of tissue
Asexual reproduction
Interphase mitosis
Engaged in metabolic activity in prep for mitosis
Chromatin replicated
Prophase mitosis
Chromatin condenses
Nuclear envelope disintegrates
Centrioles move to opposite poles of cell, extend fibres
Metaphase mitosis
Spindle fibres align chromosome along equator
Ensure that during anaphase, each new nucleus receives 1 copy of each chromosome
Anaphase mitosis
Paired chromatids pulled to opposite poles of cell after being separated at centromeres
Telophase mitosis
Chromatids arrive at opposite poles of cell
Chromosomes get longer and thinner
Cytokinesis mitosis
Actin fibre ring around cell centre contracts, pinching cell into 2 daughter cells
Binary fission
Circular DNA replicated, both copies attach to cell membrane
Plasmids replicate, cell membrane grows between 2 DNA molecules, pinches, divides cytoplasm
New cell wall forms between 2 DNA molecules
Plasmid numbers in daughter cells vary
Differences in mitosis in eukaryotes and prokaryotes
No nuclear envelope
1 chromosome
Virus replication
Not living, cannot undergo cell division Attach to host cell via attachment proteins Inject nucleic acid (RNA DNA) Host cell produces viral components Assembled into new viruses New viruses burst out of cell
Describe how the mass of the cell changes during mitosis
Intense chemical activity in interphase
Chromatin replication, protein production increases cell mass
Cell undergoes mitosis, cell mass halves
Causes of cancer
Mutations in DNA, affects regulation of division bad cell cycle
Divide at higher rate, proliferate
Uncontrolled abnormal mitosis, escape normal mitotic controls
Tumours
Mass of cancer cells, grows, releases proteins into body to attract blood vessel growth to supply it with steady oxygen, glucose supply
Malignant and benign
Grow more rapidly, life threatening
Grow more slowly, less life threatening
Metastasis
Cancer cells break away from tumour travel through bloodstream to different parts of body
Start new tumours elsewhere
Treating cancer
Chemo, kills dividing cells, block part of cell cycle
Prevents DNA replication, inhibits metaphase, interrupts spindle formation
Effectiveness of chemo on cells
Affects cell cycle of all cells, more effective against rapidly dividing cells
Cancer cells damaged to a greater degree, fast dividing cells are vulnerable to damage, hair
Mitotic index
Measure of proliferation status of a cell population
Elevated during processes that promote division, growth, repair
Prognostic tool for predicting response of cancer cells to chemo
Cell in mitosis
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Interphase meiosis
Chromatin replicated into
Prophase I meiosis
Chromatin condenses into chromosomes
Nuclear envelope breaks down
Recombination
Metaphase I meiosis
Homologous chromosome pairs move to equator of cell
Anaphase I meiosis
Chromosomes move to opposite sides of cell
Telophase, cytokinesis I meiosis
Chromosomes gather at poles of cell
Cytoplasm divides
Prophase II meiosis
2 daughter haploid cells
New spindle fibres form around chromosomes
Metaphase II meiosis
Chromosomes line up at equator
Anaphase II meiosis
Centromeres divide
Chromatids move to opposite poles of the cells and pulled apart
Telophase and cytokinesis II meiosis
Nuclear envelope forms around each set of chromosomes
Cytoplasm divides
4 grand daughter cells
How meiosis increases variation
Independent segregation
Recombination
Random fertilisation of 2 haploid gametes
Independent segregation
Random assortment of maternal and paternal genes in meiosis I, II in metaphase
Recombination
Crossing over to form recombination chromosome
Random fertilisation of 2 haploid gametes
Homologous pairs, maternal, paternal chromosomes in homologous pairs have same genes at the same loci, diff alleles
Lytic cycle
Attachment Entry of phage DNA, degradation of host DNA Synthesis of viral genomes and proteins Self assembly Release
Attachments
Tail fibres bind to specific surface proteins on cell that acts as receptors
Entry of phage DNA, degradation of host DNA
Sheath of tail contracts, inject phage DNA into cell, leaving empty capsid outside.
Cell DNA hydrolysed
Synthesis of viral genomes and proteins
Phage DNA directs production of phage proteins and copies of the phage genome by host and viral enzymes, with components from cell
Self assembly
3 separate sets of proteins self assemble to form phage
Phage genome packaged inside caspids as head forms
Release
Phage directs production of enzyme that damages bacterial cell wall, allow fluid to enter
Cell swell, lyses, release, phages
