Eukaryotic cell division - mitosis Flashcards
(22 cards)
Mitosis definition
The process by which a cell divides to produce two genetically identical daughter cells
What is a karyotype
A way of displaying an image of the chromosomes of a cell to show the pairs of autosomes and sex chromosomes
Phases of the cell cycle
G1 - the time between the end of the previous round of cell division and the start of chromosome duplication
S - the stage when chromosomes replicate and become double stranded chromosomes
G2 - when organelles and other materials need for cell division are synthesised
M - mitosis when cells are actively dividing
C - cytokinesis, when the new cell separates
Cyclins
Small proteins that build up during interphase and are involved in the control of the cell cycle by their attachment to cyclin dependent kinases
Cyclin dependent kinases
Enzymes involved in the control of the cell cycle by phosphorylating other proteins activated by attachment to cyclins
The stages of mitosis
Prophase
Metaphase
Anaphase
Telophase
Prophase
Genetic material is replicated
Nucleolus breaks down centrioles which pull apart and begin to form spindles
Metaphase
Nuclear membrane has broken down
Centrioles have moved to opposite poles of the cell forming spindle
Chromosomes line up at the equator
Anaphase
Centromeres split as spindle fibres pull them apart to opposite poles of the cell
Telophase
Spindle fibres break down and nuclear envelopes form around the two sets of chromosomes
Nucleoli and centrioles are reformed
Cytokinesis
A ring of contractile fibres tighten around the centre of the cell
Continue to contract until the cells have been separated
Strategies for asexual reproduction
Producing spores
Regeneration
Producing buds
New plant structures
Producing spores
Sporulation - involves mitosis and the production of asexual spores that are capable of growing into new individuals
The spores can usually survive adverse conditions and are easily spread
Regeneration
When organisms replace parts of the body that have been lost
Fragmentation inn regeneration
When an organism reproduces themselves asexually from fragments of their original body
Producing buds
Budding - an outgrowth from the parent organism producing a smaller but identical individual
This bud eventually detaches from the parent and has an independent existence
New plant structures - vegetative propagation
A plant forms a structure that develops into a fully differentiated new plant - may be propagated from the stem, leaf, root or bud of the parent
What is the most accurate way of measuring growth
Dry mass
Drawback with measuring using dry mass
Dry mass means you have to remove all water from an organism so you must kill it
This means we cant measure any future growth
2 growth patterns
Continuous
Discontinuous
Where does growth take place in plants
Meristems
Mitosis and repair
Mitosis never stops as cells are constantly becoming worn out and being replaced
