Mitosis and meiosis Flashcards
(15 cards)
Two differences in the data cells following mitosis and meiosis
Daughter cells are genetically identical in mitosis and genetically different in meiosis
The number of chromosomes stays the same as it is a diploid cell in mitosis and the number of chromosomes halves as it is a haploid cell in meiosis
What happens to chromosomes in anaphase?
Sister chromatids separate as distance between centromeres is increased
Chromosomes are pulled towards spindle poles as distance between them and poles decreases
Where in a plant cell does mitosis occur and why?
The meristem as it is a region of growth
Why would the mass of DNA in some cells be 6.8 Au and in other cells be 3.4 AU?
3.4 units DNA before replication in early interphase
6.8 units of DNA as DNA doubles due to DNA replication
6.8 units of DNA will be present during prophase metaphase and anaphase
3.4 units will also be present when the quantity of DNA halves and returns to its original value following cytokinesis
What happens to the cell mass during mitosis?
Interphase the mass of cell increases
As does cell size
Mass of cell continues to increase
Due to replication of DNA and organelles and possibly due to formation of spindle fibres
Cell undergo cytokinesis and mass of cell halves
Which organ of the plant shows meiosis?
Ovary
Differences between telophase one and telophase 2 in meiosis
Telophase one chromosomes are being pulled to opposite poles whereas in telophase 2 the chromatids are being pulled to opposite poles
Telophase 1 the central medias do not divide and two they do divide
Telophase one is diploid and two is haploid
What genetic variation occurs in prophase one?
Chiasmata is taking place
What genetic variation occurs in metaphase?
Independent assortment occurs
Why is genetic variation important?
Allows the species to adapt in changeable environments
Why were the inability to form microtubles affect the growth of organisms?
Slower increase in size
No spindle formed
No mitosis, cell division would stop at prophase
Why does cell division not occur in bacteria?
No spindle or centrioles in bacteria
Bacteria don’t have chromosomes
Bacteria have no nuclei
Interphase for mitosis
DNA replication
Replication
Synthesis of ATP
Synthesis of proteins
Where would the mitosis index be higher
Tissues where new cells are being made will have a higher proportion of cells undergoing mitosis because cells are being worn away rapidly
E.g. skin cells gut lining liver cells
Effects of high soncentration of cancer cells
Uncontrolled mitosis
Cancer or tumours form
