Lecture 14: Mitosis Flashcards
How do eukaryotic cells store genetic information
Chromosomes: linear genome type
double-stranded FNA
What is a Karyotype
An ordered, visual representation of the chromosomes in a cell.
image of cell division stoped at metaphase
All but X and Y chromosomes are present in homologous pairs
What are homologous chromosomes
A pair of chromosomes with the same genes, one inherited from the father and one from the mother.
What is a Locus
Location of a gene
What is an Allele
An alternative version of a gene
What is a duplicated chromosome
Consists of two sister chromatids which are genetically identical.
These separate during mitosis
What happens at G2 of interphase
Nuclear envelope intact
Nucleolus visible, contains one or
more nucleoli (singular = nucleolus)
Two centrosomes form
Duplicated chromosomes cannot
be seen individually as they have
not yet condensed
What are the 5 phases of mitosis
Prophase
prometaphase
metaphase
Anaphase
Telophase & Cytokinesis
What happens at prophase of mitosis
Nucleoli disappear
Duplicated chromosomes
condense and appear as
two identical sister
chromatids joined at their
centromeres.
Mitotic spindle begins to
form. Microtubules legnthen and centrosomes move to opposite poles
What happens in prometaphase of mitosis
Nuclear envelope breaks down and chromosomes fully condense.
A kinetochore (a protein structure) forms at the centromere of each chromatid.
Microtubules that attach to the kinetochores are called kinetochore microtubules.
Nonkinetochore microtubules lengthen the cell by interacting with those from the opposite pole of the spindle.
What happens in metaphase of mitosis
Centrosomes are now at
opposite poles of the cell.
Kinetochore microtubules are
attached to the kinetochores
of all sister chromatids.
Duplicated chromosomes alight at metaphase plate. Homologous pairs do NOT interact
Centromeres on metaphyseal plate, equal distance between poles
What happens in Anaphase of mitosis
Sister chromatids disjoin at the
centromeres. Each chromatid becomes an independent daughter chromosome.
Daughter chromosomes move
towards opposite poles as their
kinetochore microtubules
shorten.
The nonkinetochore microtubules
lengthen, and the cell elongates.
Ends when 2 poles each contain identical and complete collections of chromosomes
What happens in Telophase of mitosis
Chromosomes become less
condensed. Spindle breaks down
Two daughter nuclei nform in the cell. Nuceloli reappear
Mitosis is now complete
What is in each daughter cell at the end of mitosis
Each daughter cell has one copy of each duplicated chromosome
What happens in cytokinesis of mitosis
Cytoplasm divides, thus 2 daughter cells
In animal cells, cytokinesis
involves the formation of a
cleavage furrow, which pinches
the cell into two.
In plant cells this involves a cell plate between daughter cells
