Everything you need to know bout Mitosis Flashcards
(30 cards)
DNA
Deoxyribonucleic Acid or DNA is the molecule that holds the genetic information in every cell that makes up your body
Chromosome
Densely packed material made of protein called histones and a single molecule of DNA.
Where are chromosomes found?
They are found in the nucleus of a cell
Chromatin
When a chromosome is in its thread-like form it is called chromatin.
It is in this state in non-dividing cells.
Chromosome number
The amount of chromosomes each cell in a species has.
Humans have 23 pairs of chromosomes which will give us a number of 46 chromosomes [23x2]
Dogs have 39 pairs [39x2=78]
While chromosome number is the same,combinations, each combination is different making each individual unique.
Chromatid
One half of a duplicated chromosome
2 identical chromatids are known as sister chromatids.
Chromatid Formation
Formed when chromosomes duplicate and are joined at a point called the centromere
Structure of Chromosome
They have a unique structure that keeps DNA tightly wrapped around proteins called histones
Advantage #1 of the Structure of Chromosomes
This packaging of DNA allows it to fit inside a cell,
otherwise it would be too long to fit
Fun Fact of Chromosome Structure
If all DNA molecules in one human cell, were unwound from their histones and placed end to end, they would stretch 6ft.
Mitosis
A type of cell division where a genetically identical copy of a cell is made
Where does Mitosis occur?
Somatic cells (all body cells) EXCEPT gamete cells(sex cells)
What happens when mitosis occurs
He entire genome or genetic composition is copied
NB. All cells reduced this way will have the same chromosome number and same combination of genes
Diploid
A cell that has the complete set of chromosomes for its species. Denoted by “2n”
Haploid
Cell with half the number of chromosomes of the parent cell.
Denoted by “n”
The parent
The original cell that will be split
The daughter cells
The cells produced after division
Stages of Mitosis
Interphase[before cell division] Prophase Metaphase Anaphase Telophase Cytokinesis[cytoplasm splits at end of telophase]
Interphase
Cell prepares for division
Chromosomes become shorter and fatter
Each chromosome makes exact copy of itself forming two chromatids joined at centromere
Replication of hormones allows chromosomes to copy itself exactly
Carries genetic material as DNA
Structure is double helix or made of two chains
Prophase
Chromosome made of two chromatids are visible
Nucleus shrinks and disappears
Centrioles form and move to opposite sides of cell which is where the spindle fibers originate
Spindle fibers form
Nuclear envelope breaks down
Metaphase
Chromosomes line up along the equator of cell
Note that they still have two chromatids joined by the centromere
Anaphase
Connected chromatids now separate
They move to opposite sides of the cell
Spindle fibers shorten and contract to pull them at either poles of cell
Now exact copies are at both sides of the cell
Telophase
Chromosomes lengthen as they unravel Nuclear envelope forms around each group of chromosomes to make two nuclei New nucleoli forms in each new nucleus Two identical nuclei are formed Mitosis has ended
Cytokinesis
Cell membrane develops down middle of cell to divide in two
Two identical cells are produced
