Cell Division Flashcards
Cell division which major purpose is to growth and to replace worn out cells
Mitosis
Mitos means _______
warp thread
Who coined the term mitosis in the year 1882?
Walther Flemming
What are the alternative names for mitosis?
Karyokinesis and Cytokinesis
• equational division
• 1887
August FreidrichWeismann
How many daughter cells does mitosis produce?
2 daughter cells
Are the daughter cells and parent cells genetically identical to each other?
Yes
How many chromosomes does each cell have?
43 Chromosomes
How many PAIRS of chromosomes does each cell have?
23 pairs of chromosomes
How many times does a parent cell undergo mitosis?
Once
How many division does mitosis have?
4 division
The 4 division of Mitosis
Prophase, Metaphase, Anaphase, Telophase
Responsible for holding the sister chromatids together
Centromere
Parts of Chromosomes
p arm, q arm, telomere
Is defined as the division of the nucleus during the M phase of the cell cycle
Karyokinesis
Where do spindle fibers attach?
Kinetochore
is a cell or organism that has just a single copy of each chromosome.
Haploid or monoploid
in this phase:
- nucleus disappears
- spindle fiber forms in the cytoplasm
- spindle fibers attach to sister chromatids
- there is a complete migration of centrioles in the opposite poles of a cell
- chromatin condenses into chromosomes
Prophase
in this phase:
- chromosomes, attached to the kinetochore fibers, move to the center of the cell
- chromosomes align at the center of the cell called the equatorial plate
Metaphase
in this phase:
- the spindle fiber disassembles
- nuclear envelope forms around each set of sister chromatids
- nuclear membrane and nucleolus reappear
- chromosomes decondenses to chromatin
Telophase
sister chromatids pulled apart to the opposite poles of the cell due to the shortening of spindle fiber and this phase occur rapidly
Anaphase
Division of cytoplasm
Cytokinesis
in this phase:
- cleavage furrow are form, from a parent cell it will produce two haploid daughter cell which is genetically identical to the parent cell
Cytokinesis
- have the same number of chromosomes as each other and as the parent cell from which they were formed
- identical to each other but smaller than the parent cell
- must grow in size to become mature cells (gap one of interface)
daughter cells of mitosis
- used for growth and repair
- produce two new cells identical to the original cells
- cells are diploid
eukaryotic cell division
cause cancerous tumors
uncontrolled mitosis
- special proteins that increase the chance that a normal cell develop into a tumor cell
- produce cancer cell
oncogens
type of cell where the process mitosis occur
somatic cell
type of cell where the process of meiosis occur
gametic cells
number of cell division in mitosis
one
number of cell division in meiosis
two
number of chromosomes in parent cell and daughter cell in mitosis
diploid number of chromosome in both parent and daughter cell
number of chromosomes in parent and daughter cell in meiosis
diploid number in parent cell but haploid number in 4 daughter cell
stages or phases in meiosis
meiotic first division, meiotic second division
final product of mitosis
two deployed cell that are totally identical
final product of meiosis
four haploid cells that are non identical because of recombination of genes in gametes
process of cell division that produces haploid gametes
meiosis
also called as the reduction division
meiosis
he is a german biologist that discover and describe meiosis for the first time in sea urchin eggs in 1876
Oscar Hertwig
a british cytologist who found different numbers of chromosomes in different cells
Pierre-Joseph van Beneden
contain two copies of each chromosome (one from the sperm one from the egg) called as the homologous chromosome
zygote
True or False
gametes contain half the number of chromosome compared to somatic cells (non reproductive cell or cell bodies)
True
fussion of gametes
fertilization
XY
Male
XX
female
number of sets of chromosomes in a cell
Ploidy level
how many chromosomes do haploid cells have?
23 chromosomes
how many chromosomes does diploid cells have?
46 chromosomes
- process of duplicating a chromosome
- prior to division
Replication
lack of chromosome
monosomy
has excess chromosome
trisomy
unique features of meiosis
synapsis, crossing over, and reduction division
in this feature of meiosis the homologous chromosome pair all along their length and form a tetrad
feature #1: synapsis
in this feature of meiosis there is an exchange of genetic material from homologous chromosomes, this causes genetic variations
Feature #2: Crossing Over
in this feature of meiosis each cell contains 1/2 the genetic material
Feature #3: Reduction Division
stages of prophase 1
Leptotene, Zygotene, Pachytene, Diplotene, Diakinesis
In this stage of Prophase 1:
- leptonema
- chromosomes condenses into long threads
- two sister chromatids are tightly bound
- flower bouquet phase
Leptotene
In this stage of Prophase 1:
- zygonema
- forms tetrad
- synopsis or syndesis
- bivalent
- synaptonemal complex
Zygotene
Pair of homologous chromosome lying together
Bivalent
This is formed in between two homologous chromosomes
Synaptonemal Complex
In this stage of Prophase 1:
- dyads
- crossing over
- breakage and reunion of chromatid segments mediated by the endonuclecase and ligase
responsible for the origin of new species and does leads to evolution
- pachynema
Pachytene
In this stage of Prophase 1:
- disjunction
- chiasmata
Diplotene
homologous chromosomes start separating
disjunction
- clearly visible as X shape
- sites where the crossing over occur during pachytene
- helps in holding homologous chromosome
Chiasmata
displacement of chiasmata toward the terminal position
terminalization
- shortest phase of meiosis
- homologous chromosomes align at the center of the cell
- spindle fiber attach at the kinetochore
Metaphase 1
- separation of the homologous chromosomes
- moves towards the opposite poles
- separate due to shortening of spindle fiber
- actual reduction of chromosomes take place
- this phase of meiosis corresponds to Mendel’s law of Independent Assortment
- introduces Genetic Variability
Anaphase 1
