Cell Division Test Review
CHROMOSOME
•DNA that coils around a protein
• CHROMATIN
• Long thin UNCOILED strands of DNA.
• Form between divisions
CHROMATID
• At the beginning of cell division
• Coiled DNA
HISTONE
•The protein a chromatid wraps around to make a
chromosome.
Haploid cells/Sex cells/Gametes
• For all organisms in general• It only contains 1 chromosome
from each homologous pair and 1 sex chromosome
• A cell that contains ½ the amount of normal
chromosomes
EXAMPLES
• Diploid # of an organism is 36
• Haploid # would be?
• 18
Diploid cells/Body cells/Somatic cells
• For all organisms in general
• A cell that contains all of its homologous pairs of
chromosomes and its pair of sex chromosomes
• Ex 78
Homologous Chromosomes
• Chromosomes that are similar in size and shape and
make a pair.• They are not exact copies
•Sister chromatids• Exact copy of a chromosome
MITOSIS
Dividing of diploid cells to make more
diploid cells
MEIOSIS
The making of sex cells/ haploid cells or gametes from
diploid cells
THREE STAGES
G1 or Gap 1
1. Cell Membrane and cytoplasm double
•Cell doubles in size
2. S stage or Synthesis Stage-
Chromosomes/DNA Replicate or Double
3. G2 or GAP 2–
•Cell doubles all other organelles
Cytokinesis
• The final stage of the cell cycle where the cytoplasm and the cell membrane split creating 2 cells
• Plant cell form a cell plate between the 2 nuclei which forms a cell wall
HUMAN CELLS• Diploid Cells
• 46• Haploid
• 23
Remember
• Diploid Cells----
• have NO Genetic Variation---Identical Cells
• They are made to repair, replace and growth
• Asexual reproduction---offsprings are EXACTLY the same as parent.
Remember
• Haploid Cells----
• have Genetic Variation---COMBO of parents genes
• They are made for sexual reproduction---offsprings are NO EXACTLY the same as parent.
• Any cell that is a result of a division
• Number of chromosomes in each
cell in each phase•Know how this works
for other organisms
•Study Picture handout of Mitosis
•Prophase
•Metaphasee
•Anaphase
Telophase
Meiosis
• Homologous Chromosomes Separate during Anaphase I
• Sister Chromatids Separate during Anaphase II
• End Result ---4 Haploid Cells 4 Sex Cells
4 Gametes
Numbers of Meiosis• Interphase—46/1cell Prophase II—46/2cells• End Interphase---92/1 cell Metaphase II-46/2cells• Prophase I---92/1 cell Anaphase II—46/2cells• Metaphase I—92/1 cell Telophase II—23/4 cells• Anaphase I—92/1 cell• Telophase I—46/2 cells
• Know how this works for other organisms
• Organisms go through Meiosis for Sexual Reproduction----variation in species
• Cells as a result---Sex cells, haploid cells, Gametes
Open Constructive Response
• Answer Following Slides
PROPHASE• Nuclear membrane and
nucleolus disappear
• Spindle fibers and centrioles appear
• Chromosomes become visible
METAPHASEMETAPHASEMETA=MIDDLEMETA=MIDDLE
Spindle fibers pull Spindle fibers pull chromosomes to the center of chromosomes to the center of
the cell.the cell.
ANAPHASEANAPHASE
SISTER SISTER CHROMATIDS CHROMATIDS
SEPARATESEPARATE
TELOPHASETELOPHASENuclear Membrane and Nuclear Membrane and
nucleolus reappearnucleolus reappearCentrioles and spindle fibers Centrioles and spindle fibers
disappeardisappearCell membrane splits into two Cell membrane splits into two
new cellsnew cells
