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