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

METAPHASE META=MIDDLE Spindle fibers pull chromosomes to the center of the cell.

ANAPHASE SISTER CHROMATIDS SEPARATE

TELOPHASE Nuclear Membrane and nucleolus reappear Centrioles and spindle fibers disappear Cell membrane splits into two new cells