Bell Work: Bell Work: 2/10/132/10/13For your For your answer, draw answer, draw all the three all the three pictures and pictures and explain why explain why the third the third picture you picture you chose is chose is correct.correct.

Objectives• Describe the relationship among genes, Describe the relationship among genes,

chromosomes, and inherited traits. chromosomes, and inherited traits. (SPI 0707.4.3) (SPI 0707.4.3)

• Sequence a series of diagrams that Sequence a series of diagrams that depict chromosome movement during depict chromosome movement during plant cell division. (SPI 0707.1.4)plant cell division. (SPI 0707.1.4)

• Classify methods of reproduction as Classify methods of reproduction as sexual or asexual. (SPI 0707.4.1) sexual or asexual. (SPI 0707.4.1)

Mitosis ReviewMitosis Review1.1. Interphase- DNA is copiedInterphase- DNA is copied

2.2. Prophase- Chromatin (DNA wrapped Prophase- Chromatin (DNA wrapped around protein) forms into chromatids around protein) forms into chromatids

3.3. Metaphase- Chromatids line up in the Metaphase- Chromatids line up in the middle of the cellmiddle of the cell

4.4. Anaphase- Chromatids separateAnaphase- Chromatids separate

5.5. Telophase- two new nuclei form around Telophase- two new nuclei form around the chromatin the chromatin

6.6. Cytokinesis- two new cells formCytokinesis- two new cells form

MitosisMitosis: : process of a process of a

somatic (body) cell somatic (body) cell dividing to produce dividing to produce

an exact copy of an exact copy of itselfitself

Create the Phases of Mitosis

• Use the cards at your group to Use the cards at your group to sequence a series of diagrams sequence a series of diagrams that depict chromosome that depict chromosome movement during cell division movement during cell division (mitosis) on your desk. Label (mitosis) on your desk. Label each box with the phase name each box with the phase name and draw each phase in the and draw each phase in the boxes on your note sheet.boxes on your note sheet.

MitosisMitosisInterphaseInterphaseDNA is copied DNA is copied

(in chromatin (in chromatin form)form)

Centrioles Centrioles copy copy

Animal Cell Plant Cell

chromatin

MitosisMitosisProphaseProphase

DNA condenses into DNA condenses into chromatidschromatids

Spindle fibers begin Spindle fibers begin to formto form

Centrioles move to Centrioles move to opposite sidesopposite sides

Nuclear membrane Nuclear membrane breaks apartbreaks apart

Animal Cell

Plant Cell

chromatids

MitosisMitosisMetaphaseMetaphaseChromatids Chromatids

(chromosomes) (chromosomes) line up across line up across the center of the the center of the cellcell

Spindle fibers Spindle fibers attach to the attach to the centromeres centromeres (center of the (center of the chromsome)chromsome)

Animal Cell

Plant Cell

spindle fibers

MitosisMitosisAnaphaseAnaphase

Spindle fibers Spindle fibers pull the pull the chromatids to chromatids to opposite ends opposite ends of the cellof the cell

Animal Cell

Plant Cell

MitosisMitosisTelophaseTelophaseTwo new nuclei Two new nuclei

form around form around the chromatidsthe chromatids

Chromosomes Chromosomes unwind back unwind back into chromatininto chromatin

Animal Cell

Plant Cell

Cytoplasm still attached

MitosisMitosisCytokinesisCytokinesisDivision of the Division of the

cytoplasm cytoplasm and the rest and the rest of the cellof the cell

Two new Two new daughter daughter cells!cells!

Animal Cells

Plant Cells

In In sexual reproductionsexual reproduction, two parent , two parent cells join together to form offspring cells join together to form offspring that are different from both parents.that are different from both parents.

These parent cells are called These parent cells are called sex sex cells cells (sperm & egg).(sperm & egg).

Sex cells are made during Sex cells are made during meiosismeiosis..

MeiosisMeiosis

Challenge Question• If sex cells, created during meiosis, are

part of sexual reproduction where two parent cells join together to form offspring that are different from both parents, what type of reproduction would the cells in mitosis be a part of if they come from one cell and are identical to the parent cell?

ASEXUAL REPRODUCTIONASEXUAL REPRODUCTION

MeiosisMeiosisprocess of a cell process of a cell

dividing to produce dividing to produce 44 cells with half the cells with half the genetic materialgenetic material

Why do the cells produced in Why do the cells produced in meiosis only need half of the genetic meiosis only need half of the genetic

material?material?

MeiosisMeiosisInterphase IInterphase IDNA copies DNA copies

Centrioles copy Centrioles copy

MeiosisMeiosisProphase IProphase I

DNA DNA organized into organized into chromatidschromatids

Spindle fibers formSpindle fibers form

Centrioles move to Centrioles move to opposite sides opposite sides

Nuclear membrane Nuclear membrane breaks apartbreaks apart

MeiosisMeiosisMetaphase IMetaphase IChromatids line Chromatids line

up on each side up on each side of the center of of the center of the cellthe cell

Spindle fibers Spindle fibers attach attach chromosomeschromosomes

Meiosis is a bit different because there something called crossing-over happens with the DNA.

This crossing over is an exchange of genes. The genes are mixed up, not resulting in a perfect duplicate like mitosis.

MeiosisMeiosisAnaphase IAnaphase ISpindle fibers Spindle fibers

pull the pull the chromosome chromosome pairs apart pairs apart to opposite to opposite ends of the ends of the cellcell

MeiosisMeiosisTelophase ITelophase ITwo new nuclei Two new nuclei

formformChromosomes Chromosomes

unwind unwind (chromatin)(chromatin)

MeiosisMeiosisCytokinesisCytokinesisCytoplasm Cytoplasm

splitssplitsTwo cellsTwo cells

Predict what happens next in Interphase II

Cytokinesis Interphase II

Keep in mind the four cells at the end of meiosis only get HALF of the genetic material…

MeiosisMeiosisInterphase IIInterphase IICell restsCell restsDNA DOES DNA DOES

NOTNOT duplicateduplicate

CentriolesCentrioles duplicateduplicate

MeiosisMeiosisProphase IIProphase II

DNA organized DNA organized into into chromatidschromatids

Spindle fibers formSpindle fibers form

Centrioles move to Centrioles move to opposite sidesopposite sides

Nuclear membrane Nuclear membrane breaks apartbreaks apart

MeiosisMeiosisMetaphase IIMetaphase IIChromosomes Chromosomes

line up across line up across the center of the center of the cellthe cell

Spindle fibers Spindle fibers attach to the attach to the chromosomeschromosomes

MeiosisMeiosisAnaphase IIAnaphase IISpindle fibers Spindle fibers

pull the pull the chromatids chromatids to opposite to opposite ends of the ends of the cellcell

MeiosisMeiosisTelophase IITelophase II

Two new nuclei Two new nuclei form around the form around the chromatidschromatids

Chromosomes Chromosomes unwind unwind (chromatin)(chromatin)

MeiosisMeiosisCytokinesisCytokinesisCytoplasm splits Cytoplasm splits 4 new cells!4 new cells!Each cell with Each cell with

only half of the only half of the genetic genetic informationinformation

Mitosis vs. MeiosisMitosis vs. Meiosis

Mitosis Meiosis