Honors: Chapter

Academic: Chapter 10

(AKA--Mitotic Phase) CELLCYCLECELLCYCLE

Parts of a Homologous Pair of Chromosomes

Part 1. INTERPHASE 3 Stages: G1SG2

Parts of a Homologous Pair of Chromosomes

Period of cell growth and development that precedes mitosis and follows CYTOKINESIS (cell splitting) Longest phase of the cell cycle. I NTERPHASE CELLCYCLECELLCYCLE

1.G 1 = Growth 1—most cell growth 2.S = Synthesis—cell makes a copy of its DNA 3.G 2 = Growth 2—cell grows a little to prepare for division I NTERPHASE CELLCYCLECELLCYCLE

Part 2. Cell Division MITOSIS & Cytokinesis 4 Stages: PMAT

Chromatin condense & thicken – now called chromosome. The nuclear envelope breaks down Centrioles move to opposite "poles“ (or ends) of the cell PROPHASE ** M I T O S I S **

1.The spindle (centriole) fully develops. 2.The chromosomes align at the metaphase plate (middle) METAPHASE ** M I T O S I S **

1.Paired chromosomes separate & begin moving to opposite ends (poles) of the cell. 2.Spindle fibers lengthen & elongate the cell. 3.Each pole contains a complete set of chromosomes. ANAPHASE ** M I T O S I S **

1.Nucleus begins to form at opposite poles. 2.The nuclear envelopes and nucleoli also reappear. TELOPHASE ** M I T O S I S **

Last Event!!! CYTOKINESIS

= the division of the original cell's cytoplasm. (There are now two separate cells) CYTOKINESIS CYTOKINESISCYTOKINESIS

CELLCYCLECELLCYCLE Do You Know the Stages of Mitosis? CYTOKINESIS PROPHASE ANAPHASE INTERPHASE METAPHASE TELOPHASE

So why do our cells need to divide?? n To heal any injuries n For growth n Replace lost or damaged cells CELLCYCLECELLCYCLE

 Cell growth and division are carefully controlled.  By what 2 “supervisors”??  Not all cells will go through the cell cycle at the same rate. Examples of cells rapidly dividing: Examples of cells NOT dividing often: RB C Muscle cells Skin cells Bone marrow Digestive tract cells Nerve cells CELLCYCLECELLCYCLE Cell Cycle Regulation

What happens if cells LOSE the ability to CONTROL the cell cycle? CANCERCANCER

 Cancer = uncontrolled cell growth... cancer cells do NOT respond to regulator signals... results in masses of cells called tumors... cancer = a disease of the cell cycle CANCERCANCER

What Causes Cancer? n Gene changes due to: – diet – tobacco use – exposure to radiation – exposure to chemicals – Inherited genes (cyclins/growth factors don’t work) n Immune System Failure Carcinogens CANCERCANCER

M ITOSIS M ICROSCOPE L AB What to do: 1. Locate various phases of Mitosis. 2. Take picture of cells 3. pictures to partner to upload to PowerPoint 4. Complete PowerPoint template 5. PowerPoint to Mrs. O When finished the lab please work on “Control of the Cell Cycle” Simulation.

Mitosis At the end of Interphase Prophase MetaphaseAnaphase Telophase At the end of Interphase Prophase Metaphase AnaphaseTelophase

1. Put the following steps of the cell cycle in order: a. Cytokinesis b. Prophase c. Anaphase d. Telophase e. Interphase f. Metaphase C ELL CYCLE C LOSURE ?’ S R*E*S*P*E*C*T ACCEPTANCE

2. During which phase does DNA duplicate or make a copy of itself? 3. At the beginning of mitosis (end of interphase) are chromosomes duplicated or unduplicated? 4. How many chromosomes are in a normal human body cell? 5. In which phase does the nuclear envelope break down? 6. In which phase do the sister chromatids pull apart? 7. In which phase are sister chromatids lined up in the middle of the cell? C ELL CYCLE C LOSURE ?’ S

MEIOSISMEIOSIS Now we will look at how our sex cells are made. -Sperm & Egg What is the difference between a ‘sex cell’ and a ‘body cell?’

MEIOSISMEIOSIS Sex Cell Body Cell  Sex cells have ½ the number of chromosomes of body cells “n”  AKA: gamete  AKA: haploid  Body cells have twice the number of chromosomes as sex cells 2 “n”  AKA: somatic  AKA: diploid

MEIOSIS  GAMETE FORMATION GAMETES= SEX CELLS Female Gamete= EGG Male Gamete= Sperm MEIOSISMEIOSIS

To create cells with ½ the genetic material you need to have a special process. This process, called MEIOSIS, occurs in the testes (men) and ovaries (females) in humans. MEIOSISMEIOSIS

LET’s COMPARE!! M & M MEIOSISMEIOSIS

(AKA--Mitotic Phase) CELLCYCLECELLCYCLE

Part 2. MEIOSIS I & MEIOSIS II MEIOSIS

Part 1. INTERPHASE 3 Stages: G1SG2

Interphase in all cells is the same. So, all you have to do is remember what you already know… I NTERPHASE CELLCYCLECELLCYCLE WHAT HAPPENS DURING INTERPHASE????

1.G 1 = Growth 1—most cell growth 2.S = Synthesis—cell makes a copy of its DNA 3.G 2 = Growth 2—cell grows a little to prepare for division I NTERPHASE CELLCYCLECELLCYCLE At the end of interphase each chromosome consist of two identical sister chromatids attached at their centromeres. HOMOLOGOUS PAIR- each chromosome that came from dad (orange) has a corresponding chromosome from mom (red)

(AKA--Mitotic Phase) CELLCYCLECELLCYCLE

MEIOSIS I

The first part of Meiosis (called Meiosis I) is responsible for reducing the chromosome number by 1/2. ** M E I O S I S ** MEIOSIS I n This part consists of 4 phases: a.Prophase I (crossing over) b.Metaphase I (independent assortment) c.Anaphase I d.Telophase I & Cytokinesis

-Prophase I is the longest and most complex phase. All of the events that occurred during prophase of mitosis occur PLUS … PROPHASE I ** M E I O S I S ** 1)Homologous chromosomes come together to form a TETRAD. 2)CROSSING-OVER occurs.

CROSSING OVER: Portions of 1 chromatid breaks off and attaches to an adjacent chromatid on the homologous pair. ** Exchanging of alleles** PROPHASE I ** M E I O S I S ** This INCREASES variability within a species!!!! TETRADTETRAD

*MEIOSIS**MEIOSIS* LET’s COMPARE!! M & M

There are 2 major events: 1) Homologous chromosomes line up in the Middle of the cell… RANDOMLY= independent assortment (helps to mix up the genetic material) 2) Each centromere becomes attached to a spindle fiber. METAPHASE I ** M E I O S I S **

*MEIOSIS**MEIOSIS* LET’s COMPARE!! M & M

-Homologous chromosomes separate and move towards the poles. -The sister chromatids remain attached at their centromeres. ** M E I O S I S ** ANAPHASE I

-Telophase I is the last step in meiosis I. (just like mitosis). - Following Telophase I.. Cytokinesis occurs and 2 haploid daughter cells are formed. TELOPHASE I ** M E I O S I S **

*MEIOSIS**MEIOSIS* LET’s COMPARE!! M & M

MEIOSIS I RECAP ** M E I O S I S ** Q: What is the purpose of Meiosis I? A: To decrease the # of chromosomes by 1/2 Q: What 2 features of Meiosis I increase the diversity of the daughter cells? A: Crossing Over & Independent Assortment

MEIOSIS II

n Meiosis II is broken into 4 events: –prophase II –metaphase II –anaphase II –telophase II. Meiosis II comes directly after cytokinesis. No growth (interphase) takes place. The steps of Meiosis II are IDENTICAL to Mitosis. ** M E I O S I S ** MEIOSIS II

** M E I O S I S ** MEIOSIS II

Interphase Telophase I Anaphase I Metaphase I Prophase I Cytokinesi s Images from: What happens here?? What type of cell am I??

Coming from Meiosis I Prophase II Metaphase II Anaphase II Telophase II Cytokinesis Images from:

MEIOSIS C OLORING A CTIVITY ** M E I O S I S ** Material: Coloring Activity Handout 4 colored pencils (different colors) Pen/Pencil Key: = Dad’s Chromosomes = Mom’s chromosomes = Nuclear Envelope = Centrioles & Spindles

CELL CYCLE 1. Interphase 2. Cell Division= Mitosis + Cytokinesis MITOSIS 1.Prophase 2.Metaphase 3.Anaphase 4.Telophase

CYTOKINESIS: P LANT C ELL VS. A NIMAL C ELL CYTOKINESISCYTOKINESIS