Materials: worksheet GET OUT BINDER FOR ME TO CHECK! Make sure notes 3.6 (textbook pages 246-252) are in there Catalyst: What does a restriction enzyme do? Describe one way that recombinant DNA is used in our world today.

Announcements Work on Mutant Makers project this weekend DUE next Wednesday for periods 1, 2, 4, 6. Due in 2 weeks for periods 5, 7 New tutorial days: Monday and Wednesday Bring back progress report signed for EC. AUCTION TODAY!

Objectives I can name and identify the parts of a chromosome. I can differentiate between body cells and gametes. I can name and define the steps of the Cell Cycle.

Mitosis vs. Meiosis

Chromosomes condense at the start of mitosis. DNA wraps around proteins (histones) that condense it. DNA double helix DNA and histones Chromatin Supercoiled DNA

Chromatin: DNA and proteins. chromatid telomere centromere Condensed, duplicated chromosome Chromatin: DNA and proteins. Chromatid: One half of a duplicated chromosome Sister chromatids: held together at the centromere. Telomeres: protect DNA and do not include genes. Homologous Chromosomes: pairs of chromosomes that carry the same genes

Cell Types The body has 2 types of cells. Gametes: sex cells (sperm and egg) that combine to make a new person Body Cells: all cells that are not gametes. Example???

Cell Types

Cell Types 2 main types of cells in our bodies: Gametes: sex cells (egg and sperm) that combine to make a new individual Body cells: all cells that are not gametes (examples: blood cell, brain cell)

Body cell or gamete?

sperm

Skin cell

egg

Brain cell

Blood cell

Hair cell

Body Cells Body cells have 2 copies of each chromosome (46 chromosomes total!)

Body Cells Diploid (2n): having 2 copies of each chromosome Body cells are diploid.

Gametes have 1 copy of each chromosome (23 chromosomes total) Haploid (1n): Having 1 copy of each chromosome Gametes are haploid (23 chromosomes)

Gametes Haploid (1n) gametes combine to make diploid (2n) body cells

Cell Types: THINK How many chromosomes do body cells have? How many chromosomes do gametes have? Why does it make sense that gametes have half the chromosomes as body cells? A body cell has 20 chromosomes. How many does the gamete have?

MITOSIS

Mitosis/Asexual Reproduction Mitosis: how body cells are formed Asexual reproduction: reproduction with 1 parent cell divides in half

Requires DNA Replication Produces 2 identical diploid cells Mitosis/Asexual Reproduction Requires DNA Replication Produces 2 identical diploid cells

Think What are some times when we would use mitosis?

Challenge With your partner/group Take out ONLY the picture cards Put the picture cards in logical order THINK: what do we start with in Mitosis? THINK: what do we end with in Mitosis?

Steps of the Cell Cycle Memory Trigger A___________________: ____________________ T___________________: _____________________

Mitosis and cytokinesis produce two genetically identical daughter cells. Parent cell centrioles spindle fibers centrosome nucleus with DNA Interphase prepares the cell to divide. During interphase, the DNA is duplicated.

During prophase, chromosomes condense and spindle fibers form. Mitosis divides the cell’s nucleus in four phases. During prophase, chromosomes condense and spindle fibers form.

During metaphase, chromosomes line up in the middle of the cell. Mitosis divides the cell’s nucleus in four phases. During metaphase, chromosomes line up in the middle of the cell.

Mitosis divides the cell’s nucleus in four phases. During anaphase, sister chromatids separate to opposite sides of the cell.

During telophase, the new nuclei form and chromosomes begin to uncoil. Mitosis divides the cell’s nucleus in four phases. During telophase, the new nuclei form and chromosomes begin to uncoil.

In animal cells, the membrane pinches closed. Cytokinesis differs in animal and plant cells. In animal cells, the membrane pinches closed. In plant cells, a cell plate forms.

CHALLENGE With your partner/group: Place the picture cards in the correct order Assign the correct phase name to each picture Assign the correct description to each picture FIRST TEAM TO GET IT ALL CORRECT GETS 8 TICKETS EACH PERSON!

Classwork Finish the 8 questions on the back of your worksheet (Classwork 3.6)

STOP HERE FOR NOTES 3.6!

Sexual Reproduction Sexual reproduction: reproduction with 2 parents 2 gametes (egg and sperm) combine Fertilization: egg and sperm meet to form a new individual (zygote)

Body Cells Chromosomes come in pairs (called homologous chromosomes) Body cells have 2 copies of each chromosome (46 chromosomes total) Diploid (2n): 2 copies of each chromosome Body cells are diploid (46 chromosomes)

Meiosis

Meiosis Meiosis: how gametes are formed Meiosis = sexual reproduction. 1 diploid cell divides into 4 haploid gametes Meiosis 1 Body cell (diploid) 4 gametes (haploid)

Meiosis Meiosis has 2 cell divisions When a cell goes through meiosis the chromosome number cuts in half Meiosis 1 Body cell (diploid) 4 gametes (haploid)

Meiosis 1

Meiosis 1

Meiosis I occurs after DNA has been replicated. Meiosis I divides homologous chromosomes in four phases.

Meiosis II divides sister chromatids in four phases. DNA is not replicated between meiosis I and meiosis II.

Crossing over during meiosis increases genetic diversity. Crossing over is the exchange of chromosome segments between homologous chromosomes. occurs during prophase I of meiosis I results in new combinations of genes

Think What does meiosis form? How many cells does meiosis make? How many times does the cell divide in half in meiosis? What happens to the number of chromosomes in a cell as it goes through meiosis?

Think: Mitosis or Meiosis?

Asexual Reproduction

Gametes

Produces 2 cells

Variation

Sexual Reproduction

Cell divides in half

No variation

2 cell divisions

Produces 4 cells

Mitosis vs. Meiosis MITOSIS MEIOSIS Asexual Sexual Diploid Haploid 1 2 Sexual or Asexual? Diploid or haploid formed? Number of Divisions? Number of cells produced? Variation or Stability? Asexual Sexual Diploid Haploid 1 2 4 Stability Variation