bellringer Write the questions and answers in your composition books. (YOU CANNOT USE YOUR NOTES) What is mitosis in your own words? What is the acronym used when describing mitosis? How many cells are made at the end of mitosis? Are they identical or different?

Mitosis & Meiosis Mitosis animation: http://www.youtube.com/watch?v=2WwIKdyBN_s&feature=related

Mitosis: If a cell wants to make a duplicate of itself, it first must copy its DNA (part of a chromosome). The copies then must be separated & sorted into two sides of the cell. The cell then splits in two. Part of each parent is carried to the two new cells. Results in cells such as internal organs, skin, bones, blood, etc.

This may you remember these terms: MITosis takes the cell and Makes It Two (diploid) Meiosis has to do with sex From the cell’s point of view: mITosis results in Identical Twins mEioSis results in Egg and Sperm (haploid) Clyde Freeman Herreid – Dept. of Biological Sciences: Buffalo State Univ. of New York

Bell ringer: When a cell is diploid how many chromosomes does it have? When a cell is haploid, how many chromosomes does it have? Provide an example of a diploid cell and a haploid cell? What is the difference between a gene mutation and a chromosomal mutation?

Each resulting cell still has chromosomes from mom & dad Mitosis: Meiosis: Explain the randomness in meiosis End of first class Each resulting cell still has chromosomes from mom & dad

Interphase occurs just before Mitosis begins: DNA is replicated along with organelles and other cellular components and the cell prepares for division. http://www.bioweb.uncc.edu/1110Lab/notes/notes1/lab6.htm

Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm Mitosis Interphase Animal cell Plant cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

1st step in Mitosis: Prophase (preparation phase) The DNA recoils, and the chromosomes condense; the nuclear membrane disappears, and the mitotic spindles begin to form. http://www.bioweb.uncc.edu/1110Lab/notes/notes1/lab6.htm

Bell Ringer: Write the questions What is occurring inside of the cells during prophase of mitosis? What are the possible genotype for an individual with blood type B? What are autosomes? What type of cell is 2n?

Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm Mitosis Prophase Animal cell Plant cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

2nd step in Mitosis: metaphase (organizational phase) The chromosomes line up the middle of the cell with the help of spindle fibers attached to the centromere of each replicated chromosome. http://www.bioweb.uncc.edu/1110Lab/notes/notes1/lab6.htm

Bell ringer (write the question) At which phase of mitosis do you expect to see the nucleus forming again? When do you first see the mitotic spindles? Explain what is occurring in anaphase?

Meiosis: As in mitosis, if a cell wants to make a duplicate of itself, it first must copy its DNA (part of a chromosome). Results in reproductive cells (sperm, eggs, etc). Part of each parent is carried to the four new cells. Meiosis has evolved to solve a problem. The problem is this: some organisms have sex with other organisms – that is, they combine their genes together (creating genetic diversity). Why would this be a problem?

Mitosis Metaphase Animal cell Plant cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

3rd step in Mitosis: Anaphase (separation phase) The chromosomes split in the middle and the sister chromatids are pulled by the spindle fibers to opposite poles of the cell. http://www.bioweb.uncc.edu/1110Lab/notes/notes1/lab6.htm

Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm Mitosis Anaphase Plant cell Animal cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

4th step in Mitosis: Telophase The chromosomes, along with the cytoplasm and its organelles and membranes are divided into 2 portions. This diagram shows the end of telophase. http://www.bioweb.uncc.edu/1110Lab/notes/notes1/lab6.htm

Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm Mitosis Telophase Animal cell Plant cell Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm

After Mitosis: Cytokinesis Beginning of cytokinesis in a plant: The actual splitting of the daughter cells into two separate cells is called cytokinesis and occurs differently in both plant and animal Cells. Beginning of cytokinesis in an animal: http://www.bioweb.uncc.edu/1110Lab/notes/notes1/lab6.htm

Mitosis Booklet You are to make a mitosis booklet Must include the following: Title page (with name, date, period, and picture) (2pt) Table of contents (1 pt) Define mitosis and state why it is important for body cells to undergo mitosis (2pts) Different stages of mitosis with a sub heading. Each phase needs to have its own separate page (PMAT, cytokinesis and interphase) (6pts) Needs to give an explanation of what is happening at each stage of mitosis (PMAT, cytokinesis, and Interphase) (6pts) Picture of each stage in an animal cell and plant cell (total 12 pics) (12 pts) can be hand drawn or printed Page explaining what cancer is and why it happens. (2pts) Needs to be creative (2pts) Total pts: 33 pts (ALL THE INFORMATION NEEDS TO BE TYPED AND PASTED IN THE BOOKLET)

Meiosis Meiosis animation: http://www.youtube.com/watch?v=D1_-mQS_FZ0&NR=1 Beginning of third class

Vocabulary Diploid Haploid Germ cell Somatic cell Interphase Prophase Metaphase Anaphase Telophase Cytokinesis

Bell ringer What is fertilization? What is the process called for the formation of both reproductive cells? What is the general name for the location where meiosis occurs? Meiosis produces how many cells? Are they identical? Haploid or diploid?

Meiosis Sex cells divide to produce GAMETES (sperm or egg). Gametes have HALF the # of chromosomes. Occurs only in GONADS (testes or ovaries). Male: SPERMATOGENESIS -sperm Female: OOGENESIS - egg or ova

Fertilization The fusion of a sperm and egg to form a zygote. A zygote is a FERTILIZED EGG n=23 egg sperm n=23 2n=46 zygote

Meiosis Interphase Meiosis is preceded by interphase. The chromosomes have not yet condensed. http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

MEIOSIS I Meiosis I Homologs separate

Meiosis Interphase The chromosomes have replicated, and the chromatin begins to condense. http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

Meiosis Prophase I The chromosomes are completely condensed. In meiosis (unlike mitosis), the homologous chromosomes pair with one another Crossing over occurs http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

Metaphase I Shortest phase Tetrads align on the equator. Independent assortment occurs – chromosomes separate randomly causing GENETIC RECOMBINATION

Homologs line up at equator or metaphase plate Metaphase I Homologs line up at equator or metaphase plate OR

Meiosis Anaphase I The chromosomes move to opposite ends of the cell. http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

Meiosis Telophase I & Cytokinesis The cell begins to divide into two daughter cells. It is important to understand that each daughter cell can get any combination of maternal and paternal chromosomes. http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

Sister Chromatids Separate MEIOSIS II Sister Chromatids Separate Meiosis II

Meiosis Prophase II The cell has divided into two daughter cells. http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

Meiosis Metaphase II As in Meiosis I, the chromosomes line up on the spindle fibers. http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

Meiosis Anaphase II The two cells each begin to divide. As in Meiosis I, the chromosomes move to opposite ends of each cell. http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

Telophase II & Cytokinesis With the formation of four cells, meiosis is over. Each of these prospective germ cells carries half the number of chromosomes of somatic cells. http://morgan.rutgers.edu/MorganWebFrames/Level1/Page7/meiosis1.html

Nondisjunction Nondisjunction is the failure of chromosome pairs to separate properly during meiosis 1 or meiosis 2

Bell ringer: (write the question) How are meiosis 1 and meiosis 2 different? What is nondisjunction? Which phase of meiosis is consider the longest? (hint: were does crossing over occur) Which phase of meiosis is considered the shortest?

Question: A cell containing 20 chromosomes (diploid) at the beginning of meiosis would, at its completion, produce cells containing how many chromosomes?

10 chromosomes (haploid) Answer: 10 chromosomes (haploid)

Question: A cell containing 40 chromatids at the beginning of meiosis would, at its completion, produce cells containing how many chromosomes?

Answer: 10 chromosomes

Non-disjunctions usually occur in one of two fashions. The first is called Monosomy, the second is called Trisomy. If an organism has Trisomy 18 it has three chromosomes in the 18th set, Trisomy 21…. Three chromosomes in the 21st set. If an organism has Monosomy 23 it has only one chromosome in the 23rd set.

Common Non-disjunction Disorders Down’s Syndrome – Trisomy 21 Turner’s Syndrome – Monosomy 23 (X) Kleinfelter’s Syndrome – Trisomy 23 (XXY) Edward’s Syndrome – Trisomy 18

Amniocentesis An Amniocentesis is a prrocedure a pregnant woman can have in order to detect some genetics disorders…..such as non-disjunction.

Amniocentesis Amniotic fluid withdrawn

Karyotype (picture of an individual’s chromosomes) One of the ways to analyze the amniocentesis is to make a Karyotype What genetic disorder does this karyotype show? Trisomy 21….Down’s Syndrome

Bell ringer: write the question What is amniocentesis? What can non-disjunction produce? What are the stages of mitosis? In what stage of the cell cycle does the DNA get duplicated?