Bellwork: 1.Have out your Notecard Sticker Sheet. Lay out your notecards (definition side up) on your desk 6x5 “Allele” needs to be top left card. 2.Have out Page Write the word and label with the correct letter.

Collect Today Page 60 – Cancer Webquest Notecard Definitions Assigned Page 59 – Cell Cycle Concept Map Corrections (Monday) Notecard ALL PARTS (Friday) Cell Cycle/Vocabulary Make-Up Quiz (Friday) Most Missed Quiz Make-Up (Friday) Late Page 59 – Cell Cycle Concept Map (-50%) Page 58 – Cell Cycle Foldable (-30%)

Unit 4 – Cell Cycle Definitions Due Friday (11/6/15) All Parts Due Friday (11/13/15) 1.Allele 2.Anaphase 3.Cancer 4.Cell Cycle 5.Centriole 6.Centromere 7.Chromatid 8.Chromosome 9.Crossing Over 10.Cytokinesis 11.Daughter Cell 12.Diploid 13.Electrophoresis 14.Frameshift Mutation 15.Gamete 16.Gene 17.Genetic Disorder 18.Genome 19.Haploid 20.Interphase 21.Karyotype 22.Meiosis 23.Metaphase 24.Mitosis 25.Mutation 26.Offspring 27.Point Mutation 28.Prophase 29.Sexual Reproduction 30.Somatic 31.Telophase 32.Tumor Pg 54

Essential Question What is meiosis and how is it different from mitosis? Standard B.6G – Recognize the significance of meiosis in sexual reproduction Pg 55

On a cellular level, what happens during sex? Biologically speaking, what’s the point of sex?

If YOU are human, then YOUR cells have 46 chromosomes and your parents’ cells each have 46 chromosomes. Agreed? If you get DNA from both your parents then why wouldn’t you end up with 92 chromosomes? Aaron: It’s because the male gamete actually only contributes 35 of the chromosomes and the female gamete contributes the remaining 11 Brittney: When the male and female gamete join, the result is 92 chromosomes but as the baby develops, chromosomes that are not needed are destroyed during mitosis. Karen: There must be some way that the male and female gamete each carry only 23 of the chromosomes from each parent so that when they get together they equal 46. Blake: The gametes each contain the full 46 chromosomes from each parent but when fertilization occurs only the first 23 that pair up are used.

When gametes (sex cells) are formed, a process occurs that separates the two sets of genes so that each gamete ends up with just one set. Karen: There must be some way that the male and female gamete each carry only 23 of the chromosomes from each parent so that when they get together they equal 46.

Chromosomes are located in the cell nucleus. An organism inherits a single copy of each chromosome from both its parents. Because every organism has two parents, each organism carries two sets of chromosomes. The two sets of chromosomes (one from mom and one from dad) are homologous.

A cell that contains both sets of homologous chromosomes is said to be diploid. Diploid means “two sets”. 2N is used to represent the number of chromosomes in a diploid cell.

When gametes (sex cells) are formed, there must be a process that separates the two sets of genes so that each gamete ends up with just one set.

The gametes contain only a single set of chromosomes and are said to be haploid. Haploid means “one set”. N is used to represent the # of chromosomes in a haploid cell.

Meiosis is a process in which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell. ** Meiosis is how gametes are produced**

Meiosis usually involves two divisions called meiosis 1 and meiosis 2. By the end of meiosis, the diploid cell that entered meiosis has become four haploid cells.

During Prophase I of meiosis, chromosomes line up to form homologous pairs. When crossing over occurs genetic material is exchanged between maternal and paternal chromosomes. Crossing over results in genetic variation. Label the diagram Dad’s chromosome Mom’s chromosome Crossing over Result = genetic variation

Dad’s chromosome Mom’s chromosome Crossing Over DNA Replication Crossing Over

The diagram below shows the possible variations for just one chromosome set going through Meiosis. Imagine the possibilities you could get with 46!!!

In male animals, the haploid gametes produced by meiosis are called sperm. In female animals, the haploid gametes produced by meiosis are called eggs.

Mom’s chromosome Dad’s chromosome Identical Copy MITOSIS

Mitosis results in two genetically identical diploid cells. Mitosis is used for growth and repair. Mitosis is used for somatic (body cell) production. Meiosis results in four genetically different haploid cells. Meiosis is used for gamete production and increased genetic variation.

Mitosis is used for growth and repair. Meiosis is used for gamete production and increased genetic variation.

MitosisMeiosis