Cell Division: the process of copying and dividing entire cells The cell grows, prepares for division, and then divides to form new daughter cells.

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1 Mitosis & Meiosis SC.912.L Compare and contrast mitosis and meiosis and relate to the processes of sexual and asexual reproduction and their consequences for genetic variation.

2 1. Students will describe specific events occurring in each stage of the cell cycle and/or phases of mitosis, including cytokinesis. Cell Division: the process of copying and dividing entire cells The cell grows, prepares for division, and then divides to form new daughter cells. Unicellular organisms allows duplicate using asexual reproduction Multicellular organisms allows to grow, develop from single cell to multicellular, makes other cells to repair and replace worn out cells Three types: binary fission (bacteria and fungi), mitosis, and meiosis

3 1. Students will describe specific events occurring in each stage of the cell cycle and/or phases of mitosis, including cytokinesis. Cells divide through a process called the cell cycle which consists of interphase, mitosis, and cytokinesis. Note: majority of the cell cycle is Interphase, while a smaller portion is mitosis/cytoki nesis.

4 1. Students will describe specific events occurring in each stage of the cell cycle and/or phases of mitosis, including cytokinesis. Interphase: longest part of the cell cycle; growth, metabolism, and preparation for division occurs, duplicates chromosomes (DNA Replication)

5 1. Students will describe specific events occurring in each stage of the cell cycle and/or phases of mitosis, including cytokinesis. MITOSIS division of nucleus of the cell Prophase: duplicated chromosomes and spindle fibers appear Metaphase: duplicated chromosomes line up randomly in center of cell between spindle fibers Anaphase: duplicated chromosomes pulled to opposite ends of cell Telophase: nuclear membrane forms around chromosomes at each end of the cell; spindle fibers disappear; chromosomes disperse

6 1. Students will describe specific events occurring in each stage of the cell cycle and/or phases of mitosis, including cytokinesis. Cytokinesis: division of plasma membrane; two daughter cells result with exact genetic information In plants, a cell plate forms along the center and cuts the cell in half. In animals, a cleavage furrow develops to cut the cell in half.

7 1. Students will describe specific events occurring in each stage of the cell cycle and/or phases of mitosis, including cytokinesis. RESULTS OF MITOSIS: Two identical daughter cells Produces and occurs in somatic cells (body cells) Diploid = same number of chromosomes as original cell (humans = 46)

8 2. Students will explain how meiosis results in the formation of haploid gametes or spores. In meiosis, the cells will also start with interphase. There are TWO cell divisions instead of one, but the cell only does interphase ONCE prior to the first cell division. Meiosis is a reduction division process (chromosome numbers are divided in half) Each cell division consists of prophase, metaphase, anaphase, and telophase Occurs only in sex cells (gametes) and produces only gametes (egg and sperm)

9 2. Students will explain how meiosis results in the formation of haploid gametes or spores. First Division: Produces cells containing half # of double stranded chromosomes Prophase 1 crossing over occurs Metaphase 1 chromosomes line up in homologous pairs, independent assortment occurs Anaphase 1 chromosomes move towards each side Telophase 1 cells contain HALF of # of chromosomes

10 2. Students will explain how meiosis results in the formation of haploid gametes or spores. Crossing over: genes are essentially switching places on chromosomes in prophase I Independent assortment: the genes randomly move towards ends of cell in metaphase I THESE BOTH RESULT IN GENETIC VARIATION!

11 2. Students will explain how meiosis results in the formation of haploid gametes or spores. Second Division: Results in formation of four cells, each haploid (half the number of original chromosomes) (humans = 23)

12 2. Students will explain how meiosis results in the formation of haploid gametes or spores. RESULTS OF MEIOSIS: Four unique daughter cells Unique due to genetic variation such as crossing over and independent assortment Produces and occurs in gametes (sex cells) Haploid = half number of chromosomes as original cell (humans = 23) Sex cells combine during sexual reproduction to produce a diploid individual

13 3. Students will compare and contrast sexual and asexual reproduction. SEXUAL REPRODUCTION Pattern of reproduction that involves the production and fusion of haploid sex cells Haploid sperm from father fertilizes haploid egg from mother to make a diploid zygote

14 3. Students will compare and contrast sexual and asexual reproduction. ASEXUAL REPRODUCTION A single parent produces one or more identical offspring by dividing into two cells. Diploid cells are clones of parent cell.

15 DNA Replication SC.912.L.16.3 Describe the basic process of DNA replication and how it relates to the transmission and conservation of the genetic information.

16 1. Students will describe the process of DNA replication and its role in the conservation and transmission of genetic information. DNA Replication: DNA must replicate during the cell cycle (in both mitosis and meiosis) in order for genetic information to be passed on to daughter cells Semi-Conservative: the new daughter cells will have one strand of parent DNA and one strand of new DNA

17 2. Students will explain the basic process of transcription and/or translation and their roles in the expression of genes. DNA Replication occurs in two steps: 1. TRANSCRIPTION: DNA helicase unzips and unwinds the double helix; RNA primase inserts RNA into each strand as a place holder Base pairs must match! A U (because this is RNA) and C G! DNA polymerase then adds the appropriate matching nucleotide Again, base pairs must match! A T (because now we are adding DNA) and C G 2. DNA ligase links the two strands of DNA together and proofreads to be sure base pairs are matched correctly

18 2. Students will explain the basic process of transcription and/or translation and their roles in the expression of genes. Each strand of parent DNA makes TWO strands of daughter cell DNA!

19 2. Students will explain the basic process of transcription and/or translation and their roles in the expression of genes. Practice matching this strand of DNA to its parent strand of DNA:

20 2. Students will explain the basic process of transcription and/or translation and their roles in the expression of genes. Practice matching this strand of DNA to its parent strand of RNA: U U U

21 2. Students will explain the basic process of transcription and/or translation and their roles in the expression of genes. After DNA Replication has began, the process of Protein Synthesis simultaneously begins: Once the first stage of transcription has occurred (DNA base pairs matching with RNA base pairs), the RNA is then sent out of the nucleus and moves towards to ribosome through a process called TRANSLATION. Once in the ribosome, the RNA strand is converted to amino acids (building blocks of proteins) through the use of codons.

22 2. Students will explain the basic process of transcription and/or translation and their roles in the expression of genes. You must be able to read a codon table: AUG UCA CAA??? Met Ser - Gin

23 3. Students will describe gene and chromosomal mutations. Sometimes the process of DNA replication will become flawed, resulting in mutations. Mutations: changes in the genetic code Passed from one cell to new cells Transmitted to offspring if it occurs in sex cells Most will have no effect

24 3. Students will describe gene and chromosomal mutations. Gene Mutation: change in a single gene Chromosome Mutation: change in many genes Can be spontaneous or caused by environmental mutagens (radiation, chemicals, etc)

25 Mendel & Inheritance SC.912.L.16.1 Use Mendel s laws of segregation and independent assortment to analyze patterns of inheritance.

26 1. Students will use Mendel s laws of segregation and independent assortment to analyze patterns of inheritance. Mendel s Law of Segregation: gene pairs separate when gametes (sex cells) are formed; each gamete as only one allele of each gene pair Review: Heterozygous = the two alleles are different (hybrid) Aa or Bb Homozygous = the two alleles are the same (AA or aa)

27 1. Students will use Mendel s laws of segregation and independent assortment to analyze patterns of inheritance. Mendel s Law of Independent Assortment: different pairs of genes separate independently of each other when gametes are formed This means when chromosomes line up in homologous pairs during Metaphase I of meiosis that not ALL of moms chromosomes are on one side and not ALL of dads chromosomes are on one side THEY ARE INTERMIXED!

28 1. Students will use Mendel s laws of segregation and independent assortment to analyze patterns of inheritance. Dominant Traits: shown with capital letters; controlling trait Example: Brown hair over blonde hair; Huntington s disease Recessive Traits: shown with lowercase letters; hidden allele Examples: Cystic fibrosis and Tay Sach s can be a carrier OR must have two recessives for it be expressed

29 1. Students will use Mendel s laws of segregation and independent assortment to analyze patterns of inheritance. Inheritance can be predicted using a Punnett square Results show the probability of an offspring receiving that trait, and may be expressed in percent, ratios, or fractions Genotype probability (genetic makeup of the organism): TT 25%, ¼, or 1:4 Tt 50%, ½, or 2:4 (1:2) Tt 25%, ¼, or 1:4

30 1. Students will use Mendel s laws of segregation and independent assortment to analyze patterns of inheritance. Practice predicting Punnett square results. Express results for both genotype and phenotype (physical appearance of an organism)

31 1. Students will use Mendel s laws of segregation and independent assortment to analyze patterns of inheritance. Two Types of Crosses: Monohybrid: Contains four boxes; a cross between two heterozygous would produce a 1:2:1 genotype ratio and a 3:1 phenotype ratio Dihybrid: Contains sixteen boxes; a dihybrid cross involves two traits for each parent and a cross between two heterozygous parents would produce a 9:3:3:1 phenotype ratio

32 1. Students will use Mendel s laws of segregation and independent assortment to analyze patterns of inheritance. Dihybrid Cross:

33 2. Student s will identify, analyze, and/or predict inheritance patterns cause by various models of inheritance. Patterns of Inheritance: Sex Chromosomes: 23 pairs, XY = males, XX = females Sex-Linked Traits: traits linked with particular sexes, X-linked traits are inherited on X chromosome from mother (examples: hemophilia, color-blindness, baldness); more common in males since females have another X Multiple Alleles: presence of more than two alleles for a trait (eye color) Polygenic Trait: one trait controlled by many genes (hair color, skin color); genes may be on the same chromosome or different

34 2. Student s will identify, analyze, and/or predict inheritance patterns cause by various models of inheritance. Patterns of Inheritance (Continued): Codominance: phenotypes of both homozygous parents are produced in heterozygous offspring so both alleles are expressed (black + white chickens = checkered chicken; sickle cell anemia) Incomplete Dominance: phenotype of a heterozygote is a mix of the two homozygous parents; neither allele is dominant, but combine to display both traits (white flower + red flower = pink flower)

35 2. Student s will identify, analyze, and/or predict inheritance patterns cause by various models of inheritance. A pedigree may be used to show patterns of inheritance squares = males and circles = females shaded = affected, halfshaded = carrier