11/22/2015 Cell Cycle A. The Cell Theory: 1. All organisms are composed of one or more cells. 2. The cell is the basic unit of life. 3. All cells come from existing cells. B. Cells go through a Cell Cycle to: 1. Grow 2. Repair 3. Replace 4. Create haploid cells that can combine to make an organism

11/22/2015 Cell Cycle - Interphase: G 1 - growth: increase size of cell G 0 - resting phase (*neurons, liver, muscle cells) S - growth as in DNA Synthesis (replication) G 2 - growth: organelles and biochemicals - M Phase (Mitotic Phase) Mitosis: division of nuclear material Prophase, Metaphase, Anaphase, Telophase Cytokinesis: division of cytoplasm & organelles

11/22/2015 Cell Cycle

11/22/2015 Cell Cycle Regulation Can DNA synthesis begin? Did DNA replicate properly? Can sister chromatids separate properly? Promoting factors –Cyclins regulatory proteins for the cell cycle –Cdks cyclin-dependent kinases enzyme activates cellular proteins –MPF maturation (mitosis) promoting factor combo of a cdk (enzyme) and cyclin (substrate) –APC anaphase promoting complex

11/22/2015 Faulty Cell Cycle Regulation unlimited growth turn on growth promoter genes ignore checkpoints turn off tumor suppressor genes escape apoptosis turn off suicide genes immortality = unlimited divisions turn on chromosome maintenance genes promotes blood vessel growth turn on blood vessel growth genes overcome anchor & density dependence turn off touch sensor gene DNA damage is caused by heat, radiation, or chemicals. p53 allows cells with repaired DNA to divide. Step 1Step 3 p53 triggers the destruction of cells damaged beyond repair. NORMAL p53 Cell division stops, and p53 triggers enzymes to repair damaged region. Step 2 DNA repair enzyme p53 protein p53 protein DNA Polymerase I

11/22/2015 Mitosis 1 division daughter cells genetically identical to parent cell produces 2 cells 2n  2n Diploid  Diploid produces cells for growth & repair No homologous chromosomes pairing no crossing over Meiosis 2 divisions daughter cells genetically different from parent produces 4 cells 2n  1n Diploid  Haploid produces gametes for reproduction Homologous chromosomes and tetrads crossing over Synapse (homologous chr together Chiasma Nondisjunction

11/22/2015 Mitosis vs Meiosis

11/22/2015 Nondisjunction

4 genetically unique cells 1 egg 3 smaller polar bodies 4 genetically unique sperm Synapsis - pairing of homologous chromosomes Chiasma - point where crossing over occurs Haploid (n) or Diploid (2N)? Meiosis - production of gametes from a Germ Cell Interphase Prophase I Metaphase I Anaphase I Prophase II Metaphase II Anaphase II Telophase II Telophase I No Interphase between Meiosis I and Meiosis II, means that G 1, S, and G 2 do not occur. What is the end result in terms Of the chromosome number? What 3 things happen here?

11/22/2015 tetrad Homologous chromosomes Crossing over

11/22/2015 KaryotypePedigree ? Crossing Over

11/22/2015 Writing Prompt 1. What are the phases of the cell cycle and what is occurring? –Sentence starter: A cell that has divided goes into ___ phase where… 2. Not all cells move through the cell cycle in the same way. Give examples of three different cells and their destiny. –Sentence starter: The frequency of cell division varies with cell type, one example is … 3. Discuss the 3 checkpoints of the cell cycle, where they take place, what indicates the cells readiness to continue, and what chemicals triggers the “go ahead.” –Sentence starter: In the cell cycle, there are three defined checkpoints for cells, the first one…

Genetics Overview

Inheritance Genetic Information Passes on as genes at a certain location on a chromosome (locus) Chromosomes are paired –Autosomal (22 pairs) –Sex-Linked (1 pair)

Terms Traits - Alleles Dominant - Recessive Genotype - Phenotype Homozygous - Heterozygous Pure - Hybrid P generation - Filial generations Gametes - Offspring Law of Segregation Law of Inheritance

Terms Codominant Incomplete dominance Epistasis Pleiotropy Multiple alleles Polygenic Sex-linked

Locus

Punnett Squares Punnett Squares show: 1. The alleles in the gametes of each parent, 2. Possible results of genetic crosses, and 3. The genotypes of the offspring. Steps to Creating and Using Punnett Squares: 1. Identify the trait and possible alleles (dominant and recessive) 2. Determine the genotype of the parents 3. Create the Punnett Square - each trait needs 2 boxes to represent it 4. Put the male across the top, Female along the side. 5. Fill in the Punnett Square representing the offspring produced 6. Determine the Genotype Ratio (GR) of the offspring. 7. Determine the Phenotype Ratio (PR) of the offspring.

Punnett Squares Monohybrid Dihybrid FOIL Method

Two-Point Cross Data BVbvBvbV bv BbV v bbvvBbvvbbVv Expecte d Results 575 Actual Results  Calculations  Parental Genotypes  965 (42%) +944 (41%) = 1909  1909/2300 = 83%  Recombinant Genotypes  206 (9%)+185 (8%) = 391  391/2300 = 17%  If independent assortment was to occur, the percentages would be 25% a piece.  Based on the data, the recombinants arose because of crossing over Sunday, November 22,  If the majority of the offspring have a genotype similar to one of the parents, then the genes are linked.  If the majority of the offspring have a recombinant genotype, then the genes are unlinked.