Unit 4 Review - Genetics. UNIT 4 Vocabulary topics: Cell Reproduction, Cell Cycle, Cell Division, Genetics

Transcription

1 Unit 4 Review - Genetics Sexual vs. Asexual Reproduction Mendel s Laws of Heredity Patterns of Inheritance Meiosis and Genetic Variation Non-Mendelian Patterns of Inheritance Cell Reproduction/Cell Cycle/ Mitosis/ Meiosis UNIT 4 Vocabulary topics: Cell Reproduction, Cell Cycle, Cell Division, Genetics 4.1- Asexual-reproduction, Gamete, Sexual Reproduction, Binary Fission, Genetic Variation, Budding, Fertilization, Vegetative Propagation, Cancer, Carcinogen, Cell Cycle, Chromosomes, Mitosis, Mutation 4.2- Allele & Genes, Genetic Cross, Gamete, Phenotype & Genotype, Dominant & Recessive, Gamete, Punnett square, Principle of Independent Assortment, Principle of Segregation, Homozygous & Heterozygous, Mendel, Heredity, P1 generation (parental generation), F1 Generation (first filial generation,, F2-generation (second filial generation) pp / Diploid & Haploid Numbers of Chromosomes, Homologous Chromosome, Meiosis, Crossing-over, Codominance, Karyotype, Incomplete dominance, Polygenic Traits, Genetic disorder, Pedigree, Sex-linked, Multiple Allele, Gene mapping

2 EQ: What is is the Difference Between Sexual and Asexual Reproduction? SEXUAL REPRODUCTION-MEIOSIS e.g. mammal reproduction, conjugation in bacteria-any male + female sex cell, syngamy ASEXUAL REPRODUCTION-MITOSISe.g. Budding, Cuttings, binary fission, regeneration, cloning, genetic engineering, parthenogenesis (819) Requires 2 parents or sex cells or gametes (Sperm + egg) with haploid no. of unite to to form a zygote with diploid no. of of Requires only 1 parent Meiosis is is the cell division that forms the sex cells or or gametes Mitosis is is the cell division involved in in asexual reproduction Genetic diversity occurs as genes recombined from 2 parents No No genetic diversity occurs.all offspring =identical EQ: What are the Advantages and Disadvantages of Asexual vs vssexual Reproduction? Advantages of Sexual Reproduction *Sexual reproduction two organisms formation of gamete cells. The gametes fuse together causing genetic diversity *This increases the chances of the organism evolving into a healthier and more adaptable species. Genetic diversity ensures, there is is a lesser chance of diseases and defects seen in in parents being passed on to their children. Disadvantages of Sexual Reproduction *Reproduction cannot occur until gametes from 2 parents fuse together.-time and energy *Only half of the population that is, female species are capable of gestation. *There is no guarantee that the nucleus of the male gamete will fuse with the female gamete after mating. baby *The time taken to produce an offspring by sexual reproduction is is very long. Advantages of Asexual Reproduction *One parent is is needed to complete the process of asexual reproduction. *In majority of the cases, one is is sure an offspring will be produced. *The gestation period or growth period is is very short. *The offspring has the same phenotype and genetic make up as the parent. *As there is is no genetic diversity the chance of mutation is is very less. Disadvantages of of Asexual Reproduction *As the same genetic material from parent is is directly passed on to to the off spring, it it causes all all the diseases and defects to be passed on to the offspring as as well. *As no recombination of genes occurs, chances of evolution are very low.

3 EQ: What are the phases + events of the cell cycle? THE CELL CYCLE OCCURS IN EUKARYOTIC CELLS - pp281 The CELL CYCLE includes - INTERPHASE + CELL DIVISION + CYTOKENESIS G1 growth Increase in size + makes new organelles S - synthesis of DNA DNA + Chromosomes are replicated G2 growth-more organelles are produced; shortest phase Mitosis or Meiosis-Cell Divides P-M-A-T Cytokinesis - Cytoplasm splits Cell Division ** In PROKARYOTIC Cells - No cell Cycle just Binary fission How is is cell cycle and cancer related? pp289 The cell is unable to pick up signals to stop dividing due to a defective gene or mutation.= gene mutation It continues to over divide tumors Cancer. It It is a problem with regulation of cell division How are Mitosis & Mitosis Meiosis Meiosis Different - p326 *No. of Divisions 1 2-Meiosis 1 and Meiosis 2 *# of Cells we begin and end with Begin with 1 cell End with 2 cells Begin with 1 cell End with 4 cells Product Genetic diversity *No. of in beginning compared with the number we end with (Haploid +diploid) Body Cells/somatic cells with same # we started with. Ex. brain, nerve, any cell but sex cell No crossing over of -no genetic diversity Diploid=same # as Body Cells.We begin and end with same # 2n 2n Sex cells/gametes /sperm/egg/ovum-with ½ # of of we started with Crossing over of occur in in Meiosis 1-1- metaphase=genetic diversity Haploid=1/2 we end with 1/2 of # of of body cells 2n n

4 EQ: What are the differences between Mitosis and Meiosis? pp326 EQ: What happens During MEIOSIS 1? PROPHASE 1 = Formation of Tetrads and Crossing Over ANAPHASE 1 = Segregation of Chromosomes //RESULT= Reduction of Chromosome Number M1 = Tetrads Crossover & Segregate

5 EQ: What are the stages in Mitosis and Meiosis Chart shows location of during cell division) Memory Chart of Phases Mitosis + Meiosis: Location/ Phase Where are the Chromosomes P = prophase Prepare M = metaphase Middle A = anaphase Apart T = telophase (May include cytokinesis) Tails Please Make All The..Classes Interesting) EQ: What is the difference between HAPLOID and DIPLOID Cells? Organism Clue body cell gamete haploid cell diploid cell Sperm gamete egg gamete pp327 N 2N 1.a gamete of a housefly has a human muscle cell has a leaf cell of corn has a haploid cell of of fruit fly fly has a diploid duck cell has

6 EQ: What is the difference between the results of MITOSIS and MEIOSIS? MITOSIS IS Starting ting Ending EXAMPLE 1 cell with x 2 cells and the 1 cell with 10 same number of x 2 cells each with 10 =DIPLOID=BODY CELLS MEIOSIS 1 cell with x Ending with HAPLOID=1/2 body cells. 4 cells each with half of original number of of x 1 cell with 10 4 cells each with 5 ( ½ of of 10 ) =HAPLOID =SEX CELLS, GAMETES, EGG, SPERM HAPLOID = n = 1/2 number of = only one of of each pair DIPLOID = 2n = HAPLOID x 2 = both in a the pair MITOSIS Produces Body cell or Somatic cell e.g. skin cell Starts with x number of End with each cell same # End product 2 Diploid cells w. same # MEIOSIS Produces the sex cell, egg, sperm or gamete Starts with x number of End with each having ½ of of original cell End product = 4 Haploid cells w ½ # Crossover occurs genetic variation Associated with Mendel laws of Heredity and genetic inheritance

7 EQ: What are HOMOLOGOUS CHROMOSOMES? EQ: What is CROSSING OVER? Chromosomes that carry the same genes are termed homologous (compare w. homologous structures) Homologous cross over or mix & match genetic materia during Metaphase 1 of Meiosis causing genetic variation. This is associated with Mendel s law of segregation + independent assortment. EQ: Describe the experiments done by Gregor Mendel? Pp EQ: Which organisms he used + why EQ: Which processes he did EQ: Which traits did Mendel observe in pea plants (7 traits) pp 310 Mendel-Experimented w. Pea plants showed Complete Dominance of one trait over the other trait pp310 Why? Peas have a fast reproductive rate and male + female parts of the flower were in the same flower. Processes-Cross and self pollination fertilization Traits Mendel Observed?

8 EQ: Name the 3 main Principles in Mendel s Genetics. The inheritance of biological characteristics is determined by factors called genes. Law of Dominance: Each parent has a gene pair in each cell for each trait studied ( like Tt for height,) where one allele for the trait is Dominant over the other Recessive allele.. These two alleles comprise the gene pair. Law of Segregation: Alleles /letters for each gene pair segregate into a gamete, thus each gamete only carries one member of the gene pair. Happens in Meiosis when separate. Law of Independent Assortment: Genes for different traits segregate + sort independently of each other. e.g. eye color separates independently of skin color. Happens in Meiosis 1 during Crossing-over in Prophase 1 EQ: What are the Exceptions to Mendel s Laws? 1. Codominance = Both Alleles completely show its characteristics (e.g. sickle cell. AB Blood Type) p Incomplete Dominance = Blending in Heterozygous offspring, Trait appears to be between the two parents Characteristics (e.g. Red/Pink/White Snapdragon flowers; Curly/Wavy/Straight Hair Texture) p Multiple Alleles = More than two different Characteristics for a trait (e.g. ABO Blood cells; Brown, Green, Blue Eye Color) pp Polygenic Traits = Many Genes influence the Trait; observed in traits that show a Range of characteristics instead of only two (e.g. skin color, height) 1. Sex Linked Traits = Gene is Found on the X or Y Sex Chromosome 2. (ex. color blindness, hemophilia) 3. Non Disjunction during Meiosis causes egg or sperm to have an extra or missing chromosome; Leads to Trisonomy (ex. Down Syndrome is Trisomy of chromosome #21) p 401

9 EQ: What did each Important Genetic Scientists do? Mendel, Gregor - GENETICS - +Laws of Genetics, genes, inheritance Hershey +Chase - DNA-Material in viruses is DNA not protein. Franklin, Rosalind - DNA is has a shape that appears double. Watson & Crick - DNA-based on Franklin s Xrays confirmed that DNA has shape of a double helix. Chargoff, Edwin - DNA-The bases AT are equal in numbers just line C+G are equal in numbers. Linnaeus, Carolus - Taxonomy/classification of living organisms Darwin, Charles = Scientific Theory /evolution/natural selection adaptation survival reproduction new species/speciation. EQ: How are sex linked genes like hemophilia and color blindness transmitted through to the next generation? 1. Hemophilia and color blindness are carried on the recessive gene on X chromosome. 2. Because there are 2 XX in females one X dominates over the other X H, the female has less chance of being color blind or having hemophilia. 3. Men with XY chromosome have a higher chance of being color blind or having hemophilia 4. XX h x XY=Sex Linked Color blindness or hemophilia X X h X XX XX h Y XY X h Y