Biology Notes Genetics Part 4 Pages 177 191

Biology Notes Genetics Part 4 Pages 177 -191

Standards 5. 4 ____ Describe the process of meiosis including independent assortment and crossing over. Explain how reduction division results in the formation haploid gametes or spores ____ Use Mendel’s laws of segregation and 5. 6 independent assortment to analyze patterns of inheritance ____ Discuss observed inheritance patterns 5. 7 caused by various modes on inheritance, including dominant, recessive, co-dominant, sex-linked, polygenic, and multiple alleles

Essential Question 1. How do genes influence the variety of organisms that exist?

trait I. Heredity = any _____ that is passed down parent from _______ to offspring • Trait = a specific characteristic that is inherited _____ e. g. hair color, eye color, height, weight, shoe size heredity • Genetics = the scientific study of ____

A. Gregor Mendel • Mendel was an ____ scientist who is Austrian genetics considered the father of modern _____ blending • Before Mendel, there was the _____ hypothesis that explained how people looked

pea • In the 1860’s, Mendel studied ____ plants sexually v pea plants reproduced ____ but they self are ____ pollinating meaning the flower egg contains both the _____ and the _______ sperm v when pea plant true ______, they make breed identical plants _____ to the parents

pollinated • Mendel cross _____ the pea plants P v In his notes, the ____ generation is the parental generation, the ___ was the first _____ F 1 filial F 2 generation, and the ____ was the second _____ generation. filial vhybrid = the offspring of crosses between different parents with _____ traits

7 Mendel studied ___ traits for pea plants 7 pea plant traits: seed shape, seed color, pod shape, pod color, seed coat color, flower position, plant height

II. Mendel’s Laws: 2 A. Law of Dominance = when __ alleles in a 1 gene pair are different, __ allele is dominant recessive and the other allele is _____ • Gene = part of a chromosome that trait (hair color, eye color) determines a ___________ gene • Allele = different versions of a _____ for trait the same ____ e. g. red hair vs. blond hair green eyes vs. blue eyes

DIAGRAM:

2 • for any trait, a person always has ___ alleles; mom one from _____ and one from ____ dad vdominant = those alleles that are considered ______ and are _____ when in a gene pair strong seen – represented by a _______ letter capital Tall = T e. g. Black = B • recessive = those alleles that are not observed allele _____ if the dominant ______ is present – represented by a _____ letter used to lowercase dominant abbreviate the _____ allele e. g. white = b short = t

2 • homozygous = organisms that have __ identical alleles for the same trait e. g. BB bb TT tt • heterozygous = organisms that have _____ alleles for the same trait different e. g. Bb Tt

• genotype = the genetic make-up of an organism _____ e. g. BB bb TT tt Bb Tt observed • phenotype = what is physically _____ in an organism e. g. Black white Tall short Black Tall

B. Law of Segregation = during meiosis, each pair of alleles separates into different ___________ gametes (egg & sperm) DIAGRAM: predict • resulted in being able to _______ what offspring could ______ look like

Punnett square = a diagram that shows the ____ combinations that might result from a possible genetic ______ combination vmonohybrid cross = cross involving only ___ trait 1 v. Steps forming a Punnett square: key 1. make a ____ showing dominant and _____ alleles recessive alleles 2. determine the _______ in the gametes of parents the ____

dad 3. place the alleles from ____ on top and the mom alleles from _____ on the side boxes 4. combine the alleles in the ______ genotypes 5. determine the _____ and phenotypes of the offspring inside the boxes Example: Mom = Bb Dad = BB B = Black B B b = white B BB BB b Bb Bb Genotypes = ½ BB ½ Bb Phenotypes = 4/4 Black

Aa aa Aa Aa Aa

fractions Probability = the use of ____ or ratios to predict the likelihood of an event’s occurrence genotypes v used to predict the _____ and phenotypes of offspring in breeding experiments e. g. What is the probability of black fur in Bb x Bb in rabbits where B= black fur and b = white fur? B b B = Black B BB Bb b = white Bb b bb ¾ black = 75%

2 • the probability that __ events will both happen is multiplying calculated by ______ their separate probabilities e. g. What is the probability of black fur for 2 generations in rabbits for Bb x Bb where B= black fur and b= white fur? 3/4 * 3/4 = 9/16

C. Law of Independent Assortment = during alleles meiosis, genes for different _______ sort randomly into different ____ gametes • this means that alleles are not ______ linked • Mendel tested _____ shape and seed color seed 2 • Dihybrid cross = crosses involving only __ traits • once the parent’s _____ are known, the genotypes most important step is to list all _____ possible gamete combinations for EACH _______ parent

e. g. What would be the outcome of the F 2 generation if the parents (P) are RRGG x rrgg? R = Round r = wrinkled G = Green g = yellow P = RRGG * rrgg F 1 = Rr. Gg (self pollinate) = Rr. Gg * Rr. Gg possible gametes: RG Rg r. G rg

RG RG RRGG Rg RRGg r. G Rr. GG rg Rr. Gg Rg RRGg RRgg Rr. Gg Rrgg r. G Rr. Gg rr. GG rr. Gg rg Rr. Gg Rrgg rr. Gg rrgg 9 = R_G_ round, green 3 = R_gg round, yellow 3 = rr. G_ wrinkled, green 1 = rrgg wrinkled, yellow