Study Guides (238,527)
Canada (115,195)
Biology (180)
BIOL 1103 (16)
all (5)

chapter 11 notes.doc

13 Pages
Unlock Document

Carleton University
BIOL 1103

Chapter 11 Mendel Genes and InherenceGregor Mendel is an Augustinian monk known as the founder of geneticsHe used garden peas to stuffy the pattern of inheritanceTo test his hypothesis he bred generations of pea plants and observed their patterns of what traits the parent transmits to their offspringsHes findings founded the science of genetics and still have the power to explain some of the most puzzling aspects of inheritance111 The beginning of GeneticsUntil the 1900 scientist believed in the blending theory of inheritance which meant that hereditary traits blend evenly in offsprings like mixing coffee and creamProblem if this were true why dont very short and very tall people disappearWhy do blue eyed children pop out of brown eyed familiesIn 1860s Mendel did an experiment with garden peas and he studied heritable characteristics called characters such as flower colours or seed shapeA variation in a character is called atrait such as the flowers colorMendels established that characters are passed onto offsprings in discrete hereditary factors now known as genesHe observed that instead of blending many parental traits stayed the same and some disappears just to reappear unchanged in the nextThis is a result of segregation of chromosomes when genes are located to gametes in meiosisChose pea plants because their easy to grow and cheapHe chose pea plants that wheretruebreeding meaning when they selffertilize they pass trains without changing from one generation to the nextGametes are produced in structures of flowersThe male gametes are sperm nuclei contained in the pollenwhich is produced in the anthers of the flowerThe females gametes are egg cells produced in the carpel of the flowersNormally pea plants selffertilize aka self pollinate when sperm nuclei in pollen produced by anthers fertilize egg cells housed in the carpel of the same flowerMendel prevented selffertilization by cutting off the anthersThis means pollen must come from a different plant This is called crosspollinationFlower color is one of the seven characteristics of Mendel usesOne truebreeding purple flower and one true bleeding with white flowersMendel took pollen from the anthers of plants with purple flowers and placed it in the white flower plantsHe placed the pollen on the stigmathe part of the carpel that receives pollen in flowers He did the same but the other way around putting white flower pollen into thesigma of the purple flowerThe crosses all resulted with seeds and the seed contained a zygote or an embryoThe seeds become pea plants and the first generation from the crosses are the F1 generation F stands for filus sonPlants used in the initial cross are called parental or P generationThe plants grown from the F1 seeds all formed purple flowersno blendingMendel the allowed F1 plants to self pollinate and produce seeds known as F2 generationAnd when he planted them the white flowered trait reappearedboth purple and white flowers where produced705 plants purple flowers and 224 white flowers31 ration75 purple vs 25 whiteMendel also observed trains like seed colour green and yellow and same patterns were observedMendels first hypothisis The adult plants carry a pair of factors that govern the inheritance of each characterMendels factors are called genes which are located in chromosomes and different versions of gametes produces different traits of characters the alleles of genesIn the garden pea there are two alleles of the gene that govern flower colour one is purple the other is whiteOrganisms with two copies of each gene are known asdiploidsthe two alleles of a gene in a individual may be identical or differentWhen traits seem to disappear its because they are masked by a stronger allele Dominant allele is expressed Recessive allele is maskedMendels second hypothesisif an indivisuals pair of genes consisted of different alleles one is dominant over the other When a dominant allele is paired with a recessive allele dominant alleles is expressedA recessive allele is only expressed when there are two copies of the allele presentMendels third hypothesis is the pairs of alleles that control a character segregate as gametes are formed half the gametes carry one allele and the other half carry the other allelethis is known as Principle of SegregationDuring fertilization fusion of the haploid maternal and paternal gametes produces a diploid nucleus called the zygote nucleus this receives one allele for the character from the male and one from the female gametesMandels three hypothesis explained the result of the crossesThe purple color was dominant and is represented by P and the white flower is recessive and symbolized with p
More Less

Related notes for BIOL 1103

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.