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1 opic: Mendel Pea Plan Workshee Summary: Sudens will learn how Mendel discovered classical geneics using pea plans. Sudens will simulae how alleles express alernae versions of genes using a monohybrid cross. Goals & Objecives: Sudens will be able o describe how Mendel came up wih his laws of geneics. Sudens will be able o use classical geneic erminology. Sandards: CA Biology 3a. Sudens know how o predic he probable oucome of phenoypes in a geneic cross from he genoypes of he parens and mode of inheriance (auosomal or X-linked, dominan or recessive). 3b. Sudens know he geneic basis for Mendel s laws of segregaion and independen assormen. ime Lengh: 40 minues Maerials: exbook Handous Procedures: 1. Suden work alone o answer quesions on how Mendel discovered geneics. Accommodaions: Sudens wih an IEP can ake he handou home if hey need exra ime or if hey need modificaion, only answer odd numbered problems. Evaluaion: Quesions 1-8 are worh 2 poins each, for a oal of 16 poins. Quesions 9-16 are worh 1 poin each, for a oal of 8 poins. his assignmen is worh a oal of 24 poins.

2 Name: Row: Dae: Period: Mendel s Pea Plans Gregor Mendel experimened wih pea plans in a garden. He would ake he male par of he flower called he anher which produces pollen and he female par of he flower called he carpel which has an ovary conaining ovules. Mendel had several socks of rue-breeding pea plans. he rue-breeding (homozygous) pea plans were allowed o self-pollinae and produce offspring idenical o he paren pea plans. he rue-breeding pea plans le Mendel conrol his experimen when he cross-pollinaed a green seed pea plan wih a yellow seed pea plan. He cross pollinaed he pea plans by aking pollen from he green seed sock, and ferilized he flowers of he yellow seed sock. He ferilized he flowers by brushing he pollen from he flower of yellow pea plans and wiping he pollen on he carpel of green seed pea plans. his process is known as crosspollinaion where he seeds came from wo differen plans. Mendel sudied seven differen pea plan rais: plan heigh, he posiion of he flowers, pea pod shape, pea pod color, seed shape, seed color, and flower color. 1) Why was i imporan for Mendel o use rue-breeding pea plans? (Hin: scienific mehod) 2) Wha is a cross-pollinaion of pea plans? Mendel crossed he pea plans wih conrasing rais, like all plans and shor plans, and sudied heir offspring. he original pair of plans is called he P (parenal) generaion. he offspring is called he F 1 (firs finial) generaion. Offspring from parens of differen or conrasing rais are called hybrids. When Mendel crossed he wo P generaion plans, all he F 1 generaions had characerisics from he P generaion. Of all he F1 generaion plans, only one of he characerisics was expressed and he oher characerisic seemed o be los. Mendel learned wo hings from hese crosses: inheriance of rais (genes) is passed from one generaion o he nex and he principle of dominance. Alleles are usually he geneic code for a gene found in a cerain locaion on a chromosome. 3) Explain how Mendel used he F1 generaion o conclude ha genes are inheried. 4) Why was only one of he paren s characerisics for a rai expressed, while he oher seemed o be los?

3 Scieniss oday sudy herediy by using Punne squares. Alleles may be represened as wo leers because he plan or animal has wo ses of genes, one from heir faher and one from heir moher. When he wo leers are he same, eiher boh capiol or boh lower case, hey are called homozygous. When he wo leers are opposie, hey are called heerozygous. Since Mendel use rue-bred pea plans, he purple flowers alleles are. he whie flower alleles are. Fill in he Punne square below of he rai flower color for wo rue-breading pea plans. Purple = dominan Whie = recessive 5) Afer looking a he punne square and using he vocabulary erms above, why were all he offspring in he F 1 generaion showing he dominan characerisic? 6) Any ime you have a capial leer in one or boh alleles, he dominan form of he rai is expressed. Only when you have boh alleles as lower case leers is he recessive form of he rai expressed. In he Punne square above, do all of he offspring express he purple or whie flowers? Since he offspring in he F 1 generaion only displayed one of he paren s characerisics, Mendel did no know wha happened o he oher. He decided o cross wo of he offspring of he F 1 generaion o creae a F 2 generaion. Analogy: P = parens, F 1 = kids, F 2 = grandkids of pea plans. Mendel noiced somehing very differen in he F 2 generaion. Please fill in he wo punne squares below of hree generaions, from he rue-bred P generaion o F 2 generaion. he plans from he F1 generaion were allowed o self-pollinae. Use he offspring in he F1 generaion o self-pollinae o creae he parens of he F2 generaion. Purple = dominan Whie = recessive F 1 F 2

4 When a homozygous dominan plan is crossed wih a homozygous recessive plan, all he offspring are heerozygous and express he dominan characerisic of he rai. Bu when he plans in he F 1 generaion are allowed o self-pollinae, a few of he recessive plans reappear in he F 2 generaion. Mendel hypohesized ha alleles segregae from each oher during he formaion of gamees (seeds). his means ha one of each paired chromosomes goes ino each seed, or only one leer from each paren goes ino each square (offspring) of a Punne square. Mendel s hypohesis became he law of segregaion. 7) Explain how Punne squares use he law of segregaion. An organism s physical appearance of he rais is called a phenoype. Mendel sudied pea plan rais including seed color. For he rai seed color, is phenoype would be eiher yellow or green. he genoype is he gene responsible for he phenoype. A diploid organism has wo copies of each chromosome and his is why here are wo alleles which make up he individual's genoype. Now ha you have learned how o disinguish beween genoype and phenoype, you can deermine heir raio or probabiliy. he genoypic raio is wrien using numbers ha sar wih homozygous dominan, hen heerozygous, hen homozygous recessive. An example of genoypic raio looks like 2:2:0. Yellow seed = dominan Green seed = recessive 8) Use he Punne square above o answer he quesions below? All possible genoypes: All possible phenoypes: Genoypic raio: Phenoypic raio:

5 Pea Plan Crosses Fill in he following punne squares and mach he punne square wih he probabiliies in he following quesions. Firs, deermine who were he parens, hen deermine he possible raios for he offspring. Each punne square may be used more han once. Wrie he leer A, B, C, or D for he Punne square ha would represen each cross. (A) (B) (C) (D) 9) Mendel crossed dominan all plans wih all plans. he resuls in he F 1 generaion were 84 all plans and 29 recessive shor plans. 10) Mendel crossed dominan axial flower posiion plans wih recessive erminal flower posiion plans. he resuls in he F 1 generaion were 15 axial flower plans and 17 erminal flower plans. 11) Mendel crossed dominan green pod plans wih recessive yellow pod plans. he resuls in he F 1 generaion were 40 green pod plans and 0 yellow pod plans. 12) Mendel crossed dominan smooh pod plans wih smooh pod plans. he resuls in he F 1 generaion were 51 smooh pod plans and 0 recessive consriced pod plans. 13) Mendel crossed dominan purple flower plans wih recessive whie flower plans. he resuls in he F 1 generaion were 206 purple flower plans and 197 whie flower plans. 14) Mendel crossed dominan gray seed coa plans wih dominan gray seed coa plans. he resuls in he F 1 generaion had a raio of 3 gray coa plans o every one recessive whie seed coa plans. 15) Mendel crossed dominan yellow seed plans wih dominan yellow seed plans. he resuls in he F 1 generaion were all yellow seed plans and no recessive green seed plans. he resuls in he F 2 generaion were 714 yellow seed plans and 106 green seed plans. 16) Mendel crossed dominan round seed plans wih recessive wrinkled seed plans. he resuls in he F 1 generaion were all round seed plans and no wrinkled seed plans. he resuls in he F 2 generaion were 318 round seed plans and 121 wrinkled seed plans.