Inheritance of Traits Ch. 3

What are traits? Traits are ________________ or qualities Can be ________________ or behavioral Living things ________ (are different) in their _________

Gregor Mendel A _______ who lived in the mid _____________ Studied math and science Liked to ________________ Curious about why plants of the same type had ___________ traits

Gregor Mendel Noticed that plants often had the _____ traits as their ______________ The _________ of traits from parents to offspring is known as ________________

Gregor Mendel Set up many _____________ using pea plants to understand heredity ______________ were a good choice because of their traits

Mendel’s Experiments First he created __________ for each trait –These plant always produced _____________ just like them –Ex. Tall purebreds always produced _________ offspring

Mendel’s Experiments Then he _______ one type of purebred with another –Ex. tall with short The purebreds = the P(arent) _________________ The offspring = the ______1 generation

Mendel’s 1 st Experiment Purebred __________ crossed with Purebred __________ Offspring all __________ Surprise! __________ disappeared!

Mendel’s 1 st Experiment Crossed two of the tall __________ ______ generation was ______ tall, _______ short ___________________ reappeared!

Further experiments Mendel did similar experiments for 6 other pea plant ___________ ___________ of results was always the ______________

Conclusions Used ______ to figure out that each trait must be ___________ by 2 ______________ One factor must come from each _____________ One factor could _________ the other –Ex. Tall factor can mask short

Father of Genetics Mendel’s work was _____________ in the 1900’s Became the foundation of modern _________________ Now we call factors _______

Genes Sections of ___________ We know that DNA contains ______________ for how to make ____________ Each section ________ for a different protein

Genes Genes  proteins  __________ But how do genes tell the ____ how to make proteins? Proteins are made on ____________________ DNA is in _______________ Need away to get _______ from DNA to ribosome

Protein Synthesis Cell uses _____________ –Only _______ side –______ instead of T –Pairs up with DNA or other RNA using same __________ _____ types: mRNA and tRNA DNAATCG RNA__

Protein Synthesis mRNA = __________________ –_________ DNA of gene and goes to ribosome tRNA = ____________________ –Translates mRNA code into a ________________ –Happens on _______________ DNA(gene)  _______  protein  trait

Mutations Remember that __________ are any changes in the DNA If DNA is _________, mRNA is changed and ___________ is made differently This can change the ______

Mutations If this happens in a _______ cell the mutation will only affect that ________ If this happens in an ______ or a ______ cell, it can affect the ____________

Mutations Not all mutations are ___________________ Some _________ the protein or trait Some have ___ affect on the protein or trait

Alleles The __________ forms of the factors Mendel described are known today as _______ Alleles= _________ of genes Every body cell has _______ copies of each gene

Alleles One copy from one _______, one ________ from the other These copies can be the ________ allele or _________ alleles

Alleles Alleles can be ____________ or recessive Dominant alleles can mask ___________________ alleles If you have the dominant allele, that is the one that will be copied and translated into a _________________

Alleles We use _________ to represent alleles Usually the letter is connected to the _________________ trait ____________ letters represent dominant alleles Lower case letters represent __________________ alleles

Alleles Example –Trait = Height –Dominant allele = ____ (tall) –Recessive allele = ___ (short)

Alleles The combination of _________ = the ___________________ If the two alleles are the _____ the genotype is _____________ –Ex. TT or tt If the two alleles are ________ the genotype is ________________/___________ –Ex. Tt

Alleles The genotype determines the ____________________ This is the __________ Examples: GenotypePhenotype TT Tt

Inheritance Genes are carried on ____________________ Each chromosome contains thousands of ____________ The two alleles are carried on __________ chromosomes that form a ____________

Inheritance Chromosome pair - Contain different alleles of the same genes From “mom” From “dad”

Inheritance One _______________ came from sperm, other from egg This means sperm and eggs only have one _____ of each chromosome These special cells are called ___________ cells

Meiosis Organisms do a special process of _______ to create sex cells Process makes sure chromosome pairs are _____ so each sex cell has one __________________ set

Meiosis Sex cells

Meiosis Each sex cell has a different _______________ of alleles This is why siblings are not ___________________

Inheritance If we know the _________ of the parents, we can calculate the _____________ combinations in the offspring And the ___________ of each

Punnett Squares For one trait, we make a 4 square

Punnett Squares Down the left side we put the alleles that the mom has… T T ‘Mom’

Punnett Squares …across the top we put the alleles that dad has T T ‘Mom’ ‘Dad’ tt

Punnett Squares In each box we write the combination of the mom allele from that row and the dad allele from that column T T ‘Mom’ ‘Dad’ tt Tt

Punnett Squares Each square represents a possible genotype of the offspring T T ‘Mom’ ‘Dad’ tt Tt Tt

Probability In this cross, there’s a _____ chance of offspring having the Tt genotype. There’s a ________ chance of offspring having the ‘tall’ phenotype T T ‘Mom’ ‘Dad’ tt Tt Tt

Probability In this cross, there’s a ____ chance of having TT and ____ of having Tt. There’s a _______ chance of offspring having the ‘tall’ phenotype T T ‘Mom’ ‘Dad’ Tt TT Tt

Probability In this cross, each offspring will have a ______ chance of being TT, _____ chance of being Tt, and ______ chance of being tt. There’s a ______ chance of being tall and ______ of being short T t ‘Mom’ ‘Dad’ Tt TT Tt tt