Heredity Exam: What to Study UHS AP Bio

Here’s what you need to study in order to demonstrate your understanding of gene tics:● Meiosis

○ Where it happens○ Why?○ What kind of ce lls it produces○ Ploidy of ce lls produced○ Diffe rence be tween me iosis and mitosis○ What happens when me iosis goes wrong

Meiosis● Responsible for

production of game tes● Produces haploid ce lls ● Also known as reduction

division

Meiosis: Homologous Chromosomes

● Homologous pairs have the same size , same length, have the same genes in the same orde r but have diffe rent alle le s

Overview of Major Events in Meiosis Meiosis I:Synapsis, Crossove r, Independent Assortment and separation of homologous pairs Meiosis II: Separation of siste r chromatids and segregation of alle le s

Crossing Over: A Mechanism for Creating Genetic Varie ty

● Crossove r occurs at Prophase I

● Pieces of NON-SISTER chromatids exchange DNA with one anothe r to create recombinant chromosomes

Independent Assortment of Chromosomes in Meiosis: Basis for Mende l’s Law of Independent Assortment

● Chromosomes line up along me taphase plate at random; the re is no prede te rmined way they will line up

Allele Segregation in Meiosis: Basis for Mendel’s Law of Segregation

● Occurs at anaphase II● Alle le s will segregate so

that a game te has only one half of an alle le pair

● In othe r words, a game te will not have two yy, it will only have one y.

When Meiosis Goes Wrong: Nondisjunction● Failure of e ithe r:

○ Homologous pairs to separate

○ Siste r chromatids to separate

● Causes aneuploidy: an incorrect chromosome number

Here’s what you need to study in order to demonstrate your understanding of gene tics:

● Mendelian Genetics ○ Laws of Gene tics○ Basic gene tics crosses○ Probability and how to solve gene tics problems using it○ Inte rpre ting pedigrees and the ir patte rn of inhe ritance

Mendel’s Laws of Genetics

● Law of Independent Assortment● Law of Segregation

Genetics Crosses: Monohybrid

● Know how to se t one up● Know phenotypic and genotypic

ratio for: ○ Cross be tween 2

he te rozygote s○ A te st cross

Genetics Crosses: Dihybrid

● Know how to se t one up

● Know phenotypic ratio for: ○ Cross be tween

2 he te rozygote s

○ A te st cross ● Use probability to

solve problems

Use of Multiplication Rule and Addition Rule to Solve Gene tics Problems● You can use probability to

solve most gene tics problems; a Punne tt Square is not needed

● Multiplication Rule : treat each event as an independent event, multiply the probabilitie s of each event

● Addition Rule : each event is mutually exclusive , they are not re liant on one anothe r, add the individual probabilitie s to one anothe r

Pedigrees: Patterns of Inheritance

Examples of traits: ● Achondroplasia● Huntington

Disease (HD)

Pedigrees: Patterns of Inheritance

● Examples of traits: ○ PKU○ Cystic

fibrosis ○ Tay-Sachs

Disease

Here’s what you need to study in order to demonstrate your understanding of gene tics:

● Non-Mendelian Inheritance○ Sex-linked inhe ritance○ Multiple Alle le s ○ Codominance

Sex-Linked Inhe ritance● Trait is located on X

chromosome● Passed on by mothe r to

son ● Males are more affected

than females ● Examples

○ Colorblindness○ Hemophilia ○ Duchenne Muscular

Dystrophy

Multiple Alleles

● More than one alle le for a trait

● Blood types are an example

Codominance

● More than one alle le is dominant; two alle le s are dominant to one othe r

● Examples:○ Sickle Ce ll Anemia○ Blood Types (A and B

are codominant to O)

Math You Need to KnowCh i-sq u a re (“g ood n e ss o f fit ”) t e st● W e u se t h is t o d e t e rm in e if

t h e re is a st a t ist ica lly sig n ifica n t d iffe re n ce b e tw e e n ou r e xp e c t e d d a t a a n d ou r ob se rve d d a t a .

● W e u se it t o t e st a n u ll h yp o th e sis (Ho)

● Re m e m b e r a n u ll h yp o th e sis is a st a t e m e n t t h a t st a t e s t h e re is n o d iffe re n ce b e tw e e n w h a t is ob se rve d a n d w h a t is e xp e c t e d

Re m e m b e r t h a t d e g re e s o f fre e d om = n u m b e r o f ch o ice s -1

Also ou r p va lu e is a lw a ys p = 0 .0 5

Math You Need to KnowCh i-sq u a re (“g ood n e ss o f fit ”) t e st● W e u se t h is t o d e t e rm in e if

t h e re is a st a t ist ica lly sig n ifica n t d iffe re n ce b e tw e e n ou r e xp e c t e d d a t a a n d ou r ob se rve d d a t a .

● W e u se it t o t e st a n u ll h yp o th e sis (Ho)

● Re m e m b e r a n u ll h yp o th e sis is a st a t e m e n t t h a t st a t e s t h e re is n o d iffe re n ce b e tw e e n w h a t is ob se rve d a n d w h a t is e xp e c t e d

Re m e m b e r t h a t d e g re e s o f fre e d om = n u m b e r o f ch o ice s -1

Also ou r p va lu e is a lw a ys p = 0 .0 5