Unit 7 Lesson 4: Understanding Genetics and Heredity through Gregor Mendel's Discoveries, Study notes of Law

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Life Science Unit 7 Lesson 4 Attendance link: http://goo.gl/forms/AiHjMA4cQJ

HETEROZYGOATS

Just allele uneven.

2

EXPECTATIONS

Required Class Connects Tuesday, Wednesday, & Thursday 1:30-2:30 pm Be active and participate in class. Be respectful to your classmates Be positive in the chat box and use it correctly. Have a working microphone! You will need it during the lessons and break out rooms. If you have a question, please place it in the chat box and repost it if I don’t see it.

What is Genetics?

 Genetics is the scientific study of

heredity or inheritance

What is a Trait?  A trait is a specific characteristic that varies from one individual to another.  Examples: Brown hair, blue eyes, tall, curly

What are Genes?

 Genes are the

sequence of DNA

that codes for a

protein and thus

determines a

trait.

Dominant vs. Recessive

 Dominant - Masks the other trait; the trait that shows if present  Represented by a capital letter  Recessive – An organism with a recessive allele for a particular trait will only exhibit that trait when the dominant allele is not present; Will only show if both alleles are present  Represented by a lower case letter

R

r

Mendel’s Conclusions 1.Law of Segregation – Two alleles for each trait separate when gametes form; Parents pass only one allele for each trait to each offspring 2.Law of Independent Assortment – Genes for different traits are inherited independently of each other

Genotype vs. Phenotype  Genotype – The genetic makeup of an organism; The gene (or allele) combination an organism has.  Example: Tt, ss, GG, Ww  Phenotype – The physical characteristics of an organism; The way an organism looks  Example: Curly hair, straight hair, blue eyes, tall, green

Punnett Squares  Punnett Square – Diagram showing the gene combinations that might result from a genetic cross  Used to calculate the probability of inheriting a particular trait  Probability – The chance that a given event will occur

Punnett Square Parent Parent Offspring

Y-Yellow y-white Genotype: 1:2: (YY:Yy:yy) Phenotype: 3 Yellow 1 White

You Try It Now!  Give the genotype and phenotype for the following cross: TT x tt (T = Tall and t = Short)

TT x tt Step Two: Complete the Punnett Square T T t t

Tt Tt

Tt Tt

TT x tt Step Three: Write the genotype and phenotype T T t t

Tt Tt

Tt Tt

Genotype: 4 - Tt Phenotype: 100% Tall Remember: Each box is 25%