Content Objectives Write these down!

I will be able to identify:

• Key terms associated with Mendelian Genetics

• The patterns of heredity explained by Mendel

• The law of segregation

• The relationship between GENOTYPE and PHENOTYPE

Language Objectives Write these down!

I will complete a graphic organizer in key terms associated with Mendel’s work on Heredity defining terms in my own words

I will discuss and record important ideas, facts, and concepts about heredity using Cornell Notes.

I will read and discuss with my group a short passage on Mendel’s Theory.

Adapted from Holt Biology 2008

Chapter 12 Section 2: Mendel’s Theory

Key Vocabulary Terms

Mendelian theory of heredity Mendelian theory explains simple

patterns of inheritance. In these patterns, two of several versions of a gene combine

and result in one of several

possible traits.

Allele 1. One of two or more alternative forms of a gene, each leading to a unique trait. Symbolized with a single letter. 2. One member of a pair or series of genes that occupy a specific position on a specific chromosome.

Dominant

Describes an allele that is fully expressed whenever the allele is present in an individual.

Use a capital letter.

Recessive

Describes an allele that is expressed only when there is no dominant allele present in an

individual

Use a lower case letter.

Genotype A specific combination of

alleles in an individual

(two or more letters to show which alleles are

present).

The genetic constitution of a cell, an organism, or an individual (i.e. the specific

allele makeup of the individual).

Phenotype “genotype determines phenotype”

The detectable trait or traits that result from the genotype of an individual

(words that describe a trait).

The appearance of an organism resulting from

the interaction of the genotype and the

environment.

Homozygous

Describes an individual that has two identical alleles.

Having identical pairs of genes for any given pair of hereditary characteristics.

Heterozygous

Describes an individual that has two different alleles

Having different alleles at one or more corresponding chromosomal loci.

Law of segregation

When an organism

produces gametes,

each pair of alleles

is separated and

each gamete has an

equal chance of

receiving either one

of the alleles.

Dihybrid cross

Cross between F1 offspring of two individuals that differ in two traits of

particular interest.

Linked genes

Two or more genes that are inherited together

found on the same Chromosome

(red hair and freckles)

Content Objectives Write these down!

I will be able to identify:

• define and use in a sentence, Key Terms associated with Mendel’s Theory of heredity.

• The patterns of heredity explained by Mendel

• And explain The law of Segregation

• The relationship between GENOTYPE and PHENOTYPE

Language Objectives Write these down!

I will complete a graphic organizer in key terms associated with Mendel’s work on Heredity defining terms in my own words

I will discuss and record important ideas, facts, and concepts about heredity using Cornell Notes.

I will read and discuss with my group a short passage on Mendel’s Theory.

Vocabulary List Use in a Sentence!

• Allele

• Dominant

• Recessive

• Genotype

• Phenotype

• Homozygous

• Heterozygous

• Law of segregation

• Dihybrid cross

• Linked genes

Adapted from Holt Biology 2008

Chapter 12 Section 2:

Mendel’s Theory

Notes

Mendel’s Conclusions for the 7 characters in pea plants

1. Each parent contributes one factor (allele) per trait in the offspring.

Mendel’s Conclusions for the 7 characters in pea plants

2. The factors (alleles) separate randomly when gametes form. (Law of segregation)

3. A dominant allele is expressed when one or two of the dominant alleles is inherited.

Mendel’s Conclusions for the 7 characters in pea plants

4. A recessive allele is only expressed if both of the inherited alleles are recessive.

Mendel’s Conclusions for the 7 characters in pea plants

Mendel’s codes for alleles are still used today.

• Capital letters for the dominant allele

• Lower case letters for the recessive allele.

• The letter for the character is the letter of the dominant trait.

12-2 Mendel’s Theory

• Genotypes: PP Pp pp

– Homozygous X X

– Heterozygous X

• Phenotypes: Purple Purple White

– Why does the Pp genotype have a purple phenotype?

Mendel’s Second Experiments

Dihybrid cross: initial parents

had TWO contrasting characters

(traits).

Mendel’s Dihybrid Cross Conclusion Law of Independent Assortment

During gamete formation (meiosis), the alleles of each

gene segregate independently. The alleles for seed color and seed shape can randomly mix and

match.

Genes on Chromosomes

We now know that genes that are on the same chromosome are inherited together

(linked).

Linked genes do NOT follow the Law of Independent Assortment