6-4 Traits, genes, alleles.ppt

8/13/2019 6-4 Traits, genes, alleles.ppt

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Section 6-4Traits &

Genes

Write everything that isunderlined


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6.4 Traits, Genes, and Alleles

KEY CONCEPT

Genes encode proteins that produce adiverse range of traits


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Important Vocabulary Terms for You to Know

Please make a chart or table at the top of your notes for thesevocabulary terms:

Gene

Allel le Homozygous

Heterozygous

Genome

Genotype

Phenotype

Dominant

Recessive


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A. The same gene can have many versions

1. A gene is a piece of DNAthat tells a cell to make a

certain protein Each gene has a locus,

a specific position

on a pair of

homologous chromosomes


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Pea plants have 2

alleles for shape - they

receive one from each

parent

For shape, there is a

wrinkled allele and a

round allele

2. An allele is an alternative form of a gene

-

Each parent donates one allele for everygene


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B. Genes influence the development of

traits

All of an organisms genetic

material is called the genome

A genotype refers to the actual

genes

A phenotype is the physicalexpression of a trait


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C. Genotype:

1. The gene combination of an

organism

It consists of 2 alleles For example:

Pure dominant, 2 dominant genes

Pure recessive, 2 recessive genesHybrid, 1 dominant and 1 recessive

gene


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D. Phenotype:

1. The way an organism

looks

No matter what genes are

present, phenotype of a

tall pea plant is tall and a

short pea plant is short


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A dominant allele is expressed

as a phenotype when at leastone allele is dominant

A recessive allele is expressed

as a phenotype only when two

copies are present

2. Dominant alleles are

represented by

uppercase letters

3. Recessive alleles by

lowercase letters


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Think fast!!!

Determine if the following is genotype or phenotype.

A horse with white stockings

A pink rose that was bred from a white rose and

red rose A pig that has super heavy muscling


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E. Mendels observed traits

1. Dominant traits: covers up the othertraits

2. Recessive traits: traits that

disappear

3. Rule of Dominance: When a

dominant trait is present therecessive trait is hidden


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Hows it related????

You have 4 minutes and 25 seconds to draw a concept

map to show (with words, chart, or a concept map) how

these terms are related.

Gene Genotype

Phenotype

Allelle

Dominant traits

Recessive traits


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Most traits occurin a range and do

not follow simple

dominant-

recessive

patterns


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F. The Law of Independent Assortment:

Genes for different traits are

inherited independently of

each other

When you have 2 or more

different traits they are notstuck together


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Example (for your genetics book)

Seed types of Parents:

Wrinkled,yellow

Round,green

You can get offspring with:

Wrinkled, green seeds

Or Round yellow seeds

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6-4 Traits, genes, alleles.ppt