Heredity – notes
Topic
Details
Heredity
• Heredity is the passing of __________________ from parents to offspring
• __________________ is the study of heredity
Gregor
Mendel
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Traits
Known as the “Father of __________________”
Experimented with “True Breeding” pea plants in his garden
True Breeding
– Plants that produce __________________ offspring when allowed to
self pollinate
– AKA “Purebred”
Discovered how __________________ are passed from parent to offspring in
sexual reproduction
A trait is __________________ feature or quality in a person
• __________________ - Received from biological parent
– Eye color
– Height
– Blood Type
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__________________ - Acquired during lifetime; not inherited
– Ability to ride a bike
– Scars
– Pierced ears
Some traits can be both!
__________________ - received genes from parents & also affected by sun exposure
Genes
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A gene is a unit of __________________
Occupies a specific location on a __________________
Codes for or determines a specific trait
– Most traits are not coded for by just one gene
Genes and
Chromosomes
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Genes are located on __________________
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Chromosomes come in pairs
– Each pair is called a homolog
On each homolog are sites where specific genes are located
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Alleles
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Alleles are various forms of the same __________________.
Example 1:
– Gene: Eye Color
Alleles: _________________________________
Example 2:
– Gene: Seed Color
Alleles: _________________________________
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Mendel also performed experiments with __________________ plants
– Hybrids - Plants that were produced by parents with different traits
In these experiments, he discovered that traits are inherited by parents passing
__________________ to their offspring
Individuals carry __________________ alleles for each trait, but only pass
down one to their offspring
One __________________ is dominant over another .
__________________Allele: an allele whose trait is always shows up in the
organism when the allele is present
– Expressed if only one is present
– Example: brown eye color
__________________ Allele: an allele whose trait is hidden whenever the
dominant one is present
– Can only be expressed if two are present
– Example: blue eye color
Phenotype
and Genotype
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Alleles are represented by symbols
– Dominant represented by a _______________________________
• Example: Widows Peak =W
– Recessive represented by the ___________________________letter
• Example: Straight Hair Line = w
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Alleles Interact to Produce Traits
– Each parent contributes __________________allele for a given trait
– The __________________ of alleles from parents can result in varying
traits in their offspring
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__________________: An organisms genetic makeup, or alleles an organism
has for a trait is its genotype
– Ww, Bb, bb, ww, etc
__________________: An organism’s physical appearance, or visible traits is
its phenotype.
– Widow’s peak, brown eyes, blue eyes, straight hairline, etc
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Heterozygous
and
Homozygous
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Terms used to describe an organisms genotype
– __________________ – an organism that has two different alleles for a
trait is said to be heterozygous
• Example: Ww, Bb
– __________________– An organism that has two identical alleles for a
trait is said to be homozygous
• Example: WW, ww, BB, bb
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