Download Mendelian Genetics

Mendelian Genetics
CH. 5 SEC.1 AND 2
Inheritance
 For a long time, general ideas of inheritance were
known…
Cows give birth to cows… not horses.
 Brown dogs usually give birth to brown dogs.

 What was really lacking was an understanding of how
particular traits were passed down to their offspring.
Gregor Mendel
 The basic laws of heredity
were first formed during the
mid-1800’s by an Austrian
botanist monk named
Gregor Mendel. Because
his work laid the foundation
to the study of heredity,
Mendel is referred to as
“The Father of Genetics.”
Heredity and
Gregor Mendel
 Heredity: The passing of traits from parents to
offspring.
 Mendel discovered the principles of heredity.
 Mendel studies pea plants. They were selfpollinating (have both male and female
structures, so it can pollinate itself).
 Pea plants can also cross-pollinate (pollinate a
different flower).
Mendel’ Pea Plants
Mendel based his laws on his studies of
garden pea plants. Mendel was able to
observe differences in multiple traits over
many generations because pea plants
reproduce rapidly, and have many visible
traits such as:
Pod color
Seed Color
Plant Height
Green
Green
Tall
Short
Yellow
Yellow
Seed Shape
Pod Shape
Wrinkled
Smooth
Pinched
Round
Studying Pea Plants
 Mendel studied one
characteristic at a time.
 A characteristic is a
feature that has different
forms in a population.
 The different forms of
these characteristics are
called traits.
Mendel’s Experiments
 Mendel saw some interesting traits
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appear when plants were crossed.
The first generation offspring are called
the F1 generation.
The second generation offspring are
called the F2 generation.
Dominant traits are observed in the
organism’s characteristics if present.
Recessive traits are traits that are hidden
if the dominate trait is present.
Recessive traits can only be seen in the
organisms if both alleles are recessive.
Mendel’s Observations
Traits and Inheritance
 Gene: One set of instructions for an inherited trait.
 Each parent gives their offspring one set of genes.
 The different forms of a gene are called alleles.
•Homozygous: When
alleles from both parents
are the same. HH or hh
Called a purebred
•Heterozygous: When
alleles from parents are
different. Hh
•Called a hybrid
Genotype Vs. Phenotype
 Phenotype: An organism’s appearance (what you see:
hair color, height, eye color etc.)
 Genotype: The genetic make-up of an organism– the
alleles that are present for a trait. (Hh or AA)
Karyotype
 Photograph of an organism’s chromosomes.
Heredity Concept Map
Heredity
Use the following terms to
complete the concept map
below:
Alleles
parents
Heredity
Phenotype
Genes
Offspring
genotype
Characteristics
dominant
Heredity Concept Map
Heredity
Use the following terms to
complete the concept map
below:
Alleles
parents
Heredity
Phenotype
Genes
Offspring
genotype
Characteristics
dominant
Question #1
Different forms of a gene
are called:
#traits
#alleles
#chromosomes
Question #2
One set of instructions for
an inherited trait is called:
#gene
#allele
#trait
Question #4
The genetic make-up of an
organism:
#phenotype
#appearance
#genotype
Question #4
Traits that are hidden if the
dominate trait is present:
#dominant
#recessive
#gene