Download Mendelian Genetics

§ An organism produces gametes (sex
cells) to maintain the same number of
chromosomes from generation to
generation.
§ Human gametes contain 23
chromosomes.
§ A cell with n chromosomes is called a
haploid cell.
§ A cell that contains 2n chromosomes is
called a diploid cell.
§  The sexual life cycle
in animals involves
meiosis.
§  Meiosis produces
gametes.
§  When
gametes
combine in fertilization,
the number of
chromosomes is
restored. n + n = 2n.
§ Asexual reproduction
§ The organism inherits all of its
chromosomes from a single parent.
§ The new individual is genetically
identical to its parent.
§ Sexual reproduction
§ Beneficial genes multiply faster over
time.
Mendelian Genetics
How Genetics Began
The passing of traits to the next generation is
called inheritance, or heredity.
§ Gregor Mendel performed crosspollination in pea plants.
§ Mendel followed various traits in the
pea plants he bred.
Gregor Mendel: 100 Greatest Discoveries
Mendelian Genetics
Mendelian Genetics
§ Mendel studied seven different traits.
§ Seed or pea
§ Seed pod shape
color
§ Stem length
§ Seed pod color § Flower position
§ Seed shape or
texture
§ Flower color
Review Scientific Method:
Independent Variable
Dependent Variable
Constants
Mendelian Genetics
Genes in Pairs
§ Allele
§ An alternative form of a single gene
passed from generation to generation
§ We use letters of the alphabet to
represent alleles
§ Recessive (lowercase letter)
§ Dominant (uppercase letter)
Mendelian Genetics
Dominance
§ An organism with two of the same
alleles for a particular trait is
homozygous. Both alleles are either
dominant or recessive.
§ An organism with two different alleles
for a particular trait is heterozygous.
One allele is dominant, and one allele
is recessive.
Mendelian Genetics
Genotype and Phenotype
§ An organism’s allele pairs are
called its genotype.
§ The observable characteristic or
outward expression of an allele
pair is called the phenotype.
Make a Bunny!
and
Bioethics in Genetic
Testing!
Which symbol is used to represent the
number of chromosomes in a gamete?
A.  #
B.  x
C.  r
D.  n
Which person is known as the
father of genetics?
A.  Felix Mendelssohn
B.  Gregor Mendel
C.  Bill Nye
D.  Albert Einstein
Which term refers to the outward
physical expression of an allele pair?
A.  gamete
B.  hybrid
C.  phenotype
D.  genotype
What are the segments of DNA that
control the production of proteins?
A.  chromatids
B.  chromosomes
C.  genes
D.  traits
What type of organisms can only
reproduce asexually?
A.  bacteria (prokaryote)
B.  protists (unicellular eukaryote)
C.  plants (eukaryote)
D.  animals (eukaryote)
What is the name for different forms of a
single gene that are passed from generation to
generation?
A.  alleles
B.  genotypes
C.  phenotypes
D.  traits
Which pair of alleles is heterozygous?
A. RR
B. Rr
C. rr
D. yR
Homozygous Dominant
Heterozygous
Homozygous Recessive
What is this process called?
A.  fertilization
B.  gamete formation
C.  inheritance
D.  reproduction