Download Chapter 8 - Heredity

Chapter 8 - Heredity
• Heredity – is the passing of traits from parent
to offspring.
• We call these “inherited traits”.
Inherited Traits
• Living things inherit many traits, or
characteristics from their parents.
• Recall that _________, determine the
inherited traits of an organism.
• Traits are determined by the genes you
receive from your parents.
Genotype vs. Phenotype
• Genotype – “genetic makeup” of an organism.
• Phenotype –– the way an organism looks and
behaves as a result of its genotype ---“physical makeup”.
• Genotype DETERMINES phenotype
Chromosomes
• Genes are located on structures called
chromosomes.
• Cells of different kinds of organisms contain a
different number of chromosomes.
• A human baby receives ______ chromosomes
from its mother, and ______ from its father.
Human body cells contain _______
chromosomes.
• Each pair of chromosomes are given a number
from 1 to 23.
• Genes that determine a specific trait are in
matching locations on paired ---“homologous”
chromosomes.
Check List
• 1) _________ is the passing on of traits from
parents to offspring.
• 2) A trait is contained in a ___________?
• 3) What is the difference in genotype and
phenotype?
• 4) How many chromosomes are in the human
body cell? How many from dad and mom?
• 5) What are homologous chromosomes?
• Traits are controlled by a single gene.
• An example of a gene is one that causes
earlobes to be attached to the head & another
form that causes earlobes to be free from the
head.
• Allele – different forms of a trait
that make up a gene pair.
– “alternate forms of the same
gene”
• Alleles may be either dominant
or recessive for a particular
trait.
Dominant vs Recessive Alleles
• Dominant allele – is one that is expressed
when two different alleles are inherited.
• Recessive allele – is not expressed unless an
organism inherits two copies of it.
Identifying Genotype and Phenotype
• Each pair of genes is part of an individual’s
genotype (Ff, Bb, Gg, etc)
• Genotype identifies which alleles have been
passed on to an organism.
• Capital letter – dominant
• Lowercase letter – recessive
• Offspring receive two copies of each gene –
one from each parent.
• 3 possible genotypes: FF, Ff, ff.
• Homozygous genotype - is made up of two
dominant or two recessive alleles “the same”
– Ex: FF or ff
• Heterozygous genotype - is made up of one
dominant and one recessive allele “not the
same”
– Ex: Ff
Punnett Square
• Punnett Square – is a tool
used to predict the results
when two organisms mate.
• Used to calculate the
probability of genotypes
and phenotypes in
offspring.
Check List
• 1) What is the passing on of traits from parent
to offspring called?
• 2) What is an organism’s genotype?
• 3)An organism’s expressed traits make up its
____________?
• 4) How many total chromosomes are their in a
human cell? How many pairs?
• 5) _________ is two different forms of the same
gene.
• 6) An allele can be either ______________ or
___________?
Father of Genetics
• Gregor Mendel – is considered
the “father” of genetics.
• First experimented with pea
plants in 1856.
• He was a Austrian monk who
was fascinated with
crossbreeding plants.
• First to develop punnett square
to predict probabilities.
Advances in Genetics
• Genetic Engineering – where scientist alter
the DNA of an organism to benefit.
• 3 advantages of genetic engineering:
– 1) Gene transfer (out with the bad in with the good)
– 2) Genetically engineered plants
– 3) Genetically engineered animals
Chapter 8 - Heredity
• Heredity - ____________________________
• ____________ are passed on to future
generations
Inherited Traits
• Recall that _________, determine the traits of
an organism.
• Traits are determined by the genes you
receive from your parents.
• Genotype –
_____________________________________
_____________________________________
• Phenotype –
_____________________________________
_____________________________________
• Genotype DETERMINES phenotype
Chromosomes
• 23 pairs of
chromosomes in each
cell = __________
total
• Each pair has a
chromosome from a
mom and a dad.
• On each chromosome
is an alternating
___________.
Chapter 8 Check List
• 1) _____________ -is the process of passing traits from
parents to offspring.
• 2) The genetic makeup or genes of an organism is called
its _________________.
• 3) _________ determines the inherited traits of an
organism.
• 4) ______________ - is the way an organism looks and
behaves –“expressed or physical makeup”
• 5) More complex organisms generally contain ________
chromosomes.
• 6) Genes code for certain _____________.
• 7) Inherited traits means we get our characteristics from
our ______________. If we have 2 parents, there is
______________ in the offspring.
• 8) Above in #7, what type of reproduction has been
involved?
Section 2
Chromosomes
• Genes are located on structures called
chromosomes.
• Cells of different kinds of organisms contain a
different number of chromosomes.
• Traits are controlled by a single gene.
• An example of a gene is one that causes
earlobes to be attached to the head & another
form that causes earlobes to be free from the
head.
• Allele _____________________________________
• Alleles can be either _______________ or
_______________.
• Dominant Allele _____________________________________
• Recessive Allele _____________________________________
• Each pair of genes is part of an organism’s
_________________. (ex: Ff, Dd, Tt)
• Genotype shows which alleles have been
passed on.
• Capital Letter = ___________ allele
• Lowercase Letter = _________ allele
• Offspring receive two copies of each gene – one
from each parent.
• 3 possible genotypes:_______, _______, ______
• Homozygous genotype ______________________________________
– Ex:
• Heterozygous genotype _______________________________________
– Ex:
Section 3
•
•
•
•
•
Genotype vs Phenotype
Tt vs Tall
Homozygous vs Heterozygous
Dominant vs. Recessive
3 genotypes
Punnett Square
• Punnett Square –
______________________
______________.
• Used to calculate the
_________ of genotypes
and phenotypes in
offspring.
Task 1
• Draw a punnett square when a heterozygous
parent for tallness mates with a homozygous
parent for shortness. ( use T and t ).
Task 2
• Draw out a punnett square for two organisms
that mate: one is Heterozygous for being
athletic, and the other is homozygous
recessive for being athletic (Use A or a)
Task 3
• A male eastern fox squirrel is notorious for
mating in the winter months and for finding a
mate who is always homozygous dominant. If a
male eastern fox squirrel is homozygous for being
slow and finds a mate draw a punnett square
(F=fast; f=slow) and predict these:
–
–
–
–
What is the probability of the offspring being fast?
What is the probability of the offspring being slow?
What % will be homozygous?
What % will be heterozygous?
Section 3 cont.
Father of Genetics
• Gregor Mendel –
______________________.
• First experimented with pea
plants in 1856.
• Used the ___________________
in his studies.
Advances in Genetics
• Genetic Engineering –
_____________________________________
______________________.
• 2 advantages of genetic engineering:
– 1)
– 2)