Transcript Chapter 3 Genetics Notes

Chapter 3 Genetics:
The Science of
Heredity
Section 1: Mendel’s Work
Section 1- Objectives:
 To
describe Mendel’s genetics
experiments
 To
identify the factors that control the
inheritance of traits in organisms
 To
explain how geneticists use symbols
to represent alleles.
Vocab
 1.
trait
A characteristic that an organism can
pass on to its offspring through its
genes.
 2.
heredity
The passing of traits from parents to
offspring.
 3.
genetics
The scientific study of heredity.
 4.
purebred
An organism that always produces
offspring with the same form of a trait
as the parent.
 5.
gene
A segment of DNA on a chromosome
that codes for a specific trait.
 6.
alleles
The different forms of a gene.
 7.
dominant allele
An allele whose trait always shows up in
the organism when the allele is present.
 8.
recessive allele
An allele that is masked when a
dominant allele is present.
 9.
hybrid
An organism that has two different
alleles for a trait; an organism that is
heterozygous for a particular trait.
Notes
 1.
Gregor Mendel
_______________________
is
called the “father of genetics”
 2.
Mendel used peas because:
have many traits that exist in only 2 forms
– A. They
_________________________
Garden peas produce large numbers of
– B. _________________________
offspring in one generation so it is easy
to collect large amounts of data to analyze
 3.
Traits are controlled by
inheritance
_________________
of
genes
_____________
one
Organisms inherit ______
allele
each
from _________
parent.
 4.

5. Some alleles are
____________________and
others are
dominant
recessive
__________________________.
Chapter 3 Genetics:
The Science of
Heredity
Section 2: Probability &
Genetics
Section 2 -Objectives:
 To
describe the principles of probability
and how Mendel applied them to
inheritance
 To state how geneticists use Punnett
squares
 To explain the meaning of the terms
phenotype, genotype, homozygous,
heterozygous, and codominance.
Vocab
 10.
probability
The likelihood that a particular event
will occur.
 11.
Punnett square
A chart that shows all the possible
combinations of alleles that can result
from a genetic cross.
 12.
phenotype
An organism’s physical appearance, or
visible traits.
 13.
genotype
An organism’s genetic makeup, or allele
combinations.
 14.
homozygous
Having two identical alleles for a trait.
 15.
heterozygous
Having two different alleles for a trait.
 16.
codominance
A condition in which neither of two
alleles of a gene is dominant or
recessive.
Notes
 1.
Probability is the
likelihood
___________________
that a
particular event
____________________
will occur.
 2.
Mendel
_____________________
was the
first scientist to recognize that the
principles
________________________
of
probability
________________________
can be
used to predict the result of genetic
crosses.
 3.
Geneticists use Punnett squares to:
– A. Show all the possible outcomes of a
genetic cross
– B.
Determine the probability of a particular
outcome
 4.
Phenotype
_________________________ is
the physical appearance, while
genotype
________________________
is the
Genetic makeup
_______________________
make-up.
5. Punnett Square
practice:
 B-Blue
 b-red
B


Genotype:

Phenotype:
1 BB: 2Bb: 1bb
3 Blue, 1 red
b
B
b
BB
Bb
Bb
bb

5. Punnett Square
practice:
G- Green
 g-Yellow


Genotype:

Phenotype:
–2 Gg: 2gg
–2 Green: 2 Yellow
g
g
G
g
Gg
gg
Gg
gg
Your turn. Practice sheet.
 Independent
and Silent
 Refer to your notes.
 Go over as a group.
Chapter 3 Genetics:
The Science of
Heredity
Section 3: The Cell and
Inheritance
Section 3: The Cell and
Inheritance
 To
describe the role of chromosomes in
inheritance
 To
identify and describe the events
that occur during meiosis
 17.
meiosis
The process that occurs in sex cells
(sperm and egg) by which the number of
chromosomes is reduced by half.
Notes
 1.
Sex cells have exactly
half
____________
the number of
other
chromosomes as ____________
cells.

2. The chromosome theory of inheritance
states:
Genes are carried from parents
to their offspring on chromosomes

http://www.pearsonsuccessnet.com/snpapp/iText/products/013-036738-9/ch3/videoBlank.html?/ebook/products/0-13036738-9/video/vtchromo.mov
 3.


During meiosis, the chromosome:
The chromosome pairs
separate and are distributed
to two different cells. The
resulting sex cells have only
have half as many
chromosomes as the other
cells in the organism.
http://www.pearsonsuccessnet.com/snpapp/iText/products/0-13036738-9/ch3/videoBlank.html?/ebook/products/0-13-0367389/video/vtmeiosi.mov
See pg. In text
 4.
Genes
____________________ are
located on chromosomes.
 5.
23
Our bodies have ________
pairs of
chromosomes that contain over
60,000
__________
genes.
Chapter 3 Genetics:
The Science of
Heredity
Section 4: The DNA
Connection
Section 4: The DNA Connection Objectives:
 To
explain the term “genetic code”:
 To
describe the process by which a cell
produces proteins
 To
describe different types of
mutations and how they affect an
organism.
 17.
messenger RNA
RNA that copies the coded message
from DNA in the nucleus and carries
the message into the cytoplasm.
 18.
transfer RNA
RNA in the cytoplasm that carries an
amino acid to the ribosome and adds it
to the growing protein chain.
Notes
 1.
The main function of genes is to:
Control the production of
proteins in the organism’s cells.
Proteins help to determine the
size, shape, and many other
traits in an organism.
order
The _________
of
nitrogen
_______________
bases along a
gene
_____________
forms a genetic code
that specifies what type of
protein
___________
will be produced.
 2.


http://www.pearsonsuccessnet.com/snpapp/iText/products/0-13036738-9/ch3/videoBlank.html?/ebook/products/0-13-0367389/video/vtgeneti.mov
http://www.pearsonsuccessnet.com/snpapp/iText/products/0-13036738-9/ch3/videoBlank.html?/ebook/products/0-13-0367389/video/vtprotei.mov
mutation
A _____________
is a change in a
gene
___________
or
chromosome
____________________.
 3.
 DNA
mutations:
http://www.youtube.com/watch?v=_ajRf8yMBe0
 4.
Mutations can be:
Harmful
 A. ____________ and an example
cancer
would be ______________.
Helpful
 B. ____________ and an example
Antibiotic resistance in bacteria
would be ______________.
Neither harmful or helpful
 C. ______________________
and an
A white buffalo color on
example would be ______________.
a farm (versus a white
buffalo color in the wild)