Transcript Heredity

Heredity
Objective 8
Describe the function of chromosomes.
 Identifying genes as parts of
chromosomes that carry genetic traits.
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Let’s
consult with Tim and
Moby.
Heredity film.
 In
the past, traits were thought to
be carried by the blood.
 We now know what genes are
responsible for certain traits and
that the genes are in every cell.
 We have used this information and
completed the Human Genome
project. The mapping out of the
human DNA.
Pass it on
Every
organism requires a
set of instruction for
specifying its traits.
Heredity is the passage of
these instruction from one
generation to another.
Heredity
The
passing of
traits from
parent to
offspring.
Heredity
information is
contained in genes, located
in the chromosomes of
each cell.
Each gene carries a single
unit of information.
 The different forms of a
gene are called alleles.
Alleles
Different forms of a single
gene.
One is inherited from each
parent and is located on a
specific chromosomes
They can be dominant or
recessive.
An
inherited trait of an
individual can be determined
by one or by many genes,
and a singles gene can
influence more than one
trait. A human cell contains
many thousands of different
genes.

Let’s watch Tim and Moby give
information about Genes.
Genes
Segments
of DNA that
carry hereditary
instructions and are
passed from one parent
to offspring; located on
the chromosome.
Chromosomes
They
are composed of
genes that provide the
instruction for making
all the proteins in an
organism.
They
take on an X
Shape so they can more
easily divide among
daughter cells.
Chromosomes are
directly related to the
passing on of traits.
A
cell that has lost its
chromosomes will be
missing some genes
and unable to produce
offspring.
Chromosomes control
all cell processes

This photomicrograph shows a specialized type
of giant chromosomes called polytene
chromosomes. Polytene chromosomes occur in
many species of two-winged flies.
Homologous chromosomes
Chromosomes
that
have the same
sequence of genes
and have the same
structure.
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Down syndrome is
often called Trisomy
21 because most
people with this
condition have three
copies of the number
21 chromosome.
Down syndrome
almost always results
in mental retardation,
though the severity
of the retardation
varies.
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http://www.brainpop.com/health/genetics
growthanddevelopment/genetics/
Have
you ever wonder ,
where did I get this red
hair, blue eyes or dark
skin color?
Well it is all because of
traits.
Traits
inherited
characteristic: a
quality or characteristic
that is genetically
determined.
Traits
can be dominant
or recessive.
Let’s the difference.
Dominant Trait
The
trait observed when
at least one dominant
allele for a characteristic
is inherited, and can be
seen in every generation
of offsping.
Recessive Trait
A
trait that is apparent
only when two recessive
alleles for the same
characteristic are
inherited and is not seen
in every generation of
offspring.
Human Genome Project
Completed in 2003, the Human Genome
Project (HGP) was a 13-year project
coordinated by the U.S. Department of
Energy and the National Institutes of
Health.
 After mapping out each gene then they
begin to look at each chromosome. May
of 2006 they were finish with all 26 pairs
of chromosomes.

Project goals were to

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identify all the approximately 20,000-25,000
genes in human DNA,
determine the sequences of the 3 billion
chemical base pairs that make up human DNA,
store this information in databases,
improve tools for data analysis,
transfer related technologies to the private
sector, and
address the ethical, legal, and social issues
(ELSI) that may arise from the project.
What are some practical benefits
to learning about DNA?
Knowledge
about the effects
of DNA variations among
individuals can lead to
revolutionary new ways to
diagnose, treat, and someday
prevent the thousands of
disorders that affect us.
The end