Transcript Genetics - Edgartown School

Genetics
What’s it all about?
Questions: what we will answer.
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What is genetics?
How do chromosomes work?
What is the history of genetics?
Genetics and probability: What are Punnett
Squares?
How does the study of genetics affect our
lives?
What is the future of genetics?
Genetics is the science of heredity.
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Heredity - the passing of traits from parents to
offspring.
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Traits - characteristics or features of an individual,
not always apparent or obvious
Chromosomes: the mechanisms that make it all
possible
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Chromosomes are in pairs, found in the nuclei of cells.
A single chromosome is composed of many genes, which
determine hereditary traits.
Chromosomes are made of a molecule called deoxyribonucleic
acid (DNA).
Human cells contain 46 (23 pairs) of chromosomes totally about
35,000 genes on them.
There are 2 to the 23rd power (or 8,388,608) possible gene
combinations.
Gametes (sex cells : sperm and eggs) contain only half the
number of chromosomes.
Chromosomes are made of DNA. Segments of
chromosomes are called genes.
Deoxyribonucleic Acid (DNA)
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The double helix shape resembles a
spiral staircase.
The shape was first correctly identified
in 1953 by James Watson and
Francis Crick, who then won the
Nobel prize in 1962.
The unique shape allows the molecule
to “unfold” or “unzip” along a portion
of the molecule.
When a strand of DNA “unzips”, an
exact copy of the “unzipped” portion
can be replicated (copied)
DNA replication is how cells make
proteins, which build new cells, repair
cells, and many other functions that
keep the cells functioning.
DNA replication (making copies)
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The unique shape of DNA
allows the molecule to “unzip”
along a portion of the strand.
When a strand of DNA “unzips”,
an exact replica of the
“unzipped” portion can be
replicated (copied)
DNA replication is how cells
make proteins, which build new
cells, repair cells, and countless
other functions that keep cells
functioning.
DNA replication is happening
constantly in cells.
DNA vs RNA
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Double-stranded
Longer
Master template for all a
cell’s information
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Usually single-stranded
Shorter, simpler
Made using DNA as the
template
mRNA, tRNA, snRNA
(different forms)
One cell’s DNA unraveled is estimated at 4-12 feet
long!
Total in one human body?
10-20 billion miles, or enough to travel from Earth to
the Sun 70 times!!
Click here to watch this short video (4:05)
on Watson and Crick, and the sad story of
another great scientist, Rosalind Franklin