Transcript Genetics Review

Genetics Review
Honors Human Anatomy &
Physiology
Mr. Mazza 2009-10
Why review genetics in a course
on anatomy & physiology?
Genes control the layout, make-up and function
of the bodies of all organisms. Examples of
traits influenced by genes:
• Appearance (hair, skin, eyes, height, etc.)
• Body structure of an organism
• Susceptibility to diseases
• Personality traits
• Behavior (instincts as well as other behaviors)
*Environment interacts with genes to produce
the final phenotype (physical trait)
Where do your genes come from?
50% of
your genes
from dad
50% of
your genes
from mom
It’s the stuff that genes are made of:
DNA
• made of 4
•
•
nitrogenous bases
(adenine, guanine,
cytosine, thymine)
A pairs with T; C pairs
with G
Each gene is a
unique sequence of
the 4 bases
CHROMOSOME
DNA
gene
What information do genes
contain?
• Each gene on the DNA is an instruction to
build a protein
• Proteins are the main structural
components of the body (bones, muscle,
skin, hair, nails, blood vessels, organs,
etc.) and regulate all chemical reactions in
the body
Human Karyotype
From Genes to Proteins
How a protein is made
Transcription (making of RNA)
DNA
mRNA (has copy
of DNA information)
ribosomes
Translation
(making of a protein)
protein
The Genetic Code
Each protein is made of amino acids - every 3
bases is a codon (code) for one amino acid
mutation
A change in the genetic code
Flow of genetic information in a cell
(Central dogma of molecular biology):
DNA
Mutated
DNA
RNA
Mutated
RNA
PROTEIN
Defective
protein
Why is this important?
• Our susceptibility to any disease is
affected by the variations of genes we
inherit from our parents and/or mutations
we get via the environment (i.e. radiation,
chemical exposure, etc.)