Transcript From Gene to Protein - South Kingstown High School

From Gene to Protein
What is a gene?
1 and 3
1. A unit of inheritance
2. A favorite article of clothing
3. A small portion of a DNA molecule
that codes for a protein and thus
determines a trait
Proteins
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•
•
•
•
•
These are essential macromolecule.
Make up about 45% of the human body.
WATER
Most of the rest of the body is made of_______?
Builds and repairs body tissue including muscle
Make up enzymes.
Make up molecules in the immune system and
hormones, which regulate bodily functions
such as sex drive.
Proteins are absolutely essential
for good health!
• Below are diagrams of the structures of
different types of proteins. Their complex
structures led many scientists to believe…
genes were carried on proteins NOT DNA
More about Proteins
• Proteins coordinate cellular activities—
they allow cells to communicate with each
other. They control vital functions like the
beating of your…
And more…
• Proteins are involved in molecular
transport.
• Hemoglobin is the protein in your blood
that makes it RED. It carries oxygen from
your lungs to all of the cells in your body.
• Oxygen is used for which cellular process?
• What is the purpose of this process?
And more…
• Proteins are made of amino acids.
• There are 20 different amino acids that
can be combined together into the
thousands of types of proteins found in a
human.
• Your body KNOWS which proteins to
produce because of the DNA code!
• The code is written in the letters A-T-C-G.
From Gene to Protein
• Each gene on a DNA molecule provides the directions
(in code) for making 1 type of protein.
• The protein may determine the color of your hair, or if
you can taste PTC!
In the Nucleus!
• The code is copied
from the DNA molecule
by messenger RNA
(mRNA).
• This process is called
transcription.
• It takes place in the
nucleus of the cell
Messenger RNA
• mRNA is similar to DNA
except
A) It is much shorter than
DNA
B) It is only made of one
strand NOT two
C) It has four nitrogen
bases
Cytosine matches with
Guanine
Adenine matches with
Uracil
Messenger RNA
• This is how mRNA works.
• A section of one strand of a DNA molecule has
the nitrogen bases:
TCGATCCCA
• mRNA uses complementary bases to match
the sequence. Because it is RNA the “A”
(adenine) matches with “U” (uracil).
AGCUAGGGU
• Transcription
In the Cytoplasm!
• After transcribing a
small section of
DNA the mRNA
leaves the nucleus
and enters the
cytoplasm.
• There it attaches
itself to a ribosome
containing
ribosomal RNA
(rRNA).
Translation
• At the ribosome, the code is read by
transfer RNA (tRNA)
• This process is called translation.
• tRNA reads the code and builds a protein
from the information.
Translation
• The code is read as a series of three letter
“words”.
• Each three-letter word is called a CODON.
• Each codon specifies a different amino
acid.
GCA = ALANINE
Transcription and Translation
Reading the Code
All the Proteins put Together
make up
YOU!