Download DNA RNA Lecture Website

4 days til break 
Please put your things in the back & start the
journal a.s.a.p.
If we work hard the next two days, then
Thursday will consist of a holiday themed
application lesson… so be good!
The Genetic Code:
Transcription, Translation, Protein Synthesis
The Genetic Code
The DNA molecule,
with its four nitrogenous
code for
bases, is the ____
proteins that are
all _______
made in a cell.
Genes are made of _____.
DNA A gene is
coded DNA instructions
the _________________that
controls
the production of specific _________,
proteins
such as enzymes, structural proteins,
oxygen-carrying proteins, etc.
The Genetic Code
 The DNA inherited by an organism dictates the
synthesis of certain proteins. Proteins are the link
between genotype & phenotype.
The proteins that are made will determine what
traits show up in the offspring.
 Gene expression:
The process by which DNA directs the synthesis of
proteins.
The expression of genes includes two stages:
transcription and translation
The Genetic Code
Quick Talk
How does the DNA of a human relate to the
DNA of a mouse? to the DNA of an apple
tree? to the DNA of a mosquito?
From DNA to Protein
1. Proteins are made of building blocks called:
amino acids.
20 different amino acids and ____
four
2. There are ___
different nucleotides (since there are four
different nitrogenous bases).
three nucleotides in
3. It was discovered that ______________
amino acid
sequence must specify each __________.
This would provide for ___
64 possible
combinations of amino acids.
triplet of nucleotides is called a
4. Each ______
codon
_______.
From DNA to Protein
amino acid When many
5. Each codon calls for a specific __________.
amino acids are linked together a ______
protein is made.
__________
instructions for making specific
6. Genes provide the __________
proteins, but a gene does not build a protein directly.
The bridge between DNA and protein synthesis is:
RNA
Secret Language of RNA
Quick Talk
In what way/(s) is RNA like a secret language
to create proteins from DNA?
So, what is RNA?
Differences Between
DNA and RNA:
• RNA is a single strand;
DNA is a double strand.
• The sugar in RNA is
ribose; the sugar in DNA
is deoxyribose.
• RNA has uracil that pairs
with adenine; DNA has
thymine that pairs with
adenine.
Types of RNA
• Messenger RNA (mRNA) is the “messenger” between the
DNA in the nucleus and the ribosomes in the cytoplasm.
message carried by
• Transfer RNA (tRNA) reads the ________
mRNA and gathers the right ___________
amino acids for making
_______
protein
that _______.
Amino acid will be
attached here
A cell keeps its
cytoplasm stocked with
all 20 amino acids.
mRNA to the
• Ribosomal RNA (rRNA) binds the _______
tRNA to make everything work together.
_______
Transcription
1. Transcription is the process of forming a strand of
RNA from a strand of DNA.
2. This process occurs in the nucleus.
3. The cell must make RNA to send to the cytoplasm to
tell the ribosomes how and which proteins to make.
Transcription
4. The RNA molecule is a faithful copy of a gene’s
protein building instructions. This type of RNA is called
messenger RNA (mRNA).
5. RNA polymerase catalyzes this reaction.
Quick Task
Synthesize the appropriate mRNA strand from the
DNA provided to model transcription.
Make Good Choices
Please put your things in the back & start the
journal a.s.a.p.
If we work hard today, then Thursday will
consist of a holiday themed application
lesson… so be good!
Phones need to be out of sight.
From Yesterday…
transcription
Translation
translation
• The synthesis of proteins is called ___________.
The cell must translate the base sequence of an
mRNA molecule into the __________
amino acid sequence of a
______
protein.
protein synthesis occurs
• The site of translation, or _________________,
in the _________.
ribosome The ribosome facilitates the orderly
linking of amino acids into proteins.
Ribosomes
• Ribosomes consist of two subunits.
– The large subunit has three binding sites for tRNA.
– The small subunit binds to mRNA.
Translation Steps
- mRNA attaches
to part of the
ribosome, tRNA
w/ first amino acid
binds to start
codon
- tRNA brings
a.a. to mRNA to
create growing
peptide chain
- Stop codon in mRNA
releases the polypeptide
chain
Language of RNA (recap)
These three codons
represent three different
amino acids
___________.
Quick Task
From your chart of amino
acids, determine the three
amino acids coded for by
these codons:
UCGCACGGU
UCG - CAC - GGU
serine - histidine - glycine
Overview of Protein Synthesis
1. In the nucleus, DNA transcribes RNA.
2. The RNA is sent to the cytoplasm in the form of mRNA.
3. The mRNA attaches to a ribosome.
4. As each codon of the mRNA molecule moves through the
ribosome, the proper amino acid is brought into the ribosome
by tRNA. The amino acids are lined up in the right order on
the ribosome.
5. The ribosome hitches the amino acids together with peptide
bonds and proteins are made.
Recap
Why it all matters…
Genes are nothing
more than
instructions for
building proteins.
What do proteins
have to do with the
color of a flower, a
human blood type,
or dimples?
The answer is….
EVERYTHING!
The traits of any
organism are the result of
the proteins being built
within the cells.