Transcript Protein Synthesis PPT - Get a Clue with Mrs. Perdue

Happy Tuesday! – 2/9
In this model, weak hydrogen
bonds connect which of the
following?
A G to C
B x to y
C y to G
D G to T
DNA, Protein Synthesis,
and Gene Expression
Video clip - http://www.youtube.com/watch?v=41_Ne5mS2ls
Two Types of Nucleic Acids
1. DNA
2. RNA
a. mRNA (messenger)
b. tRNA (transfer)
Where are proteins made?
Ribosomes
Compare DNA & RNA
DNA: deoxyribonucleic
acid
DNA is double
stranded.
Contains sugar
deoxyribose.
DNA contains bases
adenine, thymine,
guanine, cytosine.
DNA never leaves the
nucleus.
RNA: ribonucleic acid
RNA is single stranded.
Contains sugar ribose.
RNA contains bases
adenine, URACIL,
guanine, cytosine.
RNA can leave the
nucleus.
Overall process of Protein Synthesis
transcription
DNA
translation
mRNA
Protein
DNA’s tragedy
DNA
DNA contains
volumes of
information about
making protein.
Unfortunately,
DNA is too huge
to leave the
ribosomes
nucleus.
nucleus
How does the cell solve this
problem….transcription
That’s where
mRNA comes in. DNA
mRNA helps get
DNA’s message
out to the
ribosomes...
mRNA
First, DNA unzips itself...
DNA unzips
itself, exposing
free nitrogen
bases.
First, DNA unzips itself...
DNA unzips
itself, exposing
free nitrogen
bases.
First, DNA unzips itself...
DNA unzips
itself, exposing
free nitrogen
bases.
First, DNA unzips itself...
DNA unzips
itself, exposing
free nitrogen
bases.
First, DNA unzips itself...
DNA unzips
itself, exposing
free nitrogen
bases.
Transcription
a. The process of going DNA to mRNA
b. Occurs in the nucleus
Transcription
c. Steps of Transcription:
1. First DNA unzips itself along the segment of
code (gene) needed for a certain protein.
2. mRNA is made by forming complementary
bases on the unzipped portion of DNA.
Transcription
3. DNA’s code is copied into groups of 3 bases
at a time called a codon.
4. Each codon codes for 1 amino acid.
5. Once the mRNA strand is transcribed, it
leaves the nucleus to find a ribosome.
Next, mRNA is made...
mRNA is made
from the DNA
template
mRNA matches
with free DNA
nitrogen bases in
a complimentary
fashion
Next, mRNA is made...
mRNA is made
from the DNA
template
mRNA matches
with free DNA
nitrogen bases in
a complimentary
fashion
Next, mRNA is made...
mRNA is made
from the DNA
template
mRNA matches
with free DNA
nitrogen bases in
a complimentary
fashion
Next, mRNA is made...
mRNA is made
from the DNA
template
mRNA matches
with free DNA
nitrogen bases in
a complimentary
fashion
Next, mRNA is made...
mRNA is made
from the DNA
template
mRNA matches
with free DNA
nitrogen bases in
a complimentary
fashion
Next, mRNA is made...
mRNA is made
from the DNA
template
mRNA matches
with free DNA
nitrogen bases in
a complimentary
fashion
Next, mRNA is made...
mRNA is made
from the DNA
template
mRNA matches
with free DNA
nitrogen bases in
a complimentary
fashion
Next, mRNA is made...
mRNA is made
from the DNA
template
mRNA matches
with free DNA
nitrogen bases in
a complimentary
fashion
Next, mRNA is made...
mRNA is made
from the DNA
template
mRNA matches
with free DNA
nitrogen bases in
a complimentary
fashion
Next, mRNA is made...
mRNA is made
from the DNA
template
mRNA matches
with free DNA
nitrogen bases in
a complimentary
fashion
Next, mRNA is made...
mRNA is made
from the DNA
template
mRNA matches
with free DNA
nitrogen bases in
a complimentary
fashion
Next, mRNA is made...
mRNA is made
from the DNA
template
mRNA matches
with free DNA
nitrogen bases in
a complimentary
fashion
Next, mRNA is made...
mRNA is made
from the DNA
template
mRNA matches
with free DNA
nitrogen bases in
a complimentary
fashion
Next, mRNA is made...
mRNA is made
from the DNA
template
mRNA matches
with free DNA
nitrogen bases in
a complimentary
fashion
Next, mRNA is made...
mRNA is made
from the DNA
template
mRNA matches
with free DNA
nitrogen bases in
a complimentary
fashion
Next, mRNA is made...
mRNA is made
from the DNA
template
mRNA matches
with free DNA
nitrogen bases in
a complimentary
fashion
Next, mRNA is made...
mRNA is made
from the DNA
template
mRNA matches
with free DNA
nitrogen bases in
a complimentary
fashion
Next, mRNA is made...
mRNA is made
from the DNA
template
mRNA matches
with free DNA
nitrogen bases in
a complementary
fashion
Translation
a. The process of going mRNA
to proteins
b. Occurs in the cytoplasm
c. Involves tRNA
d. Every tRNA has one anticodon and one amino acid.
Translation
e. Steps of Translation:
1. Ribosome reads mRNA and brings in
matching tRNA.
2. The codon of mRNA bases pairs to anti-codon
of tRNA.
3. tRNA drops off amino acid to ribosome and
then float away.
4. Ribosome pieces together amino acids to
build proteins.
Regulation of Transcription and
Translation
 Think about your house, do you keep all the
lights on ALL the time in every room??
 Gene expression is a regulated process where
genes can be turned on and off as needed due to
environmental factors.
In summary…
 DNA contains the information needed to
make proteins.
 However, DNA is too large to leave the
nucleus.
 RNA carries instructions to ribosomes so
they can make proteins.
Gene expression is a regulated process.