Biology Journal 10/14/2014
Convert the DNA to mRNA
Then, Convert the mRNA to amino acids.
GTG TGA CTA GTT ATC
CAC ACU GAU CAA UAG
Histidine
Threonine
Aspartic Acid
Proline
What do we call this step?
Transcription
What do we call this step?
Translation
Stop
Biology Journal 10/14/2013
What do the letters in the acronyms DNA and
RNA stand for?
Deoxyribonucleic Acid and Ribonucleic Acid
What are the 4 most commonly occurring
elements in living things?
Carbon, Hydrogen, Oxygen, Nitrogen
What 5 elements are found in DNA?
Carbon, Hydrogen, Oxygen, Nitrogen,
Phosphorous
No Journal Today.
Get right to work on your
Replication Models. They
are due tomorrow when
you come in.
This assignment is
evidence, so take the time
to do a good job, and
double check that you’ve
done everything on the
checklist!
Biology Journal 10/1/2014
One of the standards of 2.6 is Draw a simple diagram of the
structure of nucleotides of DNA and RNA, using:
o circles = phosphates
o pentagons = pentoses
o rectangles = bases
Topic 2: Molecular biology (21 hours)
2.7 DNA replication, transcription and translation: Genetic information in DNA can be accurately copied and can be
translated to make the proteins needed by the cell.
Nature of science: Obtaining evidence for scientific theories—Meselson and Stahl obtained evidence for the semiconservative replication of DNA.
Understandings:
• The replication of DNA is semi-conservative and
depends on complementary base pairing.
• Helicase unwinds the double helix and separates
the two strands by breaking hydrogen bonds.
• DNA polymerase links nucleotides together to form
a new strand, using the pre-existing strand as a
template. The different types of DNA polymerase
do not need to be distinguished.
• Transcription is the synthesis of mRNA copied from
the DNA base sequences by RNA polymerase.
• Translation is the synthesis of polypeptides on
ribosomes.
• The amino acid sequence of polypeptides is
determined by mRNA according to the genetic
code.
• Codons of three bases on mRNA correspond to one
amino acid in a polypeptide.
• Translation depends on complementary base
pairing between codons on mRNA and anticodons
on tRNA.
Applications and skills:
• Application: Use of Taq DNA polymerase to produce
multiple copies of DNA rapidly by the polymerase chain
reaction (PCR).
• Application: Production of human insulin in bacteria as
an example of the universality of the genetic code
allowing gene transfer between species. There are ethical
implications in altering the genome of an organism in
order to produce proteins for medical use in humans.
• Skill: Use a table of the genetic code to deduce which
codon(s) corresponds to which amino acid.
• Skill: Analysis of Meselson and Stahl’s results to obtain
support for the theory of semi-conservative replication of
DNA.
• Skill: Use a table of mRNA codons and their
corresponding amino acids to deduce the sequence of
amino acids coded by a short mRNA strand of known base
sequence.
• Skill: Deducing the DNA base sequence for the mRNA
strand.
DNA Replication
Better make some new cells.
The two strands of DNA can be
separated, called unzipping.
•
Remember, the 2 strands are connected by hydrogen
bonds, which are much weaker than covalent bonds.
DNA Helicase is the enzyme that unzips
DNA. DNA Helicase un-does the double
helix.
All the cool kids wear ironic
science t-shirts
DNA Helicase
Simplified
model
DNA Helicase
Space-filling
model
DNA Helicase
Model showing
-helixes and
-sheets.
DNA unzips during
replication (when
DNA copies itself)
When do you think your cells would
replicate their DNA?
Your cells replicate their DNA before they divide to make new
cells. They do this…
For routine replacement of cells (such as skin cells, blood
cells, stomach cells, etc)
When you grow or gain weight
When you are injured and need to replace dead cells
If one strand of DNA has these
base pairs, then what are the base
pairs on the complementary strand?
CTAATCGTATATAGTCC
GATTAGCATATATCAGG
In replication…
DNA helicase unzips DNA.
DNA polymerase adds the
complementary bases to each
single strand, creating 2
identical strands.
semi-conservative
replication:
newly replicated
DNA contains one
“old” strand and
one “new”
strand.
It took scientists a while to figure out that DNA
replication was semi-conservative, as opposed
to some other pattern.
Your assignment:
Build a model of DNA replication!
Biology Journal 10/15/2013
What are the names of the two most
important enzymes in DNA replication?
What does each one do?
DNA helicase: unzips DNA, making 2
single-strands.
DNA Polymerase: adds in new
complementary bases (and backbone) to
each single strand, making 2 complete
copies of DNA.
Biology Journal 10/3/2014
In DNA replication, what do you start
with?
DNA
What do you end with?
2 sets of the original DNA (through semiconservative replication)
What is the purpose of replication?
When cells divide, each new cells needs
a full set of DNA.
DNA Replication
• DNA helicase unzips the DNA
• DNA polymerase connects
together matching bases to
make 2 new strands.
Making
a copy
Youtube videos
DNA Replication: The Cell's Extreme Team Sport. Nice
narrated cartoons spelling out why cells divide, and the steps of
replication. 8 minutes.
https://www.youtube.com/watch?v=5qSrmeiWsuc
Transcription and
Translation
DNA has the “recipe” to make proteins.
A gene is a segment
of DNA that has the
instructions to make
a particular protein.
“Hmmm… how many teaspoons of
cytosine was I supposed to add?”
The base pairs on DNA
determine the amino
acid sequence, and thus
the final shape and
function, of a protein.
For example… we all have genes for hair color.
The base pairs on this DNA determines what
proteins are in our hair, and thus, what our hair
looks like.
Of course, you can
always change it later…
What does it
mean to be a
translator?
What does it
mean to
transcribe
something?
Ancient Egypt was well known for its
scribes that made copies of documents.
Nowadays we
don’t really need
them, we have
copy machines…
When does your body need to make
different kinds of proteins?
Transcription and translation is done
every time a cell makes a protein.
Muscle is motor proteins! When you work out, your
body builds more motor proteins…
DNA and RNA comparison
Transcription is making a copy of the DNA onto
mRNA (messenger RNA). The enzyme that
makes it is called RNA polymerase.
Some people
transcribe
their homework
all the time.
mRNA is a temporary, disposable copy of DNA.
It’s sent from the nucleus to the ribosome.
DNA is permanent.
You don’t want to
change or mess with it.
RNA is a disposable copy.
If this was a chain of DNA, what
would the mRNA strand be?
CTGACTTAGATA
GACUGAAUCUAU
What does DNA have the
“recipe” to make?
DNA is the recipe to make protein!
What do
ribosomes
do?
Ribosomes make proteins!
What are proteins made out of? Why do
they have the shape that they have?
Proteins are made out of amino acids. The
different chemical properties of the amino
acids cause the chain to fold up in specific
ways.
Translation: mRNA goes to the ribosome,
and it is translated into an amino acid
sequence.
tRNA (transfer
RNA) brings the
correct amino
acid for every 3
base pairs.
•Ribosomes have 2 “subunits” or pieces.
Large Subunit
Small Subunit
The 3 bases on
tRNA is called
an anti-codon.
The 3 bases on
mRNA is called a
codon.
How many different kinds of amino
acids are used in the human body?
Every 3 base pairs corresponds
to a different amino acid.
What amino acids does this mRNA code for?
AUG
UUA GAC CUC UGA
A translator puts information from one
language into another.
Translation puts the genetic code (AGTC’s)
into the code of amino acids.
What amino acids does this mRNA code for?
GUA AAA CUU CUA UAG
The translator
(ribosome and tRNA)
The scribe
(RNA polymerase)
Protein
DNA
mRNA
What do we call
this step?
What do we call
this step?
Transcription
Translation
Convert the DNA to mRNA
Then, Convert the mRNA to amino acids.
GCC TAT TCA CTA CTG
CGG AUA AGU GAU GAC
Argenine
Isoleucine
Serine
Aspartic Acid
What do we call this step?
Transcription
What do we call this step?
Translation
Aspartic Acid
Making a Protein
Making a Protein
Transcription
RNA polymerase
Replication
DNA helicase
DNA polymerase
mRNA
Translation
Ribosome
tRNA
Protein
DNA
Happens in the nucleus
Happens in the cytoplasm /
at the ribosomes
Label each molecule (the pictures).
Label the process that makes each molecule (the purple arrows).
List the name of the enzymes / molecules that carry out each process.
Identify the location where each of these molecules / processes are.
This is called the central dogma of biology.
(That just means that it is a really
important idea)
•At the start of every gene is a TATA box. It
tells the mRNA polymerase where to start
copying. TATA box
Actual gene being transcribed
DNA strand:
TCCACGACTATACCGACTACTCTACGGGAATATG
mRNA strand:
GGCUGAUGAGAUGCCCUUAUAC
•mRNA gets a 5’GTP and a poly-A tail to
mark the beginning and end. This helps
identify it and “protect” it.
5’ GTP
Poly-A tail
PPPG
AAAAAAAAA
Biology Journal 10/6/2014
Transcription
RNA polymerase
Replication
DNA helicase
DNA polymerase
mRNA
Translation
Ribosome
tRNA
Protein
DNA
Happens in the nucleus
Happens in the cytoplasm /
at the ribosomes
Label each molecule (the pictures).
Label the process that makes each molecule (the purple arrows).
List the name of the enzymes / molecules that carry out each process.
Identify the location where each of these molecules / processes are.
Biology Journal 10/21/13
Compare and contrast DNA and RNA in a Venn
diagram.
DNA
Both
RNA
Biology Journal 10/21/13
Compare and contrast DNA and RNA in a Venn
diagram.
DNA
Both
RNA
Has deoxyribose as
its sugar
Has a sugar
phosphate backbone
Has ribose as its sugar
Has the nitrogenous
base T
Has the nitrogenous
bases A, C, and G.
Has the nitrogenous
base U
Double stranded
Contains the genetic
code for proteins
Single stranded
Stays in the nucleus
Can leave the nucleus
Comes in 1 kind
Has several kinds:
mRNA, tRNA, and
rRNA
Biology Journal 10/25/13
DNA replication is semi-conservative. What
does that mean?
Biology Journal 10/8/2014
What does DNA have the
“recipe” or code to make?
What is the purpose of…
replication?
transcription?
translation?
Protein!
Originally, it was thought that every gene codes for
exactly 1 protein. However, there are many
exceptions. Some genes code for multiple proteins,
some genes manipulate other genes…
Biology Journal 10/7/2014
What is the name of this molecule? Label its parts.
What does it do?
It’s tRNA (transfer RNA)!
Amino Acid
or
Monopeptide
Anticodon
This is made
out of RNA
(ribonucleic acid)
tRNA brings the amino acid that is coded for on the mRNA to the ribosome
and adds it to the growing protein. Then the “empty” tRNA is “reloaded”
with another amino acid, and is ready to do this again.
• What do we call this process?
Translation
• What is the end product of this process? Protein
Cell membrane
Nucleus
Anti-codon
Cytoplasm
Codon
DNA
Transcription
mRNA
Translation
Protein
or
Polypeptide
(this is the end
product!)
Amino Acid
Or
Ribosome
tRNA
Monopeptide
Convert the DNA to mRNA
Then, Convert the mRNA to amino acids.
GTG TGA CTA GTT ATC
CAC ACU GAU CAA UAG
Histidine
Threonine
Aspartic Acid
Proline
What do we call this step?
Transcription
What do we call this step?
Translation
Stop
Read This!
No Journal today
Finish your Transcription / Translation models
ASAP. If you don’t show them to Mr. Lawton
today, then you have to come afterschool for that.
Get a review guide (brown sheet called D-N-A and
Y-O-U)
The test on all of the DNA topics will be on
Monday.
•Ribosomes have 2 “subunits” or pieces.
Large Subunit
Small Subunit
Biology Journal 10/29/13
Explain what the ribosome does
(3 points)
•At the start of every gene (almost) is a TATA
box. It tells the mRNA polymerase where to
start copying.
TATA box
Actual gene being transcribed
DNA strand:
TCCACGACTATACCGACTACTCTACGGGAATATG
mRNA strand:
GGCUGAUGAGAUGCCCUUAUAC
•mRNA gets a 5’GTP and a poly-A tail to
mark the beginning and end. This helps
identify it and “protect” it.
5’ GTP
Poly-A tail
PPPG
AAAAAAAAA
Biology Journal 10/14/2014
•At the start of (almost) every gene is a TATA box. It
tells the mRNA polymerase where to start copying.
TATA box
Actual gene being transcribed
DNA strand:
TCCACGACTATACCGACTACTCTACGGGAATATG
mRNA strand:
GGCUGAUGAGAUGCCCUUAUAC
•mRNA gets a 5’GTP and a poly-A tail to
mark the beginning and end. This helps
identify it and “protect” it.
5’ GTP
Poly-A tail
PPPG
AAAAAAAAA
No journal today. You have today to work on
models. Read these pieces of advice first!!!
1. Your “original” DNA strand should be put together so it is
read right-to-left. If you mess it up, this will have bad
consequences later on!
Like this!
Not like this!
1
4
2
3
3
2
4
1
2. Don’t tape everything together. You should have:
• One connected DNA strand, by itself
• One connected mRNA strand, by itself
• One connected tRNA/Protein strand, by itself
That’s
3 separate
strands of
stuff!
3. Read the directions carefully. You should start transcribing
after the TATA box, and add a GTP, and a poly-A tail. If you
don’t know what the heck those are, refer to the directions!
We are going to make a model of all of
these pieces and steps!
Youtube videos
Protein Synthesis and the Lean, Mean Ribosome Machines.
Nice narrated cartoons spelling out why transcription and
translation. 7 minutes.
https://www.youtube.com/watch?v=h5mJbP23Buo
Transcription and Translation. Narrated video of computermodeled molecules of transcription and translation happening in
“real time.” 4 minutes.
https://www.youtube.com/watch?v=41_Ne5mS2ls
Transcription and translation videos:
Real-time molecules moving with narration (4 min)
https://www.youtube.com/watch?v=41_Ne5mS2ls
Description, live narrator and pictures (12 min)
https://www.youtube.com/watch?v=h3b9ArupXZg
Tips for the project
Make 1 big, long strip of DNA. It’s direction is
numbered (1) to (4)
Tips for the project
Match the complementary bases to make mRNA
Tips for the project
Attach the mRNA to each other, not to the DNA!
Tips for the project
Use your “Amino Acid Codon Wheel” to look up the
correct amino acid for the codons, and write in the
correct amino acid
Tips for the project
Some of the pieces you have to create, such as the
enzymes
Wrestling
First Meeting in room 133