Download DNA, RNA and Protein Synthesis

DID YOU KNOW?????
 Elephants
have been
known to
remain
standing after
they die.
DNA, RNA and
Protein Synthesis
Chapters 12
PROTEIN REVIEW



Proteins are large molecules formed by
smaller molecules called amino acids.
Amino acids are known as the building
blocks of proteins.
In your body, proteins aid in muscle
contractions, give structure to cells and act
as enzymes.
GENES
 A segment
of DNA that codes for a
protein.
 DNA is organized into units called
genes.
 Found in the nucleus.
 Contain instructions on how to make
proteins.
Nucleic Acids
 Both
DNA and RNA are known
as nucleic acids.
 Just like the building block for
proteins are amino acids, the
building blocks for nucleic
acids are NUCLEOTIDES.
Who discovered DNA?
In 1953, Watson
and Crick were
the first to identify
the structure of
DNA.
 Won a noble prize
in 1962.

DNA
 Deoxyribonucleic
acid
 Fundamental building block of all
living things.
 Passes on information from
generation to generation by
duplicating itself.
The Structure of DNA
 Shaped
like a
double helix – two
strands twisted
around each other
like a winding
staircase.
NUCLEOTIDES

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Building blocks of DNA.
Subunits that make up DNA.
Each consist of 3 parts:
1. Five carbon sugar called
deoxyribose
2. Nitrogen base
3. Phosphate group
NUCLEOTIDE

Make sure you know how to draw and label
this!
Nitrogenous
base
Phosphate
group
5 Carbon Sugar:
DEOXYRIBOSE
NITROGENOUS BASES

Four different nitrogen bases in DNA:
1. Adenine
Purines
2. Guanine
3. Thymine
Pyrimidines
4. Cytosine
NUCLEOTIDE

The only part that changes in a DNA
molecule is the nitrogenous base!
Nitrogenous
base
Phosphate
group
1.
2.
3.
4.
5 Carbon Sugar:
DEOXYRIBOSE
ADENINE
THYMINE
GUANINE
CYTOSINE
Warm Up
1.
2.
3.
What are the building blocks of
DNA?
Name one thing proteins do in
your body.
What is a gene?
ANSWERS
1.
2.
3.
What are the building blocks of
DNA? NUCLEOTIDES
Name one thing proteins do in your
body. AID IN MUSCLE
CONTRACTIONS.
What is a gene? SEGMENT OF
DNA LOCATED ON A
CHROMOSOME.
Did you know???????????????????

A cockroach can live
for several weeks
without it’s head!
Complementary Base Pairing
ONLY CERTAIN BASES CAN LINK
TOGETHER. THESE BASES ARE
CALLED “COMPLEMENTARY”.
A always pairs with T
C always pairs with G
* Bases are held together by hydrogen
bonds.

Complementary Strands
Fill in the blanks:
One side of DNA:
ACTGGCTATGC
Other side:
TGACCGATACG
DNA Replication
Process of making a copy of DNA.
One DNA strand serves as a template to
build the other.
1st the DNA strand “unzips” or splits down
the middle.
2nd Complementary nucleotides attach to
the single strands
What if there are mistakes?
Sometimes the wrong nucleotides are added.
An enzyme called DNA polymerase proof
reads the strand and checks for errors in
the nucleotide pairings.
The chance in a mistake is reduced to 1 error
per every billion nucleotides!
FROM GENES TO PROTEINS:
Decoding the information in DNA

Traits such as eye color as encoded in
DNA.
How are these traits passed on from
generation to generation?
This job takes both DNA and something
called RNA.
FROM GENES TO PROTEINS:
RNA


Like DNA, RNA is a nucleic acid, ribonucleic acid.
RNA differs from DNA in 3 ways.
DNA
RNA
Double stranded
Single stranded
Sugar is
deoxyribose
Nucleotides
ACTG
Sugar is ribose
Nucleotides
ACUG
Warm Up
1.
2.
The sugar in DNA is called
______________, while the sugar in RNA
is called____________________.
What are the two steps of DNA
replication?
WARM UP ANSWERS
1.
2.
The sugar in DNA is called
DEOXYRIBOSE, while the sugar in RNA
is called RIBOSE.
What are the two steps of DNA
replication? 1. DNA MOLECULE
UNZIPS 2. NUCLEOTIDES ATTACH TO
THE NEW STRAND.
DID YOU KNOW?????????????
IF YOU HAVE HAD
YOUR PILLOW
FOR OVER 5 YEARS,
ONE TENTH OF IT’S
TOTAL WEIGHT IS
DUST MITES AND
THEIR POOP!
FROM GENES TO PROTEINS:
Uracil instead of Thymine

No thymine bases are found in RNA,
instead uracil pairs with adenine.
DNA
A-T
C-G
RNA
A-U
C-G
From DNA to RNA
Original DNA strand
ATTACGAAGGCTA
UAAUGCUUCCGAU
New RNA strand
THREE TYPES OF RNA
1.
2.
3.
mRNA- messenger RNA
tRNA- transfer RNA
rRNA- ribosomal RNA
We will learn more about these
later.
FROM GENES TO PROTEINS: The
Big Picture

2 STEP PROCESS:
1st. TRANSCRIPTION- from DNA to
RNA
2nd. TRANSLATION - from RNA to
proteins.
FROM GENES TO PROTEINS:
Transfer of Information, From DNA to RNA


TRANSCRIPTION – process of taking
information found in DNA and transferring
it to a RNA strand. RNA is produced.
Genetic information encoded in DNA is
transferred to an RNA molecule.
Occurs in the nucleus, where DNA is found.
*******THIS IS NOT THE SAME AS DNA
REPLICATION*********
Transcription vs. Replication
FROM GENES TO PROTEINS:
Results of Transcription
FORMATION OF ONE
SINGLE-STRANDED
RNA MOLECULE
FROM GENES TO PROTEINS:
mRNA
-The type of RNA that carries out
transcription is called mRNA.
-mRNA will deliver the new strand
to the site of translation.
WARM UP 11/15
1.
2.
NAME THE THREE TYPES OF RNA.
WHAT IS THE RESULT OF
TRANSCRIPTION?
Warm up Answers 11/15
1.
1.
NAME THE THREE TYPES OF RNA.
1. Messenger RNA
2. Transfer RNA
3. Ribosomal RNA
WHAT IS THE RESULT OF
TRANSCRIPTION? The formation of
one single stranded RNA molecule.
DID YOU KNOW????????????
The average human
produces a quart
of saliva a day!!
That’s about
10,000 gallons in a
lifetime!
Why do we need mRNA?
Remember, DNA is only found in the nucleus of the
cell.
 mRNA is needed to carry information out of the
nucleus to other parts of the cell.
For example,
Imagine that your name is DNA and you are
on house arrest. If you need McDonalds you must
send someone else with your message (order) to
McDonalds.

FROM GENES TO PROTEINS: The
Genetic Code, Codons



The mRNA instructions are written as three
nucleotide sequences called CODONS.
Each nucleotide triplet in mRNA specifies for a
particular amino acid.
Each codon along the mRNA strand
corresponds with a specific amino acid.
AUC
CODON
GGA
CODON
UUA
CCC
CODON
CODON
mRNA codes for Specific Amino Acids
mRNA
AUC
GGA
UUA
CCC
CODON
CODON
CODON
CODON
Isoleucine
Glycine
Leucine
Proline
Now you try……………

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
UAA
Stop
UGU
Cysteine
GAU
Aspartic acid
FROM GENES TO PROTEINS:
RNA’s Roles in Translation



Takes place in the cytoplasm at the
ribosomes. In order for translation to occur,
mRNA must migrate to the ribosomes.
tRNA and ribosomes help in the synthesis
of proteins. Proteins are made from mRNA.
The mRNA moves out of the nucleus to the
ribosomes. There tRNA carries the amino
acid to it’s correct codon. The sequence is
then converted into an amino acid
sequence.
FROM GENES TO PROTEINS:
Translation


tRNA consists of a single strand of RNA with an
amino acid linked to the end.
Each tRNA contains an
anticodon – three nucleotide
sequence that is complementary
to an mRNA codon.
From DNA mRNA tRNA Proteins
DNA Strand
ATCGATCCG
mRNA Strand
UAGCUAGGC
codons
tRNA Strand
AUCGAUCCG
anti-codons
Proteins
Isoleucine, etc
What happens when there is a mistake?

Normally process is very accurate, but
occassionaly they make a mistake known
as a mutation.
ex. THE DOG BIT THE CAT
THE DOG BIT THE CAR
**One change can make a huge difference!
3 Types of Mutations
1.
2.
Point mutation – only a single nucleotide
changes. (Only changes one protein)
ATCGAA Serine, Arginine
ATGGAA Stop, Arginine
Deletion mutation – base is removed or
entire segments.
THE CAT ATE
THE ATA TE
3. Frameshift mutation – base is added or
deleted, causes a change in all of the
amino acids after the mutation. Causes the
gene to be read wrong. Ex. Include
deletion and addition mutations.
Warm Up
FOR YOUR QUIZ –
WHICH WILL BEGIN 10
MINUTES AFTER THE
BELL!
STUDY