Download LECTURE 10.1 DNA

Chapter 10
DNA
RNA
Protein Synthesis
History
of DNA
2
History of DNA



Early scientists thought protein was the
cell’s hereditary material because it was
more complex than DNA
Proteins are composed of 20 different
amino acids (Monomer) in long polypeptide
chains
DNA only has 4 monomers called
nucleotides, (A, T, G, C)
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Transformation



Fred Griffith worked with
virulent S and nonvirulent R
strain Pneumoccocus bacteria
He found that R strain could
become virulent when it took in
DNA from heat-killed S strain
Study suggested that DNA was
probably the genetic material
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Griffith Experiment
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History of DNA


Chromosomes are made
of both DNA and
protein
Experiments on
bacteriophage viruses
by Hershey & Chase
proved that DNA was
the cell’s genetic
material
Radioactive
32P
was injected into bacteria!
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DNA Structure
Rosalind Franklin took
diffraction x-ray
photographs of DNA
crystals
 In the 1950’s, Watson &
Crick built the first model
of DNA using Franklin’s
x-rays

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Rosalind Franklin
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A. Found in the ________________ of the
cell
B. Control _____________ synthesis and
thus control cell activities
C. Has shape of a
____________________(twisted ladder)
D. Building block is a _______________
DNA


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DNA is often called
the blueprint of life.
In simple terms,
DNA contains the
instructions for
making proteins
within the cell.
Proteins are the building blocks of
life…..
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Why do we study DNA?
We study DNA for
many reasons,
e.g.,
 its central
importance to all
life on Earth,
 medical benefits
such as cures for
diseases,
 better food crops.
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
In which process do organisms transfer
the energy in organic molecules to ATP
molecules?


A) Excretion
C) Digestion
B) cellular respiration
D) Photosynthesis
Which group of organic compounds includes
enzymes?
A) carbohydrates
B) Sugars
C) Nucleic Acids
D) Proteins
Chromosomes and DNA
Our genes are on
our
chromosomes.
 Chromosomes
are made up of a
chemical called
DNA.

CELL NUCLEUS  Chromosomes  Genes  DNA
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DNA
Stands for
Deoxyribonucleic acid
 Made up of subunits
called nucleotides
 Nucleotide made of 3
things:
1. Phosphate group
2. 5-carbon sugar
3. Nitrogenous base

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DNA Nucleotide
Phosphate
Group
O
O=P-O
O
5
CH2
O
N
C1
C4
Sugar
(deoxyribose)
C3
C2
Nitrogenous base
(A, G, C, or T)
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Nucleotides
O
O -P O
O
O
O -P O
O
One deoxyribose together
with its phosphate and base
make a nucleotide.
O
O -P O
O
Phosphate
Nitrogenous
base
O
C
C
C
O Deoxyribose
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Four nitrogenous bases
DNA has four different bases:

Cytosine C

Thymine T

Adenine A

Guanine G
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Two Kinds of Bases in DNA

Pyrimidines are
single ring bases.

Purines are
double ring bases.
N
N C
O C
C
N C
N
N C
C
C
N
N C
N C
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PURINES = double ring structure
adenine (A)
“Another Guido
guanine (G)
Pumps”
N
C
Adenine
N
C
C
N
O
N
C
N
N
C
N
C
C
C
N
Guanine
C
N
N
C
PYRIMIDINES – single ring structure
thymine (T) “Tut & Cleopatra
cytosine (C)
= Pyramids”
N
O
C
C
O
C C
N
C
thymine
N
O
C
C
N
C
N
C
cytosine
Nucleotide Bases
phosphate
group
ADENINE
(A)
GUANINE
(G)
THYMINE
(T)
CYTOSINE
(C)
deoxyribose
Evidence for DNA Structure:
1) 1951 – Chargaff determines that
the number of adenine always equaled
the number of thymine; and the number
of guanine always equaled the number
of cytocine
A=T and G=C
This is known as CHARGAFF’S RULE
(base-pairing rule)
Question:
 If
there is 30% Adenine,
how much Cytosine is
present?
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Answer:
 There
would be 20%
Cytosine
Adenine (30%) = Thymine
(30%)
 Guanine (20%) = Cytosine
(20%)
 Therefore, 60% A-T and
40% C-G

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Question:
 If
there is 22% thymine,
how much guanine is
present?
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2) 1952 Rosalind Franklin used x-ray
diffraction to observe the structure of DNA.
A powerful x-ray beam was
aimed at
the sample and the scattering
pattern
was recorded on film. Showed a circular
shape with “rungs” sticking into the middle.
She
worked with Maurice Wilkins.
3) A few weeks later Watson and Crick
examined Franklin’s work and in 1953
they had determined the structure of
DNA by building a model.
In 1962, Watson and Crick shared the
Nobel prize for their discovery. Franklin
had died in 1958 and did not share the
prize.
WATSON
WATSON AND CRICK
82 yrs old
(2010)
Died 2004
What are the 6 bonds we learned?

Covalent
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Share e-
Peptide

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
Ionic

Give or take e-

Polar Covalent


Hydrogen

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Weak
H+ and anything (-)

Holds proteins
C-N-C
Holds H2O together
Glycosidic

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Holds sugar
C-O-C

1) Which process removes carbon dioxide from the
atmosphere rather than adding it?



2) The following equation takes place in which organelle?

Carbon dioxide + Water  Sugar + Oxygen

A. Mitochondria
C. Ribosome
D. Vacuole
A. Vacuoles
B. Nuclei
C. Ribosomes
D. Mitochondria
4) Which statement best describes a cell membrane?



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
B. Chloroplast
3) Most of the reactions by which energy from sugars is
released for use by the cell happens within the


A. Cellular Respiration B. Combustion of Gasoline
C. Photosynthesis
D. Deforestation
A. Is only found in animal cells
B. Is an immovable structure
C. It controls reproduction is a cell
D. It controls the passage of materials into the cell
5) A rotten egg gave off a foul-smelling gas containing
sulfur, which decomposing compound found in an egg is the
most likely source of the odor?

A. Carbohydrates
B. Proteins
C. Lipids
D. Nucleic Acids
What bond holds together proteins?
 What are the two purines?



How will we remember them?
What are the base-pairing rules?

Who came up with them?
What is one nucleotide made up of?
 Is DNA a single or double strand?
 What bond holds together the two
sides of the “ladder”?

C. The Watson-Crick Model of DNA
1. Double Helix = like a twisted ladder
a) backbone = __________________
rungs = _____________________
(always a purine to a pyrimidine, A-T or C-G)
b) 2 sides of DNA held together by
weak
__________________ bonds
c) backbone held together by
__________________ bonds
DNA Double Helix
“Rungs of ladder”
Nitrogenous
Base (A,T,G or C)
“Legs of ladder”
Phosphate &
Sugar Backbone
The Shape of the Molecule



DNA is a very long
polymer. Why a
polymer???
The basic shape is like
a twisted ladder or
zipper.
This is called a double
helix.
One Strand of DNA


The backbone
of the molecule
is alternating
phosphates and
deoxyribose
sugar
The teeth are
nitrogenous
bases.
phosphate
deoxyribose
bases
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Two Stranded DNA


Remember,
DNA has two
strands that fit
together
something like
a zipper.
The teeth are
the nitrogenous
bases but why
do they stick
together?
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C
N
N
C

C
N
N
C
O

The bases attract each
C and G has
other because of
three
hydrogen bonds.
hydrogen
bonds
Hydrogen bonds are
weak but there are
millions and millions of
them in a single
molecule of DNA.
N
C
The bonds between
cytosine and guanine
C
are shown here with
dotted lines
C
C

N
Hydrogen Bonds holds the
two strands together
N
C
N
O
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Hydrogen Bonds, cont.



When making
hydrogen bonds,
cytosine always
pairs up with
guanine
Adenine always
pairs up with
thymine
Adenine is
bonded to
thymine here
N
O
C
C
O
C C
N
A and T share only two
hydrogen bonds
C
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P
D
N base N b
P
D
N base N b
P
D
N base N b
P
D
N base N b
Human Genome Project

Project completed in
2003 where scientists
sequenced 25,000
genes (short segment
of dna that codes for a
protein) and FOUND
where they are on
EACH of the 46
CHROMOSOMES!
Why would we want to know where
our genes are and what they do?
Why does it make sense to hold
the 2 strands of DNA together
by weak H bonds?

Bc 2 strands need to break easily to
duplicate or copy DNAREPLICATION
Replication Facts



DNA has to be copied before a
cell divides in mitosis
DNA is copied during the S or
synthesis phase of interphase
New cells will need identical
DNA strands
In a DNA molecule, the letters A, T, G, and C represent
1)
a. Sugars
c. proteins
d. Nitrogen bases
In DNA, the base represented by an A always
pairs with the base represented by a
2)
3)
b. starches
a. T
b. U
c. G
d. C
Which statement describes how DNA controls cellular
activities?
a.
b.
c.
d.
It regulates the concentration of molecules on both sides of the cell
membrane
It varies the rates of starch synthesis
It coordinates active and passive transport
It determines the order of amino acids in protein molecules
4) Enzyme molecules are synthesized primarily from
a. monosaccharides
b. fatty acids
c. phospholipids d. amino acids
5) Matter made up of only one kind of atom is a(n)
a. fat
b. nucleus
c. compound
d. element
DNA Replication


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Begins at Origins of Replication
Two strands open forming Replication
Forks (Y-shaped region)
HELICASE  pervert enzyme that
unzips the DNA (genes)
New strands grow at the forks
S
3’
P
5’ Parental DNA Molecule
3’
S
Replication
Fork
P
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5’
DNA Replication
Enzyme Helicase unwinds
and separates the 2 DNA
strands by breaking the
weak hydrogen bonds
 Single-Strand Binding
Proteins attach and keep
the 2 DNA strands
separated and untwisted

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3) New complimentary bases from the cell’s
nucleoplasm are added to the unraveled DNA
strands by DNA POLYMERASE, and new H bonds are
made between the bases. “ZIPS UP”
DNA polymerase can then add the new nucleotides
DNA Replication


P
5’
DNA polymerase can only add
nucleotides to the 3’ end of the
DNA
This causes the NEW strand to be
built in a 5’ to 3’ direction
S
3’
Nucleotide
DNA Polymerase
RNA
Primer
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5’
4)
Bonds form between the phosphates and sugars
of the new backbone.
5) 2 DUPLICATED DNA strands are made! Each
with an old and a new strand
Semiconservative Model of
Replication



Idea presented by Watson & Crick
The two strands of the parental
molecule separate, and each acts as a
template for a new complementary
strand
New DNA consists of 1
PARENTAL (original) and 1 NEW
DNA Template
strand of DNA
Parental DNA
New DNA
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Replication starts at several points along
the helix, thus allowing replication to take
place at a much quicker rate.
If replication did not start at several points at
one time, the replication process of the
chromosomes of a fruit fly would take 16 days!
It actually takes approximately 3 minutes (6000
sites copied simultaneously).
The cells lining the stomach divide rapidly and
can replicate their DNA every 20 minutes.
Bases are added at a rate of 50 – 100 bases per
second. (500/sec in bacteria)
DNA REPLICATION BEGINS AT MANY SITES ALONG
A GIANT DNA MOLECULES
Proofreading New DNA



DNA polymerase initially makes
about 1 in 10,000 base pairing
errors
Enzymes proofread and correct
these mistakes
The new error rate for DNA that
has been proofread is 1 in 1 billion
base pairing errors
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A group of more than 20 repair
enzymes recognize and remove
damaged nucleotides or
MUTATIONS ( wrong pairs, the
oopsies) and replace them with
new ones.
1)
2)
3)
4)
5)
6)
7)
What are the main functions of DNA?
What are the 2 types of Bonds found in DNA
and the locations of each?
What does Helicase do?
What does DNApolymerase do?
Where does replication happen? (hint: well
where is DNA found)
What is the shape of a DNA molecule?
The process of duplicating DNA is _______.
8) What would be the complementary DNA strand for the
following DNA sequence?
DNA 5’-CGTATG-3’
1)
2)
3)
4)
5)
6)
7)
8)
Stores and transmits genetic info
Covalent bonds b/w the phosphate and sugar
backbone and Hydrogen bonds join the
nitrogen bases
Helicase attaches to DNA and breaks the
hydrogen bonds so the strands unzip
DNA polymerase attaches to the unzipped
strand, identifies the unpaired base on the
template strand, locates a complementary
nucleotide, and attaches it.
Nucleus
Double helix
Replication
DNA 3’-GCATAC-5’

Which statement best describes the relationship between cells, DNA,
and proteins?




A. Cells contain DNA that controls the production of proteins
B. DNA is composed of proteins that carry coded information for how
cells function
C. Proteins are used to produce cells that link amino acids together into
DNA
Which two organ systems provide materials required for the human
body to produce ATP?


A. reproductive and excretory
C. respiratory and immune
B. digestive and respiratory
D. digestive and reproductive

Replication must happen (Before or after) the cell divides.

The sugar found in DNA is


A. splendose
B. glucose
c. ribose
d. deoxyribose
Most of the oxygen in our atmosphere comes from processes carried
out

A. In the soil
B. by animals
c. in factories
d. by plants
QUICK REVIEW



What is replication? Making ____ from ___
What are the 2 enzymes involved in
replication? Who is the pervert?
What are the base-pairing rules for
replication?
10.2 RNA
a) Same as DNA except: it is
_________-stranded
b) _________ replaced thymine
(bonds with ___________)
c) responsible for the movement
of genetic info from nucleus to
cytosol
d) sugar = _____________
(one more oxygen atom than deoxyribose)
e) Used in Transcription and translation
- transcription is making mRNA from DNA in nucleus
- translation is making proteins from RNA at a
ribosome
RNA Differs from DNA
1. RNA has a sugar ribose
DNA has a sugar deoxyribose
2. RNA contains the base uracil (U)
DNA has thymine (T)
3. RNA molecule is single-stranded
DNA is double-stranded
4. 1 type of DNA
3 Types of RNA
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SO IF MY DNA READ
ATTACGGC….my mRNA would read

UAAUGCCG
THIS IS TRANSCRIPTION!!!!!!!!
(covalent
bonds)
B. Types of RNA
1)
mRNA – _____________ RNA
– consists of RNA nucleotides in the form
of a single uncoiled chain (gene
transcirption). mRNA carries genetic info
from Nucleus (DNA) to cytosol.
rRNA = _______________RNA
- most abundant form of RNA
- consists of RNA nucleotides in the globular
form
- makes up the ribosomes where proteins r
made,
3) tRNA = _______________ RNA
2)
- translates mRNA to the amino acid
- carries the amino acid to the ribosome
has an _______________ to match the
mRNA’s CODON (series of 3 nucleotides long)
That is 3 letters ex. AAU, CGG, AUC
has an _________________ to pick up the
correct amino acid.
Gene Transcription
DNA
RNA Polymerase
mRNA
Complementary
mRNA
transcript
A A U
Protein Synthesis



The production (synthesis)
of polypeptide chains
(proteins)
Two phases:
Transcription & Translation
mRNA must be processed
before it leaves the nucleus
of eukaryotic cells
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DNA  RNA  Protein
Nuclear
membrane
DNA
Transcription
Eukaryotic
Cell
Pre-mRNA
RNA Processing
mRNA
Ribosome
Translation
Protein
82


Two Parts of Protein
Synthesis….from DNA to
Proteins
Transcription makes an RNA
molecule complementary to a portion
of DNA…because DNA is too big to
get out of nucleus (2 strands
…..mRNA only 1 strand)
Translation occurs when the
sequence of bases of mRNA
DIRECTS the sequence of amino
acids in a polypeptide
83


Greenhouse gases in the atmosphere a. keep Earth warm b. are
released mostly from greenhouses c. are valuable as fuels d.
reduce holes in the ozone layer
Which is an example of a biotic factor that affects the size of a
population in a specific ecosystem?
a.
b.
c.
d.
The
The
The
The
average temperature of the ecosystem
number and kinds of soil minerals in the ecosystem
number and kinds of predators in the ecosystem
concentration of oxygen in an ecosystem
IN the following food chain, which is the most abundant organism?
Corn plants  mice  Snake  Hawks
a. corn b. mice c. snake d. hawk

Plants help maintain the quality of the atmosphere by
a. opening holes in the ozone layer b. causing global warming c.
storing oxygen d. storing carbon dioxide
Adding Nucleotides
5’
growing RNA transcript
3’
5’
3’
direction of transcription
Addition of nucleotides in the 5’ to 3’ direction of the DNA
B. Transcription (“written across”)
1) RNA polymerase attaches to a
special place (called promoter) on
the DNA molecule and moves
along the strand, unwinding and
separating the strands.
2)
RNA polymerase then begins
reading and copying the DNA as it
goes along.
RNA Polymerase



Enzyme found in the nucleus
Separates the two DNA
strands by breaking the
hydrogen bonds between the
bases
Then moves along one of the
DNA strands and links RNA
nucleotides together
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From the supply of nucleotides in the
nucleus, nucleotide pairing begins
for RNA transcription (A-U, C-G);
3) Pairing of the nucleotides
continues until the enzyme
reaches a sequence of nucleotides
on the DNA that tells it to STOP (
termination codon.)
Gene Transcription
DNA
RNA Polymerase
RNA
Complementary
mRNA
transcript
4)
The mRNA separates from the DNA,
then mRNA will carry the genetic
information out of the nucleus to the
ribosome.
Messenger RNA (mRNA)
Carries the information for a
specific protein to a ribosome
 Made up of 500 to 1000
nucleotides long
 Sequence of 3 bases called codon
 AUG – methionine or start codon
 UAA, UAG, or UGA – stop codons

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Prokaryote –
transcription
and translation
take place in
the
Eukaryote –
Transcription
takes place in the
Translation in the
C. Replication vs Transcription
These two processes are similar except:
1)
_________ replaces THYMINE in mRNA
2) The RNA completely ___________ from
the DNA strand







Copying of DNA to DNA is ____________
Copying of DNA to mRNA is ___________
What three things make up a nucleotide
_______, ______, _______
What are t he three types of RNA?
Who is the main enzyme in transcription?
What does he do? He _____ the DNA and
puts a ______ strand together.
What are the base-pairing rules for
transcription?





Water is an example of a) a molecule but not a compound b)
compound but not a molecule c) both a molecule and a compound
neither a molecule or a compound
d)
What are the most common building blocks of lipids? A) glycerol and
amino acids b) glycerol and fatty acids c) monosaccharides and amino
acids d) monosaccharides and fatty acids
The analysis of data gathered during a particular experiment is necessary
in order to a) formulate a hypothesis for the experiment b) develop a
research plan for the experiment c) design a control for the experiment
d) draw a valid conclusion from that experiment
A species scientific name includes information from
a) division
and genus b) genus and order c) species and phylum d) genus and
species
A group of related classes of organisms make up an a)genus b) order c)
kingdom d) phylum

DNA  DNA is __________________



DNA  mRNA is _________________



Occurs where ________________
Enzymes involved __________________
Occurs where ____________________
Enzyme involved __________________
Original DNA is AATTGCGCA


Replicated __________________
Transcript ___________________
TRANSLATION
tRNA
amino acids are assembled into a
polypeptide chain at the ribosome
_____________ anticodons
translates from ______________
codons
Transfer RNA (tRNA)





Made up of 75 to 80 nucleotides long
Picks up the appropriate amino acid
floating in the cytoplasm
Transports amino acids to the mRNA
Have anticodons that are
complementary to mRNA codons
Recognizes the appropriate codons on
the mRNA and bonds to them with
H-bonds
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




Who has the codon?
Who has the anit-codon?
Is replication involved in making a protein?
Does replication occur before or after cell
division?
Who took an x-ray of DNA?

What did it show?
GLOBULAR
“HAIRPIN”
Why are proteins important?
 They
literally MAKE UP cell parts
and enzymes

Don’t 4get… your whole body is made up
of cells and every reaction needs some
type of enzyme
What are the monomers of proteins?







Amino acids
AA + AA 
DIPEPTIDE
AA + AA + AA (or more) 
POLYPEPTIDE
2 or more polypeptides 
PROTEIN
A. Overview of Protein Synthesis:
an organism’s genotype (genes) is
translated into its phenotype (how it
looks).
DNA
RNA
PROTEIN
TRANSCRIPTION AND TRANSLATION ARE THE ONLY 2 PROCESSES
INVOLVED IN MAKING A PROTEIN!!!!!! Why not replication?????
sequence of bases =
sequence of amino acids in a
protein.
A
U
G
C
T
G
…
B. genetic code for amino acids must be
at least ___________
nucleotides –
A TRIPLET CODE or ______________


Set of 64 base triplets
Codon -Nucleotide bases read in
blocks of three on ____________

Start codon  AUG

Stop codon  UAA, UAG, UGA
The triplet code is universal for all living
organisms!
(WE ARE ALL CONNECTED !! –
EVOLUTION)

Most amino acids can be specified by
more than one codon

Ex. 6 codons specify leucine

UUA, UUG, CUU, CUC, CUA, CUG
I. Genetic Code
A. Link between:
gene structure (N base sequence)
to
protein structure (amino acid sequence).
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II. Translation
Once the mRNA reaches the
___________, the cell can begin
to build a protein.
A. The ________________
translates the mRNA’s code into a
particular protein.
1)
•
•
•
STRUCTURE:
________-strand of RNA looped
back on itself
Has __________ on 1 side (matches
up with mRNA codons)
Has _____________ of amino acid
on the other side
2)
FUNCTION: to carry proper amino
acid to mRNA at the ribosome
Example: tRNA with anticodon GCU
codes for Arginine
(mRNA codon is:
1) ggu
B. Process of Translation
1)
2)
3)
A ______________ attaches to the
mRNA at a start codon - AUG
The “AUG” codon pairs with the
anticodon “UAC” on a specific tRNA.
This tRNA carries the amino acid
__________________
Free vs. Attached

Where are ribosomes found in a cell again?
What are they made up of again….think?
Free ribosomes in cytosol produces proteins
that are used inside the cell
Proteins that need to be Prepared, Packaged,
and Said PEACE to be shipped outside the
cell are produced by ribosomes attached to
the Endoplasmic reticulum
4)
5)
2nd codon is now ”read” by the ribosome.
Then a tRNA
Then its amino acid is attached to the
polypeptide chain
An enzyme joins the first two amino acids
in the chain by a PEPTIDE bond.
The first tRNA is now empty and the
second is holding both amino acids. The
empty tRNA leaves the ribosome
5) The peptide continues to grow until
the ribosome reaches a STOP
CODON on the mRNA
STOP CODONS: UAA
UAG
UGA
Ribosomes
tunnel
small ribosomal subunit
large ribosomal
subunit
has the binding site for
has the binding site
the mRNA
for
the tRNA
intact
ribosome
Translation

Three steps:
1. initiation: start codon (AUG)
2. elongation: amino acids linked
3. termination: stop codon
(UAG, UAA, or UGA).
Let’s Make a Protein !
121
mRNA Codons Join the
Ribosome
Large
subunit
P
Site
A
Site
mRNA
A U G
Small subunit
C U A C U U C G
122
Initiation
aa1
aa2
2-tRNA
1-tRNA
anticodon
hydrogen
bonds
U A C
A U G
codon
G A U
C U A C U U C G A
mRNA
123
Elongation
peptide bond
aa1
aa3
aa2
3-tRNA
1-tRNA
anticodon
hydrogen
bonds
U A C
A U G
codon
2-tRNA
G A A
G A U
C U A C U U C G A
mRNA
124
aa1
peptide bond
aa3
aa2
1-tRNA
3-tRNA
U A C
(leaves)
2-tRNA
A U G
G A A
G A U
C U A C U U C G A
mRNA
Ribosomes move over one codon
125
aa1
peptide bonds
aa4
aa2
aa3
4-tRNA
2-tRNA
A U G
3-tRNA
G C U
G A U G A A
C U A C U U C G A A C U
mRNA
126
aa1
peptide bonds
aa4
aa2
aa3
2-tRNA
4-tRNA
G A U
(leaves)
3-tRNA
A U G
G C U
G A A
C U A C U U C G A A C U
mRNA
Ribosomes move over one codon
127
aa1
peptide bonds
aa5
aa2
aa3
aa4
5-tRNA
U G A
3-tRNA
4-tRNA
G A A G C U
G C U A C U U C G A A C U
mRNA
128
peptide bonds
aa1
aa5
aa2
aa3
aa4
5-tRNA
U G A
3-tRNA
G A A
4-tRNA
G C U
G C U A C U U C G A A C U
mRNA
Ribosomes move over one codon
129
aa4
aa5
Termination
aa199
aa3 primary
structure
aa2 of a protein
aa200
aa1
200-tRNA
A C U
terminator
or stop
codon
C A U G U U U A G
mRNA
130
End Product –The Protein!


aa2
aa1
The end products of protein
synthesis is a primary structure of
a protein
A sequence of amino acid bonded
together by peptide bonds
aa3
aa4
aa5
aa199
aa200
131
What Happens to the
New Polypeptides?


Some just enter the cytoplasm
Many enter the ER and move through the
cytomembrane system where they are
processed, packaged, and transported out
of cell
Question:

What would be the
complementary RNA strand
for the following DNA
sequence?
DNA 5’-GCGTATG-3’
138
Answer:
 DNA
5’-GCGTATG-3’
 RNA 3’-CGCAUAC-5’
139
Question:
 If
there is 15% Adenine,
how much Cytosine is
present?
140

35% cytosine and guanine
Question:
 If
there is 26% Thymine,
how much Adenine is
present?
142

26%........duh … A=T
REVIEW QUESTIONs!





A codon might cause any of the following
events to occur EXCEPT
a. the binding to a molecule with a cell.
b. the starting of translation.
c. the coding for an amino acid.
d. the stopping of translation.
A protein is a polymer consisting of
a specific sequence of




Amino acids
Fatty acids
RNA nucleotides
DNA nucleotides
The genetic code specifies the
correlation between



A DNA nucleotide sequence and an RNA
sequence
An mRNA sequence and a tRNA sequence
An RNA nucleotide sequence and an
amino-acid sequence
The goal of DNA is ultimately to
make a

PROTEIN
The function on DNA is to

Store our information--- our genetic code
During translation, one end of a
tRNA molecule pairs with a
complementary




A. nucleotide sequence in DNA
B. mRNA codon
C. tRNA molecule
D. protein molecule
What is the difference between a
codon and anticodon?


Codon found in mRNA
Anticodon found on tRNA
After transcription, where does the
mRNA go

To a ribosome either in the cytoplasm or
on rough ER
tRNA
Peptide bond
ribosome
anticodon
mRNA
Amino acid
Who were the two scientist who
discovered the DOUBLE HELIX
model of DNA

Watson and Crick
She took an x-ray of DNA and
discovered its circular shape

Rosalind Franklin
In what organelles can DNA be
found

Mitochondria and nucleus and chloroplasts