DNA & PROTEIN SNTHESIS
(Words to Know)
 1. Transfer RNA
 2. Peptide Bond
 3. Dipeptide Bond
 4. ATP
 5. Translation
 6. Anticodon
 7. Transcription
 8. Messenger RNA
 9. Codon
 10. Ribosomal RNA
 11. Ribosomes
•12. Nucleus
•13. Protein Synthesis
•14. Replication
•15. Hydrogen Bonds
•16. Complementary Base Pairs
•17 Amino Acids
•18 Nucleotide
•19. DNA
•20. Proteins
•21. Double Helix
•22. Watson & Crick
•23. Purines
•24. Pyrimidines
•25. RNA
 CHAPTER 11
 relating the structure of DNA to its function
 the role of DNA in protein production
 distinguish amongst different types of mutations.
 Proteins are important
components of living cells.
 Metabolism of cells is
controlled by proteins
called enzymes.
 Proteins are essential for
life.
 Every cell is capable of
making all the thousands
of different kinds of
proteins it may need.
 DNA of the chromosomes is the genetic material that
is passed from generation to generation.
 Genes are sections of DNA.
 DNA controls cellular activities by controlling the
production of enzymes.
Think On This…
 How does the cell synthesize proteins?
 What determines the kinds of enzymes
present in each cell?
 The molecule that controls the production of
proteins is a nucleic acid called
Deoxyribonucleic Acid (DNA).
 DNA is found in the chromosomes in the nucleus.
 DNA carries information for running the cell.
 DNA is made of nucleotides.
DNA Structure
DNA is made up of nucleotides
Nucleotides Have Three Parts
1.
2.
3.
Simple Sugar (5-carbon sugar)
Phosphate group
Nitrogen Base
Looking at the Structure of DNA
 In 1953 Watson and Crick solved the
puzzle
(p. 290 Fig. 11:3)
 These two scientists viewed x-ray images
of DNA crystals that were created by
Rosalind Franklin and Maurice Wilkins.
 DNA Structure
 Resembles a ladder
 sides: sugar and phosphate
 rungs (steps): complementary pairs
of nitrogen bases
The structure (shape) of the DNA
is referred to as a double helix.
•In DNA, there
are four possible
nitrogen bases:
•adenine (A)
•guanine (G)
•cytosine (C)
•thymine (T)
 Purines
 Adenine
(A)
 Guanine (G)
 Pyrimidines
 Thymine
(T)
 Cytosine (C)
Adenine (A) to Thymine (T)
And
Guanine (G) to Cytosine (C)
DNA Replication
Replication of DNA
 DNA molecules can build an exact copy of itself.
 This is called Replication. (ATP is the energy source)
 Replication is important for reproduction and
must occur every time a cell divides.

That way each cell has a complete set of instructions
for making proteins.
Steps to Replication
1.
2.
3.
4.
5.
6.
In the nucleus, weak hydrogen bonds break
between the bases of DNA.
This causes the DNA to unzip like a zipper.
Enzymes in the nucleus called DNA
Polymerase directs free floating nucleotides
in the nucleus to attach to each strand.
This results in two identical strands of DNA.
This is called Replication (doubling of
chromosomes).
This happens at the end of interphase.
:
REMEMBER: DNA is in the Nucleus
Proteins are synthesized in the Ribosomes
“ How can the information get to the ribosomes?”
By coping a near message >>mRNA
(messenger RNA)
The process of transferring the information from
DNA to RNA is called transcription
Transferring the info….
 To carry the genetic
message from the
nucleus into the
cytoplasm we have
mRNA.
 Any RNA strand is a
direct order from the
DNA.
RNA Structure
(looks like one half of a zipper)
 The Sugar is Ribose
 Single Strand
 Bases are:
Adenine (A) to Uracil (U)

Guanine (G) to Cytosine (C)
**Thymine is NOT found in RNA **
Thymine is substituted with Uracil

3 Types of RNA



mRNA (messenger RNA)
*Carries genetic information from
nucleus to ribosomes.
rRNA (ribosomal RNA)
*Found in ribosomes
*binds to mRNA and uses instructions to assemble the
amino acids in the correct order
tRNA (transfer RNA)
* Found in the cytoplasm
* Carries amino acids in the cytoplasm
to the ribosomes
DNA….to Proteins
 DNA Replicates….mRNA carries message to the
Ribosome…
The Genetic Code
 There are 4 bases
 There are 20 different kinds of
 amino acids in cells
(A.A. are the building blocks of proteins)
 The groups of three bases (3 letter code) in
mRNA are called codons or triplets.
UUU,
Codon
Or
triplet
AUA,
Codon
Or
Triplet
ACG,
Codon
Or
Triplet
 Each codon codes for a particular A.A.
 Each codon always codes for the same A.A
 The sequence can be different…this gives rise to different
proteins.
 There are 64 possible 3 letter code words.
 Only 20 common A.A.
 Some codons do not code for A.A., they provide instructions
for making the proteins
Example: UAA (is a stop codon)
this indicates that the protein ends at this point
Example:AUG (is a start codon and codes for an A.A.)
TRANSLATION
(see p. 294)
 Bonding A. A. to form proteins is called
Translation (from mRNA to Protein)
 tRNA:
* Is shaped like a cloverleaf (Fig. 11:8)
*one end has an attached site for an A.A.
* the other end has an exposed base
triplet called and anticodon

Translation:
Information is
decoded
* If a codon (3 bases on mRNA)
is AUC …..then
Its’ anticodon (3 bases on tRNA) is UAG
*In the cytoplasm are the A. A. necessary
for building proteins. tRNA will carry the
proper A.A. to the mRNA and line them
in the correct order.
* Once the RNA attaches to its’ specific
A.A. the combination moves toward a
ribosome (protein factory)
Transfer RNA (tRNA) (p. 293)
Three base anticodon
Amino Acid Codons
Genetic Changes (11:3)
 Mutation: any change in the DNA
sequence.
Mutagen: any agent that can cause a change in
DNA…(radiation, chemicals, and even high
temperatures.
Effects of Mutation: (p. 298)
 Point mutation: Change in a single base
pair in DNA
 Frameshift Mutation: A single base is added or
deleted from DNA
Four Kinds of Chromosomal
Mutations (see.p. 300)
 Deletion: part of the chromosome is left out
 Insertion: part of the a chromatid breaks off and
attaches to its sister chromatid
 Inversion: part of a chromosome breaks off and
reattaches backwards
 Translocation: part of one chromosome breaks off
and is added to a different chromosome
Terms
1.
2.
3.
4.
5.
6.
7.
8.
Protein: A complex chain of amino acids
essential in cell structure.
DNA: A nucleic acid “molecule of life”
Nucleus: Control center of the cell
Protein Synthesis: the making of proteins
Double Helix: the shape of DNA
Watson & Crick: Constructed DNA model
Ribosomes: Protein factory
ATP: Energy used to break chemical bonds
More Terms
9.
10.
11.
12.
13.
14.
15.
16.
Hydrogen Bonds: holds nitrogen bases
together (they are weak)
Replication: ability to build an identical
copy of itself
Messenger RNA (mRNA): Brings the
code from the DNA to the ribosomes
(sets of 3 are codons)
Transcription: Process by which the DNA code is copied onto a
strand of mRNA.
Nucleotide: contains a 5-carbon sugar,
nitrogen base and phosphate
Amino Acid: the building blocks of proteins
Purines: Adenine and Guanine
Pyrimidines: Cytosine and Thymine
More Terms
17. Complementary Base Pair: A (to) T
C (to) G
18. RNA: Ribonucleic Acid
Ribosomal RNA (rRNA): makes up the major part of
ribosomes
20. Codon: a sequence of 3 nucleotide bases that code for 2 amino
acid in a
protein…(found on mRNA)
19.
21. Anticodon: An exposed base triplet at the end of the RNA
(found on tRNA)
22.
Translation: Process of bonding A.A. in a sequence to form a
protein
23.
Dipeptide Bond: 2 or more A. A. joined
24.
Peptide Bond: the bond that forms between A.A. to join
another
Transfer RNA (tRNA): “Picks up” and carries A.A. to the
25.
DNA Worksheet
1. Name the molecule of life.
2. What are proteins essential for?
3. What are the building blocks for proteins?
4. Who studied the structure of DNA?
5. Where do you find DNA?
6. What is the job DNA?
7. Name the 4 bases in DNA.
8. How do these bases pair?
9. What does the DNA structure look like?
10.What is the protein factory of the cell?
11. Name three types of RNA..
12.Name two jobs of RNA..
13.What base does adenine bond with? How many bases does it take to
make one amino acid?
14.How many amino acids are common?
15. What is the anticodon for ACG?
16.If DNA read A-T-T-A-C-G-G-C-C what would the RNA read? Why is
DNA replication important?
1.
2.
3.
4.
5.
What is the shape of the DNA molecule?
Who are the two men that proposed DNA?
What base will pair with cytosine?
What base will pair with adenine?
The shape of the DNA structure is twisted, it is better
known as ___.
6. What is the process called when DNA
copies itself?
7. Name the three types of RNA.
8. What is transcription?
9. What is translation?
10. What kind of information does the DNA contain?
DNA Story
In the living world there are millions of different kinds of (1)
____. How are these made by cells? It has been found that
protein synthesis in a cell is controlled by a complex
macromolecule called (2)_____. This compound is not a
protein but a (3)______. A nucleic acid is made up of 3
parts. A 5-Carbon (4)____ molecule, nitrogen containing
(5)____, and a (6)____ group. DNA looks like a ladder
twisted into a shape known as (7)____. Each side of the
“ladder” is a long strand made of connecting nucleic acids.
Each base is joined by a weak (8) ___ to a base on the other
strand forming “rungs” in the ladder. The bases form
complementary pairs. Adenine bonds with (9) ____;
cytosine bonds with (10)___. During DNA (11)_____, the
hydrogen bonds break and each strand finds new
complimentary bases.
DNA Story cont.







In the nucleic acid RNA, adenine
always pairs with (12)______.
There are three kinds of RNA.
(13)______ RNA carries genetic
information from the nucleus to the
cytoplasm.
During (14)____. Information is
transferred from DNA in the nucleus to
mRNA.
The DNA molecule opens up and the
mRNA forms a single complementary
(15)_____.
The four bases of RNA can be
combined into 64 different
(16)______ combinations.
Each triple, known as a (17)___, codes
for one specific (18)____.
The order of the triples will determine
the order of the amino acids in the
______ (19) synthesized.
Word Bank
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PROTEIN
AMINO ACIDS
SUGAR
BASE
HYDROGEN
MESSENGER
PROTEINS
THYMINE
REPLICATION
STRAND
THREE BASE
CONDON
GUANINE
PHOSPHATE
DNA
DOUBLE HELIZ
URACIL
TRANSCRIPTION
NUCLEIC ACID