2/9/12Ch 12 DNA/RNA vocabulary
1. Nucleotide
2. Chromatin
3. Replication
4. Gene
5. Transcription
6. Codon
7. Translation
8. Anticodon
9. Mutation
Nucleic Acids and
Protein Synthesis
DNA (deoxyribonucleic
acid) is…




An organic compound
A type of nucleic acid
Double stranded
Made up of subunits called
NUCLEOTIDES
Nucleotides have 3 parts
 Sugar molecule
called
DEOXYRIBOSE
 PHOSPHATE
GROUP
 NITROGEN
CONTAINING BASE
THE 4 NITROGEN
CONTAINING BASES IN DNA:
 ADENINE=A
 GUANINE=G
 CYTOSINE=C
 THYMINE=T
PURINES
 ADENINE and
GUANINE are
PURINES
 Bases that have 2
rings of carbon and
nitrogen atoms
PYRIMADINES
 CYTOSINE &
THYMINE are
PYRIMADINES
 Bases that have 1
ring of carbon and
nitrogen atoms
WATSON & CRICK
 WATSON & CRICK suggested that DNA
is made of 2 nucleotide chains that wrap
around each other to form a spiral shape
called a double helix.
THE COMPLEMENTARY
BASE PAIRING RULES
 In a double helix, cytosine pairs with
guanine & adenine pairs with thymine.
 Therefore, A=T & C=G.
REPLICATION
 The copying of DNA is called REPLICATION.
 The 2 nucleotide chains separate by
unwinding-each chain serving as a template for
a new nucleotide chain.
 If the original DNA strand sequence is: A-T-TC-C-G, the new nucleotide chain would read:
T-A-A-G-G-C.
 When replication is finished, 2 new exact
copies of the original DNA molecule are
produced & the cell is ready to undergo cell
division.
DNA Replication
 A change in a nucleotide
sequence is called a
MUTATION.
 DNA may be damaged by a
variety of things, such as
chemicals and ultraviolet
(UV) rays from the sun.
Quick Quiz
 What are the three parts of a
nucleotide?
 What is stated by the
complimentary base pairing
rules?
 What is replication?
2/10/12
Do Now:
1. DNA is made of small subunits called _____.
2. Nucleotides have three parts. They are ___, ___, &
___.
3. The sugar found in DNA is ________.
4. According to Chargaff’s Rules (complementary base
pairing rules), adenine pairs with ____ & _____ pairs
with guanine.
5. Purines have ___ ring(s) of carbon & nitrogen, while
pyrimadines have ___ ring(s) of carbon & nitrogen.
6. The copying of DNA is ______.
7. If the original strand of DNA reads ACTGGCTA, the
new strand will read _______.
8. Any change in DNA is referred to as a _____.
9/13/11-Pick up your book.
Do-Now:
Pick up and complete the DNA & Protein
Synthesis Puzzle.
Set out your vocab flashcards, DNA color
sheet, & Scientist Graphic Organizer
from yesterday.
RNA (ribonucleic acid) is…





An organic compound
Type of nucleic acid
Made up of nucleotides
Single strand
THYMINE is rarely part of RNA. URACIL
(another pyrimadine) replaces thymine in
RNA. This means that URACIL, not
thymine, pairs with ADENINE in RNA.
 U=A
Compare RNA to DNA
Types of RNA (all 3 help to
make proteins)
1.MESSENGER RNA (mRNA)
is made of a single, uncoiled
chain. mRNA carries genetic
info from the DNA in the
nucleus to the cytosol of a
eukaryotic cell.
Types of RNA, cont.
2. TRANSFER RNA (tRNA) is
a single chain of RNA
nucleotides folded into a
hairpin shape that binds to
specific amino acids.
Types of RNA, cont.
3. RIBOSOMAL RNA (rRNA)
is the most common RNA.
rRNA is made of RNA
nucleotides that are in
globular form. rRNA makes
up the ribosomes where
proteins are made.
TRANSCRIPTION
 The process by which genetic info is
copied from DNA to RNA
 All 3 types of RNA are made in this
process
 Continues until the TERMINATION
SIGNAL is reached
 Think of using a variety of colored paper
in the copy machine…
TRANSCRIPTION
Recall that…
 The making of proteins is called
PROTEIN SYNTHESIS
 PROTEINS are made of AMINO ACIDS
that are linked together by PEPTIDE
BONDS.
 The function of the protein is decided by
the amino acids that make it up.
GENETIC CODE
 The relationship between a nucleotide
sequence and an amino acid sequence is
called the GENETIC CODE.
 It is used to translate mRNA transcripts
into proteins.
 The genetic info needed for making
proteins is encoded in a series of 3
mRNA nucleotides called a CODON.
Genetic Code, cont.
 Each codon codes for a specific amino
acid.
 Some codons signal for translation of an
mRNA to start or stop.
 The START CODON (AUG) makes a
ribosome start translating an mRNA
molecule.
 STOP CODONS (UAA, UAG, UGA)
cause the ribosome to stop translating
the mRNA.
9/14/11-Pick up your book.
Student Summaries for Sat. School?
Do-Now:
1. DNA is made of small subunits called _____.
2. Nucleotides have three parts. They are ___, ___, & ___.
3. The sugar found in DNA is ________.
4. According to Chargaff’s Rules (complementary base pairing
rules), adenine pairs with ____ & _____ pairs with guanine.
5. Purines have ___ ring(s) of carbon & nitrogen, while
pyrimadines have ___ ring(s) of carbon & nitrogen.
6. The copying of DNA is ______.
7. If the original strand of DNA reads ACTGGCTA, the new
strand will read _______ (replication).
8. Any change in DNA is referred to as a _____.
Genetic Code, cont.
TRANSLATION
 The process of assembling polypeptides
from info encoded in the mRNA
 Begins when mRNA leaves the nucleus
through pores in the nuclear membrane
 mRNA migrates to a ribosome where
protein synthesis takes place
Translation, cont.
Translation, cont.
 Amino acids floating in the cytosol are brought
to the ribosomes by the tRNA molecules
 On the opposite side of the tRNA molecule
(from where the amino acid is attached), there
is a loop that has a sequence of 3 nucleotides
called an ANTICODON.
 The tRNA anticodon is complementary to and
pairs with its corresponding mRNA codon.
 For example, a tRNA with an anticodon of AAA
would bind to the mRNA codon sequence of
UUU.
Translation, cont.
Protein Assembly
 Starts with start codon (AUG)
 As a ribosome moves down an mRNA
transcript, each mRNA codon is paired with
its tRNA anticodon.
 This causes an amino acid to attach,
forming a peptide bond.
 As each amino acid is added to the chain,
the ribosome moves 3 nucleotides (1
codon) ahead on the mRNA transcript,
where the next amino acid will be
translated.
 It ends with a stop codon.
 Read p. 307-308
Practice!
1. DNA replication is taking place. The original
strand is ACTGCATCA. The new strand will
read _____.
2. Transcription is taking place. Transcribe your
DNA (answer) from #1 to make mRNA.
3. Translation is taking place. Translate your
mRNA (answer) from #2 to determine the
amino acid sequence. Use the genetic code
from your book or your notebook.
9/15/11-Get your book.
Do-Now:
1. Copying DNA to make new DNA is called ___.
2. Copying DNA to make RNA is called ____.
3. Using the information on mRNA to assemble
amino acids to make proteins is called ___.
4. The monomers of DNA & RNA are ____.
5. The 3 parts of a nucleotide are __, __, & __.
6. List the 3 types of RNA & what they do.
More Practice!
1. DNA replication is taking place. The original
strand is TAGCATGGGCAT. The new strand
will read _____.
2. Transcription is taking place. Transcribe your
DNA (answer) from #1 to make mRNA.
3. Translation is taking place. Translate your
mRNA (answer) from #2 to determine the
amino acid sequence. Use the genetic code
from your book or your notebook.
9/28/10-Pick up your book.
 Do-Now:
Complete the crossword puzzle on the back of
your DNA word search. If you turned this into
me, I have put it on your desk for you.
Quick Quiz
 What are two differences between RNA
and DNA?
 What is transcription?
 What is translation?
 What is the genetic code used for?