DNA
"The Blueprint of Life"
Vocabulary
1. Nucleotide
2. Base pairing
3. Chromatin
4. Histone
5. Replication
6. DNA Polymerase
7. mRNA
8. rRNA
9. tRNA
10.Transcription
11.RNA Polymerase
12.Promoter
13.Intron
14.Exon
15.Codon
16.Translation
17.Anticodon
18.Mutation
DNA stands for...
DeoxyriboNucleic Acid
DNA FACTS
•established by
James Watson
and Francis Crick
•Shape of a double
helix
•codes for your genes (traits/allleles)
•made of repeating subunits called
nucleotides
What is a nucleotide?
Has three parts:
PHOSPHATE
DEOXYRIBOSE (5 Carbon sugar)
BASE (A,T,G,C)
Base-Pair Rule
Adenine <==> Thymine
Guanine <==> Cytosine
The sides of the DNA
ladder are phosphate
& sugar
held together
by hydrogen bonds
Mnemonic
Come up with a memory device/slogan/phrase to
remember the 4 nitrogen bases and how they pair up.
Review Quiz!
Base Pair Rule
One side:
Other side:
A T A
T C A
T G C
G G G
Let’s Practice
Fill In the complementary base pairs
AAT
GAC
CCG
TAG
GGC
GAT
DNA Coloring
DNA REPLICATION
the process by which DNA makes a copy of
itself (cell division)
SEMI-CONSERVATIVE - half of the old strand is saved
Steps of DNA Replication
1
2
3
• Enzyme Helicase separates the DNA
strands
• Enzymes called DNA polymerases add the compatible
nucleotides (found floating in nucleus) to the original strands
• Hydrogen bonds form between the new nitrogen bases
• DNA polymerases are released
• 2 DNA molecules, identical, are created
Errors in Replication
• DNA replication usually occurs with great accuracy.
• Only about 1 error for every BILLION pairs of nucleotides
(for example: retyping your Biology text book 1000 times
and only making 1 typo)
• When a mistake occurs, the base sequence is changed;
this is called a MUTATION
DNA Replication Video
Review Quiz #2
Protein Synthesis
A gene (a segment on a DNA strand) codes for a
specific hereditary item (ie hair color).
The gene is the instruction for the making of the
protein that creates that item (ie blond hair).
To get the instructions to the ribosome (where
proteins are made) DNA uses RNA to deliver the
genetic information to the ribosome where the
protein is created.
This entire process= PROTEIN SYNTHESIS
RNA - the messenger
*single strand
*ribose sugar
*contains no thymine, uracil instead
*follows base pair rules
DNA: A T A G C G
RNA:
RNA carries the
"message" to the
ribosomes, where
proteins are made
DNA --> RNA --> Protein
Proteins are the building
blocks of the organism (traits)
Transcription - process where RNA is
made from DNA
Translation - process where proteins
are made from RNA
Steps of Transcription
1
• RNA polymerase binds to a promoter
• The DNA strands unwind and separate
2
• RNA polymerase adds free RNA nucleotides that are compatible
with the DNA strand
• Unlike DNA replication, transcription only codes for a particular
gene (not the entire strand)
3
• RNA polymerase reaches a termination signal that marks the
end of the gene
• RNA polymerase releases, DNA rewinds and the new RNA
strand goes on to perform its job
Transcription and Translation Video Clip
Transcription and Translation Coloring
Types of RNA
mRNA
rRNA
tRNA
• Messenger
RNA
• A single
strand,
carries
instructions
to
ribosome
• Ribosomal
RNA
• Part of the
structure of
the
ribosome
• Transfer
RNA
• Transfers
amino
acids to the
ribosome
to make a
protein
Quick Review Quiz #3
How the Code Works
The combination of A,T,G,C determines what
traits you might have.....
C A T C A T = purple hair
T A C T A C = yellow hair
Think of the bases of DNA like letters.
Letters form words....
Words form sentences....
*endless
combinations
The Genetic Code
3 adjacent nucleotides (‘letters’) in mRNA specify a particular
amino acid (‘word’). 3 nucleotides also = a codon.
There are 64 codons that encode most organisms.
GCU, GCC, GCA, and GCG are all codons that code for the
amino acid, Alanine.
What would the
amino acid be for
the following
codons:
AAA
UGC
CCG
AUA
Steps of Translation—the making of Proteins
1
• tRNA and mRNA join together
• Codons match up with anticodons on the tRNA
2
• Polypeptide chain is put together
• The amino acids that are coded for begin to make a chain
3
• The chain continues to grow as more amino acids are
added as the codons instruct
4
• The ribosome reaches a ‘stop’ codon and the polypeptide
chain is complete.
DNA Song
Protein Synthesis Coloring
Packet Review, Protein Synthesis and RNA
Protein Power Game