chapter 12: molecular genetics
DESCRIPTION
Chapter 12: Molecular Genetics. DNA structure Replication Protein synthesis. DNA: The Genetic Material. Section 1 – p. 329. The “OLD” people of DNA. Fredrick Griffith Oswald Avery Hershey and Chase Erwin Chargaff Watson and Crick. Fredrick Griffith-1928. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/1.jpg)
Chapter 12: Chapter 12: Molecular GeneticsMolecular Genetics
• DNA structureDNA structure
• ReplicationReplication
• Protein synthesisProtein synthesis
![Page 2: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/2.jpg)
DNA: The Genetic DNA: The Genetic MaterialMaterial
Section 1 – p. 329
![Page 3: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/3.jpg)
The “OLD” people of DNA
1.Fredrick Griffith
2.Oswald Avery
3.Hershey and Chase
4.Erwin Chargaff
5.Watson and Crick
![Page 4: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/4.jpg)
Fredrick Griffith-1928
In 1928, British scientist Fredrick Griffith was trying to learn how certain types of bacteria caused pneumonia.
He isolated two different strains of pneumonia bacteria from mice and grew them in his lab.
Performed the first major experiment that led to the discovery of DNA as the genetic material
![Page 5: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/5.jpg)
So Griffith, Avery, Hershey and Chase all helped discover DNA and the importance that it plays in transferring Genes.
But what is DNA???
what is it made of???
what does it look like??????
![Page 6: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/6.jpg)
What is DNA?1. A genetic code
2. A molecule made of subunits called nucleotidesnucleotides
3. A complex molecule that is arranged as a double helixdouble helix.
![Page 7: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/7.jpg)
NUCLEOTIDES
are repeating subunits are repeating subunits (monomers) that include:(monomers) that include:
Phosphate group
5-Carbon sugar
Nitrogen base
![Page 8: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/8.jpg)
NUCLEOTIDES
the smallest subunit of DNA
![Page 9: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/9.jpg)
Two Kinds of bases in DNA
Pyrimidines are single ring bases.
Thymine & Cytosine
Purines are double ring bases.
Adenine & Guanine
Memory trick “Y” are you single?
![Page 10: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/10.jpg)
A G C T
![Page 11: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/11.jpg)
Erwin Chargraff-
Analyzed the amounts of A, C, T, and G in DNA; Discovered A=T & C=G
![Page 12: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/12.jpg)
The Shape of DNA
DNA often is compared to a twisted ladder.
Rails of the ladder are represented by the alternating deoxyribose and phosphate.
The pairs of bases (cytosine–guanine or thymine–adenine) form the steps.
![Page 13: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/13.jpg)
Watson and Crick
Built a model of the double helix that conformed to the others’ research
1. two outside strands consist of alternating deoxyribose and phosphate
2. cytosine and guanine bases pair to each other by three hydrogen bonds
3. thymine and adenine bases pair to each other by two hydrogen bonds
![Page 14: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/14.jpg)
Watson and Crick
suggested the structure for DNA and Hypothesized a method of replication
![Page 15: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/15.jpg)
Refer to the DNA handoutRefer to the DNA handout
1. Locate the Phosphate groupsPhosphate groups (small circles). Label each one with “PP”
2. Color all phosphate groups orangeorange
3. Locate the deoxyribose sugardeoxyribose sugar molecules (large pentagon shapes attached to the P’s). Label them by name.
4. Color all sugars blueblue
![Page 16: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/16.jpg)
Refer to the DNA handoutRefer to the DNA handout
1.Locate the nitrogen bases. Label the first base by name and the others “NB”.
2.What do you notice about these molecules?
![Page 17: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/17.jpg)
4 Nitrogen Bases4 Nitrogen BasesPurines are
larger basesPyrimidines are
smaller bases
Adenine Thymine
Guanine Cytosine
![Page 18: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/18.jpg)
Refer to the DNA handoutRefer to the DNA handout
1. Locate the nitrogen bases – 2 large, 2 small
2. Label one of the large bases AdenineAdenine
3. Label the other large base GuanineGuanine
4. Label one of the smaller bases ThymineThymine
5. Label the other small base CytosineCytosine
6. Color each base a different color.
![Page 19: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/19.jpg)
CHARGAFF’S BASECHARGAFF’S BASE PAIRING RULES
A binds with T
G binds with C
![Page 20: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/20.jpg)
Hydrogen Bonds
Fig. 4. Adenine-Thymine base pair with two hydrogen bounds.
Fig. 5. Guanine-Cytosine base pair with three hydrogen bounds
C = Carbon = gray N = Nitrogen = blue O = Oxygen = red
![Page 21: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/21.jpg)
3-D Animation of DNA
http://www.umass.edu/molvis/tutorials/dna/dnapairs.htm
![Page 22: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/22.jpg)
Stop & ReviewStop & Review1. What is the smallest subunit of DNA?
2. List 3 parts to #1?
3. What are the side chains of DNA made of?
4. What are the “steps” of DNA made of?
5. What are the base pairing rules of DNA?
6. Describe the structure of DNA in 2 words.
![Page 23: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/23.jpg)
ANSWERS
1.Nucleotide2.Sugar, phosphate and a
nitrogen base3.Sugar and phosphate4.Nitrogen base5.A=T, C=G6.Double Helix
![Page 24: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/24.jpg)
How are genesgenes, chromosomes and DNA related?Genes are portions of DNA that are tightly packed into chromosomes and code for the manufacture of proteins.
![Page 25: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/25.jpg)
How are genesgenes, chromosomes and DNA related?
Think of chromosomes as socks and genes as stripes on the socks.
![Page 26: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/26.jpg)
Place in order from smallest to largest.
Gene
DNA
Chromosomes
![Page 27: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/27.jpg)
![Page 28: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/28.jpg)
Have Your DNA & eat it too!Have Your DNA & eat it too!
1.Collect materials
2.Follow instructions
*A (pinkpink) pairs with T (greengreen)
*C (orangeorange) pairs with G (yellowyellow)
![Page 29: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/29.jpg)
Semi-conservative Semi-conservative replicationreplication
Part 2
![Page 30: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/30.jpg)
Essential Questions
What is replicationreplication and how is it done?
What’s the role of the enzymes helicasehelicase and DNA polymeraseDNA polymerase?
![Page 31: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/31.jpg)
ReplicationReplicationA complete copy of the
DNA is made
The DNA code is in the middle of the helix, so how does it get copied if it’s obscured by the side chains and twist of the helix shape?
![Page 32: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/32.jpg)
Replication
DNA replication is an important part of the cell division process.
Before a cell divides, it first duplicates its DNA so that the new cell will have the same genetic information.
The specific base pair matching during replication ensures that exact DNA copies are made.
![Page 33: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/33.jpg)
The DNA code is in the middle of the helix, so how does it get copied if it’s obscured by the side chains and twist of the helix shape?
![Page 34: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/34.jpg)
Replication1. Enzymes (helicasehelicase) will “unzip” or
unwind the double helix by weakening H-bonds creating a replication fork replication fork where the two chains separate
2.2. DNA polymeraseDNA polymerase assembles new DNA using each original strand as a template
3. The replicated DNA is proofread and mistakes are edited
Replication
![Page 35: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/35.jpg)
ReplicationReplication forkfork
![Page 36: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/36.jpg)
Boring person explaining
![Page 37: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/37.jpg)
Replication is discontinuousReplication is discontinuous
Short fragments of DNA called Okazaki fragmentsOkazaki fragments are added near the replication fork
Then gaps are filled in by DNA DNA polymerasepolymerase
Bases are added following the base pairing rules (A-T, C-G)
* The lengths of Okazaki fragments are between 1,000 to 2,000 nucleotides long in bacteria and are generally between 100 to 200 nucleotides long in eukaryotes.
![Page 38: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/38.jpg)
Copy the following sequence to your foldable.
T--T--
A--A--
C--C--
A--A--
A--A--
A--A--
C--C--
T--T--
T--T--
A--A--
C--C--
T--T--
--A--A
--T--T
--G--G
--T--T
--T--T
--T--T
--G--G
--A--A
--A--A
--T--T
--G--G
--A--A
Remember that H-bonds hold complementary bases together
![Page 39: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/39.jpg)
Unzip sequence to your foldable.
TT
AA
CC
AA
AA
AA
CC
TT
TT
AA
CC
TT
AA
TT
GG
TT
TT
TT
GG
AA
AA
TT
GG
AA
Step 1: HelicaseHelicase enzyme “unzips” double helix by weakening H-bonds
![Page 40: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/40.jpg)
Using the original DNA sequence on the foldable make a copy.
TT
AA
CC
AA
AA
AA
CC
TT
TT
AA
CC
TT
AA
TT
GG
TT
TT
TT
GG
AA
AA
TT
GG
AA
Step 2: DNA DNA polymerase polymerase enzyme adds DNA bases to the exposed nucleotides on the leading strand
AA
TT
GG
TT
TT
TT
GG
AA
AA
TT
GG
AA
![Page 41: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/41.jpg)
Using the original DNA sequence on the foldable make a copy.
TT
AA
CC
AA
AA
AA
CC
TT
TT
AA
CC
TT
AA
TT
GG
TT
TT
TT
GG
AA
AA
TT
GG
AA
While Okazaki Okazaki fragmentsfragments are added on the lagging strand
AA
TT
GG
TT
TT
TT
GG
AA
AA
TT
GG
AA
AA
CC
AA
AA
CC
AA
CC
TT
![Page 42: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/42.jpg)
Using the original DNA sequence on the foldable make a copy.
TT
AA
CC
AA
AA
AA
CC
TT
TT
AA
CC
TT
AA
TT
GG
TT
TT
TT
GG
AA
AA
TT
GG
AA
Step 3: Polymerase Polymerase also proofreads and edits any gaps
AA
TT
GG
TT
TT
TT
GG
AA
AA
TT
GG
AA
T T
AA
CC
AA
A A
AA
CC
T T
TT
AA
CC
TT
![Page 43: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/43.jpg)
RESULTS
TWO strands of identical DNA
DNA replication is known as semiconservative meaning each DNA molecule contained one original strand an one new strand.
![Page 44: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/44.jpg)
![Page 45: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/45.jpg)
Have Your DNA & eat it too!
1.Now replicate the DNA, using 2 more pieces of licorice but use black sticks
![Page 46: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/46.jpg)
3-2-13 steps cells undergo in replication
2 words meaning the structure of DNA
1 word for duplicating cell DNA
![Page 47: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/47.jpg)
Protein synthesisProtein synthesisPart 3
![Page 48: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/48.jpg)
Warm-Up Quiz: DNA Warm-Up Quiz: DNA 101101
1. DNA is a double stranded sequence of ___________ (smallest unit of DNA).
2. DNA is a code of instructions for building ___________ (molecule).
3. DNA is stored in the _________ (control center of the cell).
4. The DNA code must be transmitted to the ___________ where proteins are built. Today we’ll see how this happens.
![Page 49: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/49.jpg)
Essential Questions
7. What is the primary function of DNA?
8. How do RNA and DNA compare?
9. What are the three main types of RNA? What are their roles?
10. How do the base-pairing rules for RNA compare to the rules for DNA?
11. Describe the roles of DNA and RNA in the overall process of protein synthesis.
![Page 50: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/50.jpg)
The role of DNA is to store and transmit genetic information
![Page 51: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/51.jpg)
How do DNA & RNA compare?How do DNA & RNA compare?
RNA
Ribose sugar & phosphate “backbone”
URACIL replaces thymine
Single-stranded, globular, hairpin (huh? Hairpin???)
DNA
Deoxyribose sugar & phosphate “backbone”
N-bases: A, C, G, T
Double helix
![Page 52: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/52.jpg)
Check your understanding…Decide with your partner whether the following describes DNA or RNA:
1. Master Plan
2. Blueprint copy
3. Stays in nucleus
4. Goes to ribosome
5. Involves Thymine
6. Involves Uracil
7. Single-stranded
8. Double-stranded
9. Involves codons
10.Polymerase
![Page 53: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/53.jpg)
Types of RNATypes of RNA
Messenger RNA
(mRNA)The original DNA
code is transcribed then carried from the nucleus to the
ribosome.
mRNA is written in the form of
codonscodons.
![Page 54: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/54.jpg)
Types of RNATypes of RNA
Transfer RNA (tRNA)The anticodonanticodon that matches the codon found on mRNA.
It transfers an amino acid in order
to assemble a protein chain.
![Page 55: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/55.jpg)
Types of RNATypes of RNA
RibosomalRNA
(rRNA)RNA &
proteins that make up
ribosomes where
proteins are made.
![Page 56: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/56.jpg)
Base Pairing in DNA vs. RNABase Pairing in DNA vs. RNA
RNA
A - Uracil
C - G
DNA
A - T
C - G
![Page 57: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/57.jpg)
PROTEIN PROTEIN SYNTHESIS SYNTHESIS
Step 1 Transcription
Step 2 Translation
![Page 58: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/58.jpg)
Step 1: TRANSCRIPTION DNA is changed into a different form
of nucleic acid called RNA (ribonucleic acid)
The new code is “read” 3 nucleotides at a time called a codoncodon
Occurs in the nucleus
Why? Because mRNA can leave the nucleus whereas DNA cannot.
![Page 59: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/59.jpg)
TRANSCRIPTIOTRANSCRIPTIONN1. Enzymes unzip helix
2.2. RNA polymerase RNA polymerase assembles mRNA nucleotides but base pairing rules changes slightlya. Thymine in DNA pairs with Adenine
b. Adenine in DNA pairs with UracilUracilc. Cytosine still pairs with Guanine
![Page 60: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/60.jpg)
T - -
A - -
C - -
A - -
A - -
A - -
C - -
T - -
T - -
T - -
G - -
A - -
DNA
U
A
C
A
A
A
C
U
U
U
G
A
mRNA
A
T
G
T
T
T
G
A
A
A
C
TCo
py
the
foll
ow
ing
DN
A s
equ
ence
.
Write th
e com
plem
entary n
ucleo
tide seq
uen
ce.
Slide
- - A
- - T
- - G
- - T
- - T
- - T
- - G
- - A
- - A
- - A
- - C
- - TWri
te t
he
com
ple
men
tary
co
do
n s
equ
ence
.
Step 1: HelicaseHelicase enzyme “unzips”
double helix by weakening
H-bonds
Step 2: RNA RNA polymerase polymerase
enzyme forms complementary mRNA strand
![Page 61: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/61.jpg)
Step 2: Step 2: TRANSLATIONTRANSLATION The language of DNA is
translated into the language of amino acids
Occurs in the cytoplasm on a ribosome
![Page 62: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/62.jpg)
TRANSLATIONTRANSLATION
1. The mRNA travels to the ribosome where each codon is read
2. The codon of mRNA matches an anticodonanticodon on tRNA
3. When the codon and anticodon match the amino acid being carried by the tRNA is transferred to a growing protein chain.
![Page 63: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/63.jpg)
Let’s use your foldable from before.A
T
G
T
T
T
G
A
A
A
C
T
DNA
U
A
C
A
A
A
C
U
U
U
G
A
mRNA
Open the foldable and translate the mRNA code into the correct amino acid sequence.
![Page 64: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/64.jpg)
![Page 65: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/65.jpg)
The translation…A
T
G
T
T
T
G
A
A
A
C
T
DNA
U
A
C
A
A
A
C
U
U
U
G
A
mRNA
LeucineLeucine
LysineLysine
TyrosineTyrosine
STOPSTOP
![Page 66: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/66.jpg)
Central Dogma of BiologyCentral Dogma of Biology
DNA codes for RNA, which guides the synthesis of proteins.DNA RNA Protein1.DNA is unzipped
2.RNA polymerase uses DNA as a template for making mRNA (Uracil is incorporated instead of thymine)
3.mRNA moves out of nucleus to ribosome
4.tRNA carries amino acids to ribosome where they are assembled into a peptide chain
5.Upon reading a STOP codon, the complete protein chain is released
![Page 67: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/67.jpg)
Now consider this…
1. On a sheet of paper, write the word CATS.
2. Try rearranging the letters to form as many 3-letter words as you can.
3. Write each word on your paper, and then add a definition for each word.
4. Did any of the codes you formed have the same meaning?
![Page 68: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/68.jpg)
The DNA AlphabetThe DNA Alphabet
• Like CATS, there are only 4 nitrogen bases in the DNA alphabet.
• Like the CATS activity, DNA “words” are only 3-letters. These triplet base sequences are called codonscodons.
![Page 69: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/69.jpg)
How many codons can be made using the four letters of the four different bases? Hint: A codon is made up of 3 nucleotides. So there are 3 spots and a possibility of 4
bases in each.4 bases x 4 bases x 4 bases
= 64 possible codon combinations.
Since the nitrogen base is the only unit to change, the sequence of bases makes up the
code.
BRAIN TEASERBRAIN TEASER
![Page 70: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/70.jpg)
How is DNA How is DNA like Morse like Morse code?code?
![Page 71: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/71.jpg)
![Page 72: Chapter 12: Molecular Genetics](https://reader036.vdocuments.mx/reader036/viewer/2022062321/56812d0e550346895d91e7e3/html5/thumbnails/72.jpg)
How is DNA How is DNA like Morse like Morse code?code?
It is a series of single repeating units (sounds or symbols) that make up a message. The repeating units are the nucleotides of the DNA molecule. The message is the final protein that is produced. Proteins can be structural, enzymatic, hormones, etc.