1. RNA

2. Review of DNA DNA is a double Helix that is a code for something
What?
Structure/Shape explains how it is replicated, but not how genes work.
Helicase and DNA Polymerase
Chargaff’s Rule
Nucleotide
5 Carbon Sugar (Deoxyribose), Phosphate and Nucleic Acid (Guanine, Cytosine, Adenine, Thymine)

3. First Step in Decoding Messages:
Copy DNA (Deoxyribonucleic Acid) into RNA (Ribonucleic Acid)
Note: “Deoxyribo” in Deoxyribonucleic Acid is in reference to the 5-Carbon Sugar in the backbone of the molecule
Deoxyribose
So what do you think the 5-Carbon Sugar is in the backbone of Ribonucleic Acid?
Ribose

4. Differences (Between DNA and RNA)
DNA RNA
Deoxyribose Ribose
Double Stranded Single Stranded
Thymine Uracil

5. RNA is a disposable copy of DNA
3 Types of RNA
mRNA
Messengers – they carry copies of the instructions for proteins. (From Nucleus to Ribosome)
rRNA
Ribosomal – where the proteins are assembled.
Reminder: Ribosomes are made up of protein and RNA
tRNA
Transfers each amino acid to the ribosome

6. How is a copy made? Transcription RNA Polymerase Where does it start?
“Transcribe” or
write a code
Only 1 strand
is made!
RNA Polymerase
Separates DNA strands (at Hydrogen bonds) and acts as “Police” in creating the mRNA
Where does it start?
There are “start sites” called Promoters
Just like promoters for events let people know what is going on.

7. Introns Exons Codons “Extra” parts that are cut out of
the final mRNA strand.
Exons
“Good” parts that are spliced
together to make the final mRNA
strand
Codons
3 (consecutive) nucleotides long
Each one specifies for one of 20 amino acids
64 different codons

8. Special Codons:
Start Codon: AUG
Stop Codons: UAA, UAG, UGA

10. Translation “Translates” from one language to another
Creates a chain of amino acids
Known as a protein.
It is the process of translating codons (mRNA) by using anti-codons (tRNA) into the amino acids they code for (which makes proteins)
Occurs at the Ribosomes
Anti-codons are complementary to codons

11. Translation Can you identify the following: 1. mRNA 2. Codon
3. Anti-Codon
4. Amino Acid
5. Protein

12. What is the big picture? DNA is the Master Plan mRNA is the Blueprint
Remains safe in the nucleus
mRNA is the Blueprint
Disposable copy
rRNA is the Building site
tRNA are the builders
Workers that make the proteins (amino acid chains)
DNA makes proteins and proteins express genes!

13. Mutations Changes in the letter sequence of the DNA Chromosomal Gene
Whole chromosome has been changed
Change in the number of chromosomes or their structure.
Gene
Single gene change (one or more letters)
Two types
Point
Frameshift

14. Point Mutation
One nucleotide changes – May change the Amino Acid it codes for (and it may not)

15. Frameshift Mutation Typically makes the entire protein not useable.
Deletion
Removal of one or more Nucleotides
Insertion
Addition of a Nucleotide

16. Frameshift Mutation (Continued)