1. RNA Structure and Protein Synthesis
GT Biology Feb. 23, 2011
RNA Structure and Protein Synthesis

2. Warm-up How does DNA replicate? What is the central dogma?
Quiz on Thursday March 3rd

3. Objective
SWBAT explain the structure of RNA, its role in protein synthesis and how proteins are synthesized

4. Homework
Read pgs
Complete questions 1-6

5. Today
RNA Structure
Types of RNA

6. RNA Structure

7. What is RNA? RiboNucleic Acid
It is involved in the relaying of genetic information from DNA to the cytoplasm of the cell to produce proteins
The production of proteins is known as protein synthesis
RNA is found in the nucleus and the cytoplasm

8. RNA Structure Like DNA, RNA is made of nucleotides which contain:
A sugar called ribose
A phosphate group
One of 4 nitrogenous bases
Cytosine
Guanine
Adenine
Uracil (this is in the place of thymine)

9. RNA Structure Cont. Single helix There are 3 types of RNA:
Messenger RNA (mRNA)
Transfer RNA (tRNA)
Ribosomal RNA (rRNA)

10. Messenger RNA (mRNA)
Carries the genetic information from the DNA in the nucleus to ribosomes in the cytoplasm

11. Transfer RNA (tRNA)
Match the proper amino acid with the mRNA code to produce a protein
Each tRNA contains an anticodon which contains 3 bases the correspond the codons on the mRNA
Amino Acid

12. Ribosomal RNA (rRNA)
Make up the ribosome (this is where proteins are made)
These also allow mRNA to attach to the ribosome

14. Contain the genetic information
DNA vs RNA
Type of Nucleic Acid
DNA
RNA
Sugar
Nitrogenous Bases
Structure
Location
Function
Deoxyribose
Ribose
A,T,G,C
A,U,G,C
Double Helix
Single Helix
Nucleus and Cytoplasm
Nucleus
Contain the genetic information
Protein formation

15. Protein synthesis

17. Protein Synthesis Begins in the nucleus with the DNA
mRNA is created by a process called transcription

18. Transcription The first step in transcription is to “unzip” the DNA
Just like in replication this means the weak hydrogen bonds must be broken
Next RNA polymerase matches complimentary RNA to the DNA
C with G
A with U instead of T
Once the mRNA has been created the DNA strand closes back up

19. Transcribe the DNA
DNA: ATGGCACTGCAT
mRNA:
UACCGUGACGUA

20. Translation
After transcription the mRNA leaves the nucleus and enters the cytoplasm
Once in the cytoplasm the mRNA attaches to a ribosome to begin making proteins
The ribosome moves down the mRNA and “reads” the information
The information on mRNA is read in codons (a groups of 3 bases)

21. Codons 3 bases make up 1 codon
Each codon corresponds to a specific amino acid
Amino acids are the building blocks of proteins
Amino acids can be found free floating in the cytoplasm
To determine what amino acid each codon codes for there is a codon table

22. ACU CGA GGC UAA
Thr
Arg
Gly
STOP

23. Translation
The end of the protein is signaled by the reading of 1 of the 3 stop codons
The series of amino acids produced by the ribosome create a protein
Each protein produced plays a specific role in the appearance and behavior of the organism

25. Putting It All Together
Beginning in the nucleus, DNA is unzipped so mRNA strands can be created from the template
The mRNA strand exits the nucleus and enters the cytoplasm
The mRNA attaches to the ribosome which is composed of rRNA
The ribosome reads the mRNA with each codon producing a different amino acid, the amino acids are brought in by tRNAs
The amino acids string together to create proteins

27. The Central Dogma
DNA RNA Protein

28. What Protein Is Produced?
DNA: GTTATCCTTCGCAATCACATTGCG
mRNA:
Protein:
GUUAUGGAAGCGUUAGUGUAACGC
---
Met
Glu
Ala
Leu
Val
STOP
---

29. Practice