RNA and Proteins

1. Biology
02/13/2013
• Objective(s)
• SWBAT
• Outline the flow of genetic information from DNA to proteins
• Compare the structure and function of RNA with that of DNA.
• Summarize the process of translation and transcription.
• Bell Ringer: Outline the flow of genetic information from
Ringer
DNA to proteins
• Exit Question: What are the locations and functions of genes?

2. • Instructions for proteins are in
Gene Expression nucleotide sequence of genes
• (2) different types of RNA
• What differences / molecules read instructions
similarities can you and put together amino acids
observe in the that make up the protein
pictures below?
• Process by which proteins are
• Why are there
differences?
made is based on information
in DNA = Gene Expression

4. DNA vs. RNA
RNA DNA
• Single Stranded • Double Stranded
• Three Different Types • One type involved in the
involved in the process of process of replication and
going from DNA to proteins. protein production
• Nucleic acid • Nucleic acid
• Composed of nucleotides • Composed of nucleotides
• Sugar – Ribose • Sugar – Deoxyribose
• Shorter in length • Longer in length
• Base Pair Rules – AU CG • Base Pair Rules – AT CG

5. • RNA polymerase adds
complementary nucleotides starting
Transcription: DNA to RNA at the gene’s promoter region (start
signal) during Transcription
• 1. RNA pol. binds to the promoter
• 2. RNA pol. unwinds and separates
the double helix
• 3. RNA pol. Moves along the
nucleotides of DNA adding
complementary bases, AU and CG
• RNA pol. continues until it reaches
(stop signal)
• RNA pol. Is released along with RNA
molecule

6. Transcription vs. Replication
Features
RNA DNA
• Uses (1) strand of DNA as a • Uses (2) strands of DNA as a
template for making RNA template during DNA
during Transcription Replication
• Transcription occurs in • Replication occurs in
cytoplasm of prokaryotic cytoplasm of prokaryotic
cells cells
• Transcriptions occurs in • Replication occurs in
nucleus of eukaryotic cells nucleus of eukaryotic cells
• Many RNA molecules are • (2) Identical DNA copies
made from a (1) gene made from (1) DNA

7. REVIEW – Cornell Format
02/13/13
1. Outline the steps for the process of going
from DNA to proteins.
2. What are three features of DNA and RNA?
3. What are proteins made of?
4. What biochemical structures within the
body enable you to have unique features?
5. What is the Central Dogma of DNA?
6. List the steps of Transcription.
7. What are two features of replication of
DNA and transcription of RNA?

8. Genetic Code In Three-Nucleotide
Words
• Different types of RNA are made during
Transcription
• mRNA is made when a cell needs a particular
protein
• Messenger RNA (mRNA) carries instructions
for making a protein and delivers it to the site
of Translation
• Question: When is mRNA made and what is its
function?______________________________

9. INSTRUCTIONS
• RNA instructions are written as series of (3)
nucleotide sequences on the mRNA called
codons ex. UAA, UGA, AUG
• Each codon in mRNA corresponds to an a.acid
or codes for a start or stop signal for
translation
• Nirenberg deciphered the first codon, UUU.
• UUU in mRNA = the a.acid phenylalanine
• Question: What are codons and who
discovered them?_______________________

10. Genetic Code
• Sequence of nucleotides that specifies the
a.acid sequence of proteins and the start and
stop signals in mRNA.
• There are 64 mRNA codons
• Many of the codons code for the same a.
acids.
• Question: What is the genetic code and how
many codons does it contain? _____________

12. • 1. Transfer RNA (tRNA):
Many RNAS Are Used to
Make a Protein Single strands of RNA that
temporarily carries a
specific a.acid at one end
and an anticodon (3
nucleotide sequence that
binds to complementary
codon in mRNA) at the
other end.
• Question: What (2) structures
do tRNA molecules carry?
_______ and _________

13. tRNA molecule and Ribosomal RNA molecule
Anticodon (UAC) on tRNA binds to codon (AUG) on
mRNA
Amino acid Methionine (Met) is carried on top of
tRNA

14. Review
• 1. What is the first step in Transcription?
• 2. If there was a mutation in the promoter sequence, what
would happen to protein production?
• 3. What is the codon sequence for the amino acid sequence:
• Isoleucine-Valine-Glycine-Serine-Alanine ?
• 4. What is the a.acid sequence for the codon sequence: AUG-
CCA-CAA-AAG-UUA ?
• 5. What structures are carried by tRNA?
• Who diciphered the first codon and what a.acid did it contain
the instructions for?

15. Ribosomal RNA and Translation
• RNA molecules that contain RNA and are part
of the structures of Ribosomes = Ribosomal
RNA (rRNA)
• Cytoplasm contains thousands of ribosomes
composed of (2) subunits; large and small
• Each one can temporarily hold (1) mRNA and
(2) tRNA

16. Assembling Proteins
• 1. Ribosome subunits, mRNA and tRNA carrying the a.acid
Methionine bind together at P site of ribosome
• 2. tRNA with the a.acid specified by the codon in the A site
arrives
• 3. Peptide bonds forms between adjacent a.acids.
• 4. tRNA in the P site detaches and leaves the a.acid behind
• 5. The tRNA in the A site moves to the P site. The tRNA
carrying the a.acid specified by the mRNA codon arrives to
the A site
• A peptide bond forms between adjacent a.acids repeat steps
4-5 until stop codons of: UAG, UAA or UGA is reached

18. • http://www.brookscole.co
Translation m/chemistry_d/templates/
• Animation of the student_resources/shared_
Translation resources/animations/prot
Process. ein_synthesis/protein_synt
hesis.html
• http://www.hippocampus.org/Biolo
gy;jsessionid=00CCE1F5BD67C4889D
BB76E3C3A0C27D

19. Bell Ringer
04/01/2009
1.What is the total number of
mRNA codons? pg.209
2.What is the common
features among all RNA
molecules?
3.RNA instructions are written
in a series of 3 nucleotide
sequences called__________
pg. 209
4.What molecules do tRNA
carry? pg. 210

20. Prokaryotic Gene Regulation
• There are several thousand genes for
prokaryotic organisms
• There are more than 100,000 genes for
eukaryotic organisms.
• Not all genes are Transcribed and Translated
at the same time.
• Organisms are able to regulate (control) which
genes are expressed based on the needs of
the cell.

21. Gene Regulation in E.coli
• When you eat or drink dairy products, the
disaccharide lactose (milk sugar) becomes
available to E.coli.
• E.coli can break down lactose into (2) sugars,
glucose and galactose.
• This requires (3) different enzymes which are
coded by different genes.

22. Turning Genes on and off
• Lactose metabolizing genes are located next
to each other and are controlled by the same
promoter site. Fig. 10-6 pg. 213
• A control switch (operator) activates
transcription when lactose is available and
deactivates transcription when it is not
available.
• The operator is a piece of DNA that overlaps
the promoter site (on/off switch)

23. Lac Operon and Repressors
• Operon: Groups of genes that code for
enzymes involved in the same function, their
promoter site and the operator that controls
them.
• Repressor proteins bind to an operator and
blocks RNA pol. from binding to a promoter
site. Fig. 10-6 pg. 213.

24. Lactose and Repressor Proteins
• When lactose is present, it binds to the
repressor and causes it to be released from
the operator: Transcription occurs
• When lactose is not present, repressor
remains attached to operator: Transcription
does not occur

25. Transcription Diagram

26. Point Mutations and Physiology

27. Mutations Continued