1. Protein Synthesis
by: MaKenna McGough

2. What is a protein? signaling from one cell to another of hormones
Proteins are complex, unbranched macromolecules that carry out many functions in the body such as…
signaling from one cell to another
of hormones
enzymatic activity
movement

3. What codes for proteins?
Thanks to , scientists know that genes are what determine an organism's phenotype (physical characteristics).
and , discovered that genes are responsible for changing enzymes (proteins). They were able to discover this by observing mutations in bread mold. They came up with the ”one gene, one enzyme” hypothesis.
Later it was discovered that one gene actually produces one protein and then revised again to one gene produces one polypeptide chain which are the monomers of a protein.

4. “
“You too can win Nobel Prizes. Study diligently. Respect DNA. Don't smoke. Don't drink. Avoid women and politics. That's my formula.”
George Beadle

5. The intermediate between DNA and proteins
DNA holds the “blueprints” for making proteins
but DNA is inside the nucleus where is can’t leave so...
DNA converts to which travels to the and this is where proteins are synthesized!

6. Structure
is simply the linkage of amino acids held together by peptide bonds
is a single polypeptide chain held together by hydrogen bonds
is 3-D folded protein
is multiple chains that have folded
Proteins are made up of amino acids and have four different levels - primary, secondary, tertiary, and quaternary

7. The Genetic Code Discovery How it works
Heinrich Matthaei and Marshall Nirenberg “broke the genetic code” and discovered how it is used in the process of protein synthesis. Nirenberg, Holly, and Khorana shared a Nobel Prize in 1968.
The unique thing about the genetic code is that it is shared by all organisms!
It also has..
each codon ( ) is specified for an amino acid
UUU and UUC can both code for Phe and even GGU, GGC, GGA, and GGG ALL code for glycine

9. It starts with Transcription
Where?
What?
How?
Transcription takes place inside the nucleus where the DNA is held.
Transcription is the making of a mRNA strand from a DNA template.
Four steps:
Initiation
Elongation
Termination
RNA processing
Transcription uses a “promoter region” to initiate copying. The “ ” identifies where RNA polymerase should start.

10. Elongation
After RNA polymerase unwinds the DNA and connects at the TATA box, it pairs RNA nucleotides to the DNA bases. RNA polymerase works in a ’ to ’ direction so the DNA gene is in a 3’ to 5’ direction while being copied.

11. Termination
RNA polymerase will keep transcribing until it reaches a signal or codon to stop (the terminator).
In bacteria there are two types…
Rho-dependent ( )
The RNA contains a binding site for the protein called Rho factor. Once Rho factor binds, it climbs up towards the RNA polymerase and pulls the transcript and DNA template apart, releasing the RNA molecule.
Rho-independent ( )
This depends on specific sequences in the DNA
When it is time to stop transcription, RNA polymerase will hit a region of the template that is full of C and G nucleotides, causing the RNA to fold on itself and thus making the C and G bases pair. This results in a “hairpin” structure and causes RNA polymerase to stop.

13. RNA Processing for Eukaryotes
A guanine nucleotide is added to the 5’ end. This ensures safe transportation to the ribosome where proteins will be synthesized
This is how different proteins are made from the same copy of DNA. Different exons are put together.
Many adenine nucleotides are added to the 3’ end to control the length of protein synthesis
Spliceosomes are made up of smaller snRNP’s

14. For Prokaryotes...
they do have introns so there is no processing (splicing)
both transcription and translation take place at the site of the DNA because they do not have a nucleus!

15. After exon shuffling and the added caps, it is now ready to enter the cytoplasm for translation

16. Protein synthesis takes place at a
Translation
turning the mRNA made in the nucleus to a protein made in the cytoplasm
Protein synthesis takes place at a
Ribosomes are made of rRNA and contains two subunits. There are three sites where the tRNA (containing the correct amino acid) attaches. A site is where the tRNA first arrives and the P site is where a second tRNA that attaches to the tRNA in the A site. The E site can stand for EXIT because it is where the tRNA leaves.

17. tRNA carries the correct amino acid: 3 Steps
This is the building of the polypeptide chain. There are a total of 20 amino acids that we need to survive! The R side-chain is what makes them different.
Almost always the initiator tRNA is carrying Met, this attaches to the small subunit at the A site. The anticodon binds to the mRNA. Then the large subunit connects.
A stop codon (release factor) codes for the translation to stop, ending the chain. The ribosome disassembles itself!
ELONGATION : The tRNA has moved to the P site and another anticodon arrives in the A site carying another amino acid which joins to the other one by a PEPTIDE bond.

18. The protein is then sent to different parts of the cell where they are needed but most are first fed into the ER.
if they have a (signal recognition particle) the ribosome is taken the ER and the amino acid chain entere the lumen (interior) of the ER.
This is where the protein folds and may have other things such as glucose groups attached to them.
Most are shipped from there, but some stay to do their “jobs” in the ER. If so, they are tagged.

20. What? detail effect Type of Mutation A single base pair is replaced
Substitutions
A single base pair is replaced
3 types:
silent: no effect on amino acids
nonsense: results in a stop codon, unfinished protein
missense: changes amino acid
Insertions or Deletions
1 or more bases are added or removed
often called
mutation
causing the reading frame to change (reads 3 at a time) unless THREE bases are added or deleted

21. Thanks!
Any questions?
playfactile.com/proteinsynthesismcgough

22. QUIZ TIME!
Please describe the process of transcription in detail using the words: DNA, Nucleus, RNA polymerase
Please describe the process of translation in detail using the words: mRNA, tRNA, cytoplasm, ribosome
If the sequence AGC was added into the DNA, would effect would this have? Would there be a frameshift?
Does intrinsic or extrinsic termination use the Rho factor?
What is added to the 3’ end of the mRNA?
What about the 5’ end?
What happens during RNA processing? Does this happen in prokaryotes?