Protein Synthesis

Protein Synthesis

Transcription

Processing

Translation

TranscriptionDNA used as a template to make pre-mRNA

1. Transcription factors bind

2. RNA polymerase (transcriptase) binds

3. Strand unwound

Transcription - Initiation

Nucleus

Transcription - Elongation

Transcription - Overview

Creates pre-mRNA

mRNA Processing

Introns- Non-coding DNA *Unnecessary*

Exons- Coding DNA

5’ cap- guanine

Poly-A tail- adenines

RNA Splicing

Carried out by spliceosome

made up of several snRNPs (“snurps”)

Removes introns, leaves exons

Recap

Transcription

Initiation

Elongation

Termination

Pre-mRNA processing

Translation

Process of assembling amino acids into polypeptide

**Variable R side chain changes identity of AA

Initiation

mRNA first binds to tRNA (in cytosol)

carries aa methionine

Both of them then attach to small ribosomal subunit

Finally, larger ribosomal subunit attaches

GTP is energy source

Translation - Initiation

mRNA moves through ribosome - codons are “read”

tRNA w/ corresponding anticodon brings appropriate aa

tRNA stops temporarily in A site

growing polypeptide shifts from tRNA in P site to tRNA in A site

all tRNA molecules move over one site

Elongation

Translation - Elongation

Termination

When stop codon is reached, no aa is brought in

Release factor is used instead

Causes polypeptide to break away, ribosome disassembles; protein folds!

Translation - Termination

Protein Transport Signal WHERE DO PROTEINS GO?

Prokaryotic v. Eukaryotic

Similarities? Differences?

Graded protein synthesis free response on Friday! No notes or outside help. Time limit will be given.

Genetic Mutations POGIL