Protein Synthesis: Translation and Mutations Guided Notes

This set of flashcards covers key terms and concepts related to protein synthesis, genetic code, and mutations based on the lecture notes provided.

Monomer

Amino Acid, the basic building block of proteins.

Polymer

Polypeptide, a chain of amino acids linked together.

Covalent bond

Peptide bond, which links amino acids in a protein.

First level of protein structure

1° - Polypeptide Chain.

Second level of protein structure

2° - Alpha helices and beta pleated sheets.

Third level of protein structure

3° - 3D structure determined by side chains.

Fourth level of protein structure

4° - 2+ Polypeptide chains interacting.

Why does protein synthesis proceed faster in prokaryotes than in eukaryotes?

Simpler structure allows for simultaneous transcription and translation.

Codon

A sequence of three nucleotides in mRNA that codes for a specific amino acid.

Start Codon

AUG, the codon where translation begins.

Stop Codons

UGA, UAA, UAG; these codons signal the end of translation.

Characteristics of the genetic code

1. Universal: used by nearly all organisms. 2. Redundant/Degenerate: some amino acids are coded by multiple codons. 3. Unambiguous: no codon specifies more than one amino acid.

Universal genetic code

Enables genetic modification techniques like gene splicing in organisms.

GMO uses

1. Insulin production in bacteria. 2. Pesticide production in crops.

Steps of genetic modification process

1. Isolate gene of interest. 2. Amplify using PCR. 3. Cut with restriction enzyme and insert into plasmid. 4. Insert into host organism.

tRNA structure

Single strand of RNA folded into a 3D structure with an anticodon and an amino acid binding site.

Aminoacyl-tRNA synthetase

An enzyme that attaches the correct amino acid to the tRNA.

Ribosome structure

Composed of rRNA and protein, consisting of a large subunit and a small subunit.

Ribosome A site function

Aminoacyl-tRNA binding site for the incoming tRNA.

Ribosome P site function

Peptidyl-tRNA binding site for the tRNA holding the growing polypeptide chain.

Ribosome E site function

Exit site for discharged/empty tRNA.

Translation initiation events

Small ribosomal subunit binds to mRNA and scans for start codon; initiator tRNA binds and large subunit assembles.

Translation termination

Occurs when a stop codon is in the A site, leading to polypeptide release.

Function of post-translational modification

Involves chemical group addition and peptide bond cleavage post-translation.

Definition of a mutation

Structural changes or alterations in the DNA sequence.

Point mutations (substitution)

Change of a single nucleotide; can result in synonymous or non-synonymous mutations.

Frameshift mutations

Insertion or deletion that alters the reading frame of the genetic code.

Impact of mutations on polypeptide functionality

Mutations in amino acids can affect proper folding and function, especially in critical regions.

Causes of mutations

Errors in DNA replication, exposure to mutagens, environmental factors, and mistakes in DNA repair.

Somatic cells

Cells in the body that are not germ cells; mutations here do not get passed to offspring.

Germ cells

Cells that produce sperm and eggs; mutations can be inherited.

Impact of mutations on fitness

Mutations can be neutral, harmful, or beneficial, affecting an organism's adaptability.