Protein Synthesis: Transcription and Translation Process

Protein synthesis

1. The process your cells use to make proteins, which determine your traits and help your body function

2. Way we build proteins causes us to have a particular trait or phenotype (proteins are missing link b/w genotype and phenotype)

DNA

The blueprint for making proteins and contains the instructions (genes) for making proteins.

mRNA

Messenger RNA that carries the genetic code from DNA.

tRNA

Transfer RNA that brings amino acids to the ribosome.

Codons

3-base 'words' on mRNA that code for amino acids.

Anticodons

Complementary 3-base sequences on tRNA.

Initiation (Transcription)

RNA polymerase binds to the promoter region of DNA opening DNA like a zipper

Elongation (Transcription)

RNA polymerase moves along the DNA, matching RNA bases to the DNA template.

Termination (Transcription)

RNA polymerase reaches a terminator sequence and stops copying. Then it leaves nucleus and travels to ribosome

Initiation (Translation)

mRNA binds to ribosome and the first tRNA pairs with the start codon (AUG = methionine).

Elongation (Translation)

tRNA brings amino acids, anticodons pair with codons, and peptide bonds form.

Termination (Translation)

A stop codon (UAA, UAG, or UGA) enters the ribosome and tells it to stop building the protein.

Polypeptide chain

A chain of amino acids formed during translation, which becomes a protein.

RNA polymerase

The enzyme that synthesizes mRNA from the DNA template.

Promoter

The 'start' part of the DNA recipe where RNA polymerase binds.

Terminator

The 'stop' signal in the DNA that tells RNA polymerase to stop copying.

Amino Acids

Building blocks of protein.

Transcription

The process where DNA is copied to mRNA in the nucleus, facilitated by RNA Polymerase (1st step)

Translation

The process where mRNA is translated into a protein in the ribosome (2nd step)

Point Mutations

Changes in 1 nucleotide that can be silent, missense, or nonsense.

Silent Mutation

A point mutation that results in no change in the amino acid because genetic code is redundant (multiple codons have same amino acid_

Missense Mutation

A point mutation that changes one amino acid to a different one which may affect protein function based on how different the new amino acid is

Nonsense Mutation

A point mutation that creates a STOP codon, leading to an early end to protein synthesis.

Frameshift Mutations

Mutations that insert or delete nucleotides (NOT in multiples of 3), shifting the reading frame and changing many amino acids.

Functional Protein

A chain of amino acids that has folded into a specific 3D shape, giving it its function.

Mutation

A change in the DNA sequence that can affect how proteins are built, potentially leading to diseases or different traits.