Biology Transcription, Translation, Protein Synthesis

Protein Synthesis

The process of reading the instructions in DNA to

make a polypeptide.

Polypeptide

a chain of amino acids; can bind to others and fold into a protein

DNA

instructions,

located in the

nucleus (which it

can’t leave)

Ribosome

Where are proteins made?

DNA —> (Transcription) —> RNA —> (Translation) —> protein

Steps of Protein Synthesis:

mRNA (messenger)

copies instructions in DNA and carries these to the ribosomes in the cytoplasm

tRNA (transfer)

binds and carries specific amino acids to the ribosome

rRNA (ribosomal)

along with proteins, they make up the ribosome (also help catalyze the formation of peptide bonds)

TRANSCRIPTION PURPOSE

DNA —> mRNA- To carry the code/instructions out of the nucleus

TRANSCRIPTION DEFINITION

DNA is copied into a complementary strand of mRNA.

5’ —> 3’

RNA Direction

3’ —> 5’ 

DNA template reading direction

RNA Splicing

This process removes introns and splices exons together.

introns

(non-coding regions)

exons

(coding regions)

poly A tail

added to the 3’ end 🡪 helps the mRNA leave the nucleus.

5’ cap

added to the 5’ end 🡪 facilitates binding to a ribosome

Genetic Code:

code of instructions for how to make proteins

Codon

a set of 3 nucleotides on the mRNA

Anticodon

“complementary” 3 nucleotides on tRNA

Amino acid

monomer (building block) for making proteins, held together by peptide bonds

TRANSLATION PURPOSE

mRNA 🡪 polypeptide- Read/follow the instructions carried on the mRNA to make a polypeptide (located in ribosomes)