Protein Synthesis

The Central Dogma of Molecular Biology

It describes the flow of genetic information in a cell, from DNA → RNA → Protein.

Protein Synthesis

It is the process by which cells make proteins using the genetic information stored in DNA.

Proteins

-perform most of the functions in the cell
-are the ‘executor’ of cell life activities

Peptides

are short chains of amino acids.

mRNA

-made in the nucleus, then moves to the cytoplasm

-Carries the genetic message from DNA to the ribosome.

tRNA

-found in the cytoplasm, works at the ribosome

-Brings the correct amino acid to the ribosome by matching its anticodon with the codon on mRNA.

rRNA

-produced in the nucleolus and found in ribosomes in the cytoplasm

-Forms the structure of the ribosome and helps catalyze the formation of peptide bonds during protein synthesis.

DNA Replication

-It is the process of making an exact copy of DNA before cell division

-Ensures each new cell has a complete set of genetic instructions.

enzymes

molecules that speed up the rate of chemical reaction

Helicase (unzipping enzyme)

an enzyme that unzips the double helix by breaking the hydrogen bonds between the complementary bases

Primase (the initializer)

an enzyme that synthesizes short RNA sequence called primers.

DNA Polymerase (the builder)

an enzyme that replicates DNA to build a new strand

Ligase (the gluer)

an enzyme that connects two strands of DNA together

Transcription

-the process by which a segment of DNA is copied into RNA

-first step in making proteins.

Translation

-is the process by which the genetic code carried by mRNA is used to make a protein.

-It’s the final step in the flow of genetic information: DNA → RNA → Protein.

Codon

-a set of three nucleotides on mRNA that codes for a specific amino acid

Anticodon

-a set of three nucleotides on tRNA that pairs with a complementary codon on mRNA

Mutation

It is a permanent change in the DNA sequence

Substitution

It occurs when one nucleotide base is replaced by another.

Insertion

-An extra base is added into the sequence.

-This shifts every subsequent triplet over.

Deletion

A base is removed from the sequence. Like insertion, this disrupts the entire reading frame.