B1.2.4 - Infinite variety of possible peptide chains

For a polypeptide with n no. of A.A.s, what is the number of possible combinations?

20^n

Where are proteins synthesized in the cell?

By ribosomes

Outline the 2 main steps through which proteins are synthesized by ribosomes

1. Transcription: DNA is copied into mRNA (a messenger RNA “recipe”).

2. Translation: a ribosome reads the mRNA in 3-base codons, and tRNA (transfer RNA) brings matching amino acids to build a chain.

define primary structure

the linear sequence (order) of amino acids in a polypeptide chain

Why is the primary structure important in proteins?

it influences how the protein folds & interacts → changes shape & functional ability

How are particular protein conformations stabilized?

through interactions between r-groups, like hydrogen bonds, ionic attractions, and hydrophobic clustering

What kind of functional features can result from folding?

enzyme active sites, binding pockets, or interaction surfaces needed for protein-protein binding

define a secondary structure

define a tertiary structure

define a quaternary structure

Why can proteins have many different functions?

r-groups differ + sequences differ