Protein Structure, Coding, and Translation: Key Concepts for Biology

What are the monomers of proteins?

Amino acids

How many different types of amino acids are there?

20 different types

What is the primary structure of a protein?

A linear sequence of amino acids

What type of bonding causes the secondary structure of proteins?

Hydrogen bonding

Name two common types of secondary structures in proteins.

Alpha-helix and beta-pleated sheet

What does the tertiary structure of a protein refer to?

Intra-molecular R group interactions that give the overall 3-D structure

What is the quaternary structure of a protein?

A multi-subunit composition made of multiple polypeptide chains

What determines the structure and functional properties of a protein?

The amino acid sequence

What techniques are used to determine protein structures?

X-ray crystallography, nuclear magnetic resonance spectrometry, cryogenic electron microscopy, and AI predictions

What is the 'coding-decoding' problem in relation to mRNA?

If each base in mRNA specified one amino acid, only 4 amino acids could be translated; three bases are needed per amino acid.

What is the genetic code?

A triplet code that uses four nucleotide bases to specify amino acids

How must the genetic code be read?

In groups of three bases, called codons

What is the significance of the initiation codon AUG?

It establishes the correct reading frame for decoding the mRNA

What happens when the ribosome encounters a stop codon?

Release factors bind, causing the completed polypeptide to be released and the ribosomal subunits to detach from the mRNA

What is translation?

The process of decoding mRNA to make proteins

What components are required for translation?

20 amino acids, tRNAs, aminoacyl tRNA synthetases, and ribosomes

How does tRNA function in translation?

The 3' end of tRNA binds a specific amino acid, and the anticodon recognizes and binds to a codon in mRNA.

What is the tRNA charging reaction?

The process where an enzyme called aminoacyl-tRNA synthetase attaches the appropriate amino acid to the tRNA.

What are polysomes?

Many ribosomes translating a single mRNA, functioning as a protein production line.

What are the three stages of translation?

Initiation, elongation, and termination

What occurs during the initiation stage of translation?

mRNA binds to a small ribosomal subunit and recruits initiator tRNA.

What happens during the elongation stage of translation?

The ribosome moves along the mRNA, reading codons and linking amino acids together by peptide bonds.

What is the role of ribosomes in translation?

Ribosomes facilitate the decoding of mRNA and the assembly of amino acids into polypeptide chains.