Unit 2 - Proteins Flashcards
What are the monomeric units of proteins?
Amino acids
Where do we get amino acids from?
Our diet
Outline the journey an amino acid takes from food to protein in a cell
- food is ingested
- enzymes in the stomach/small intestine hydrolyse protein into amino acids
- the amino acids are absorbed by the gut wall into the blood
- the amino acids leave the blood in the tissue fluid and enter cells
- proteins are synthesised on the ribosomes
How many common amino acids are there?
20
Give 4 functions of proteins
- enzymes
- hormones
- antibodies
- structural proteins
What do the interactions of differing R-groups determine?
The folding of the protein
What type of reaction occurs to form a protein from 2 amino acids?
Condensation
What type of bond is formed from the synthesis of a protein?
Peptide
What is produced in the condensation reaction between two amino acids?
Water and dipeptide
What is the general formula of an amino acid?
Between which parts of the amino acid molecules does the condensation reaction between two amino acids occur?
The carboxyl group of one amino acid and the amine group of another amino acid
What is a chain of amino acids called?
A polypeptide
What is the end of a polypeptide with an amino group called?
The N-terminus
What is the end of the polypeptide with a carboxyl group called?
The C-terminus
What is the definition of primary structure of a protein?
The SEQUENCE of amino acids
What type of bonding holds the primary structure of a protein together?
Peptide
What shape is the primary structure of a protein?
Linear
What forms the secondary structure of a protein?
The folding of the primary structure
What type of bonds hold together the secondary structure of a protein?
Hydrogen bonds
In the secondary structure, what do hydrogen bonds form between?
Partially positive H and partially negative O
What are the two possible shapes of the secondary structure?
- alpha helix
- beta pleated sheet
What is the tertiary structure formed by?
The folding of the secondary structure
Why do proteins fold at the tertiary level of structure?
Due to the interactions between the R-groups
What are the 4 types of bond formed at the tertiary level of structure?
- ionic bonds
- hydrogen bonds
- disulfide bonds
- hydrophobic and hydrophilic interactions
What do ionic bonds form between?
Positively and negatively charged ions
What do hydrogen bonds form between?
Partially positive H and partially negative O
What do disulfide bridges form between?
Sulfur atoms contained within R-groups
Which amino acid contains sulfur?
Cysteine
What do hydrophobic and hydrophilic interactions form between?
Polar and non-polar R-groups