Biological molecules 1: Proteins Flashcards
What are proteins
Proteins are biological molecules made up by one or more polypeptides joined together a series of peptide bonds through condensation reactions
What is the monomer of a protein
Amino acids
What is a dipeptide
Two amino acids joined together by a peptide bond through a condensation reaction
What are polypeptides
Polypeptides are two or more amino acids joined together by peptide bonds through condensation reactions
How many variations amino acids are there
20
What are the differences bettween the amino acids
Their R groups
What bonds occur between the formation of dipeptides and polypeptides
Peptide bonds
What groups on the amino acids does bonding occur between
An amine group on one amino acid and a carboxyl group of another
What is the primary structure of a protein
The sequencing of amino acids in a polypeptide chain
What is the secondary structure of a protein
The coiling and folding of the polypeptide chain based on the sequencing of amino acids
What forms during the secondary structure
Alpha (α) helices
Beta (β) pleated sheets
What is the tertiary structure of a protein
The further coiling and folding of a polypeptide chain causing a 3D structure held together by different interactions between R groups of amino acids
What is the quaternary structure of a protein
The structure formed when two or more polypeptide chains joined together
What are the two main 3D structures that occur during the tertiary structure
Fibrous structure
Globular structure
When do hydrogen bonds occur during the tertiary structure
They occur when their are different attractions between negative and positive charges of different parts of the molecule
When do disulphide bridges occur during the tertiary structure
They occur when two cysteine are close together and a sulphur atom in one cysteine bonds with a sulphur on another - causing a double bond between them
What do the ionic bonds form between in the tertiary structure
They form between the opposite attraction of the negative and positive charges of the R groups on amino acids
What structures do globular proteins form
Round and spherical structures
What structures do fibrous proteins form
Long and narrow structures
What is the structure of an enzyme and how does it help with its function
Globular structure - Folded in a way where it has the correct orientation and active site as it’s substrate so can form enzyme substrate complexes
What structure do antibodies have and how does it help its function
Globular structure - Easy to transport meaning they can get to antigens quickly
What structure do transport proteins have and how does it help its function
Globular structure - Contains both hydrophobic and hydrophilic amino acids causing protein to fold up into a channel
What structure do structural proteins have and how does it help its function
Fibrous structure - Long polypeptide chain lay parallel to each other with cross links between them making them very strong
What shape are fibrous proteins
Long and narrow
What shape are globular proteins
Round and spherical
What function do fibrous proteins have
Structural
What function do globular proteins have
Functional
What causes fibrous proteins to have a long and narrow shape
Their amino sequencing is repetitive
What causes globular proteins to have a round and spherical shape
Irregular amino acid sequencing
Examples of fibrous proteins
Collagen and Keratin
Examples of globular proteins
Enzymes and haemoglobin
What is glycine
An amino acid with an R group only containing a hydrogen
What binds are present in the tertiary of a protein
- Ionic bonds
- Disulphide bridges
- Hydrogen bonds
