3.6, 3.7, Proteins, Types of Protein Flashcards
What are the properties of each amino acid determined by?
Their Variable group
Describe the basic structure of an amino acid.
-There are 3 groups in an amino acid.
-One Amine group (NH2)
-One Carboxyl group (COOH)
-One Variable Group (R)
Are amino acids soluble or insoluble?
-Amino acids are soluble in water, and form polar ions when added to water, some some R groups are non-polar.
What are peptides?
-Polymers made up of amino acid molecules
What are proteins made up of?
Proteins consist of one or more polypeptides arranged as complex macromolecules, and all have specific biological functions
What do all proteins contain?
Carbon, Hydrogen, Oxygen and Nitrogen
What group determines which amino acid it will be?
The R group.
How many different amino acids are there?
20
How is a dipeptide produced?
When the amine group of one amino acid and the carboxyl group of another react with eachother in a condensation reaction
What type of bond connects two amino acids together?
A peptide bond
What catalyses the reaction between two amino acids?
Peptidyl transferase
What type of reaction is it when polypeptide is broken down?
Hydrolysis reaction.
How do polypeptides form proteins?
Different R groups of the amino acids making up a protein interact with eachother, forming different types of bond.
What determines the shape of a protein?
The sequence of the amino acids
What does the shape of a protein determine?
Its function
How many levels of protein structure are there? And what are their names?
4, Primary, Secondary, Tertiary, Quarternary
What is the Primary Structure of a protein?
-The sequence in which the amino acids are joined.
What are amino acids joined by in a polypeptide chain?
Peptide bonds
What directs the sequence of amino acids?
Information carried within DNA
What does the particular amino acids in a sequence influence?
How the polypeptide folds to give the protein’s final shape.
What is the Secondary Structure of proteins the result of?
Hydrogen bonds pulling polypeptide chains into different shapes.
How is the Secondary Structure formed?
-The oxygen, nitrogen and hydrogen atoms of the repeating structure of the amino acids interact.
-Hydrogen bonds form within the amino acid chain, or between polypeptide chains, and pull the structures into one of two shapes.
What are the two shapes found in secondary structure?
Alpha Helix or Beta Pleated Sheet
Do all proteins have a secondary structure?
Yes
True or false: Proteins can only have one shape in their structure
False, proteins can have both alpha helixes AND beta pleated sheets in their structure, but the helix is the most common of the two
How do proteins form the secondary structure of an alpha helix?
Hydrogen bonds form WITHIN an amino acid chain, pulling it into a coiled shape, which is the alpha helix.
How do proteins form the secondary structure of a beta pleated sheet?
-Hydrogen bonds join SEPARATE polypeptide chains that lie parallel to eachother.
-The pattern formed by the individual amino acids causes the structure to appear pleated (forming the shape of a beta-pleated sheet)
Where do the Secondary Structures form?
Regions along long protein molecules
What is Tertiary Structure?
The folding of a protein into its final shape, that often involves sections of secondary structure.
How does Tertiary Structure form?
The folding of sections of proteins into their secondary structures brings R groups of different amino acids closer together, so they are close enough to interact and further foldings of these sections occurrs.
What are the different types of interactions between R-Groups in Tertiary Structure?
-Hydrophobic and Hydrophilic interactions
-Hydrogen bonds
-Ionic bonds
-Disulfide bonds/bridges
What are hydrophilic and hydrophobic interactions in Tertiary Structure?
Weak interactions between polar and non-polar R groups
What are hydrogen bonds in Tertiary Structure?
The weakest of the bonds formed
What are ionic bonds in Tertiary Structure?
Stronger than hydrogen bonds, and formed between oppositely charged R groups. Vulnerable to changes in pH
What are disulfide bonds in Tertiary Structure?
Covalent, and the strongest of the bonds.
Only formed between R-groups that contain sulfur atoms, between adjacent cysteine molecules.
What does Tertiary Structure produce?
A variety of complex-shaped proteins, with specialised characteristics and functions.
What is Quarternary Structure?
A result of the association of two or more individual polypeptide chains.
What makes Quarternary Structure similar to Tertiary Structure?
The interactions between the subunits are the same.