Biological Molecules: Proteins Flashcards
Describe how a peptide bond is formed between two amino acids to form a dipeptide: (2 marks)
- A condensation reaction occurs between the two amino acids.
- Occurs in one amino acid’s amine group and the others carboxyl group
The secondary structure of a polypeptide is produced by bonds between amino acids. Describe how: (2 marks)
Hydrogen bonds from between one amino acid’s NH group and the others C=O group.
Two proteins have the same number and type of amino acids but different tertiary structures. Explain why : (2 marks)
Different primary structure forms hydrogen bonds in different places.
What bonds link amino acids together in a polypeptide chain?
Peptide bonds
Haemoglobin is made up of multiple polypeptide chains. Name the level of structure that forms haemoglobins final 3D structure:
Quaternary
(because it is made up of multiple polypeptide chains)
Which two substances are formed when two amino acid molecules join together?
Peptide
Water
Explain how a change in the primary structure of a globular protein may result in a different three-dimensional structure:
- Sequence of amino acid changes
- Tertiary structure changes/folds in a different way
-Bonds form in different places
What is the bond between two amino acids called?
Peptide bond
What is a dipeptide?
Two amino acids joined together
What is a polypeptide chain?
Many amino acids joined together
Explain how two enzymes with different amino acid sequences can catalyse the same reaction:
- Enzymes active site changes slightly
- Becomes complementary/specific to substrate
- Although enzymes tertiary structures are different, they change slightly to form enzyme-substrate complex.
What is the primary structure of a protein?
Sequence of amino acids in its polypeptide chains.
What is the secondary structure of a protein?
Folding of a polypeptide chain
What type of bonding is found in the secondary structure?
Hydrogen bonds
What type of bond are found in the primary structure?
Peptide bonds
What causes the tertiary structure of a protein?
Hydrogen and ionic bonds between side groups of amino acids.
What is the tertiary structure of a protein?
3D folding of the polypeptide chain
During the secondary structure of a protein, proteins can either turn into a ________ or a __________.
Alpha helix
Beta pleated sheet
What causes the secondary structure of a protein?
Hydrogen bonds between the groups of peptide bonds
What 3 types of bonds are found in the tertiary structure of a protein?
- Hydrogen bonds
- Ionic bonds
- Disulfide bridges
What is the quaternary structure of a protein?
2 or more polypeptide chains joined together.
A protein is known as conjugated if it contains a _______.
Prosthetic group
Name the bonds that join amino acids in the primary structure:
Peptide bonds
What is the molecular formula of an amine group?
NH2
How many amino acids are there?
20
Amino acids are joined together by _______ reactions.
Condensation
The bonds formed between amino acids are called _______ bonds.
Peptide
