Proteins Flashcards
Amino Acids/ Peptide/ Secondary/ Tertiary/ Quaternary
What is the monomer for proteins called and how many of them exist in all life forms? (2)
- Amino acids
- Only 20 amino acids exist
What elements are proteins made up of? (4)
- Carbon
- Oxygen
- Hydrogen
- Nitrogen
Where is the nitrogen in proteins found? (1)
In the amine group
Draw a labelled amino acid (10)
Draw and label:
- Variable group (R)
- Carbon (c)
- Amine group (H2 N)
- Carboxyl group (COOH)
Hydrogen (H)
State and describe the two types of proteins there are (4)
- Globular proteins - Spherical, compact, soluble
- Fibrous proteins - Long, form fibres, insoluble, structure, support and protection for tissues
Draw a dipeptide and label the peptide bond (4)
Draw and label:
- Two amino acids bonded
- H2 O removed
- Double bond between carbon and oxygen
- Peptide bond labelled between carbon and nitrogen
State the 4 structural levels of a protein (4)
- primary structure
- secondary structure
- tertiary structure
- quaternary structure
Describe the primary structure of a protein and include the importance of it; refer to enzymes (3)
- It is the number and sequence of amino acids in a polypeptide chain
- This affects the secondary and tertiary structure as changes to number and sequence of amino acids means that bonds are formed in a different place and a different 3D shape is formed.
- Also affects the shape of the active site in enzymes
Describe the secondary structure of a protein and include the importance of it (4)
- Hydrogen bonds are formed between the amino acids
- Causes the chain to coil into an a-helix or fold into a B-pleated sheet
- Most channel proteins are made out of a-helixes
- The many hydrogen bonds makes the protein stable
Describe the tertiary structure and include the importance of it + give examples (5)
- The 3D shape of the polypeptide chain
- Has a specific shape due to the number and sequence of amino acids
- The chain is folded and bonds together by
- Hydrogen and ionic bonds as well as disulphide bridges (covalent bonds)
- Examples: All enzymes, antibodies and some hormones have a tertiary structure
Describe the quaternary structure and give examples it (2)
- When more than one polypeptide chain is bonded together
- Examples: Antibodies and haemoglobin
