Amino Acids, Proteins and DNA: Proteins Flashcards
1
Q
What are proteins?
A
- Proteins are condensation polymers of amino acids joined by peptide links
2
Q
Draw the structure of a general amino acid
A
3
Q
Draw the general equation for the formation of a peptide link
A
4
Q
How can a protein be broken down into its constituent amino acids?
A
- By hydrolysis
5
Q
What are the conditions for protein hydrolysis?
A
- Add aqueous 6 moldm^-3 hydrochloric acid
- Heat mixture under reflux for 24 hours
6
Q
What are the different types of protein structure?
A
- Primary
- Secondary
- Tertiary
- Quaternary
7
Q
What is the primary structure of a protein?
A
- Sequence of amino acids
8
Q
What is the secondary structure of a protein?
A
- Hydrogen bonds form between peptide links
- Forms an α-helix or β-pleated sheets
9
Q
What is the tertiary structure of a protein?
A
- Polypeptide chains folded into a 3D coil with hydrogen and disulfide bonding
10
Q
What are the two main bonds that hold proteins in shape?
A
- Hydrogen bonds
- Disulfide bonds
11
Q
How are hydrogen bonds formed in proteins?
A
- Hydrogen bonds form between polar groups -OH and -NH2
- Electronegative atoms (O and N) induce δ+ charge on H
- H forms bond to lone pair on adjacent O atoms
12
Q
How are disulfide bonds formed in proteins?
A
- Formed between multiples of amino acid cysteine
- Cysteine contains thiol group (-SH)
- Thiol group can lose H and form a covalent disulfide bond with another thiol group
