Lecture 1 +2 Flashcards
(22 cards)
What is the difference between L and D stereoisomers?
L and D stereoisomers refer to the orientation of the amino group in relation to the carbon chain.
What are alpha and beta-amino acids?
Alpha-amino acids have the amino group attached to the carbon adjacent to the carboxylic acid, while beta-amino acids have the amino group on the second carbon.
List the 20 α-L-amino acids based on their side chain classification.
- Nonpolar aliphatic
- Aromatic
- Polar uncharged
- Positively charged
- Negatively charged
Draw a dipeptide of your choice to represent the peptide bond.
A dipeptide consists of two amino acids linked by a peptide bond.
How are amino acids classified based on the polarity, hydrophilicity, and hydrophobicity of their radicals at pH=7?
Amino acids can be classified as polar, nonpolar, hydrophilic, or hydrophobic based on their side chains.
List the essential amino acids.
- Histidine
- Isoleucine
- Leucine
- Lysine
- Methionine
- Phenylalanine
- Threonine
- Tryptophan
- Valine
Define primary structure of proteins.
Primary structure refers to the linear sequence of amino acids in a polypeptide chain.
Define secondary structure of proteins.
Secondary structure involves the local folding of the polypeptide chain into structures such as α-helices and β-pleated sheets.
Define tertiary structure of proteins.
Tertiary structure is the overall three-dimensional shape of a polypeptide, determined by interactions between side chains.
Define quaternary structure of proteins.
Quaternary structure refers to the assembly of multiple polypeptide chains into a single functional unit.
What is a schematic representation of α-helix?
An α-helix is a right-handed coil where each amino acid corresponds to a 100-degree turn.
What is a schematic representation of β-pleated sheet?
A β-pleated sheet consists of beta strands connected laterally by hydrogen bonds, forming a sheet-like structure.
Provide examples of amino acids that are products of metabolism or post-translational processing.
- Ornithine
- Citrulline
- Selenocysteine
- Hydroxyproline
Define heteroproteins.
Heteroproteins are proteins that contain one or more non-amino acid components.
Define isoproteins.
Isoproteins are proteins that are made up of the same type of amino acids but may differ in their sequence.
Define alloproteins.
Alloproteins are proteins that can exist in different forms or conformations.
Provide examples of globular proteins.
- Hemoglobin
- Enzymes
- Antibodies
Provide examples of fibrillar proteins.
- Collagen
- Keratin
- Elastin
List mechanisms for maintaining protein conformation.
- Hydrogen bonds
- Ionic interactions
- Hydrophobic interactions
- Van der Waals forces
What are some examined protein defects (diseases)?
- Sickle cell anemia
- Cystic fibrosis
- Huntington’s disease
What are protein defects due to?
Protein defects are often due to mutations in the gene coding for the protein, affecting its structure and function.
