Biochem

• What elements are present in proteins?

  Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N), and sometimes Sulfur (S) or Phosphorus (P).
• What are proteins made of?

  Proteins are polymers made up of long chains of smaller units called amino acids.
• How many different amino acids are there?

  There are 20 different amino acids.
• What is the structure of an amino acid?

  Each amino acid has a central carbon atom (Cα), an amino group (NH₂), a carboxyl group (COOH), a hydrogen atom (H), and an R group.
• What is the role of the R group in an amino acid?

  The R group gives each amino acid its unique properties.
• How do you label an amino acid?

  The alpha carbon (Cα) is in the center, with the amino group (NH₂) on one side, the carboxyl group (COOH) on the other, and the R group and hydrogen atom attached to the central carbon.
• How is a peptide bond formed between two amino acids?

  A peptide bond forms when the carboxyl group of one amino acid joins with the amino group of another, removing a molecule of water (H₂O).
• What is a dipeptide?


  A dipeptide is a chain of two amino acids.
• What is the difference between condensation and hydrolysis reactions?

  Condensation joins two amino acids by removing a water molecule, while hydrolysis adds a water molecule to break the peptide bond.
• How do you draw a peptide bond?

  A peptide bond is drawn between the carboxyl carbon of one amino acid and the amino nitrogen of another amino acid, represented as C-N.
• What are the primary, secondary, tertiary, and quaternary structures of a protein?

  • Primary structure: Sequence of amino acids in a chain.
  • Secondary structure: Local folding into shapes like alpha helices and beta sheets, held by hydrogen bonds.
  • Tertiary structure: Overall 3D shape of the protein, held by interactions between side chains (R groups).
  • Quaternary structure: Arrangement of multiple protein chains (subunits) working together.
• What bonds are involved in the primary structure of proteins?

  Peptide bonds (C-N) between amino acids.
• What bonds are involved in the secondary structure of proteins?

  Hydrogen bonds between the backbone atoms of the amino acids.
• What types of bonds are involved in the tertiary structure of proteins?

  Various bonds including hydrogen bonds, ionic bonds, disulfide bridges, and hydrophobic interactions.
• What bonds are involved in the quaternary structure of proteins?

  The same bonds as tertiary structure, holding multiple protein subunits together.
• What are the two types of proteins and their differences?

  • Fibrous proteins: Long and strong, usually for structure (e.g., collagen, keratin); do not dissolve easily in water.
  • Globular proteins: Round and compact, usually for function (e.g., hemoglobin, enzymes); dissolve more easily in water.