Proteins & Nucleic Acid

• What are the most abundant organic molecules in living organisms?

  Proteins
• What are the monomers of proteins?

  Amino acids
• How many common amino acids are there?


  20
• How many essential amino acids must be supplied by diet in humans?


  3
• What determines the chemical properties of amino acids?


  The R groups of the amino acids
• What are the functions of proteins?

  • Catalysts in biochemical reactions (enzymes)
  • Structural components
  • Transport molecules
  • Signaling molecules
  • Immune response
  • Energy sources
• What is the central atom in an amino acid?


  The α-carbon
• What groups are present in an amino acid structure?


  Amino group, carboxyl group, hydrogen, and side chain (R-group)
• How are amino acids represented?


  By a single uppercase letter or three letters
• What is the three-letter abbreviation for Valine?


  Val
• What is the one-letter abbreviation for Aspartic Acid?


  D
• How are amino acid monomers linked together?


  Via peptide bonds
• What type of reaction forms peptide bonds?


  Dehydration synthesis
• What is a chain of amino acids called?

  A polypeptide
• What constitutes a protein?


  One or more polypeptides
• How does the sequence and number of amino acids affect proteins?


  They determine protein shape, size, and function
• What are the four levels of protein structure?

  1. Primary
  2. Secondary
  3. Tertiary
  4. Quaternary

  
• What is the primary structure of a protein?


  The unique sequence of amino acids in a polypeptide
• What influences the primary structure of a protein?


  Gene encoding of that protein
• How do changes in DNA nucleotide sequence affect proteins?


  They can lead to changes in amino acid sequence, structure, and function
• What is the secondary structure of a protein?


  The local folding of the polypeptide
• What stabilizes the secondary structure of proteins?


  Hydrogen bonds between carbonyl and amino groups
• What are the two forms of secondary structure?

  α-helix and β-sheet
• What is the tertiary structure of a protein?


  The unique 3D structure of a polypeptide
• What interactions contribute to the tertiary structure of proteins?


  Chemical interactions between the R groups of amino acids
• What types of interactions are involved in tertiary structure?


  Hydrophobic interactions, ionic bonding, hydrogen bonding, and disulfide linkages
• What is the quaternary structure of a protein?


  Several polypeptides making up a protein
• What stabilizes the quaternary structure of proteins?


  Weak interactions
• What is denaturation in proteins?


  Changes in protein structure that lead to changes in function
• What can cause denaturation of proteins?


  Changes in pH and temperature
• What type of proteins are enzymes?


  Catalysts in biochemical reactions
• What is the specificity of enzymes?


  They only bind with specific substrates
• What are the two types of nucleic acids?

  DNA and RNA
• What is the monomer of nucleic acids?


  Nucleotides
• Where is DNA located in cells?


  • Nucleus
  • Mitochondria
  • Chloroplasts (in plants)
• What are the three parts of a nucleotide?


  Nitrogenous base, pentose sugar, and phosphate group
• What are the two types of nitrogenous bases?

  Pyrimidines and purines
• Which nitrogenous bases are pyrimidines?


  Cytosine, thymine, and uracil
• Which nitrogenous bases are purines?


  Adenine and guanine
• What are the two types of pentose sugars?


  Deoxyribose and ribose