Proteins

• What atoms do proteins contain that differentiate them from carbohydrates and lipids?

  Nitrogen atoms
• What are proteins made of?

  Proteins are polymers made of monomers called amino acids
• What is a chain of amino acids called?

  A polypeptide
• How many different types of amino acids are there?

  20 different types
• How does the shape of a protein relate to its function?

  The shape of the protein is determined by the specific sequence of amino acids in the chain, which in turn determines its function
• What are the five components of the basic structure of amino acids?

  A central carbon atom, an amino group (NH2), a carboxyl group (COOH), a hydrogen atom, and a variable R group
• What is the simplest amino acid and what is its R-group?

  The simplest amino acid is glycine, which has a hydrogen atom as its R-group
• What are essential amino acids?

  Essential amino acids are those that cannot be synthesized in our bodies and must be obtained through diet
• How do non-essential amino acids differ from essential amino acids?

  Non-essential amino acids can be synthesized by our bodies, while essential amino acids cannot
• What reaction forms a dipeptide from amino acids?

  The amino group of one amino acid reacts with the carboxyl group of another by a condensation reaction
• What is formed when two amino acids bond together?


  A dipeptide
• What is a polypeptide?


  A polypeptide is a type of polymer formed by the addition of more amino acids to a dipeptide
• What determines the primary structure of a protein?

  The primary structure of a protein refers to the sequence of amino acids in a polypeptide chain, determined by DNA
• What type of bond connects amino acids in a protein?

  A peptide bond
• What is the secondary structure of a protein?

  The secondary structure is the shape that the polypeptide chain forms due to hydrogen bonding, which can be an alpha helix or a beta pleated sheet
• How is the tertiary structure of a protein formed?

  The tertiary structure is formed by further folding and twisting of the alpha helix, maintained by various bonds
• What types of proteins arise from tertiary structures?

  Globular and fibrous proteins
• What is the role of globular proteins?

  Globular proteins, such as enzymes and hemoglobin, have a functional role
• What is the role of fibrous proteins?

  Fibrous proteins, such as keratin and collagen, have a structural role
• Why is the tertiary structure important for enzymes?

  The bonds in the tertiary structure maintain the shape of the enzyme's active site
• What is the quaternary structure of a protein?

  The quaternary structure arises from a combination of two or more polypeptide chains
• How many polypeptide chains does hemoglobin have?

  Four polypeptide chains
• What is the Biuret test used for?

  The Biuret test is a chemical test for detecting the presence of peptide bonds between amino acids
• What color change indicates the presence of proteins in the Biuret test?

  The solution changes from blue to violet in the presence of protein
• How is the intensity of the violet color in the Biuret test related to protein concentration?

  The intensity of the violet color is directly proportional to the protein concentration
• What might happen at low concentrations of protein in the Biuret test?

  At low concentrations, a color change may not be obvious
• How are amino acids joined?


  By peptide bonds, which are formed by condensation reactions
• How do condensation reactions occur?


  With the hydroxyl gorup of one amino acid, and the hydrogen group of another.