Proteins

• What are proteins made of?

  Proteins are made of monomers called amino acids.
• How does the sequence of amino acids affect a protein?

  The sequence, type, and number of amino acids determine its shape and function.
• What are some functions of proteins?

  Proteins form enzymes, hormones, transport proteins, structural proteins, contractile proteins, and immunoproteins.
• How many amino acids are found in the proteins of living organisms?

  There are 20 amino acids found in the proteins of living organisms.
• What distinguishes one amino acid from another?

  Each amino acid differs from the others due to the R group.
• What type of reaction forms peptide bonds between amino acids?

  Peptide bonds form between amino acids via a condensation reaction.
• What is removed during the formation of a peptide bond?

  A hydroxyl group is removed from the COOH and a hydrogen atom from the NH₂.
• What is a polymer?

  A polymer is a large molecule made up of repeating structural units called monomers.
• What is a monomer?

  A monomer is a small, basic molecular unit that can join together to form polymers.
• What is a hydrolysis reaction?

  A hydrolysis reaction is a chemical reaction that involves the breaking of a bond in a molecule using water.
• What is a condensation reaction?

  A condensation reaction is a chemical reaction where two molecules combine to form a larger molecule, releasing water.
• What is the monomer that forms proteins?

  The monomer that forms proteins is the amino acid.
• How do amino acids differ from each other?

  Amino acids differ from each other due to their unique R groups.
• What is the general structure of an amino acid?

  The general structure of an amino acid includes an amino group, a carboxyl group, a hydrogen atom, and an R group.
• What is the structure of the cell membrane?

  The cell membrane is composed of a phospholipid bilayer with embedded proteins.
• What is the difference between channel and carrier proteins in the cell membrane?

  Channel proteins provide passageways for molecules, while carrier proteins change shape to transport substances.
• How does pH affect proteins?

  pH affects proteins by altering their shape and function through changes in charge and bonding.
• What are two factors that affect membrane permeability?

  Temperature and the presence of cholesterol affect membrane permeability.
• What is the structure of the polysaccharide that insulin stimulates the formation of?

  Insulin stimulates the formation of glycogen, which is a branched polysaccharide.
• What are the four levels of protein structure?

  1. Primary structure: Sequence of amino acids.
  2. Secondary structure: Coiling into alpha helices or folding into beta sheets.
  3. Tertiary structure: Final 3D structure formed by further folding and bonding.
  4. Quaternary structure: Structure formed by multiple polypeptide chains.
• What are the properties and examples of fibrous and globular proteins?

  Fibrous Proteins:

  • Long strands, insoluble, strong due to cross-linking.
  • Example: Collagen.

  
  

  Globular Proteins:

  • Compact, spherical, water-soluble.
  • Example: Haemoglobin.
• What is the primary structure of a protein determined by?

  The primary structure is determined by the DNA of a cell.
• What bonds form between the amino and carbonyl groups in amino acids?

  Hydrogen bonds form between the amino and carbonyl groups in amino acids.
• What bonds can form between R groups in the tertiary structure of proteins?

  Bonds that can form between R groups include hydrogen bonds, disulfide bonds, ionic bonds, and weak hydrophobic interactions.
• What is the significance of the quaternary structure in proteins?

  The quaternary structure relates to proteins that have more than one polypeptide chain working together as a functional macromolecule.
• How does collagen contribute to connective tissue?

  Collagen is a flexible structural protein that forms tendons, cartilage, bones, and teeth.
• How is collagen structured?

  Collagen is made of three polypeptide chains coiled around each other to form a triple helix.
• What is the function of haemoglobin?

  Haemoglobin carries oxygen around the body and is soluble for easy transport in blood.
• How many oxygen molecules can each haemoglobin carry?

  Each haemoglobin can carry four oxygen molecules.
• What is the significance of the orientation of R groups in globular proteins?

  The orientation of non-polar hydrophobic R groups towards the center and polar hydrophilic R groups on the outside allows for water solubility.
• What is the role of haem in haemoglobin?

  The haem group in haemoglobin binds to oxygen.
• What is the relationship between protein structure and function?

  The structure of a protein determines its function, including the shape of its active site.
• How does the primary structure of a protein influence its tertiary structure?

  The primary structure determines the bonds formed between R groups, influencing the folding and shape of the protein.
• What is the significance of hydrogen bonding in protein structure?

  Hydrogen bonds contribute to the secondary structure by forming coils or folds in the polypeptide chain.
• What is the role of disulfide bonds in protein structure?

  Disulfide bonds provide stability to the tertiary structure of proteins.
• How do weak hydrophobic interactions affect protein structure?

  Weak hydrophobic interactions help maintain the tertiary structure by driving non-polar R groups away from water.
• What is the importance of the triple helix structure of collagen?

  The triple helix structure of collagen provides strength and flexibility to connective tissues.
• How do fibrils contribute to the properties of collagen?

  Fibrils formed by collagen chains have high tensile strength, contributing to the structural integrity of tissues.
• What is the role of glycine in fibrous proteins?

  Every third amino acid in fibrous proteins like collagen is glycine, contributing to flexibility.
• How does the structure of globular proteins facilitate their function?

  The compact, spherical shape of globular proteins allows them to be water-soluble and easily transported in the body.