L17: Non-covalent Bonds

• What are isomers in the context of carbohydrates?

  Isomers are compounds with the same molecular formula but different structures.
• What are conformers?

  Conformers are different spatial arrangements of the same molecule that can interconvert.
• What are the types of bonds and interactions mentioned in the study material?

  • Covalent bonds
  • Noncovalent interactions
  • Ionic interactions
  • Dipole interactions
  • Dipole-ion interactions
  • Hydrogen bonds
  • Dispersion forces
  • Steric repulsion
  • Hydrophobic interactions
• What is the strength range of covalent bonds compared to noncovalent interactions?

  Covalent bonds are strong (150-1000 kJ/mol), while noncovalent interactions are generally weaker.
• Why are noncovalent bonds important in biological macromolecules?

  Noncovalent bonds provide flexibility and allow for interactions necessary for biological functions.
• What is the significance of weak bonds in biology?

  Weak bonds are important because they are individually weak but collectively strong, providing flexibility.
• What happens when electron clouds overlap between atoms?

  When electron clouds overlap, repulsion occurs, which is very distance dependent.
• What is an example of van der Waals interactions in nature?

  Gecko feet utilize extended surfaces to maximize van der Waals interactions with surfaces.
• How stable is the native form of a protein compared to its denatured form?

  The native form of a protein is significantly more stable than the denatured form due to multiple interactions.
• What happens to sodium (Na) when it loses an electron?

  It becomes a sodium ion (Na⁺) with a full outer shell.
• What role do metal ions play in proteins?

  Metal ions often bind to charged and polar parts of proteins, influencing their structure and function.
• What are salt bridges in the context of ionic bonds?

  Salt bridges are formed between charged amino acids, contributing to protein stability.
• What defines a polar covalent bond?

  A polar covalent bond occurs when one atom holds onto electrons tighter than another, creating partial charges.
• What is the principle behind dipole interactions?

  Opposite charges attract while like charges repel in dipole interactions.
• What is a hydrogen bond donor?

  A hydrogen bond donor is a hydrogen atom covalently bonded to a more electronegative atom like nitrogen or oxygen.
• What factors influence the strength of hydrogen bonds?

  The strength of hydrogen bonds depends on angles and distance between the interacting atoms.
• What is hydration in the context of hydrogen bonds?

  Hydration refers to the interaction of water molecules with other substances, often involving hydrogen bonds.
• What are dispersion forces?

  Dispersion forces are weak electrostatic interactions that occur between atoms close in space due to induced dipoles.
• What percentage of the human body is composed of water?

  Approximately 66% of the human body consists of water.
• Why is water considered the solvent of life?

  Water is essential for many biochemical reactions and serves as a solvent for various substances.
• What is unusual about the solid form of water (ice)?

  Ice floats on water, which is unusual for solids.
• What are the key properties of water that make it an excellent solvent?

  • High heat capacity
  • High vaporization heat
  • Strong cohesion and adhesion
  • Hydrogen bonding
  • Freezes from the top down
• How does the structure of water contribute to its properties?

  Water's tetrahedral structure and hydrogen bonding lead to high melting and boiling points and strong cohesion.
• How does ice differ from liquid water in terms of molecular arrangement?

  Ice has an ordered lattice structure, while liquid water is more flexible and allows molecules to move closer together.
• Why is water an excellent solvent for hydrophilic molecules?

  Water's polar nature allows it to interact effectively with hydrophilic molecules, facilitating solvation.
• What happens to hydrophobic molecules in water?

  Hydrophobic molecules tend to clump together in water to minimize their surface area and exclude water.
• What is the effect of hydrophobic interactions on protein structure?

  Hydrophobic interactions lead to the formation of a hydrophobic center and a hydrophilic surface in globular proteins.
• What are the main types of noncovalent interactions?

  • Hydrogen bonds
  • Dipole interactions
  • Salt bridges
  • Hydrophobic interactions
  • Dispersion forces
  • Dipole-ion interactions
• What is the significance of bonds in biological molecules?

  • Provide shape and strength
  • Necessary for correct function
  • Many weak bonds create strong but flexible interactions
  • Examples: Gecko feet, DNA double helix, protein structure
• What are the main types of noncovalent interactions mentioned in the study material?

  The main types are ionic interactions, dipole interactions, dipole-ion interactions, hydrogen bonds, dispersion forces, and hydrophobic interactions.
• What role does water play in biochemical reactions?

  Water acts as a solvent and is involved in many reactions as a substrate or product.
• What is electronegativity and why is it important?

  Electronegativity is the ability of an atom to attract electrons, influencing bond polarity and molecular interactions.
• Why is hydration important in biological systems?

  Hydration is crucial as it facilitates interactions between water and other molecules, influencing biochemical processes.