water

• water is a major component of all cells and has many important roles within organisms
• the properties of water are due to its polar nature, which allows it to dissolve other molecules.
• In order for a cytoplasm to function as a soluble medium it has to contain water
• Water has the role of synthesising and breaking down biological molecules in condensation and hydrolysis reactions
• monomers come together to make polymers through condensation(-H2O), opposite is hydrolysis (+H2O)
• Water in photosynthesis can be called a metabolite
• The Polar Nature of Water: electrons in the covalent bonds of water are not equally shared - they lie closer to the oxygen nucleus(more positively charged protons-8 ) than the hydrogen nuclei- 1 proton
• Unequal sharing of the electrons result in oxygen atom being slightly negative & hydrogen atoms being slightly positive
• Oxygen in water= δ- , Hydrogen= δ+ (makes it polar)
• Dipoles = partial charges on either side of an electron pair bond
• Polarity = dipoles that exist within a molecule
• Polar molecules= molecules that have an uneven distribution of charge
• Water is a solvent because its polarity allows it to dissolve other polar substances such as salts or sugars.
• Water as a metabolite

  Regulates temperature, facilitates chemical reactions, maintains cellular structure, and participates in energy metabolism.
• hydrogen bonding in water: slightly positive hydrogen atoms are attracted to the slightly negative oxygen atom
• Hydrogen bond is weaker than covalent bond, stronger than most intermolecular bonds
• Hydrogen bond: a weak interaction that occurs between a slightly negatively charged atom and a slightly positively charged atom
• The state of a substance depends on the kinetic energy of the particles
• Heat of Vaporization of Water


  The amount of energy required to change 1 kilogram of liquid water to steam at standard conditions, approximately 2250 kJ/kg.
• Significance of Heat of Vaporization

  The heat of vaporization of water helps regulate Earth's temperature and maintain climate stability by removing excess heat from the system, slowing down global warming.
• when the temperature of a substance is increased, the particles have more kinetic energy
• Change in state: when the particles have enough kinetic energy to break the forces of attraction between the particles
• 5 key properties of water:

  • it is a metabolite
  • an important solvent in reactions
  • has a high heat capacity, it buffers temperature
  • has a large latent heat of vaporisation, provides cooling effect with loss of water through evaporation
  • strong cohesion between water molecules, provides surface tension
• specific heat capacity is how much energy it takes to raise the temp of one gram of something by one degree celsius
• What percentage of the human body is made up of water?

  60 to 70 percent
• What does it mean for water to be a dipolar molecule?

  It has two different regions that are charged
• What do the symbols delta in the water molecule diagram represent?

  Slight positive and slight negative charges
• What is the significance of hydrogen bonds in water?

  They lead to many of water's important properties
• What are the five key properties of water discussed in the video?

  1. Water as a metabolite
  2. Water as a solvent
  3. High heat capacity
  4. Large latent heat of vaporization
  5. Strong cohesion
• How is water involved in metabolism?

  It is involved in many chemical reactions, such as photosynthesis and hydrolysis
• What is the role of water in photosynthesis?

  Water is used in photolysis
• Why is water considered a good solvent?

  It can dissolve many substances due to its dipolar nature
• How does water's dipolar nature contribute to its solvent properties?

  The slight positive charge on hydrogen attracts negative ions, while the slight negative charge on oxygen attracts positive ions
• What type of molecules does water dissolve?

  Polar molecules
• What does it mean for lipids to be described as hydrophobic?

  They do not dissolve in water
• What is meant by water having a high specific heat capacity?

  It takes a lot of energy to raise the temperature of water
• Why does water require a lot of energy to raise its temperature?

  Because water molecules are held together by hydrogen bonds
• How does water's high heat capacity benefit organisms?

  It helps maintain stable internal temperatures
• What is the significance of a large latent heat of vaporization for water?

  It requires a lot of energy to convert water from liquid to gas
• How does sweating help regulate body temperature?

  It allows heat to be absorbed into sweat, which then evaporates