Unit 1.1 - Water Flashcards
What type of molecule is water and why?
Polar, as it has a positive electrical charge on the hydrogen end and a negative electrical charge on the oxygen end
What do you call the uneven distribution of charge that water molecules have?
Dipole
What do you call the fact that water molecules stick together due to their polar nature?
Cohesion
What do you call the bonds formed between water molecules?
Hydrogen bonds
How do you represent the bonds between water molecules?
Dotted lines
Describe hydrogen bonds
-Weak compared to covalent and ionic bonds
-So numerous in water gives them unique properties making them essential to life
Name all of waters unique properties
-Surface tension
-Cohesion
-Adhesion
-Acting as a solvent
-Thermal properties (2)
-Transparency
-Density of ice
-Metabolite
How does surface tension work?
The top layer of water has fewer hydrogen bonds than the body, making it stronger as the bond energy is shared between fewer hydrogen bonds, giving it a higher surface tension
Cohesion
Water attracts itself
Adhesion
Water attracts other cells
What are the names of the vessels in trees that cohesion tension allows water to travel up them? What do these include?
Xylem vessels, unbroken chains of water molecules
How does cohesion help us?
Cohesion tension is where the attraction between water molecules allows water to be transported in long columns up the xylem vessels in trees.
Transpiration
The loss of water vapour through the stomata of plants, cooling it down as water is moved from the roots to the leaves
How does a plant cool down?
Through transpiration, where the loss of water vapor through the stomata cools it down as water is moved from the roots to the leaves
What is another process that helps trees get the water they need?
Adhesion, where because of their polar nature, water molecules attract the cellulose in the walls of the xylem vessels, allowing water to ‘climb’ up them, through the process of capillarity
What’s the term for water ‘climbing’ up the xylem vessels by adhesion with cellulose?
Capillarity
Which substance in the walls of the xylem vessels does water bind to through adhesion?
Cellulose
Why do water particles attract charged particles?
They’re dipoles
How does water act as a polar solvent?
As they’re dipoles, they attract charged particles such as ions and other polar molecules like glucose, which then dissolve in water allowing chemical reactions to happen in the solution created. The solute is fully dissolved as all ions are surrounded by the water molecules to keep them in a solution.
What’s the phrase for the heat needed for turning liquid into vapour?
Latent heat of evaporation
How does latent heat of evaporation work?
Water molecules draw heat energy from their surroundings in order to break free of the hydrogen bonds. This cools down the body as sweat evaporates, creating a cooling effect as the average energy remaining of the water molecules decreases, giving them a lower temperature.
Define specific heat capacity
The energy required to raise the temperature of 1kg of any material by 1 degree Celsius
Two thermal properties of water
1- High latent heat of evaporation
2-High specific heat capacity
Why is water having a high specific heat capacity beneficial?
A lot of heat is required to raise the water temperature, which prevents large fluctuations in its temperature, so the temperature of aquatic environments remains stable. Orgainisms don’t have to endure extreme temperatures and enzymes within our cells work effectively as the body (70% water!) temperature is kept close to optimum for enzyme activity
Why is water being transparent useful?
-Maintains ecosystems underwater
-Light can pass through so that plants can photosynthesise
How does the density of ice benefit anything?
Less than the density of liquid water…..
-Floats on top, prevents the loss of heat underneath
-Water doesn’t freeze all the way to the bottom
-Aquatic animals and plants can survive under the ice in a relatively stable environment
What type of reactions is water involved in as a metabolite?
Biochemical
Examples of biochemical reactions that water is involved in
Hydrolysis, condensation, reactant of photosynthesis
Hydrolysis
Water breaks one or more chemical bonds in a chemical reaction in a cell
What type of solvent is water?
Polar solvent
How are charges on water written and why?
d+ and d- as they’re so small
Which of waters properties links it to the fact that it’s a good transport medium?
As a solvent
Example of water acting as a transport medium in animals
Plasma transports dissolved substances
2 examples of water acting as a transport medium in plants
-Minerals in the xylem vessels
-Sucrose and amino acids in the Phoelem
What kind of molecules do not dissolve in water? Include an example of one
Non-polar molecules like lipids
Which one of waters properties makes it a good transport medium?
It’s a polar solvent
3 examples of water being a good transport medium due to it being a polar solvent
1- Plasma in animals for dissolved substances
2- Minerals in xylem vessels
3- Sucrose and amino acids in the phoelem
What does latent heat of vaporisation actually mean?
A lot of energy is required to change water from a liquid to a vapour
What to xylem vessels look like under a longitudinal section?
Repeated lines or rings across
What does the loss of water do in the xylem?
Places tension on the water column
What type of instrinsic protein is used during active transport?
Carrier
