water and inorganic ions Flashcards
Explain how hydrogen bonds occur between water molecules
● Water is polar molecule
● Slightly negatively charged oxygen atoms attract slightly positively
charged hydrogen atoms of other water molecules
hydrogen bonds form between different water molecules between the oxygen and hydrogen atoms
this results in 5 key water properties what are they
-Metabolite
-solvent
-relatively high specific heat capacity
-relatively large latent heat of vaporisation
Strong cohesion between water molecules
where can inorganic ions occur
- solution in the cytoplasm
- body fluids of organisms
- some in high or very low concentrations
true or false water is dipolar
true
each inorganic ion has a specific role depending on its properties
what are the 4 types of inorganic ions
hydrogen ions
phosphate ions
sodium ions
iron ions
what is the function of hydrogen ions
● Maintain pH levels in the body → high concentration = acidic / low pH
● Affects enzyme rate of reaction as can cause enzymes to denature
function of iron ions
● Component of haem group of haemoglobin
● Allowing oxygen to bind / associate for transport as oxyhaemoglobin
function of sodium ions
- Involved in co-transport of glucose / amino acids into cells
- Involved in action potentials in neurons
- Affects water potential of cells / osmosis
function of phosphate ions
Component of nucleotides, allowing phosphodiester bonds to form in DNA / RNA
Component of ATP, allowing energy release
Phosphorylates other compounds making them more reactive
Hydrophilic part of phospholipids, allowing a bilayer to form
Metabolite
Used in condensation / hydrolysis / photosynthesis / respiration
Solvent
- Allows metabolic reactions to occur (faster in solution)
- Allows transport of substances eg. nitrates in xylem, urea in blood
(Relatively) high
specific heat
capacity
● Buffers changes in temperature
● As can gain / lose a lot of heat / energy without changing temperature
1. Good habitat for aquatic organisms as temperature more stable than land
2. Helps organisms maintain a constant internal body temperature
(Relatively) large
latent heat of
vaporisa
● Allows effective cooling via evaporation of a small volume (eg. sweat)
● So helps organisms maintain a constant internal body temperature
Strong cohesion
between water
molecules
- Supports columns of water in tube-like transport cells of plants
eg. transpiration stream through xylem in plants - Produces surface tension where water meets air, supporting small
organisms (to walk on water)
