Biological importance of water Flashcards
What percentage of water does an organism have ?
60-95%
What is the structure of water?
2 hydrogen atoms
1 oxygen atom
What bond do the atoms have?
Covalent
What does oxygen have that pulls electrons ro it?
- Negative charge
- attraction to electrons more than hydrogen
What are the changes of oxygen t hydrogen?
Oxygen: delta negative
Hydrogen: delta positive
Because they’re both differently changed what does that make water?
Polar
Because it has 2 differently charged regions what does it make
Dipolar
What bonds does the structure have?
Hydrogen,
What’s the strength of the bonds?
Weak
What does the weak bonds make easier?
Other molecules bonding to another oxygen
Summarise some properties of water
- Small
- polar
- hydrogen bonds
What is the function in plants?
Sticks to xylem walls (adhension)
Define adhesion.
Water substances sticking he other substances
Define cohesion:
Water molecules stick to one another
When does adhesion happen?
Water ordeals stick together like a string
When does cohesion happen?
When evaporation happens at the leaf which pulls water upwards
Benefits of water being polar
- Powerful solvent
- water can dissolve: polar molecules and ionic compounds
- used as solvent in processes
What do the hydrogen bonds prevent?
Small molecules from vaporising into gas
what do the ions allow?
Chemical reactions to happen within it
What is high heat capacity?
Retains alot of heat
What i high heat of evaporation?
Needs alot of energy to evaporate
What does solvent mean?
Can dissolve substances
Define dissolve
Be surrounded by water molecules
Why can it be a solvent?
Because it’s both delta positive and negative
What can it resist?
Temperature changes
When is it important?
Fish that live n water
What causes the high heart capacity?
Hydrogen bonds
Where is the high surface tension and cohesion used?
Xylem
What does reagent mean?
Can be used in chemical reactions
When is it less dense?
4°c
Which is less dense water or ice?
Ice
What does warn water do?
Sink
What does cold water do?
Rise
What does the rising and sinking create?
Convention current
? What does the current help with
Distribution of nutrients in bodies of Walter
Where is it used as lubricant?
Around organs
Mucus in digestive tract
What happens when it freezes??
Expands and becomes less dense
Summerise use in organisms
- Solvent
- transport medium
- liquid at normal temperature
- Ice floats
- high heat c capacity
- reagent
- transparent:plants underwater canphotosynthesis
