Zusammenfassung der Ressource
Water
- Hydrogen bonding in water
- H2O molecules polar and
linked by hydrogen bonds
- covalent bond 2H, O
- H partial positive;
O partial negative
- bent; poles are 2H and O
- positive and negative ions
attract and form ionic bonds
- water - partial charge; less
attraction, hydrogen bond
- intermolecular force
rather than bond
- slightly positive pole
weakly attracted to
slightly negative pole
- Properties of water
- Cohesive properties
- binding of two molecules
of the same type
- due to hydrogen
bonding
- useful for water
transport in plants
- xylem sucks up water
at low pressure
- Adhesive properties
- hydrogen bonds between water
and other polar molecules
- useful in leaves
- water adheres to cellulose in cell wall
- water absorbed from nearest xylem
in case of evaporation from leaf via
air network spaces to keep walls
moist for CO2 absorption
- Thermal properties
- High specific heat capacity
- H bonds restrict motion so high heat
required to break them
- relatively large amount of energy needed
- thermally stable habitat
- High latent heat of vaporisation
- lots of energy needed for
evaporation to break H bonds
- Good evaporative coolant
- High boiling point
- 100 degrees Celsius for same reason
- Solvent properties
- polarity prevents
molecules from clumping
- dissolves molecules
- cytoplasm - complex mixture
of dissolved substances
- Hydrophilic and
hydrophobic
- hyrophilic = water loving
- substances that dissolve in water like
glucose, sodium and chloride ions
- substances that water
adheres to such as cellulose
- hydrophobic = water "fearing"
- insoluble in water
- non polar and no charge
- all lipids such as fats and oils
- forces that cause non polar
substances to form groups =
hydrophobic interactions
- Comparing water and methane
- methane = waste product of
anaerobic respiration where oxygen
is lacking by certain prokar.
- methanogenic prokar. live in swamps,
wetlands, animal guts, waste dumps
- methane fuel & greenhouse gas
- both small molecules
linked by single
covalent bonds
- water polar, forms H bonds
methane non polar, cannot
form H bonds
- Cooling the body with sweat
- sweat carried via narrow
ducts to skin surface where
spread out and released
- heat on skin used
to evaporate sweat
and cool blood
- solutes in sweat left on skin
- controlled by
hypothalmus in brain
- Transport in blood plasma
- Sodium chloride
- amino acids
- Glucose
- Oxygen
- Fat molecules
- Cholestrol