Water - Unit 1 Biology SL

Water is the ____ of life

Solvent

Relevance of water/applications

Fluid in cytoplasm and organelles

Interstitial tissue fluid (between cells)

Transport of materials

Solvent of blood to carry nutrients and waste

Habitat (lakes, rivers, oceans)

Photosynthesis, transport and turgidity in plants

Polar Covalent - Why is water a polar covalent?

Unequal sharing of electrons between elements. Water is a polar covalent because oxygen has a higher electronegativity (tendency to pull on electrons), than the hydrogens, giving them charge of -ve, while hydrogen gets +ve

Water has ___ poles, and can form up to ____ bonds

Two poles, up to 4 bonds.

Cohesion

The tendency of water molecules to form hydrogen bonds through intermolecular forces. Very ephemeral (quick). It creates surface tension and allows water columns to be pulled upward under tension.

Adhesion

The attraction of water molecules to other polar or charged materials (e.g., glass, cellulose in cell walls). It contributes to capillary action.

Describe how water flows in the xylem

H-Bonds through cohesion create a continuous chain of water up, and these molecules also stick to the polar cellulose walls of the xylem vessels via adhesion.

How is dissolving ability dependent on polarity?

Polar substances are hydrophilic, and make use of interactions between opposite charges - (Ions, Polar Bonds, O-H)
Non polar substances are hydrophobic (a lot of -anes are hydrophobic), and result from cohesion from surrounding molecules (water molecules get really close together and squeeze non polar out). (C-H, Non polar bonds)

Solvation

The process where solvent (water) molecules surround and interact with solute particles and bring them into the solution.

Water is a medium of transport which carries nutrients like,

BLOOD: ions, proteins, glucose, hormones, gases

(O2/CO2)

PLANTS: minerals, amino acids, hormones

Water is a medium for metabolism which allows it to..

Provides the fluid medium and structural support that allows enzymes and reactants to bind.

Name some nutrients found in blood.

Glucose

Amino acids

Enzymes

Sodium

Potassium

Chlorine

Bicarbonate
(PFVSM - Plasma, Proteins, Fats (lipids), Vitamins, Sugars, Minerals like Sodium)

Buoyancy

Depends on density, upward force exerted by fluid to support object in water

Viscocity

Water’s resistance to an object moving through it

Thermal Conductivity

Water can hold and RETAIN heat - high thermal conductivity.

Specific Heat Capacity

Very high, needs a lot of heat before changing temperature. Explains why rivers feel cool in the summer and hot in the winter. Perspiration cools your body primarily through water's high heat of vaporization

Black-Throated Loon

Less Dense Bones → Buoyant
Not Hollow Structure → can dive underwater if needed
Loon’s legs are located far back to help them move (viscocity)
Barrier to water, water retains heat to prevent loon from losing it
H-Bonds Keep Temp stable in water

Ringed Seal

Dense Bones → Not buoyant

Overcome viscosity via streamlined body + paddle like feet
Blubber layer is insulator to prevent heat loss
H-Bonds keep temp stable