Bio Water Unit

Cohesion

Sticks to itself

Adhesion

Sticks to other things

Solvent ability

Water can dissolve other substances (nutrients, waste, and gas)

Thermal Stability

Water heats slowly and holds heat

Fluidity

Water flows easily

Properties of Water

Cohesion, Adhesion, Solvent Ability, Thermal Stability, Fluidity

Capillary Action

Water moving upwards through tiny spaces (due to adhesive properties)

Apoplastic Pathway

Water moves in gaps between cells (outside the cell walls)

Symplastic Pathway

Water moves between cells through gaps in cell walls called plasmodesmata

Physical properties of water

1. Buoyancy

2. Viscosity

3. Thermal Conductivity

4. Specific Heat Capacity

Buoyancy

Upward force that a liquid exerts on submerged objects

Biological consequence of buoyancy

Aquatic animals don't need strong limbs to support their body weight

Viscosity

How much a fluid resists movement or flow

Biological consequence of viscosity

Aquatic animals need to be streamlined to reduce drag

Thermal Conductivity

The ability to transfer heat to other things

Biological Consequence of Thermal Conductivity

Aquatic animals risk hypothermia in cold environments and need insulation to maintain body heat

Specific Heat Capacity

The amount of energy it takes to increase the temperature of a substance

Biological Consequence of Specific Heat Capacity

Aquatic environments have stable temperatures, allowing for specific evolution

Hydrogen bonds are ______ forces

intermolecular

Intramolecular forces

Covalent Bonds and Ionic Bonds

Hydrogen Bonds

“fake” bonds that form when very polar covalent molecules are attracted to each other

Requirements for hydrogen bonds

1. A very electronegative (big and greedy) molecule bonds to hydrogen

2. Asymmetrical molecule shape

Electronegativity

How much an atom attracts electrons

Elements that typically create hydrogen bonds

1. Fluorine (F)

2. Oxygen (O)

3. Nitrogen (N)

Surface Tension

The cohesive force at the surface of a liquid that resists external forces

Biological consequence of surface tension

Allows small organisms, such as water striders, to walk on the water surface

Polarity of Water

Unequal sharing of electrons creating partial negative charges on oxygen and partial positive charges on hydrogen

Importance of capillary action

Redistributes water throughout the soil, making it accessible to plant roots even when surface is dry

Water molecules adhere to _____ in the cell wall through hydrogen bonding

Cellulose

partial charge

Occurs when electrons are shared unequally in a chemical bond

partial negative in a water molecule

oxygen

partial positive in a water molecule

hydrogen

electron

negatively charged subatomic particle

covalent bond

the chemical link between atoms formed when they SHARE electrons

water is considered the ___ of life

Medium

Plasmodesmata

Channels that cross the cell walls of plants

Animal example for buoyancy

Pufferfish can float and rest in water without effort

Animal example for viscosity

Fish fins reduce turbulence and help maneuver through viscous water

Animal example for thermal conductivity

Ringed seal has a thick layer of blubber for insulation

Animal example for specific heat capacity

Ringed seal is able to live in consistent arctic waters year round

How does water support metabolic processes?

It’s solvency allows it to dissolve nutrients, minerals, and waste so they can move easily trough the bloodstream and into cells