Water Molecules

Question 1

Water is a polar molecule, what does this mean?

Answer 1

There is an uneven distribution of electrons across the molecule

Question 2

Name the bond that forms between an oxygen and a hydrogen molecule

Answer 2

A hydrogen bond

Question 3

The oxygen ________ the pair of electrons in the O-H bond more ___________ than the hydrogen atom

Answer 3

Attracts

Strongly

Question 4

Name the type of charge on a:
Oxygen atom
Hydrogen atom

Answer 4

Oxygen- delta negative charge

Hydrogen- delta positive charge

Question 5

Name as many properties of water:

Answer 5

Polar 
Hydrogen bonds
Liquid 
Lattice structure 
Solvent 
Cohesive 
Density when frozen
Thermal stability 
Reactant

Question 6

Explain the biological importance of water: LIQUID

Answer 6

Used as a liquid transport medium ( moving materials around the living organisms)

Blood in animals uses water as a liquid transport medium

Xylem and phloem tissues use water as a transport medium

Question 7

Explain the biological importance of water: SOLVENT

Answer 7

Allows ionic compounds to separate

Medium for metabolic reactions

70-95% of cytoplasm is water

Organisms can take in dissolved mineral ions

Question 8

Explain the biological importance of water: COHESION

Answer 8

(Water molecules stick to one another due to hydrogen bonds)

Allows water molecules to be pulled up the xylem vessels in transpiration stream

Created surface tension and allows small invertebrates to walk on water (habitat)

Question 9

Explain the biological importance of water: DENSITY WHEN FREEZES

Answer 9

Creates a habitat for some animals such as polar bears

The ice insulated the water below the surface means aquatic organisms do not freeze and can swim also nutrients can continue to circulate

Question 10

Explain the biological importance of water: HIGH SPECIFIC HEAT CAPACITY

Answer 10

The temperature of lakes remains stable even when outside temps change significantly as there are lots of stable hydrogen bonds

Provides a thermally stable environment for aquatic organisms —> optimum temperature= enzymes function well

Question 11

Explain the biological importance of water: HIGH LATENT HEAT OF VAPORISATION

Answer 11

Organisms use evaporation as a cooling mechanism ( sweating)

Question 12

Explain the biological importance of water: METABOLIC

Answer 12

Water takes part as reactant in chemical processes inside cells

Used in photosynthesis and hydrolysis reactions