Foundations in Biology Module 3.2 Water

Question 1

Why is water considered as polar

Answer 1

It consists of negative regions and positive regions as electrons within the covalent bond aren’t shared equally

Question 2

Why can polar molecules interact with each other

Answer 2

Their positive and negative regions attract each other

Question 3

What are hydrogen bonds known as

Answer 3

weak interactions

Question 4

Why does water have a high boiling point

Answer 4

• hydrogen bonds
  A lot of energy needed to increase temp of water and cause it to become gaseous

Question 5

Water is ……………. than ice

Answer 5

more dense

Question 6

Define cohesion

Answer 6

moves as one mass because molecules are attracted to each other
e.g. plant drawing up water from roots

Question 7

Define adhesion

Answer 7

water molecules attracted to other materials
e.g. washing hands(hands wet)

Question 8

Water can act like a 1………. because it is 2……….. allowing solutes in organisms to ………..
Example of where this can happen

Answer 8

1. solvent
2. dissolve
   - the cytosol of prokaryotes and eukaryotes as they are mainly water

Question 9

Adhesion+Cohesion= …………..
Define answer
Meaning water is a good ……..

Answer 9

Capillary action - water can rise up narrow tube against force of gravity
Transport medium

Question 10

Water can act as a 1…………….. by helping 2…………….. temperature changes during 3…………………. in cells due to lots of energy required to overcome 4…………………..

Answer 10

1. coolant
2. buffer
3. chemical reactions
4. hydrogen bonding

Important because of enzyme activity

Question 11

How can water be a habitat for living things

Answer 11

• Stable as temp changes are not easy so constant environment provided
• Ice creates an insulating layer allowing survival for aquatic organisms
• Surface tension supporting small insects to inhabit on the surface of the water as water molecules are more strongly cohesive to each other than to the air