Biological Molecules: Water

Question 1

What are the 5 properties of water?

Answer 1

• Cohesion
• Metabolite
• Solvent
• Latent heat capacity
• High specific heat capacity

Question 2

What are the 2 uses of water as a metabolite?

Answer 2

• Used in hydrolysis reactions
• Formed in condensation reactions

Question 3

What is the use of water as a solvent?

Answer 3

Dissolves and transports ions/polar molecules

Question 4

Give two examples of reactions where water is a metabolite:

Answer 4

Condensation
Hydrolysis

Question 5

What does it mean if water is a solvent?

Answer 5

Some substances dissolve in it.

Question 6

How does water help with temperature control?

Answer 6

Has a high latent heat of vapourisation
Has a high specific heat capacity

Question 7

Why are the sides of hydrogen atoms that are opposite to the shared oxygen atoms slightly positively charged?

Answer 7

The shared negative hydrogen electrons are pulled towards the oxygen atom.

Question 8

Why is the side of oxygen that is opposite to the shared hydrogen atoms slightly negatively charged?

Answer 8

It has unshared negative electrons.

Question 9

Water molecules have a slight ____ charge on one side of the atom, and a slight _____ charge on the other side.

Answer 9

Positive
Negative

Question 10

Why do hydrogen bonds form between water molecules?

Answer 10

The slightly negatively charged oxygen atom of water attract the slightly positively charged hydrogen atoms of other water molecules.

Question 11

Hydrogen bonds in water are _____.

Answer 11

Weak

Question 12

What gives water its cohesive propety?

Answer 12

Hydrogen bonding.

Question 13

What feature of water makes it a good solvent?

Answer 13

Its polarity

Question 14

What causes water to evaporate?

Answer 14

When hydrogen bonds holding water molecules together are broken.

Question 15

What does it mean if water has a high latent heat of vaporization?

Answer 15

A lot of heat is used to change it from a liquid to a gas.

Question 16

Why is water having a high latent heat of vapourisation an advantage for living organisms?

Answer 16

Means they can use water loss through evaporation to cool down without losing too much water.

Question 17

What gives water a high specific heat capacity?

Answer 17

Hydrogen bonds

Question 18

Define specific heat capacity:

Answer 18

The energy needed to raise the temperature of 1 gram of a substance by 1 degree C.

Question 19

What does it mean if water has a high specific heat capacity?

Answer 19

A lot of heat energy is needed to break up the hydrogen bonds between water molecules.

Question 20

Why is water having a high specific heat capacity an advantage for living organisms?

Answer 20

Means water does not experience a rapid temperature change, so habitats are sustainable.

Question 21

What is cohesion?

Answer 21

The attraction between water molecules of the same type.

Question 22

Why are water molecules cohesive?

Answer 22

As they are polar.

Question 23

What is a dipolar molecule?

Answer 23

A molecule with equal and opposite charges at each end.

Question 24

Define Cohesion:

Answer 24

When the positively charged hydrogen atom of one water molecule is attracted to the negatively charged oxygen atom of another water molecule, forming a hydrogen bond

Question 25

Define adhesion:

Answer 25

When water molecules are attracted to the impermeable walls of xylem tissue.