Water(topic 1)

Question 1

Is water polar or non-polar?

Answer 1

Polar

Question 2

Describe hydrogen bonds in terms of water molecules

Answer 2

Hydrogen bonds are weak, but can hold water molecules together

Question 3

What causes hydrogen bonds to form?

Answer 3

The positively charged end of a water molecule is attracted to the negatively charged end of surrounding molecules, causing hydrogen bonds to form

Question 4

Define emulsifier

Answer 4

Joins polar and non-polar together

Question 5

Describe the structure of a water droplet

Answer 5

Outer water molecules are pulled inwards and the inner water molecules are pulled in all directions

Question 6

Define cohesion

Answer 6

Water attracted to water

Question 7

Define adhesion

Answer 7

Water attracted to surfaces

Question 8

What is the difference in Hydrophilic and Hydrophobic

Answer 8

Hydrophilic: ‘Water loving’= Polar
Hydrophobic: ‘Water hating’=Non-polar

Question 9

Why can water absorb lots of heat?

Answer 9

It needs loads of energy to break, so it can absorb loads of heat (heated water moves more).

Question 10

Describe water’s high specific heat capacity

Answer 10

A lot of energy is required to raise water temp. This is due to the fact that heat energy is also used to break the hydrogen bonds between water molecules. The water still remains relatively stable and it’s important so enzymes do not denature or reduce in activity.

Question 11

What does large latent heat of vaporization mean?

Answer 11

It means that lots of energy is required to covert water from liquid to gas. This is due to hydrogen bonds, and lots of energy being needed to break them.

Question 12

Why is the large latent heat of vaporization an advantage for organisms?

Answer 12

It means water provides a significant cooling effect. For example, when a human sweats, water is released onto the skin. Large amounts of heat energy from the skin which evaporates the water, therefore, removing heat and cooling the organism.

Question 13

What is the advantage of cohesion in water?

Answer 13

It provides surface tension to water, which allows small invertebrates to move and live on the surface, providing a habitat away from predators in the water.

Question 14

What is water potential?

Answer 14

Ability of water to move.
(Water always moves from high to low water potential.)

Question 15

What is an xylem and its surrounding tissues water potentials?

Answer 15

Xylem=100KPA
Surrounding tissues=1.8KPA
Water moves from 100 KPA to 80 KPA

Question 16

Structure of triglycerides

Answer 16

Molecule of glycerol attached to 3 fatty acids bonded together
Non polar
Insoluble in water

Question 17

3uses of lipids

Answer 17

Respired to release energy
Energy storage
Some hormones stored
Insulation

Question 18

Explain the properties of water which make it ideal for a transport median

Answer 18

Water is polar which makes it sticky therefore it can hold lots of specialised cells it is also cohesive meaning it sticks to each other but it adhesive so doesn’t stick to surfaces such as the inner walls of blood vessels it is also a liquid which means it has ability to flow

Question 19

What is a platelet

Answer 19

Cell fragment that releases thromboplastin

Question 20

What is thrombin

Answer 20

An enzyme that changes fibrinogen to fibrin

Question 21

What is fibrinogen

Answer 21

A soluble protein plasma

Question 22

Two lifestyle factors that could increase chance of suffering a stroke of heart attack

Answer 22

Smoking
Being overweight

Question 23

What is hydrolysis

Answer 23

A reaction which involves adding water and breaking the glycosidic bonds