Water

Question 1

Water is involved in many metabolic reactions, what is this called

Answer 1

Water is a metabolite

Question 2

Name two reactions water is involved in

Answer 2

Condensation
Hydrolysis

Question 3

Describe condensation reactions

Answer 3

Smaller molecules join to form larger molecules

Question 4

Name the features of condensation reactions

Answer 4

• water is produced
• creates bonds

Question 5

Describe hydrolysis reactions

Answer 5

Large molecules are broken down into smaller molecules

Question 6

Features of hydrolysis reactions

Answer 6

• water is used
• breaks bonds

Question 7

Example of hydrolysis reaction

Answer 7

Digestion

Question 8

Why is water used as a transport medium

Answer 8

Because it’s a solvent and a metabolite

Question 9

What does water dissolve and why

Answer 9

Hydrophilic material because the molecules are compatible

Question 10

Thermal properties of water

Answer 10

• high specific heat capacity
• large latent heat of vaporisation
• thermostable

Question 11

What does it mean that water had a high HC

Answer 11

Large amounts of energy is required to change its temperature by 1°C

Question 12

What does water do to changes in temperature

Answer 12

Buffer them

Question 13

What shape is water

Answer 13

V-shaped

Question 14

How would you describe water

Answer 14

As a polar molecule

Question 15

Why is water polar

Answer 15

Delta + charge and a delta - charge distributed unevenly

Question 16

Why does water have a large SHC

Answer 16

Water molecules stick together with extensive hydrogen bonds, lots of energy needed to break these bonds

Question 17

How does water act as a buffer

Answer 17

Minimises temperature fluctuations in living things due to its high SHC

Question 18

What does it mean that water has a large latent heat of vaporisation

Answer 18

Large amounts of energy needed to change the state of water from liquid to gas

Question 19

How does thermostability change in water

Answer 19

The greater the volume of water the greater the stability

Question 20

How does water provide a cooling effect

Answer 20

Water particles are hydrogen bonded with extensive hydrogen bonds so it requires lots of energy to break these bonds and change state- evaporate (greater amount of energy lost, the greater the cooling effect)

Question 21

Define hydrophilic

Answer 21

Substances attracted to water (polar/ionic substances)

Question 22

What substances dissolve in water

Answer 22

Hydrophilic substances

Question 23

Define hydrophobic

Answer 23

Substances that repel water (non polar)

Question 24

Give an example of a hydrophobic substance

Answer 24

Lipids

Question 25

Why is water needed to break down large molecules in digestion

Answer 25

Large particles are too big to move by transport and insoluble

Question 26

Define digestion

Answer 26

Breakdown by hydrolysis of large, insoluble molecules into small soluble molecules

Question 27

What does it mean that water molecules are cohesive

Answer 27

They ‘stick’ together via hydrogen bonding

Question 28

Where are hydrogen bonds found

Answer 28

Between water molecules

Question 29

In what tube does cohesion allow the transport of water

Answer 29

Xylem

Question 30

What is tension created by

Answer 30

Cohesive water particles and hydrogen bonding

Question 31

How do pond skaters float

Answer 31

They have legs made out of hydrophobic material, repelling water allowing them to stay afloat due to surface tension

Question 32

describe the features of ice

Answer 32

- molecules have four hydrogen bonds - less dense than water - thermally insulates - provides a habitat on surface

Question 33

how is surface tension created in water

Answer 33

water is cohesive and hydrogen bonds to other water molecules

Question 34

what organism does surface tension provide habitats for

Answer 34

pond skaters

Question 35

how is water a solvent

Answer 35

water is polar so dissolves charged molecules and any other polar molecules

Question 36

how is water useful for photosynthesis in plants

Answer 36

- used in photosynthesis to create sugars - transparent to allow aquatic plants to photosynthesise