water

Question 1

5 properties of water

Answer 1

important metabolite
universal solvent
high latent heat of vapourisation
cohesive
high specific heat capacity

Question 2

what do polar molecules have?

Answer 2

unequal sharing of electrons among atoms

Question 3

what kind of molecule is water?

Answer 3

polar
because it has a slight negative charge on one side and a slightly positive on the other

Question 4

why is it important that water is polar?

Answer 4

it can be a universal solvent
e.g. it dissolves charged molecules like glucose, amino acids and ions
it increases the rate of metabolic reactions in solution as a result

Question 5

what is cohesion?

Answer 5

hydrogen bonds form between water molecules, effectively making water ‘sticky’

Question 6

why is cohesion an important property of water?

Answer 6

because the water molecules stick together, it helps the water to flow, hence use in transport
e.g. supports columns of water in xylem

Question 7

2 chemical reactions that require water

Answer 7

hydrolysis
condensation

Question 8

importance of water in hydrolysisi

Answer 8

it is required in hyrolysis
e.g. in mammalian digesiton, larger molecules are broken into smaller ones by breaking bonds, by adding a molecule of water

Question 9

importance of water in condensation

Answer 9

water is removed to form a chemical bond to build molecules e.g. polysaccharides & proteins

Question 10

how much of a cells content is water?

Answer 10

80%

Question 11

functions of water

Answer 11

reproduction
movement
support
transport
chemical reacitons
temperature control

Question 12

why is water an important metabolite?

Answer 12

because many metabolic reacitons involve condensation and hydrolysis reactions which involve water molecules

Question 13

explain the importance of water having a large latent heat of vaporisation

Answer 13

water takes a lot of heat energy before it evaporates
allows a cooling effect, with little lots of water

Question 14

describe the importance of water having high specific heat capacity

Answer 14

takes alot of energy to break hydrogen bonds between molecules
means it absorbs alot of heat before its temperature increases- it buffers changes in temperture which protects an organisms from fast temperature changes

Question 15

melting point of water

Answer 15

0

Question 16

boiling point of water

Answer 16

100

Question 17

importance of the melting and boiling points of water

Answer 17

it is liquid over a wide range of temperatures

Question 18

why is it important that water is liquid over a wide range of temperatures?

Answer 18

gives a range of habitats suitable for different species
when it solidifies, it forms ice which is less dense and protects aquatic habitats in the winter, increasing biodiversity

Question 19

3 ways water is important in transport

Answer 19

dissolves ions so they can be transported in solution e.g. k+, Na+
medium for the transport of glucose,amino acids and ions
it forms the transport medium in blood vessels in mammals, and in xylem;/phloem in plants

Question 20

importance of evaporaiton

Answer 20

when water evaporates it absorbs heat energy and cools the organism
cooling by evaporation is part of sweating and allows temperature control in endotherms

Question 21

other key points about water

Answer 21

-important in osmosis
-dissolves enzymes
-dissolves waste and assists excretion
-acts as a lubricant between organs
-aids reproductive processes e.g sperm swimming