water

Question 1

what type of molecule is water?

Answer 1

polar

Question 2

how much does water make up in the cell?

Answer 2

80%

Question 3

what reactions involve water? why?

Answer 3

hydrolysis and condensation because its a metabolite

Question 4

why can substances dissolve in water?

Answer 4

because its a universal solvent

Question 5

why do water molecules stick together?

Answer 5

to aid water transport

Question 6

what does water help to control?

Answer 6

temperature

Question 7

describe the structure of a water molecule

Answer 7

an O atom and 2 H atoms with shared pairs of electrons

Question 8

describe the charges in a water molecule

Answer 8

the shared H electrons are pulled towards the O atom so the other side of each H atom is left with a. slight positive charge. The unshared O atoms give O a slight negative charge

Question 9

why is water a polar molecule?

Answer 9

because it has a partial negative charge on one side and a partial positive charge on the other

Question 10

why are the charges in a H20 atom useful?

Answer 10

they allow the molecules to stick together and stick to the sides of the thing the water is moving up eg a stem

Question 11

name 5 properties of water

Answer 11

important metabolite
good solvent
high latent heat of vaporisation
can buffer changes in temp
very cohesive

Question 12

explain how and why water is a good metabolite

Answer 12

-water is in hydrolysis and condensation reactions as one uses a water molecule and the other produces it.
-reactions to occur faster in solution

Question 13

explain how and why water is a good solvent

Answer 13

-the polarity of water attracts ions and water molecules will surround them as water is attracted to both positive and negative ions. this means the ions will dissolve.
-therefore organisms can take up and absorb theses useful substances and transport them easily

Question 14

explain how and why water has a high latent heat of vaporisation

Answer 14

water evaporates when the H bonds holding water molecules together are broken. lots of heat energy is used to do this. This is useful because organisms can use this to cool down without losing too much water and heat loss lowers their temp as vaporisation takes heat energy out with it.

Question 15

explain how and why water can buffer changes in temp

Answer 15

h bonds give water a high specific heat capacity. When water is heated, a lot of heat energy is needed to break bonds so there is less heat energy available to actually increase the temp so it is hard to heat up. This makes water a good habitat due to the stable conditions and an organism can maintain a constant internal body temp despite losing or gaining energy

Question 16

explain how and why water is very cohesive

Answer 16

the polarity of H and O molecules means they attract other water molecules so water can be pulled through plants in a column

Question 17

what does it mean when water can buffer temp changes

Answer 17

it can resist them

Question 18

what is cohesion?

Answer 18

the attraction between the same type of molecule. When the positively charged hydrogen atom of one water molecule is attracted to the negatively charged oxygen atom of another water molecule, forming a/an covalent bond.

Question 19

what is a dipolar molecule?

Answer 19

A molecule with equal and opposite charges at each end