Water

Question 1

What % of a cell content is water ?

Answer 1

80%

Question 2

Why is water important?

Answer 2

Metabolite.
Solvent.
Helps with temp control.
High latent heat of vaporisation.
High specific heat capacity.
Very cohesive.

Question 3

Why is water a metabolite?

Answer 3

It’s important metabolic reactions.

Condensation/ hydrolysis.

Question 4

Why is water a solvent?

Answer 4

Substances dissolve in it and most metabolic reactors occur in solution.

Question 5

How does water help with water temperature?

Answer 5

High latent heat of vaporisation.

High specific heat capacity.

Question 6

Water molecules are very cohesive, why is this good?

Answer 6

Helps water transport in plants.

Question 7

What is the structure of water?

Answer 7

One atom of oxygen.
Joined to 2 atoms of hydrogen.
By shared electrons.

Question 8

Where is the shared negative hydrogen electron pulled towards?

Answer 8

Oxygen atom.

Meaning other side of each hydrogen atom is left with slight positive charge.

Question 9

What charge do the unshared electrons have on oxygen molecule ?

Answer 9

Slight negative charge

Question 10

So why is water a polar molecule ?

Answer 10

Partial negative charge on one side and partial positive charge on the other.

Question 11

Are the hydrogen bonds strong or weak ?

Answer 11

Weak

Question 12

Where are the hydrogen bonds found?

Answer 12

Between slightly positively charged hydrogen atom in one molecule and slightly negatively charged atom in another molecule.

Question 13

Give example of metabolic reactions?

Answer 13

Condensation and hydrolysis reaction .

Question 14

Why does a hydrolysis reaction need water ?

Answer 14

To break a bond.

Question 15

Why does a condensation reaction need water?

Answer 15

It releases one as a new bond is formed.

Question 16

Give example of condensation reaction.

Answer 16

Amino acids join together to make polypeptides

Question 17

Give example of hydrolysis reaction.

Answer 17

Energy from ATP released is through hydrolysis reaction.

Question 18

What does it mean if a substance is ionic?

Answer 18

Made from one positively charged atom and one negatively charged atom.

Question 19

Give an example of an ionic molecule ?

Answer 19

Salt
Positive sodium ion
Negative chloride ion

Question 20

How will the ions get surrounded by water ?

Answer 20

As the slightly positive charged end of water molecule will be attracted to negative ion.
Negative ion will be attracted to positive ion.
Dissolve

Question 21

So how is a water polarity good for humans?

Answer 21

They can take up substances like mineral ions dissolved in water and they can be transported around the organisms Body.

Question 22

What is a metabolic reaction?

Answer 22

Chemical reaction happening inside a living organism.

Metabolite is substance involved in the reaction.

Question 23

When will water evaporate?

Answer 23

When the hydrogen bonds holding water molecules together are broken.
Allows water molecules on surface to escape into air as gas.

Question 24

Why is it difficult for water to evaporate?

Answer 24

As it takes a lot of energy to break hydrogen bonds between water molecules.
High latent heat of vaporisation .

Question 25

What does it mean when it says a high latent heat of vaporisation ?

Answer 25

Lots of heat used to change for liquid to a gas.

Question 26

Why is vaporisation useful for organisms?

Answer 26

Water loss through evaporation to cool down without losing too much water.
When water evaporates it carries away heat energy from surface which cools surface down and helps lower temp.

Question 27

What part of the water molecule gives water a high specific heat capacity?

Answer 27

Hydrogen bonds m.

Question 28

Define specific heat capacity l?

Answer 28

Energy needed to raise temp of 1 gram of substance by 1 degrees.

Question 29

So what happens when the water is heated?

Answer 29

A lot of the heat energy used to break hydrogen bonds between water molecules.
Less water available to heat the water up.

Question 30

How does water have a high specific heat capacity?

Answer 30

Takes a lot of energy to heat up

Question 31

What does cohesion mean ?

Answer 31

Attractive between water molecules of the same type.

Question 32

Why are water molecules cohesive?

Answer 32

Due to polarity.

Question 33

Why is strong cohesion in water good ?

Answer 33

Helps water flow so good for transportation.
Also has high surface tension when it come in-contact with air.
This is why sweat forms droplets and evaporates to cool skin down.

Question 34

Example of cohesion system .

Answer 34

Water travels in column up xylem.