Unit 1 Biological Molecules (Water)

Question 1

What is the relation between water and the cells?

Answer 1

Water is a major component of cells

Question 2

What are 3 uses for water that prove it to be useful?

Answer 2

As a reactant in cells (photosynthesis and hydrolysis)
Provides structural support in cells
Keeps organisms cool to maintain an optimum body temperature

Question 3

What are the 7 properties of water that make it very useful?

Answer 3

Liquid state
Reactant / Metabolite
Density
Solvent
Cohesion & Surface Tension
High Specific Heat Capacity
High Latent Heat of Vaporisation

Question 4

What elements are water molecules made up of?

Answer 4

On oxygen atom and 2 hydrogen atoms

Question 5

What type of molecule is water?

Answer 5

A polar molecule

Question 6

What charge do the oxygen atoms have in a water molecule?

Answer 6

Oxygen atoms in water are slightly negatively charge

Question 7

What charge do the hydrogen atoms have in a water molecule?

Answer 7

The hydrogen atoms have a slightly positive charge

Question 8

What does the polarity of water molecules mean?

Answer 8

It means that a hydrogen atom on one water molecule is attracted to the oxygen atom on another water water molecule this is hydrogen bonding

Question 9

What is the relation between warm-blooded animals and the high-heat capacity of water?

Answer 9

Water is used by warm-blooded animals to more evenly disperse heat in their bodies

Question 10

What is the specific latent heat of vaporisation?

Answer 10

The amount of energy needed to change 1 kg of a liquid substance to a gas

Question 11

In a water molecule how are 2 hydrogen atoms bonded together?

Answer 11

They are covalently bonded together

Question 12

How does oxygen pull electrons?

Answer 12

Oxygen has a greater affinity for electrons than the hydrogen atom so it pulls the electrons

Question 13

What Greek letter is used to represent the slight negative or positive charge in oxygen or hydrogen atoms?

Answer 13

Delta positive or Delta negative

Question 14

Due to the oxygen being slightly negative and the hydrogen being slightly positive what happens to water?

Answer 14

Water comes to have 2 defined charged regions making it a dipolar molecule

Question 15

The properties of water are caused by what?

Answer 15

The hydrogen bonds within water

Question 16

What happens to the structure of water if there are many hydrogen bonds?

Answer 16

The structure of water is more stable

Question 17

What is the impact of water being a liquid state to organisms?

Answer 17

Liquid state water provides a habitat for aquatic organisms.

Question 17

What are the 2 impacts of liquid state water to cells within an organism?

Answer 17

It acts as a medium to surround cells as they are major component of cells
It also acts as a transport medium such as consisting of 90% of blood plasma

Question 18

Name 3 reactions in which water is used as a reactant / Metabolite?

Answer 18

Photosynthesis
Condensation
Hydrolysis

Question 19

Compare the density between Ice and water?

Answer 19

Ice is less dense than water which means ice forms on the surface of water

Question 20

If ice forms on the surface of water what happens?

Answer 20

It is able to insulate the water underneath

Question 21

What is the relation between the aquatic organisms and the density of ice on the surface of water?

Answer 21

Since ice is less dense than water and it resides on the surface of water, it provides a habitat for aquatic organisms as a stable environment

Question 21

What solvent is water also known as?

Answer 21

The Universal solvent

Question 22

Why is water a good solvent?

Answer 22

Substances can easily dissolve in water.

Question 22

Why can polar molecules readily dissolve in water?

Answer 22

Polar or charged molecules can readily dissolve in water because water is dipolar molecule

Question 23

What are polar molecules that dissolve in water also known as?

Answer 23

They are hydrophilic which means that they are attracted to water

Question 23

What are non-polar molecules that don’t dissolve in water also known as?

Answer 23

They are hydrophobic which means they are repulsed by water

Question 23

What is cohesion?

Answer 23

Water molecules sticking together due to the hydrogen bonds

Question 23

What is adhesion?

Answer 23

Water molecules sticking to other things.

Question 24

How can cohesion of water help small invertebrates?

Answer 24

Cohesion water provides habitats on the surface of water as well a method of escaping predators

Question 25

How is there high specific heat capacity of water?

Answer 25

Water has lots of hydrogen bonds which means it requires a lot of heat energy to break the hydrogen bonds between water molecules

Question 26

How is high heat capacity of water helpful for aquatic organisms

Answer 26

High heat capacity means that water is relatively stable even if the temperature fluctuates.

Question 27

What is an internal process within organisms that is not affected by the high heat capacity of water?

Answer 27

The high heat capacity of water can’t affect the denaturation of enzymes when temperature fluctuates.

Question 28

What is the latent heat of vaporisation of water?

Answer 28

The amount of energy required to break the hydrogen bonds of water from liquid state to gas state

Question 29

Give a body example of high latent heat of vaporisation of water?

Answer 29

The latent heat of vaporisation of water is shown in the release of heat energy from the skin when it is transferred to sweat that evaporates.

Question 30

What is the meaning of affinity?

Answer 30

An attraction between charges.

Question 31

(E*) What bodily process would be hindered by a lack of water?

Answer 31

Digestion

Question 32

(E*) What is the most abundant molecule on the Earth within in the atmosphere?

Answer 32

Water

Question 33

(E*) Define Water’s property of cohesion?

Answer 33

It has intermolecular forces between the water molecules

Question 34

(E*) Why does ice float on water?

Answer 34

The lattice structure of ice created through hydrogen bonding makes ice less dense than the free flowing molecules of liquid water