Water

Question 1

What is one of water’s function?

Answer 1

Water as a medium for life.

Question 2

How were the first cells evolved? where?

Answer 2

-evolved in a watery environment.
-believed to have been in the deep oceans, close to hydrothermal vents in the Earth’s crust.
-some water and solutes got trapped within a membrane.
-chemical reactions began occurring within the membrane-bound structure.
:led to the evolution of cells.

Question 3

What does water in its liquid state allow?

Answer 3

Water in its liquid state allows dissolved molecules to move around, so they are easily able to collide and react with each other.

Question 4

where do most life processes occur?

Answer 4

most life processes occur in water.

Question 5

what are the key functions of hydrogen bonds?

Answer 5

-dissolving of solutes in water.
-cohesion and adhesion of water molecules as these allow water to move up the trunk of tall trees.
-base-pairing between the two strands of DNA.

Question 6

what is the structure of hydrogen bonds helpful for?

Answer 6

the structure of hydrogen bonds help to form part of the secondary and tertiary levels of structure in proteins.

Question 7

if the hydrogen bonds are found between strands of cellulose and collagen what do they do?

Answer 7

the hydrogen bonds give those molecules their tensile strength.

Question 8

what is a fundamental property of water?

Answer 8

hydrogen bonding is a fundamental property of water.

Question 9

what is the medium in which all metabolic reactions take place in cells?

Answer 9

water.

Question 10

what is water composed of?

Answer 10

water is composed of atoms of hydrogen and oxygen.
-one atom of oxygen combines with two atoms of hydrogen sharing electrons through covalent bonding.

Question 11

despite water being electrically neutral, what is uneven between the oxygen and hydrogen atoms? why?

Answer 11

the sharing of the electrons is uneven between the oxygen and hydrogen atoms.
-the oxygen atom attracts the electrons more strongly than the hydrogen atoms, resulting gin a weak negatively charged region on the oxygen tom and a weak positively charged region on the hydrogen atom. This also results in the molecules asymmetrical shape.

Question 12

what is a dipole?

Answer 12

a dipole is when there is a separation of charge due to the electrons in the covalent bonds being unevenly shared.

Question 13

what is a polar molecule?

Answer 13

a polar molecule is one that has one end that is negatively charged and one end that is positively charged.

Question 14

what is water? (molecule)

Answer 14

water is a polar molecule.

Question 15

why do hydrogen bonds form between water molecules?

Answer 15

hydrogen bonds form between water molecules as a result of the polarity of water.
-hydrogen bonds form between the positive and negatively charged regions of adjacent water molecules.

Question 16

what happens because of the weak state of hydrogen bonds when there are few?

Answer 16

hydrogen bonds are weak, so when there few, they are constantly breaking and reforming.

Question 17

what causes many of the properties of water molecules that make them so important to living organisms?

Answer 17

hydrogen bonds.

Question 18

what is cohesion?

Answer 18

cohesion is the ability of like molecules to stick together.

Question 19

what causes strong cohesion between water molecules?

Answer 19

hydrogen bonds within water molecules allow for strong cohesion between water molecules.

Question 20

what does cohesion allow?

Answer 20

cohesion allows columns of water to move under tension through the xylem of plants.
cohesion also enables surface tension where a body of water meets the air, as these hydrogen bond occur between the top layer of water molecules to create a sort of film on the body of water. (allows pond skaters to move across the surface of water)

Question 21

what is adhesion?

Answer 21

adhesion is the ability of dissimilar molecules to stick together.

Question 22

how can water bond via hydrogen atoms to other molecules which are polar or charged?

Answer 22

water is able to bond via hydrogen atoms to other molecules which are polar or charged (e.g. cellulose) through adhesion.

Question 23

what does adhesion allow in the xylem?

Answer 23

adhesion enables water to move up the xylem during transpiration.

Question 24

what is capillary action?

Answer 24

capillary action is when water is drawn up narrow channels in soil called capillary tubes.

Question 25

what structure allows water to be drawn from xylem vessels by capillary action and allow water to flow through plant tissue?

Answer 25

the spaces between cellulose fibres in plant cell walls can draw water from xylem vessels by capillary action and allow water to flow through plant tissue.

Question 26

what is hydrophilic?

Answer 26

water-loving

Question 27

what is hydrophobic?

Answer 27

water-hating

Question 28

what molecules tend to be hydrophilic?

Answer 28

polar molecules and molecules with positive or negative charges can form hydrogen bonds with water (and dissolve) so are generally hydrophilic.

Question 29

what molecules tend to be hydrophobic?

Answer 29

non-polar molecules with no positive or negative charge cannot form hydrogen bonds with water so are generally hydrophobic.

Question 30

why is water regarded as the universal solvent?

Answer 30

water is regarded as the universal solvent as most biological molecules are hydrophobic and can be dissolved;

Question 31

what do hydrophobic molecules tend to do?

Answer 31

hydrophobic molecules tend to join together in groups due to hydrophobic interactions where hydrogen bonds form between water particles but not with the non-polar molecule.

Question 32

what affects solutes’ solubility in water?

Answer 32

different solutes have different hydrophobic and hydrophilic properties which affect their solubility in water.

Question 33

what can highly soluble molecules be?

Answer 33

highly soluble molecules can be easily transported in solution within organisms.
-salts, glucose and amino acids.

Question 34

what has evolved to assist in the transportation of the less soluble molecules?

Answer 34

different transport mechanisms.

Question 35

what type of molecules cannot dissolve in water?

Answer 35

non-polar and hydrophobic molecules cannot dissolve in water.

Question 36

what does the function of certain molecules depend on?

Answer 36

the function of certain molecules in cells depend on them being hydrophobic and insoluble.

Question 37

how does a low solubility molecule such as oxygen require assistance?

Answer 37

oxygen requires assistance through combining with haemoglobin, to allow more oxygen to be carried than directly in blood plasma.

Question 38

how is oxygen sparingly soluble?

Answer 38

oxygen is sparingly soluble but soluble enough to allow it to dissolve in oceans, rivers and lakes for aquatic animals to breathe.

Question 39

how does haemoglobin bind to oxygen?

Answer 39

haemoglobin binds to oxygen to allow sufficient oxygen to be transported to all body cells.

Question 40

why do most enzymes require water? what does this enable them to do?

Answer 40

most enzymes require water in order to hold its shape and improve it stability. This enables them to catalyse reactions in aqueous solutions.

Question 41

what do hydrogen bonds often facilitate for enzymes?

Answer 41

hydrogen bonds often facilitate the binding of the enzyme active site and its substrate molecule forming the enzyme substrate complex.

Question 42

what is specific heat capacity?

Answer 42

specific heat capacity is a measure of the energy required to raise the temperature of 1kg of a substance by 1°C.

Question 43

what is the specific heat capacity of water?

Answer 43

water has a high specific heat capacity 4200J/kg/°C.

Question 44

what is the specific heat capacity of oxygen?

Answer 44

oxygen has a lower specific heat capacity of 1000J/kg/°C.

Question 45

what does the high specific heat capacity of water mean?

Answer 45

it means that a relatively large amount of energy is required to raise its temperature.

Question 46

what causes a high specific heat capacity?

Answer 46

the specific heat capacity is due to the many hydrogen bonds present in water. It takes a lot of thermal energy to break these bonds and a lot of energy to build them, thus the temperature of water does not fluctuate greatly.

Question 47

advantages of living organisms of specific heat capacity of water?

Answer 47

-provides suitable, stable aquatic habitats since water temps will change more slowly than air temps.
-is able to maintain a constant temperature as water is able to absorb a lot of heat without wide temperature fluctuations (vital for enzyme activity).

Question 48

how can the ringed seal survive throughout the year?

Answer 48

the ringed seal is able to survive throughout the year due to stable sea temperatures.

Question 49

why does ice float on water?

Answer 49

ice floats on water because the density of ice is lower than the density of liquid water.

Question 50

what forms a habitat for the seals?

Answer 50

the fact that ice floats on water forms a habitat for the seals both on the floating ice sheets as well as below the ice due to the stable sea temps.

Question 51

what is thermal conductivity?

Answer 51

thermal conductivity refers to the ability of a substance to conduct heat.

Question 52

what makes air a good insulator for organisms living in colder climates?

Answer 52

The thermal conductivity of water is almost 30 times higher than that of air, which makes air a very good insulator for organisms living in colder climates.

Question 53

what is the black-throated loon?

Answer 53

a species of diving bird which spends much time underwater catching its prey.

Question 54

how does the black-throated loon use thermal conductivity?

Answer 54

the black-throated loon has feathers that trap an insulating layer of air, which assists them with regulating their body temperature.

Question 55

what does the seal rely on to insulate it from outside air?

Answer 55

the seal relies on a layer of fat called blubber to insulate it from the outside air.

Question 56

how does ice form an insulating layer above the water?

Answer 56

ice will form an insulating layer above the water since the thermal conductivity of ice is much lower than liquid water. This increases the sea temp below the ice as thermal energy is trapped.

Question 57

what is buoyancy?

Answer 57

buoyancy refers to the ability of an object to float in water.

Question 58

how does the black-throated loon overcome the problem of buoyancy?

Answer 58

the black-throated loon has solid bones, unlike the hollow bones that most birds species have to assist them with flight. This increases the weight of the bird and compresses air out of the lungs and feather during a dive.

Question 59

how does the ringed seal’s layer of blubber under its skin improve buoyancy?

Answer 59

the ringed seal’s layer of blubber under its skin improve buoyancy of the animal, along with providing a layer of insulation against the cold temperatures of its habitat.

Question 60

what is viscosity?

Answer 60

viscosity refers to the resistance of a fluid to flow.

Question 61

what is the viscosity of water in comparison to air?

Answer 61

the viscosity of water is much higher than air.

Question 62

what allows for the black-throated loon to fly through the air without much friction?

Answer 62

the black-throated loon can fly throat the air without much friction because the viscosity of water is much higher than air.

Question 63

how does the body shape of the loon and seal help them?

Answer 63

the body shapes makes it easy for them to move through water.

Question 64

how is the seal adapted for movement through water?

Answer 64

the seal has flippers to propel itself.

Question 65

how is the loon adapted for movement through water?

Answer 65

the loon uses its webbed feet to push against the water and the lateral location of its feet reduces drag as it moves through water.