A1.1 Water

Question 1

what did primordial earth look like?

Answer 1

molten mass, high temperatures, no water

Question 2

how were the first cells formed on earth?

Answer 2

temperatures decreased, water and water cycle formed, ocean water used as solvent for biochemical reactions, cells evolved membranes to separate cytoplasm

Question 3

define hydrophilic

Answer 3

water-loving, polar, soluble in water

Question 4

what are examples of hydrophilic solutions?

Answer 4

cytoplasm, blood, water in xylems

Question 5

define hydrophobic

Answer 5

water-hating, non-polar, insoluble in water

Question 6

what are examples of hydrophobic substances/molecules?

Answer 6

steroids, cuticles

Question 7

where is water found?

Answer 7

marine habitats, all organismal fluids, between cells

Question 8

what kinds of bonds are found within and between water molecules?

Answer 8

polar covalent bonds between oxygen and hydrogens within molecule, hydrogen bonds between molecules

Question 9

what are the charges of oxygen and hydrogen in a water molecule?

Answer 9

oxygen is δ-, hydrogen δ+

Question 10

what are hydrogen bonds?

Answer 10

weak attractions caused by polarity between hydrogen and electronegative atom; ephemeral in liquid water, locked in place in solid

Question 11

define cohesion

Answer 11

attraction between like molecules

Question 12

what is surface tension?

Answer 12

strong cohesive force between surface molecules of water; absence of water molecules pulling upwards results in stronger force pulling downwards and laterally

Question 13

define adhesion

Answer 13

attraction between unlike molecules

Question 14

define xylem

Answer 14

small tubes that water travels through in plants; extends from roots, through stem, and leaves

Question 15

define stomata

Answer 15

small openings on underside of leaf where water transpires

Question 16

define tension

Answer 16

low pressure in area around stomata formed after water transpires

Question 17

describe the process of transpiration

Answer 17

1. water rests in place in xylem due to adhesion
2. water transpires through stomata, creating tension
3. cohesion causes more water to be pulled up through xylem
4. more water enters xylem through roots

Question 18

draw three water molecules bonded together

Answer 18

solid lines for covalent bonds, dotted lines for hydrogen bonds, δ- and δ+ labels on O’s and H’s in hydrogen bonds, starts forming ring shape, H’s not in hydrogen bond outside

Question 19

define buoyancy

Answer 19

force acting on object in medium equal to weight of medium displaced by object

Question 20

define viscosity

Answer 20

substances’ resistance to objects moving through them

Question 21

define specific heat capacity

Answer 21

ability of substance to absorb/release heat without changing in temperature

Question 22

define thermal conductivity

Answer 22

ability of substance to transfer heat

Question 23

what are the physical properties of water?

Answer 23

high buoyancy, specific heat capacity, and thermal conductivity, and relatively low viscosity

Question 24

how did the black-throated loon adapt to water’s viscosity?

Answer 24

streamlined body and webbed feet

Question 25

how did the black-throated loon adapt to water’s thermal conductivity?

Answer 25

glands secrete oil that it spreads on body with beak to waterproof itself

Question 26

how did the ringed seal adapt to water’s viscosity?

Answer 26

streamlined body and paddle-like feet

Question 27

how did the ringed seal adapt to water’s thermal conductivity?

Answer 27

thick blubber under skin insulates

Question 28

what is the common theory of the origin of water on Earth?

Answer 28

asteroids brought hydrated materials

Question 29

what is the difference between typical water and heavy water?

Answer 29

hydrogen atoms in typical water molecules have no neutrons, in deuterium has one neutron

Question 30

what is the evidence of the common theory?

Answer 30

ratio of deuterium to water on asteroids was similar to ratio in oceans

Question 31

define Goldilocks zone

Answer 31

area that is not too far from or close to sun and has adequate gravity and temperature to retain water on surface as liquid, atmosphere, and magnetic field

Question 32

how many stars are in the milky way?

Answer 32

100,000 million

Question 33

how many galaxies are in the universe?

Answer 33

125 billion