properties of water

Question 1

carbon (C)

Answer 1

forms basic structure of most biomolecules

Question 2

hydrogen (H)

Answer 2

water - also involved in acid/base reactions

Question 3

oxygen (O)

Answer 3

water - also breathing

Question 4

nitrogen (N)

Answer 4

DNA, proteins

Question 5

what elements make up 96% of all living matter?

Answer 5

C, H, O, N

Question 6

sulfur (S)

Answer 6

amino acids

Question 7

phosphorus (P)

Answer 7

call membranes

Question 8

calcium (Ca)

Answer 8

nerves and muscles

Question 9

potassium (K)

Answer 9

nerves and muscles

Question 10

what elements make up 4% of all living matter?

Answer 10

S, P, Ca, K

Question 11

electron transfer/ionic bonding

Answer 11

• attraction between oppositely charged atoms or ions is an ionic bond.
• ionic bonds can form between any two oppositely charged ions, even if they have not been formed by transfer of an electron from one to the other

Question 12

importance of water

Answer 12

• approx. 70% of our planet
• most life first developed in water
• first terrestrial organisms took their watery environment with them
• significant amount of water in our bodies

EVERYTHING IS WATER BASED

Question 13

ionic bonds

Answer 13

no sharing - electron is removed

Question 14

covalent bonds

Answer 14

molecules share their electrons

two types: polar and non-polar

Question 15

non-polar covalent

Answer 15

two molecules of same element

Question 16

polar covalent

Answer 16

electrons not shared evenly

Question 17

water molecules have polar bonds

Answer 17

• o2 is more electronegative (hogs electrons)

- h2o is asymmetrical

Question 18

what are the bonds between water molecules?

Answer 18

hydrogen bonds

Question 19

are hydrogen weak or strong bonds?

Answer 19

weak bonds - this is why h20 is fluid: bonds are broken and remade all the time
essentially: strong enough to hold together, weak enough that you don’t need a special reaction to break it

Question 20

what are the properties of water?

Answer 20

1. water’s cohesion
2. water moderates temperature
3. ice is less dense than water
4. water is the “solvent of life” - pH

Question 21

water’s cohesion

Answer 21

• many organisms depend on cohesion of H2O (ex: lake bugs that walk on water due to surface tension)
• bonds are broken and remade quickly. at any given time, most H2O molecules are bound
• this creates surface tension

Question 22

water transport in plants

Answer 22

• think of why straws work or how plants drink. it is because wen you must pull water up, you are pulling up one molecule. because of the hydrogen bonds between molecules, all the other molecules get pulled up as well, which allows us to drink.

Question 23

water moderates temperature

Answer 23

temperature is due to speed of molecules. faster the speed, higher the heat.
two sub things:
- specific heat
- evaporative cooling

Question 24

definition of specific heat capacity

Answer 24

amount of heat needed to be absorbed or lost for 1g of substance to change its temp by 1 degree C

Question 25

specific heat (water and temperature)

Answer 25

- H2O has high specific heat - when water is heated, some of the heat is used to break H bonds, meaning the temperature doesn't rise very fast - when water is cooled, H bonds are formed which gives off heat, making it warmer for longer - basically, it resists well to temperature changes which allows us to regulate temperature (in our bodies, oceans, etc.)

Question 26

why is temperature stable along the coastline?

Answer 26

because oceans absorb lots of heat during the day and gives off heat at night, which stabilizes the temperature of the ocean. this is why you don't get crazy weather swings in cities like vancouver.

Question 27

evaporative cooling (water & temperature)

Answer 27

- as water is heated, molecules become excited - most excited ones are at the surface and have absorbed the most energy. they escape into the air (evaporate) taking their heat energy with them, leaving the cooler molecules behind. - this is how we regulate our body temperature: sweating

Question 28

ice is less dense than water

Answer 28

- when water freezes, all H bonds are completed forming ice crystals and heat is released - ice is less dense than water, meaning it floats - the ice also acts as insulator for water below: this allows for the survival of aquatic organisms

Question 29

"solvent of life" - water and pH

Answer 29

- everything in our body is regulated to work at pH 7 (pH of pure water) - homeostasis is used to regulate acid-base balance - acid rain is an example of how changes in pH can cause disaster in environment ( coral reefs, leafy trees, inhibits aquatic communication) - changes in pH are bad in biology

Question 30

solute

Answer 30

substance to be dissolved

Question 31

solvent

Answer 31

substance used to dissolve solute

Question 32

aqueous solution

Answer 32

solution where water is the solvent

Question 33

solution with more OH

Answer 33

basic

Question 34

solution with more H

Answer 34

acidic

Question 35

solution where OH = H

Answer 35

neutral

Question 36

biomolecules basics (organic chem)

Answer 36

- all organic molecules contain C - C can form 4 covalent bonds - C commonly forms chains by bonding with itself - C chains attach together in different configurations - forms the backbone of most organic molecules

Question 37

macromolecules/polymers

Answer 37

- made of different units - long strings of similar/identical molecules covalently bonded together - monomer is one unit - chemical methods used to make/break polymers are always the same

Question 38

explain polymers and eating food

Answer 38

basically, when we eat/digest food, we are breaking apart polymers into their monomers. the monomers are then stored (think buckets) and are used for different functions by the body.

Question 39

how to you build a polymer?

Answer 39

dehydration reaction - remove/loose an H2O molecule

Question 40

how do you break down a polymer?

Answer 40

hydrolisis - adding a water molecule back in to break a bond

Question 41

you always need water to break a bond. what else do some polymers require?

Answer 41

there are usually special enzymes that are required as well to break certain bonds

Question 42

what are the 4 main classes of biomolecules?

Answer 42

- carbohydrates - lipids - proteins - nucleic acids