Chemistry of Life

Question 1

pH of life

Answer 1

7.2 - 7.4

blood has to be slightly basic to accomodate for carbonic acid

Question 2

What elements is life mostly composed of?

Answer 2

Carbon, oxygen, hydrogen, and nitrogen

Question 3

4 macromolecules and function

Answer 3

Lipids: membranes, hormones, communication

Nucleic acids: store genetic information (can act as catalysts)

Proteins: structure, function, catalyst

Carbohydrates: store energy, indentification

Question 4

Valence shell

Answer 4

Outermost shell of electrons

Question 5

What is the bonding point?

Answer 5

Unpaired valence electrons

Question 6

4 main types of bonds

Answer 6

1. Covalent
2. Polar covalent
3. Hydrogen
4. Ionic

Question 7

Covalent bonds

Answer 7

Shared electrons

Question 8

A single covalent bond has…

Answer 8

2 electrons

Question 9

Nonpolar covalent bonds

Answer 9

electrons are shared equally

electrons are halfway between the two atoms

atoms have no charge

Question 10

Polar covalent bonds

Answer 10

Electrons are not shared equally due to electronegatively

Question 11

Why is water a polar molecule?

Answer 11

Oxygen has high electronegativity that attracts electrons. This gives it a partial negative charge and hydrogen gets a partial positive charge

Question 12

What is CH4?

Answer 12

Methane

nonpolar covalent

Question 13

What is NH3?

Answer 13

Ammonia

Question 14

Electronegativity

Answer 14

chemical property that describes the tendency of an atom to attract electrons

Question 15

What factors affect electronegativity?

Answer 15

Atomic number (# of protons)

Greater positive charge will attract more electrons

Question 16

Label the 3 atoms of life in terms of increasing electronegativity

Answer 16

H, C, O

Question 17

Strength of bonds

Answer 17

Nonpolar covalent are hardest to break (methane, hydrogen)

Polar covalent (water, ammonia)

Ionic bonds (NaCl) are easiest to break

Question 18

Ionic bonds

Answer 18

have full charge

Question 19

-OH functional group

Answer 19

hydroxyl, probably some type of alcohol

Question 20

What does a functional group with oxygen probably indicate?

Answer 20

The molecule is probably polar

This means that it is hydrophilic

Question 21

Hydrophilic substances

Answer 21

can interact with water through their charges

if it has a partial or full charge

Question 22

Hydrophobic substances

Answer 22

cannot interact with water through these partial charges

Ex: hydrocarbons have no charge

Question 23

What drives protein folding?

Answer 23

Interactions between hydrophilic and hydrophobic molecules

Question 24

Where are there hydrogen bonds in the hydrogen atom?

Answer 24

Between two different water molecules

polar covalent is actually in the molecule

Question 25

Hydrogen bond

Answer 25

an attractive interaction between polar molecules Hydrogen bonds to atoms with a high electronegativity

Question 26

What does hydrogen bonding lead to?

Answer 26

Cohesion High specific heat

Question 27

Cohesion

Answer 27

water can stick to itself surface tension

Question 28

Why is water's high specific heat important?

Answer 28

It makes a good buffer in temperature which is important for life

Question 29

Adhesion

Answer 29

water can stick to other things capillary action

Question 30

Why does water expand when it freezes?

Answer 30

the orientation of hydrogen bonds water molecules are spaced further apart in ice lattice structure (less dense)

Question 31

Why is water a great solvent?

Answer 31

The partial negative and partial positive charges can break apart substances Ex: Na+Cl- Na is attracted to negative oxygen Cl is attracted to positive hydrogen

Question 32

How does water act as a pH buffer?

Answer 32

It can dissociate itself into H+ and OH-

Question 33

H+

Answer 33

hydronium

Question 34

OH-

Answer 34

hydroxide

Question 35

What is the basis of the pH scale?

Answer 35

Proton (hydrogen ion) concentration more hydrogen ions = lower pH

Question 36

Acids

Answer 36

molecules that donate H+ makes sense that more hydrogen ions = lower pH, because acids are the ones that donate H+ Ex: HCl

Question 37

Bases

Answer 37

molecules that remove H+ raise pH Ex: NaOH

Question 38

Is water an acid or a base?

Answer 38

It can act as both because it can pick up and remove hydrogen ions

Question 39

Veins

Answer 39

carry oxygen depleted blood to the heart

Question 40

Arteries

Answer 40

carry oxygen rich blood away from the heart

Question 41

Where is CO2 high in the body?

Answer 41

Veins and tissues This reduces the affinity of hemoglobin for oxygen. Hemoglobin will release more oxygen to tissues

Question 42

How is CO2 transported in the body?

Answer 42

Dissolved in blood as carbonic acid that water has to buffer

Question 43

What happens when affinity of hemoglobin is lowered?

Answer 43

Hemoglobin is more likely to release oxygen, since it cannot carry as much

Question 44

Where is CO2 low in the body?

Answer 44

Arteries and lungs Hemoglobin has a high affinity for oxygen. It does not need to release oxygen in these places. It needs to carry it.

Question 45

What happens when CO2 levels in the blood increase?

Answer 45

more H+ is produced from forming carbonic acid lowers pH hemoglobin has a lower affinity for oxygen when pH lowers because it indicates high CO2

Question 46

When does hemoglobin's affinity for oxygen increase?

Answer 46

When pH is high This indicates less H+ ions and correspondingly less CO2

Question 47

Carbonic acid

Answer 47

an unstable intermediate molecule that will quickly dissociate into HCO-3 and H+

Question 48

If an atom has 4 electrons in its valence shell what kinds of covalent bonds can it form?

Answer 48

single, double, or triple

Question 49

When atoms in a covalent bond have the same electronegativity what type of bond form?

Answer 49

Nonpolar covalent Molecule is not charged

Question 50

How many other water molecules is one water molecule bonded to?

Answer 50

4

Question 51

Hydronium ion

Answer 51

a water molecule with an extra H+ forms from water gaining a H+ from another water molecule has a +1 charge

Question 52

Why do all living things need pH buffers?

Answer 52

Amino acid side chains have many carboxyl and amino acid groups

Question 53

A solution with a pH 5 has how many more hydrogen ions in it than a solution with pH 7?

Answer 53

100x

Question 54

What happens to HCl in water?

Answer 54

It is a strong acid, so it dissociates completely and produces lots of H+ which lowers the pH