Chemistry of Life

Question 1

What are the 5 principles important to cell biology?

Answer 1

• Characteristics of carbon
• characteristics of water
• selectively permeable membranes
• synthesis by polymerization of small molecules
• self assembly

Question 2

What is organic chemistry?

Answer 2

the study of carbon containing compounds

Question 3

What is biological chemistry?

Answer 3

the study of the chemistry of living systems

Question 4

What are covalent bonds?

Answer 4

the sharing of a pair of electrons between two atoms

Question 5

What is bond energy?

Answer 5

the amount of energy required to break 1 mole of such bonds

Question 6

What are hydrocarbons? Why are they of limited importance in biology?

Answer 6

chains or rings composed only of carbon and hydrogen. They are not soluble in water

Question 7

What functional groups are negatively charged?

Answer 7

Carboxyl and Phosphate

Question 8

What functional group is positively charged?

Answer 8

Amino groups

Question 9

What functional groups are uncharged and are they polar or non polar?

Answer 9

Hydroxyl, sulfhydroxyl, carbonyl and aldehyde. They are polar

Question 10

What are polar bonds?

Answer 10

bonds in which electrons are not shared equally between two atoms

Question 11

What are stereoisomers?

Answer 11

non-superimposable configurations that are mirror images

Question 12

What is an asymmetric carbon atom?

Answer 12

has 4 different substituents

Question 13

A compound with n asymmetric carbons will have how many possible stereoisomers?

Answer 13

2^n

Question 14

Why is water important?

Answer 14

universal solvent, most abundant component of cells

Question 15

What does water’s polarity account for?

Answer 15

• Cohesiveness
• Temperature-stabilizing capacity
• Solvent Properties

Question 16

Unequal distribution of electrons gives water its…? is it bent or linear?

Answer 16

polarity. its bent

Question 17

Hydrogen bonds account for water’s high..?

Answer 17

• surface tension
• boiling point
• specific heat
• heat of vaporization

Question 18

What is specific heat?

Answer 18

the amount of heat a substance must absorb to raise its temperature 1 degree

Question 19

Why Is water good for stabilizing temperature?

Answer 19

b/c the heat that would raise the temperature of other liquids is first used to break numerous hydrogen bonds in water - therefore changes relatively slow

Question 20

What is heat of vaporization?

Answer 20

the amount of energy required to convert 1 gram of liquid into vapor

Question 21

What is a solvent?

Answer 21

fluid in which another substance (solute) can dissolve

Question 22

What does hydrophilic mean?

Answer 22

“water loving” , solutes that have an affinity for water and easily dissolve in it

Question 23

What is an example of a hydrophilic molecule?

Answer 23

small molecules such as sugars, organic acids, some amino acids

Question 24

What does hydrophobic mean?

Answer 24

“water fearing”, molecules that are not easily soluble in water

Question 25

What is an example of a hydrophobic molecule?

Answer 25

lipids and proteins in membranes

Question 26

In water, anions and cations take part in what kind of interaction with the water molecules? And what is a result of this interaction?

Answer 26

electrostatic interaction which causes the ions to separate

Question 27

what kind of characteristics do barrier in cells need?

Answer 27

- impermeable to much of the cell contents - not completely impermeable, allowing some materials in and out - insoluble in water to maintain integrity - permeable to water to allow flow of water in and out

Question 28

What are some characteristics of the cell membrane?

Answer 28

- hydrophobic permeability barrier | - consists of phospholipids, glycolipids and membrane proteins

Question 29

what does amphipathic mean?

Answer 29

have both hydrophobic and hydrophilic regions ( ex. membrane lipids)

Question 30

What are the polar and non-polar parts of phospholipids?

Answer 30

polar - head, b/c of the negatively charged phosphate group linked to a positively charged group non-polar - hydrocarbon tails

Question 31

What happens to amphipathic molecules in water?

Answer 31

undergo hydrophobic interactions

Question 32

What is the lipid bilayer?

Answer 32

structure that results from the polar heads of membrane phospholipids facing outwards towards the aqueous environment and the hydrophobic tails facing inward away from the aqueous environment.

Question 33

What happens to the lipid bilayer because of the hydrophobic interior?

Answer 33

it is readily permeable to non polar molecules

Question 34

What can pass through the lipid bilayer?

Answer 34

- readily permeable to non polar molecules (O2, CO2) - quite impermeable to most polar molecules - highly impermeable to all ons (Na+, Cl-) - small uncharged polar molecules can sometimes get through (H2O)

Question 35

Since ions can't pass the lipid bilayer, how do they cross it?

Answer 35

must be transported across a membrane by specialized transport proteins

Question 36

What are macromolecules?

Answer 36

ordered array of linear polymers

Question 37

What are important macromolecules in the cell?

Answer 37

proteins, nucleic acids and polysaccharides

Question 38

What is cellular hierarchy?

Answer 38

biological molecules and structures are organized into a series of levels, each building on the preceding one

Question 39

What is another name for nucleic acids and why?

Answer 39

informational macromolecules. b/c the order of the four kinds of nucleotide monomers in each Is non random and carries important info

Question 40

What function do DNA and RNA do?

Answer 40

coding function

Question 41

What are the functions of proteins?

Answer 41

structure, defence, transport, catalysis, signaling

Question 42

What do polysaccharides consist of?

Answer 42

single repeating subunits or two alternating subunits

Question 43

Is the order of monomers important?

Answer 43

no, it carries no information and is not essential for function

Question 44

What is the immediate product of amino cid polymerization?

Answer 44

a polypeptide

Question 45

What happens during a condensation reaction?

Answer 45

Something is built and water is released

Question 46

What happens during hydrolysis?

Answer 46

Degradation of polymers and water is added

Question 47

What is the principle of self assembly?

Answer 47

it states that info needed to specify the folding of macromolecules and their interactions to form complex structures is inherent in the polymers themselves

Question 48

What are molecular chaperones?

Answer 48

proteins that are sometimes needed to prevent incorrect folding

Question 49

What are ionic bonds?

Answer 49

strong non covalent electrostatic interactions between two oppositely charged ions

Question 50

What are Van Der Waal interactions?

Answer 50

weak attractions between two atoms that occur only if the atoms are very close to one another and orientated properly

Question 51

What are hydrophobic interactions?

Answer 51

the tendency of non polar groups within a macromolecule to associate with each and minimize their contact with water

Question 52

What is denaturation and renaturation?

Answer 52

Denaturation is the unfolding of polypeptides that leads to loss of function Renaturation is the refolding into the correct conformation

Question 53

How do molecular chaperones work?

Answer 53

they bind to exposed regions in the early stages of assembly to inhibit unproductive assembly pathways that would lead to incorrect structures