BSCI330 biological molecules

Question 1

what are cells made up of?

Answer 1

a very distinctive but limited set of carbon-based molecules

Question 2

what are carbohydrates?

Answer 2

polymers of sugar molecules

energy storage and structural support

Question 3

what are lipids?

Answer 3

not polymers

composed of fatty acids which can link to glycerol

energy storage and assembly into membranes

Question 4

what are proteins?

Answer 4

made of amino acids

functioning molecules in most cells - perform most cellular functions

Question 5

what are nucleic acids?

Answer 5

nucleotide monomers

info storage and short-term energy storage

Question 6

what is the second law of thermodynamics?

Answer 6

cells build order (reduce entropy) - must expend energy to do so

Question 7

what is a condensation reaction?

Answer 7

combine two small molecules to make a larger molecule (condensing two molecules into one)

Question 8

what is a dehydration reaction?

Answer 8

dehydrating molecule to make water (a water molecule is removed from two molecules)

Question 9

what is a hydrolysis reaction?

Answer 9

take water, add it to molecule, break molecular bond apart (opposite of dehydration reaction)

Question 10

what is a glycosidic bond?

Answer 10

two sugar molecules to make disaccharide to generate bond

Question 11

what is a peptide bond

Answer 11

two amino acids put together

Question 12

what is a phosphodiester bond?

Answer 12

combining nucleotides

Question 13

what are carbohydrates (in-depth)?

Answer 13

energy sources

running metabolism on glucose and other sugars

build sugars into longer chains for more support (ex: cellulose in plants)

longer term storage as starches

can modify proteins and lipids to provide binding surfaces for molecules

Question 14

what is the polarity of carbohydrates?

Answer 14

highly polar (very hydrophilic) - adding them allows a molecule to dissolve in water easier

Question 15

what are the formations of carbohydrates?

Answer 15

monomers are either linear or ring form

in aqueous solution they are in equilibrium between forms

locked in ring form in polymers

many hydroxyl groups

Question 16

how are sugar linkages numbered?

Answer 16

carbons are numbered clockwise from the oxygen in the ring

positions of OH groups are either

• UP (above plane of ring) = beta
• DOWN (below plane of ring) = alpha

Question 17

what type of linked sugar do our cells work on?

Answer 17

D-glucose

Question 18

what do lipids do?

Answer 18

generate hydrophobic membrane barriers (separate two watery compartments)
- water molecules can’t cross barriers

Question 19

what are the structural subunits of lipids?

Answer 19

fatty acids

Question 20

how are fatty acids composed?

Answer 20

made up of an acidic group attached to a long chain hydrocarbon
- one end of lipid is hydrophilic, one end is hydrophobic
(this is amphipathic: molecule can interact with both water and hydrophobic molecules)

Question 21

how can you get a triglyceride?

Answer 21

by attaching three fatty acids to glycerol (non-polar and NOT ampipathic)

Question 22

what does saturated mean?

Answer 22

no double bonds

Question 23

what does unsaturated mean?

Answer 23

has double bonds

Question 24

what are gangliosides?

Answer 24

polar head group of phospholipid is replaced by a carbohydrate
(GM2 found in plasma membrane needed for cell-cell communication and neuronal plasticity)

Question 25

what is Tay-Sachs Disease?

Answer 25

too much GM2 in brain neurons causes cells to die

Question 26

what are amino acids

Answer 26

building blocks of proteins, metabolized for energy

Question 27

what is the basic structure of an amino acid?

Answer 27

amine group at one end, a carbon, a carboxyl group

Attached to the central carbon is a hydrogen and a side chain

Question 28

what happens when the amino and carboxyl group are dissolved in water?

Answer 28

they have acidic and basic properties and become charged

Question 29

at pH of 7 what are the charges of amine and carboxyl group?

Answer 29

amine is positive, carboxyl is negative

Question 30

what are the nonpolar amino acids?

Answer 30

glycine, alanine, valine, leucine, isoleucine, methionine, phenylalanine, tryptophan, proline

(hydrophobic side chain)

Question 31

what are the polar amino acids?

Answer 31

serine, threonine, cysteine, tyrosine, asparagine, glutamine

uncharged

Question 32

what are the acidic amino acids?

Answer 32

aspartate, glutamate

negatively charged

Question 33

what are the basic amino acids?

Answer 33

lysine, arginine, histidine

positively charged

Question 34

what is pK?

Answer 34

the pH at which 50% of molecule is charged and 50% is uncharged

Question 35

what are nucleotides?

Answer 35

short term energy carriers , building blocks of nucleic acids

Question 36

how are nucleotides composed?

Answer 36

sugar, phosphate group (at 5’ end), nitrogenous base

phosphate and sugar are hydrophilic, base is hydrophobic => amphipathic

Question 37

are nucleotides charged or uncharged?

Answer 37

charged

Question 38

what is the first law of thermodynamics?

Answer 38

amount of energy in a closed system is constant (energy cannot be created or destroyed)

some energy is almost always lost as heat

Question 39

what is the second law of thermodynamics?

Answer 39

all processes in the universe are driven in the direction that increases disorder (entropy)

useable energy tends to decrease

Question 40

when is a reaction energetically favorable?

Answer 40

if the amount of useable energy after reaction is lower than originally

Question 41

when is a reaction energetically unfavorable?

Answer 41

if the amount of useable energy increases

Question 42

what does a spontaneous reaction mean?

Answer 42

a reaction will occur without a net addition of energy