Quiz 1

Question 1

Requirements for life

Answer 1

• source of energy to drive processes
• raw materials
• catalysts
• compartmentalization

Question 2

Phototrophs

Answer 2

• use sunlight for energy
  examples:
• plants, green bacteria, cyanobacteria

Question 3

Chemotrophs

Answer 3

• use fuels for energy (oxidize fuels)
  examples:
• animals, most bacteria

Question 4

1st Law of Thermodynamics

Answer 4

energy of the universe is constant
- free energy of catabolic processes drives anabolic processes

Question 5

2nd Law of Thermodynamics

Answer 5

Entropy of the universe is increasing
- life persists because a system can be ordered at the expense of disordering its environment to a greater extent

Question 6

3rd Law of Thermodynamics

Answer 6

perfect crystal entropy at 0 K is zero

Question 7

Exergonic Process

Answer 7

• breakdown of some metabolites releases significant amounts of energy
  examples:
• ATP, NADH, NADPH synthesis from sunlight, fuels
• cellular concentration&raquo_space;» equilibrium concentration

Question 8

Endergonic

Answer 8

• synthesis of complex molecules, metabolic rxns require energy
• unfavorable (G>0)
• metabolite is kinetically stable

Question 9

Catalysis

Answer 9

• increases rate, lowers activation energy

Question 10

coupling

Answer 10

• coupling of energonic and exergonix rxns allows otherwise unfavorable rxns
• high energy molecule (ATP) reacts directly w/ metabolite

Question 11

Cell: universal building block

Answer 11

• living organisms are made of cells
• simplest living organisms are single-celled
• larger organisms consist of many cells w/ different functions
• not all cells are the same

Question 12

supramolecular complexes

Answer 12

• chromatin
  
  • plasma membrane
  • cellular movement

Question 13

macromolecules

Answer 13

• DNA
• protein (long polymers of amino acids)
• cellulose
• polymers

Question 14

monometric units

Answer 14

• nucleotides
• amino acids

Question 15

2 ways to express molecular mass

Answer 15

1. MR = relative molecular mass (unitless)
   eq) mass of molecule/mass of 1/12 C atom
2. Dalton
   1/12 mass of C (Da)

Question 16

∆G

Answer 16

free energy under standard state conditions
- 1 m for all reactants and products
- 1 bar if gas reactants and products
- 298 K, 25 celsius

Question 17

ΔG0’

Answer 17

free energy under standard state conditions EXCEPT [H3O+] = 1.0x10^-7 , 55.5 M H2O

Question 18

Amphibolic

Answer 18

pathway serving both anabolic and catabolic role
ex) TCA cycle

Question 19

amphipathic

Answer 19

has both a nonpolar and polar portion

Question 20

hypotonic

Answer 20

lower osmotic pressure/concentration

Question 21

hypertonic

Answer 21

higher osmotic pressure/concentration

Question 22

osmotic pressure

Answer 22

pressure applied to pure solvent to prevent osmosis
eq: π = icRT

Question 23

Noncovalent interactions

Answer 23

weak forces maintain biological functions
- transient chemical interactions form basis of biochem and life itself
- weak bonds allow for dynamic, repeated interactions

Question 24

H-bonding

Answer 24

• unique properties of water
• structure and function of proteins, DNA, polysaccharides
• binding of substrates to enzymes, hormones to receptors
• matching of mRNA and tRNA

Question 25

hydrophobic effect

Answer 25

- association of folding of nonpolar molecules in aqueous solution - main factor in 1. protein folding 2. protein-protein association 3. formation of lipid bilayers and micelles 4. binding of steroid hormones to receptors - doesn't arise b/c of some attractive direct force between 2 nonpolar molecules

Question 26

amphipathic

Answer 26

- has hydrophilic and hydrophobic portions - nonpolar portions of the amphipathic molecule aggregate so that fewer water molecules are ordered

Question 27

relationship between cell size and surface area

Answer 27

cell size increases, surface area decreases - increased ratio = higher rate of material uptake - dimensions limited by diffusion

Question 28

plasma membrane

Answer 28

- defines periphery of cell - lipid and protein molecules form hydrophobic barriers - barrier to inorganic ions, most charged or polar molecules - transport proteins allow for passage of certain ions - receptor proteins send signals

Question 29

cell makeup

Answer 29

- H, O, N, C makeup > 99.9% of most cells' mass - <30 elements are essential to life

Question 30

biomolecules

Answer 30

- carbons with functional groups - covalently linked carbons - hydrocarbon derivatives

Question 31

autotrophs

Answer 31

- can synthesize all biomolecules directly from CO2

Question 32

hetrotrophs

Answer 32

- require organic nutrients produced by other organisms

Question 33

universal molecules

Answer 33

- amino acids - nucleotides - sugars with phosphorylated derivatives - mono, di, tri carboxylic acids

Question 34

buffers

Answer 34

- resist changes in pH