Quiz 1 Flashcards
Requirements for life
- source of energy to drive processes
- raw materials
- catalysts
- compartmentalization
Phototrophs
- use sunlight for energy
examples: - plants, green bacteria, cyanobacteria
Chemotrophs
- use fuels for energy (oxidize fuels)
examples: - animals, most bacteria
1st Law of Thermodynamics
energy of the universe is constant
- free energy of catabolic processes drives anabolic processes
2nd Law of Thermodynamics
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
3rd Law of Thermodynamics
perfect crystal entropy at 0 K is zero
Exergonic Process
- breakdown of some metabolites releases significant amounts of energy
examples: - ATP, NADH, NADPH synthesis from sunlight, fuels
- cellular concentration»_space;» equilibrium concentration
Endergonic
- synthesis of complex molecules, metabolic rxns require energy
- unfavorable (G>0)
- metabolite is kinetically stable
Catalysis
- increases rate, lowers activation energy
coupling
- coupling of energonic and exergonix rxns allows otherwise unfavorable rxns
- high energy molecule (ATP) reacts directly w/ metabolite
Cell: universal building block
- 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
supramolecular complexes
- chromatin
- plasma membrane
- cellular movement
macromolecules
- DNA
- protein (long polymers of amino acids)
- cellulose
- polymers
monometric units
- nucleotides
- amino acids
2 ways to express molecular mass
- MR = relative molecular mass (unitless)
eq) mass of molecule/mass of 1/12 C atom - Dalton
1/12 mass of C (Da)
∆G
free energy under standard state conditions
- 1 m for all reactants and products
- 1 bar if gas reactants and products
- 298 K, 25 celsius
ΔG0’
free energy under standard state conditions EXCEPT [H3O+] = 1.0x10^-7 , 55.5 M H2O
Amphibolic
pathway serving both anabolic and catabolic role
ex) TCA cycle
amphipathic
has both a nonpolar and polar portion
hypotonic
lower osmotic pressure/concentration
hypertonic
higher osmotic pressure/concentration
osmotic pressure
pressure applied to pure solvent to prevent osmosis
eq: π = icRT
Noncovalent interactions
weak forces maintain biological functions
- transient chemical interactions form basis of biochem and life itself
- weak bonds allow for dynamic, repeated interactions
H-bonding
- unique properties of water
- structure and function of proteins, DNA, polysaccharides
- binding of substrates to enzymes, hormones to receptors
- matching of mRNA and tRNA
hydrophobic effect
- association of folding of nonpolar molecules in aqueous solution
- main factor in
- protein folding
- protein-protein association
- formation of lipid bilayers and micelles
- binding of steroid hormones to receptors
- doesn’t arise b/c of some attractive direct force between 2 nonpolar molecules
amphipathic
- has hydrophilic and hydrophobic portions
- nonpolar portions of the amphipathic molecule aggregate so that fewer water molecules are ordered
relationship between cell size and surface area
cell size increases, surface area decreases
- increased ratio = higher rate of material uptake
- dimensions limited by diffusion
plasma membrane
- 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
cell makeup
- H, O, N, C makeup > 99.9% of most cells’ mass
- <30 elements are essential to life
biomolecules
- carbons with functional groups
- covalently linked carbons
- hydrocarbon derivatives
autotrophs
- can synthesize all biomolecules directly from CO2
hetrotrophs
- require organic nutrients produced by other organisms
universal molecules
- amino acids
- nucleotides
- sugars with phosphorylated derivatives
- mono, di, tri carboxylic acids
buffers
- resist changes in pH
