Flashcards in ch 1 Deck (37):
Cells, the basic structural units of living organisms are:
highly organized and constant source of energy is required to maintain their ordered state
what types of molecules are used by all organisms
carbohydrates, proteins, lipids and nucleic acids
what elements are the most abundant and essential for all organisms
C, N, O, P, S, H
what elements are less abundant and essential for all organisms
Na, Mg, K, Ca, Cl
what elements abundant at trace levels are essential for all organisms?
Mn, Fe, Co, Cu, Zn
what elements abundant at trace levels are essential for some organisms?
V, Cr, Mo, B, Al, Ga, Sn, Si, As, Se, I
what is the geometry of a water molecule? what is the covalent bond angle?
how do dipoles of water and ammonia differ from that of CO2
water and ammonia have a perament dipole, while CO2 does not
how many hydrogen bonds can water form?
compared to in ice, how much less (percent) of hydrogen bonds does liquid water have?
25% of hydrogen bonds in ice are broken in liquid
what are the 4 types of noncovalent interactions? What is another name for these reactions?
reversible molecular interactions:
van der waals bonds
what is the rnage of electrostatic bond energy?
van der waals bonds?
which is the hydrogen bond donor and which is the hydrogen bond acceptor?
which one has the partial negative charge?
hydrogen donor: atom to which H is more tightly associated
hydrogen acceptor: atom to which H is less tightly associated with.
acceptor has partial negative charge
how many nanometers is an angstrom?
.1 nm = 1 angstrom
when are van der waals bonds most important?
when numerous atoms in one molecule come close to atoms inanother molecule
the distribution of electric charge around an atomc hanges with time. Therefore:
charge distribution is asymmetric, which encourages similar asymmetry around the neigboring atoms leading to attraction
what is attration of van der waals bonds dependent on?
distance dependent. strongly reuplsive at short internuclear distances, and very weak at long internuclear distances. attraction is maximal when 2 atoms are separated by their van der waals radii
what is the van der waals contact distance?
it is the distance between centers: 2.4-4.0 angstroms
what is the van der waals contact radius?
distance between outside of molecule and center: 1.2-2.0 angstoms
what are hydrophobic interactions?
interactions between nonpolar molecules due to the tendency of water to bond strongly to itself
acids are proton ______
bases are proton ______
what is Kw = ?
keq of [H2O] = [H+][OH-] = 1.0 x 10 ^ -14
equation for pH?
what is the henderson hasselbach equation?
pH= pKa + log ([A-]/[HA])
what does pKa measure?
pH at which an acid is half dissociated
what is the pH of blood? an how is it regulated?
7.4, CO2 carbonic acid - bicarbonate buffer system
what else contibutes to intracellular buffering?
proteins (hemoglobin) and phosphate
what is the bicarbonate buffer system equlibrium reaction?
HCO3 H2CO3 (aq) CO2 (g)
which bases are purines, how many rings do they have?
A, G: have 2 ring structure
which bases are pyrimidines, how many rings do they have?
U, T, C: 1 ring structure
how does ribose differ from deoxyribose
deoxyribose lacks 2' hydroxyl
who one nobel prize for double helix structure of DNA?
watson and crick 1962
what did erwin chargaff discover?
compositionally, A = T and G = C in all domains of life
what form of DNA is most common in vivo?
what for of RNA is most common in vivo?
what is unique about RNA? and why is it unique?
the 2' hydroxyl allows it to form a multitude of un ique folds and tertiary interactions, form different base pairs, and form base triples and base quartets