Exam 2 Flashcards
nucleic acids
-DNA and RNA polymers
nucleotides
-DNA and RNA monomers
RNA
-the activated genetic data for making proteins and polymerized from four monomer ribonucleotides that are named ATP, CTP, GTP, and UTP
Main role of nucleic acids
-specifying the entire phenotype of organism by directing production of particular sets of RNAs and proteins and exerting diverse genetic regulatory functions
nucleotide structures are usually linked by ___ bonds between 3’OH and 5’-OH
phosphodiester
isosteric
meaning that the positions and the distances between the C1′ carbon atoms are very similar.
how much space between turns of a B form helix of DNA
3.4 nm
how many basepairs / helix turn in a B form helix of DNA
10.5
Which of these statements about enzyme catalyzed reactions is false:
A. at saturating levels of substrate, the rate of an enzyme-catalyzed rxn is proportional to the enzyme concentration
B. if enough substrate is added, the normal Vmax of a rxn can be attained even in the presence of a competetive inhibitor
C. the rate of an in vitro reaction decreases steadily with time as substrate is depleted
D. the activation energy for the catalyzed rxn is the same as for the uncatalyzed rxn, but the equlibrium constant is more favorable in the enzyme catalyzed rxn
D is false
the number of substrate molecules converted to product in a given unit of time by a single enzyme molecule at saturation is referred to as the
turnover number
in the situation of a competitive inhibitor, an inhibitor
binds reversibly at the active site
Phenyl-methane-sulfonyl-fluoride (PMSF) inactivates serine proteases by reacting covalently with the catalytic serine residue at the active site; this enzyme-inhibitor bond is not cleaved by the enzyme. This is an example of what kind of inhibition
Irreversible
When two carbohydrates are epimers
they differ only in the configuration around one carbon atom
stopped at question 6 of exam
j
structure of Hb
- 4 polypeptides (2a and 2 B)
- 4 heme groups per tetramer
