BMSC 200- Midterm Exam Questions
with Correct Answers
when are l and d isomers "identical" and when are they different - ANSWER-
chemically identical- but they differ when reacting with chiral molecules (left and right
hands)
what is an important caveat for chirality substituents - ANSWER-the ENTIRE
GROUP is considered as the substituent, not the atom its directly bonded to
why is it useful to construct biomolecules from simple building blocks - ANSWER-
simplicity- use the same machinery
recycling- cow protein to human protein
diversity- infinite combo of molecules
how are lipids different from the other 3 biomolecules - ANSWER-they are
aggregates, not polymers
does the human body have more prokaryotes or eukaryotes (by number) -
ANSWER-prokaryotes - 100 trillion vs 30 trillion
why does context matter when studying biomolecules - ANSWER-biomolecules tend
to behave differently in vitro, vs. in vivo
State the 1st Law of Thermodynamics - ANSWER-the amount of energy in the
universe is constant
state the second law of thermodynamics - ANSWER-the total entropy of the universe
always increases (the entropy of a system can decrease, but never the universe)
what does Gibbs free energy do - ANSWER-relates the enthalpy change and
entropy change of a rxn, to tell us if it will be spontaneous (if it will proceed)
state the formula for gibbs free energy - ANSWER-
what do the signs of delta G values tell us - ANSWER-greater than 0 = non
spontaneous/endergonic
negative = spontaneous/exergonic
0=equilibrium
,describe reaction coupling and what it is used for - ANSWER-coupling an endergonic
rxn with an exergonic one (usually ATP hydrolysis)
differentiate between anabolic and catabolic - ANSWER-Anabolic = Build
Catabolic = Degrade
AB CD
why does protein folding SEEM to fly in the face of the second law of
thermodynamics - ANSWER-because the enthalpy change is 0, and the structure
gets MORE ordered
is a drug that kills 99% of e-coli an effective one? - ANSWER-no- they multiple so
rapidly they would soon be back, and would start to select for drug resistant strains
what are the 3 requirements for life to continue that DNA fulfills - ANSWER-genetic
info 1) stored in stable form
2)accurately expressed
3)easily reproduced
describe waters passive and active roles in biochemistry - ANSWER-passive=
influence how proteins fold
active=dehydration synthesis
how do weak interactions allow for cells' amazing structures and functions -
ANSWER-many weak interactions= very strong (phone book)
changing interaction means molecules can ADAPT to different functions
what percentage strength is a hydrogen bond relative to a covalent bond -
ANSWER-5%
which atom is a hydrogen bond donor, and which is an acceptor in a h-bond -
ANSWER-donor= supplies the hydrogen
why does the geometry of Hbonds have big implications - ANSWER-because shorter
bonds are stronger (more stable)- so geometry matters when forming structures
such as beta sheets
what makes the specific heat capacity and heat of vaporization of water so high -
ANSWER-the fact molecules of water will Hbond with an average of 3.4 other
waters. "flickering clusters"
why does hot water freeze faster than cold water - ANSWER-no one knows; the
opposite is not true- cold water will NOT boil faster
what should you be thinking as soon as you see an O or N in a molecule -
ANSWER-Hydrogen bonds! O and N are the primary acceptors and donors
, what do all peptides start with - ANSWER-NH³⁺
which secondary structures can be amphipathic - ANSWER-alpha helices AND beta
sheets
how is waters high specific heat capacity beneficial to humans - ANSWER-as
isotherms, we burn our body weight in ATP each day- water helps keep us cool
why was "polywater" - lower freezing point, higher b.p, etc. such a scare - ANSWER-
because life depends so much on water, it would go derp without it
define amphipathicity - ANSWER-having both polar and non polar regions
what is brownian motion - ANSWER-the inherent kinetic energy of molecules, due to
temperature
what are the 2 things that determine a substances solubility in water - ANSWER-if its
charged
if it can form hydrogen bonds (polar)
which would have greater solubility in water- a polar substance with hydrogen, or
one without - ANSWER-with hydrogen- can act as donor AND acceptor
what does a single nonpolar molecule do when placed in water, w.r.t entropy -
ANSWER-it DECREASES entropy of the WATER; makes the molecules around it
more ordered
what allows proteins to fold in water, obeying the second law of thermodynamics -
ANSWER-the fact that the proteins decreasing entropy will cause the water to
increase entropy (less surface area of protein means more water can be disordered)
name the 4 types of noncovalent interactions - ANSWER-hydrophobic interactions,
Hbonds, electrostatics, van der waals
state the function of phosphatases - ANSWER-remove a phosphoryl group
what are the 3 things a functional group in a biomolecule could Hbond to -
ANSWER-intermolecular groups
intramolecular groups
water
does Hbonding CAUSE a protein to fold? - ANSWER-NO; it just determines HOW it
folds
what Hbonding geometry is stronger - ANSWER-antiparallel
what is important to remember when discussing biochemical reactions - ANSWER-
all occur in the context of water
with Correct Answers
when are l and d isomers "identical" and when are they different - ANSWER-
chemically identical- but they differ when reacting with chiral molecules (left and right
hands)
what is an important caveat for chirality substituents - ANSWER-the ENTIRE
GROUP is considered as the substituent, not the atom its directly bonded to
why is it useful to construct biomolecules from simple building blocks - ANSWER-
simplicity- use the same machinery
recycling- cow protein to human protein
diversity- infinite combo of molecules
how are lipids different from the other 3 biomolecules - ANSWER-they are
aggregates, not polymers
does the human body have more prokaryotes or eukaryotes (by number) -
ANSWER-prokaryotes - 100 trillion vs 30 trillion
why does context matter when studying biomolecules - ANSWER-biomolecules tend
to behave differently in vitro, vs. in vivo
State the 1st Law of Thermodynamics - ANSWER-the amount of energy in the
universe is constant
state the second law of thermodynamics - ANSWER-the total entropy of the universe
always increases (the entropy of a system can decrease, but never the universe)
what does Gibbs free energy do - ANSWER-relates the enthalpy change and
entropy change of a rxn, to tell us if it will be spontaneous (if it will proceed)
state the formula for gibbs free energy - ANSWER-
what do the signs of delta G values tell us - ANSWER-greater than 0 = non
spontaneous/endergonic
negative = spontaneous/exergonic
0=equilibrium
,describe reaction coupling and what it is used for - ANSWER-coupling an endergonic
rxn with an exergonic one (usually ATP hydrolysis)
differentiate between anabolic and catabolic - ANSWER-Anabolic = Build
Catabolic = Degrade
AB CD
why does protein folding SEEM to fly in the face of the second law of
thermodynamics - ANSWER-because the enthalpy change is 0, and the structure
gets MORE ordered
is a drug that kills 99% of e-coli an effective one? - ANSWER-no- they multiple so
rapidly they would soon be back, and would start to select for drug resistant strains
what are the 3 requirements for life to continue that DNA fulfills - ANSWER-genetic
info 1) stored in stable form
2)accurately expressed
3)easily reproduced
describe waters passive and active roles in biochemistry - ANSWER-passive=
influence how proteins fold
active=dehydration synthesis
how do weak interactions allow for cells' amazing structures and functions -
ANSWER-many weak interactions= very strong (phone book)
changing interaction means molecules can ADAPT to different functions
what percentage strength is a hydrogen bond relative to a covalent bond -
ANSWER-5%
which atom is a hydrogen bond donor, and which is an acceptor in a h-bond -
ANSWER-donor= supplies the hydrogen
why does the geometry of Hbonds have big implications - ANSWER-because shorter
bonds are stronger (more stable)- so geometry matters when forming structures
such as beta sheets
what makes the specific heat capacity and heat of vaporization of water so high -
ANSWER-the fact molecules of water will Hbond with an average of 3.4 other
waters. "flickering clusters"
why does hot water freeze faster than cold water - ANSWER-no one knows; the
opposite is not true- cold water will NOT boil faster
what should you be thinking as soon as you see an O or N in a molecule -
ANSWER-Hydrogen bonds! O and N are the primary acceptors and donors
, what do all peptides start with - ANSWER-NH³⁺
which secondary structures can be amphipathic - ANSWER-alpha helices AND beta
sheets
how is waters high specific heat capacity beneficial to humans - ANSWER-as
isotherms, we burn our body weight in ATP each day- water helps keep us cool
why was "polywater" - lower freezing point, higher b.p, etc. such a scare - ANSWER-
because life depends so much on water, it would go derp without it
define amphipathicity - ANSWER-having both polar and non polar regions
what is brownian motion - ANSWER-the inherent kinetic energy of molecules, due to
temperature
what are the 2 things that determine a substances solubility in water - ANSWER-if its
charged
if it can form hydrogen bonds (polar)
which would have greater solubility in water- a polar substance with hydrogen, or
one without - ANSWER-with hydrogen- can act as donor AND acceptor
what does a single nonpolar molecule do when placed in water, w.r.t entropy -
ANSWER-it DECREASES entropy of the WATER; makes the molecules around it
more ordered
what allows proteins to fold in water, obeying the second law of thermodynamics -
ANSWER-the fact that the proteins decreasing entropy will cause the water to
increase entropy (less surface area of protein means more water can be disordered)
name the 4 types of noncovalent interactions - ANSWER-hydrophobic interactions,
Hbonds, electrostatics, van der waals
state the function of phosphatases - ANSWER-remove a phosphoryl group
what are the 3 things a functional group in a biomolecule could Hbond to -
ANSWER-intermolecular groups
intramolecular groups
water
does Hbonding CAUSE a protein to fold? - ANSWER-NO; it just determines HOW it
folds
what Hbonding geometry is stronger - ANSWER-antiparallel
what is important to remember when discussing biochemical reactions - ANSWER-
all occur in the context of water
