BMSC 200 Final Exam Questions
with Complete Solutions
where does most of the H and O in living organisms come from - ANSWER-water
life as we know it is based on what molecule - ANSWER-carbon
what is the conformation of a molecule - ANSWER-flexible spatial arrangement of
atoms within a molecule, can be changed without breaking bonds
what is the configuration of a molecule and give an example - ANSWER-fixed spatial
arrangement of atoms within a molecule, cannot be changed without breaking
covalent bonds
ex. changing D-Arg to L-Arg - changing chiral centers
ex. changing from trans to cis - breaking the double bond
cis - ANSWER-groups on same side of the double bond
trans - ANSWER-groups on opposite sides of the double bond
define chiral carbon - ANSWER-carbon with four different substituents
how do you find the number of stereoisomers a molecule has - ANSWER-2^n, where
n = the number of chiral carbons
what are the advantages of making complex molecules out of simple polymers -
ANSWER-simplicity
recycling
diversity
what class of biomolecules doesn't have covalent bonds - ANSWER-lipids
whats the difference between in vitro and in vivo - ANSWER-in vitro is in glass
in vivo is in the living
what kind of reaction is it when G > 0 - ANSWER-endergonic, non-spontaneous
what kind of reaction is it when G < 0 - ANSWER-exergonic, spontaneous
define energy coupling - ANSWER-linking reactions as a way of driving
thermodynamically unfavourable reactions
define amphipathic - ANSWER-A molecule that has both a hydrophilic region and a
hydrophobic region.
, What is the Henderson-Hasselbalch equation? - ANSWER-pH = pKa + log [A-]/[HA]
when pH is below it's pKa, it is in the:
a) protonated form
b) unprotonated form - ANSWER-protonated form (has an H+)
when pH is above its pKa, it is in the:
a) protonated form
b) unprotonated form - ANSWER-unprotonated form (lost the H+)
which amino acid does not have a chiral carbon - ANSWER-glycine
what is a disulfide bond - ANSWER-form through the oxidation of the sulfhydryl
groups of two cysteine residues to form a covalent linkage
what are peptide bonds and how do they form - ANSWER-covalent linkages
between amino acids, form by condensation reactions (loss of a water molecule)
what is the repeating pattern within the main chain of a peptide bond - ANSWER-
NCCNCC
why are peptide groups rigid and planar - ANSWER-rotation around the C-N peptide
bond is restricted (partial double bond characteristic)
what level of structure describes the linear arrangement of amino acids in a
polypeptide - ANSWER-primary structure
what level of structure represents localized patterns of folding in a polypeptide -
ANSWER-secondary structure
what are two examples of secondary structure - ANSWER-alpha helix and beta
sheet
describe an alpha helix and what stabilizes it - ANSWER-right handed helix with 3.6
residues/turn
stabilized by H-bonds which run parallel to the axis of the helix
what are some amino acids not commonly found in an alpha helix - ANSWER-
proline, glycine
describe beta sheets and what stabilizes it - ANSWER-multiple beta strands
arranged side by side, often 4 or 5 strands
stabilized by H bond between the C=O and -NH on adjacent strands
can be either parallel or antiparallel
which beta sheet is more stable - antiparallel or parallel - ANSWER-antiparallel
what level of structure describes the final folding pattern of a single peptide -
ANSWER-teritary structure
with Complete Solutions
where does most of the H and O in living organisms come from - ANSWER-water
life as we know it is based on what molecule - ANSWER-carbon
what is the conformation of a molecule - ANSWER-flexible spatial arrangement of
atoms within a molecule, can be changed without breaking bonds
what is the configuration of a molecule and give an example - ANSWER-fixed spatial
arrangement of atoms within a molecule, cannot be changed without breaking
covalent bonds
ex. changing D-Arg to L-Arg - changing chiral centers
ex. changing from trans to cis - breaking the double bond
cis - ANSWER-groups on same side of the double bond
trans - ANSWER-groups on opposite sides of the double bond
define chiral carbon - ANSWER-carbon with four different substituents
how do you find the number of stereoisomers a molecule has - ANSWER-2^n, where
n = the number of chiral carbons
what are the advantages of making complex molecules out of simple polymers -
ANSWER-simplicity
recycling
diversity
what class of biomolecules doesn't have covalent bonds - ANSWER-lipids
whats the difference between in vitro and in vivo - ANSWER-in vitro is in glass
in vivo is in the living
what kind of reaction is it when G > 0 - ANSWER-endergonic, non-spontaneous
what kind of reaction is it when G < 0 - ANSWER-exergonic, spontaneous
define energy coupling - ANSWER-linking reactions as a way of driving
thermodynamically unfavourable reactions
define amphipathic - ANSWER-A molecule that has both a hydrophilic region and a
hydrophobic region.
, What is the Henderson-Hasselbalch equation? - ANSWER-pH = pKa + log [A-]/[HA]
when pH is below it's pKa, it is in the:
a) protonated form
b) unprotonated form - ANSWER-protonated form (has an H+)
when pH is above its pKa, it is in the:
a) protonated form
b) unprotonated form - ANSWER-unprotonated form (lost the H+)
which amino acid does not have a chiral carbon - ANSWER-glycine
what is a disulfide bond - ANSWER-form through the oxidation of the sulfhydryl
groups of two cysteine residues to form a covalent linkage
what are peptide bonds and how do they form - ANSWER-covalent linkages
between amino acids, form by condensation reactions (loss of a water molecule)
what is the repeating pattern within the main chain of a peptide bond - ANSWER-
NCCNCC
why are peptide groups rigid and planar - ANSWER-rotation around the C-N peptide
bond is restricted (partial double bond characteristic)
what level of structure describes the linear arrangement of amino acids in a
polypeptide - ANSWER-primary structure
what level of structure represents localized patterns of folding in a polypeptide -
ANSWER-secondary structure
what are two examples of secondary structure - ANSWER-alpha helix and beta
sheet
describe an alpha helix and what stabilizes it - ANSWER-right handed helix with 3.6
residues/turn
stabilized by H-bonds which run parallel to the axis of the helix
what are some amino acids not commonly found in an alpha helix - ANSWER-
proline, glycine
describe beta sheets and what stabilizes it - ANSWER-multiple beta strands
arranged side by side, often 4 or 5 strands
stabilized by H bond between the C=O and -NH on adjacent strands
can be either parallel or antiparallel
which beta sheet is more stable - antiparallel or parallel - ANSWER-antiparallel
what level of structure describes the final folding pattern of a single peptide -
ANSWER-teritary structure
