LECOM BIOCHEMISTRY EXAM 1
QUESTIONS WITH CORRECT
ANSWERS
Anatomy of a cell - Correct Answers -Nucleolus, nuclear envelope ,nucleus, Rough
Endoplasmic Reticulum (RER)
Nucleus - Correct Answers -A part of the cell containing DNA and RNA
Nucleolus - Correct Answers -Found inside the nucleus and produces ribosomes; rRNA
synthesis
nuclear envelope - Correct Answers -A double membrane that surrounds the nucleus in
the cell; continuous with RER
Rough Endoplasmic Reticulum (RER) - Correct Answers -contains ribosomes made
from rRNA
Ribosomes - Correct Answers -site of protein synthesis
Smooth Endoplasmic Reticulum - Correct Answers -protein modification and membrane
synthesis
transport vesicle - Correct Answers -Vesicle that moves molecules between locations
inside the cell.
Golgi complex - Correct Answers -protein sorting
,Peroxisome - Correct Answers -contains enzymes that transfer hydrogen from various
substrates to oxygen, producing and then degrading hydrogen peroxide.
Lysosome - Correct Answers -An organelle containing digestive enzymes
plasma membrane - Correct Answers -A selectively-permeable phospholipid bilayer
forming the boundary of the cells
cytoskeleton - Correct Answers -network of protein filaments within some cells that
helps the cell maintain its shape and is involved in many forms of cell movement
Mitochondria - Correct Answers -Powerhouse of the cell, organelle that is the site of
ATP (energy) production; contains own single circular DNA, ribosomes and proteins
Endosome - Correct Answers -vesicle pinched in from the cell membrane
Secretory vesicle - Correct Answers -vesicle that releases molecules from the cell
When a secreted protein is synthesized, what is the order of locations for the movement
of this protein through the cell? - Correct Answers -RER-->SER-->Golgi-->Secretory
vesicle
perinuclear space - Correct Answers -Between the two layers of the nuclear envelope
nuclear lamina - Correct Answers -scaffolding for the chromosomes and nuclear pores
Central Dogma of Molecular Biology - Correct Answers -DNA-transcription-->RNA-
translation-->protein
Zellweger syndrome - Correct Answers -Peroxisomal disease; can't metabolize very
long chain FA (VLCFAs) or branched-chain FAs (e.g. phytanic acid, via alpha-
oxidation). Can't form myelin in CNS. Hypotonia, seizures, hepatomegaly, MR, early
death.
Prokaryotic cell - Correct Answers -cell that does not have a nucleus or other
membrane-bound organelles; same size as a mitochondria
Pili - Correct Answers -provide points of adhesion to surface of other cells
Flagella - Correct Answers -propel cell through its surroundings
Most common elements - Correct Answers -H, Na, K, Ca, C, N, O, P, S, Cl
Atomic number - Correct Answers -number of protons
,Atomic mass - Correct Answers -protons + neutrons
octet rule - Correct Answers -in forming compounds, atoms tend to achieve the electron
configuration of a noble gas
Number of electrons - Correct Answers -Number of protons
Total electrons in Nitrogen - Correct Answers -7
Total electrons in Carbon - Correct Answers -6
Total electrons in Oxygen - Correct Answers -8
Total electrons in Hydrogen - Correct Answers -1
# bonds H forms - Correct Answers -1
# bonds Boron forms - Correct Answers -3
# bonds Carbon forms - Correct Answers -4
# bonds Nitrogen forms - Correct Answers -3
# bonds Phosphorous forms - Correct Answers -3 or 5
# bonds Oxygen forms - Correct Answers -2
# bonds Sulfur forms - Correct Answers -2 or 6
# bonds Fluorine forms - Correct Answers -1
# bonds Chlorine forms - Correct Answers -7
Neutrons in an isotope - Correct Answers -atomic mass of isotope minus # protons
Nuclear pore - Correct Answers -passageway for molecules into and out of the nucleus
Endocytosis - Correct Answers -Active transport process where a cell engulfs materials
with a portion of the cell's plasma membrane and releases the contents inside of the
cell.
valence electrons - Correct Answers -Electrons on the outermost energy level of an
atom
Why is water polar? - Correct Answers -the oxygen atom has a slight negative charge
and the 2 hydrogen atoms have a slight positive charge;
, hydrogen bonding - Correct Answers -the intermolecular force in which a hydrogen
atom that is bonded to a highly electronegative atom is attracted to an unshared pair of
electrons of an electronegative atom in a nearby molecule
Hydronium ion - Correct Answers -H3O+; protonated water molecule
hydroxide ion - Correct Answers -OH-; loss of proton from a water molecule
Keq - Correct Answers -=[H+][OH-]/[H2O]
Kw at neutral pH - Correct Answers -=1x10^-14 = [H+][OH-]
What is the H+ and OH- concentration at neutral pH? - Correct Answers -1x10^-7 = [H+]
= [OH-]
Define pH - Correct Answers -pH = -log[H3O+]
Define pKa - Correct Answers -The pKa is the pH at which the concentration of the acid
form of a molecule is equal to the concentration of the base form of the same molecule.
In other words, half the molecules are in the acid form, and half are in the base form.
pKa = -log(Ka)
State the Henderson-Hasselbalch equation and explain what it is used for. - Correct
Answers -The Henderson-Hasselbalch equation is used to relate the pH of a solution
containing a mixture of the two components to the acid dissociation constant, Ka, and
the concentrations of the species in solution.
For weak acids and bases:
Ka = [H+][A-]/[HA]
pH = pKa + log[A-]/[HA]
isotonic solution - Correct Answers -A solution with the same concentration of water and
solutes as inside a cell, resulting in the cell retaining its normal shape because there is
no net movement of water.
QUESTIONS WITH CORRECT
ANSWERS
Anatomy of a cell - Correct Answers -Nucleolus, nuclear envelope ,nucleus, Rough
Endoplasmic Reticulum (RER)
Nucleus - Correct Answers -A part of the cell containing DNA and RNA
Nucleolus - Correct Answers -Found inside the nucleus and produces ribosomes; rRNA
synthesis
nuclear envelope - Correct Answers -A double membrane that surrounds the nucleus in
the cell; continuous with RER
Rough Endoplasmic Reticulum (RER) - Correct Answers -contains ribosomes made
from rRNA
Ribosomes - Correct Answers -site of protein synthesis
Smooth Endoplasmic Reticulum - Correct Answers -protein modification and membrane
synthesis
transport vesicle - Correct Answers -Vesicle that moves molecules between locations
inside the cell.
Golgi complex - Correct Answers -protein sorting
,Peroxisome - Correct Answers -contains enzymes that transfer hydrogen from various
substrates to oxygen, producing and then degrading hydrogen peroxide.
Lysosome - Correct Answers -An organelle containing digestive enzymes
plasma membrane - Correct Answers -A selectively-permeable phospholipid bilayer
forming the boundary of the cells
cytoskeleton - Correct Answers -network of protein filaments within some cells that
helps the cell maintain its shape and is involved in many forms of cell movement
Mitochondria - Correct Answers -Powerhouse of the cell, organelle that is the site of
ATP (energy) production; contains own single circular DNA, ribosomes and proteins
Endosome - Correct Answers -vesicle pinched in from the cell membrane
Secretory vesicle - Correct Answers -vesicle that releases molecules from the cell
When a secreted protein is synthesized, what is the order of locations for the movement
of this protein through the cell? - Correct Answers -RER-->SER-->Golgi-->Secretory
vesicle
perinuclear space - Correct Answers -Between the two layers of the nuclear envelope
nuclear lamina - Correct Answers -scaffolding for the chromosomes and nuclear pores
Central Dogma of Molecular Biology - Correct Answers -DNA-transcription-->RNA-
translation-->protein
Zellweger syndrome - Correct Answers -Peroxisomal disease; can't metabolize very
long chain FA (VLCFAs) or branched-chain FAs (e.g. phytanic acid, via alpha-
oxidation). Can't form myelin in CNS. Hypotonia, seizures, hepatomegaly, MR, early
death.
Prokaryotic cell - Correct Answers -cell that does not have a nucleus or other
membrane-bound organelles; same size as a mitochondria
Pili - Correct Answers -provide points of adhesion to surface of other cells
Flagella - Correct Answers -propel cell through its surroundings
Most common elements - Correct Answers -H, Na, K, Ca, C, N, O, P, S, Cl
Atomic number - Correct Answers -number of protons
,Atomic mass - Correct Answers -protons + neutrons
octet rule - Correct Answers -in forming compounds, atoms tend to achieve the electron
configuration of a noble gas
Number of electrons - Correct Answers -Number of protons
Total electrons in Nitrogen - Correct Answers -7
Total electrons in Carbon - Correct Answers -6
Total electrons in Oxygen - Correct Answers -8
Total electrons in Hydrogen - Correct Answers -1
# bonds H forms - Correct Answers -1
# bonds Boron forms - Correct Answers -3
# bonds Carbon forms - Correct Answers -4
# bonds Nitrogen forms - Correct Answers -3
# bonds Phosphorous forms - Correct Answers -3 or 5
# bonds Oxygen forms - Correct Answers -2
# bonds Sulfur forms - Correct Answers -2 or 6
# bonds Fluorine forms - Correct Answers -1
# bonds Chlorine forms - Correct Answers -7
Neutrons in an isotope - Correct Answers -atomic mass of isotope minus # protons
Nuclear pore - Correct Answers -passageway for molecules into and out of the nucleus
Endocytosis - Correct Answers -Active transport process where a cell engulfs materials
with a portion of the cell's plasma membrane and releases the contents inside of the
cell.
valence electrons - Correct Answers -Electrons on the outermost energy level of an
atom
Why is water polar? - Correct Answers -the oxygen atom has a slight negative charge
and the 2 hydrogen atoms have a slight positive charge;
, hydrogen bonding - Correct Answers -the intermolecular force in which a hydrogen
atom that is bonded to a highly electronegative atom is attracted to an unshared pair of
electrons of an electronegative atom in a nearby molecule
Hydronium ion - Correct Answers -H3O+; protonated water molecule
hydroxide ion - Correct Answers -OH-; loss of proton from a water molecule
Keq - Correct Answers -=[H+][OH-]/[H2O]
Kw at neutral pH - Correct Answers -=1x10^-14 = [H+][OH-]
What is the H+ and OH- concentration at neutral pH? - Correct Answers -1x10^-7 = [H+]
= [OH-]
Define pH - Correct Answers -pH = -log[H3O+]
Define pKa - Correct Answers -The pKa is the pH at which the concentration of the acid
form of a molecule is equal to the concentration of the base form of the same molecule.
In other words, half the molecules are in the acid form, and half are in the base form.
pKa = -log(Ka)
State the Henderson-Hasselbalch equation and explain what it is used for. - Correct
Answers -The Henderson-Hasselbalch equation is used to relate the pH of a solution
containing a mixture of the two components to the acid dissociation constant, Ka, and
the concentrations of the species in solution.
For weak acids and bases:
Ka = [H+][A-]/[HA]
pH = pKa + log[A-]/[HA]
isotonic solution - Correct Answers -A solution with the same concentration of water and
solutes as inside a cell, resulting in the cell retaining its normal shape because there is
no net movement of water.
