Cell and Molecular Biology FINAL EXAM
QUESTIONS WITH CORRECT ANSWERS
Acidic amino acids - CORRECT ANSWER✅✅✅Aspartic acid; glutamic acid
Activators - CORRECT ANSWER✅✅✅Sites around promotor that can enhance binding/stabilize RNA
polymerase binding; normally upstream of promotor
Active transport - CORRECT ANSWER✅✅✅Uniport, symport, antiport- primary/secondary:
Na+/K+ ATPase pump (primary)
SGLT1 in intestine/renal proximal tubule (symport)
NCX/AE1 in cardiac cells/erythrocyte membranes (antiport)
NHE vertebrate cells/PepT in small intestine (antiport)
Allostery - CORRECT ANSWER✅✅✅Regulatory mechanism for proteins that require additional
molecules to allow them to bind to DNA. Molecules bind to DNA-binding proteins causing a
conformational change that alters how it binds to DNA; allowing for activation/inhibition of gene
expression in response to stimuli. Different types:
Inducible repressors: Do not inhibit transcription when bound to effector molecule
Repressible repressors: Inhibit transcription when bound to effector molecule
Repressible activators: Do not activate transcription when bound to effector molecule
Inducible activators: Cause transcription when bound to effector molecule
Amino acid activation - CORRECT ANSWER✅✅✅Amino acid bound to enzyme via enzyme
aminoacyl-tRNA synthase; resulting in aminoacyl adenylate intermediate
1) Aminoacyl adenylate undergo nucleophilic attack by an uncharged tRNA to then be joined by an ester
bond; charging tRNA
,2)Aminoacyl-tRNA synthetase, the same enzyme involved in amino acid activation, facilitates this
reaction; resulting in tRNA now has an amino acids attached ready for translation
20 aminoacyl-tRNA syntheses for each amino acid; which recognizes tRNA anticodon through
complementary binding sites within enzyme/specific stem sequence
Each synthetase also has synthesis site with specific affinity for each amino acid where
activation/charging occurs; as well as editing functions so they can actually check/correct wrong amino
acid has been added to tRNA. Correct amino acid cannot enter editing site
Anaphase I vs. II - CORRECT ANSWER✅✅✅0 normal cells; 2 normal cells
Anaphase Promoting Complex (APC) - CORRECT ANSWER✅✅✅Promotes destruction of
cyclins/mitotic exit; allowing telophase to start
Anaphore A - CORRECT ANSWER✅✅✅Chromosomes are pulled polewards. Shortening of
kinetochore microtubules due to forces generated at kinetochores to move chromosomes towards their
spindle pole
Anaphore B - CORRECT ANSWER✅✅✅Poles pushed/pulled apart. Sticking force generated between
interpolar microtubules from opposite poles to push poles apart. Pulling force acts directly on them to
to move them apart. Microtuble growth at plus end of inter polar microtubules
Anticodon - CORRECT ANSWER✅✅✅tRNA sequence that is complementary to mRNA. 3rd base on
wobble to bind to other nucleotide bases that it doesn't normally bind to- non-Watson-Crick base
pairing. Additional space allows bit of RNA to move away from complementary strand. 6th nucleotide
(inosine) can be included
Autophagy - CORRECT ANSWER✅✅✅1) Autophagy induction signal leads to phagophore formation
2) Ubiquinatin-like reactions/LC3 conjugates to membrane (elongates photophore membrane)
3) Cytoplasmic components are enwrapped by phagophore
4) At the end of elongation; double membrane residue formed (autophagosome) delivered to fuse with
lysosome to form autolysosome, will degrade components
, 5) ER-localized transmembrane protein VMP1 mediates ER-phagophore dissociation via SERCA
activation/perturbing local Ca2+ concentration
Bacterial genes - CORRECT ANSWER✅✅✅Consist of promotor region, transcriptional start site, and
transcriptional terminator site
Basic amino acids - CORRECT ANSWER✅✅✅Histidine; lysine; arginine
Breakdown/reformation of nuclear envelope - CORRECT ANSWER✅✅✅Phosphorylation of nuclear
laminate that count inner membrane of nucleus inhibits their interactions; causing breaking up of
nuclear lamina/attached nuclear membrane while mitotic CDK complexes are activated. CDK
inactivation causes nuclear membrane to reform
CAP binding to Lac Operon - CORRECT ANSWER✅✅✅1) Cell runs out of ATP; producing cyclic AMP
from breaking down to ATP
2) Cyclic AMP binds to cAMP-bound catabolic activator protein (CAP)
3) Cyclic AMP acts as CAP inducible activator, which can bind to CAP binding site upstream of promoter
4) If there is no lactose to convert into glucose; repressor remains bound to DNA to prevent CAP from
helping with RNA polymerase binding. If lactose is present it is metabolized into allolactose by β-
galactosidase, which is always present in cell/acts as detector system
5) Allolactose acts as inducible repressor and binds to Lac Operon protein; causing it to undergo
conformational change/not be able to bind to operator site
6) Lac repressor protein removal from operator causes RNA polymerase w/ σ factor to bind to DNA using
CAP
7) Transcription occurs, creating RNA transcript with genes needed to make proteins, allowing lactose to
be transported into cell/broken down into glucose
8) Cyclic AMP generation reduces as glucose meets all cell energy requirements
9) Cycle restarts when lactose/allolactose levels drop/Lac repressor binds to operator
Similar mechanism for tryptophan biosynthesis- high tryptophan levels acts as repressible
repressor/turns off Operon
High maltose levels binds maltose activator protein itself for gene expression for maltose metabolism.
Low levels reduce transcription/gene expression of operon
QUESTIONS WITH CORRECT ANSWERS
Acidic amino acids - CORRECT ANSWER✅✅✅Aspartic acid; glutamic acid
Activators - CORRECT ANSWER✅✅✅Sites around promotor that can enhance binding/stabilize RNA
polymerase binding; normally upstream of promotor
Active transport - CORRECT ANSWER✅✅✅Uniport, symport, antiport- primary/secondary:
Na+/K+ ATPase pump (primary)
SGLT1 in intestine/renal proximal tubule (symport)
NCX/AE1 in cardiac cells/erythrocyte membranes (antiport)
NHE vertebrate cells/PepT in small intestine (antiport)
Allostery - CORRECT ANSWER✅✅✅Regulatory mechanism for proteins that require additional
molecules to allow them to bind to DNA. Molecules bind to DNA-binding proteins causing a
conformational change that alters how it binds to DNA; allowing for activation/inhibition of gene
expression in response to stimuli. Different types:
Inducible repressors: Do not inhibit transcription when bound to effector molecule
Repressible repressors: Inhibit transcription when bound to effector molecule
Repressible activators: Do not activate transcription when bound to effector molecule
Inducible activators: Cause transcription when bound to effector molecule
Amino acid activation - CORRECT ANSWER✅✅✅Amino acid bound to enzyme via enzyme
aminoacyl-tRNA synthase; resulting in aminoacyl adenylate intermediate
1) Aminoacyl adenylate undergo nucleophilic attack by an uncharged tRNA to then be joined by an ester
bond; charging tRNA
,2)Aminoacyl-tRNA synthetase, the same enzyme involved in amino acid activation, facilitates this
reaction; resulting in tRNA now has an amino acids attached ready for translation
20 aminoacyl-tRNA syntheses for each amino acid; which recognizes tRNA anticodon through
complementary binding sites within enzyme/specific stem sequence
Each synthetase also has synthesis site with specific affinity for each amino acid where
activation/charging occurs; as well as editing functions so they can actually check/correct wrong amino
acid has been added to tRNA. Correct amino acid cannot enter editing site
Anaphase I vs. II - CORRECT ANSWER✅✅✅0 normal cells; 2 normal cells
Anaphase Promoting Complex (APC) - CORRECT ANSWER✅✅✅Promotes destruction of
cyclins/mitotic exit; allowing telophase to start
Anaphore A - CORRECT ANSWER✅✅✅Chromosomes are pulled polewards. Shortening of
kinetochore microtubules due to forces generated at kinetochores to move chromosomes towards their
spindle pole
Anaphore B - CORRECT ANSWER✅✅✅Poles pushed/pulled apart. Sticking force generated between
interpolar microtubules from opposite poles to push poles apart. Pulling force acts directly on them to
to move them apart. Microtuble growth at plus end of inter polar microtubules
Anticodon - CORRECT ANSWER✅✅✅tRNA sequence that is complementary to mRNA. 3rd base on
wobble to bind to other nucleotide bases that it doesn't normally bind to- non-Watson-Crick base
pairing. Additional space allows bit of RNA to move away from complementary strand. 6th nucleotide
(inosine) can be included
Autophagy - CORRECT ANSWER✅✅✅1) Autophagy induction signal leads to phagophore formation
2) Ubiquinatin-like reactions/LC3 conjugates to membrane (elongates photophore membrane)
3) Cytoplasmic components are enwrapped by phagophore
4) At the end of elongation; double membrane residue formed (autophagosome) delivered to fuse with
lysosome to form autolysosome, will degrade components
, 5) ER-localized transmembrane protein VMP1 mediates ER-phagophore dissociation via SERCA
activation/perturbing local Ca2+ concentration
Bacterial genes - CORRECT ANSWER✅✅✅Consist of promotor region, transcriptional start site, and
transcriptional terminator site
Basic amino acids - CORRECT ANSWER✅✅✅Histidine; lysine; arginine
Breakdown/reformation of nuclear envelope - CORRECT ANSWER✅✅✅Phosphorylation of nuclear
laminate that count inner membrane of nucleus inhibits their interactions; causing breaking up of
nuclear lamina/attached nuclear membrane while mitotic CDK complexes are activated. CDK
inactivation causes nuclear membrane to reform
CAP binding to Lac Operon - CORRECT ANSWER✅✅✅1) Cell runs out of ATP; producing cyclic AMP
from breaking down to ATP
2) Cyclic AMP binds to cAMP-bound catabolic activator protein (CAP)
3) Cyclic AMP acts as CAP inducible activator, which can bind to CAP binding site upstream of promoter
4) If there is no lactose to convert into glucose; repressor remains bound to DNA to prevent CAP from
helping with RNA polymerase binding. If lactose is present it is metabolized into allolactose by β-
galactosidase, which is always present in cell/acts as detector system
5) Allolactose acts as inducible repressor and binds to Lac Operon protein; causing it to undergo
conformational change/not be able to bind to operator site
6) Lac repressor protein removal from operator causes RNA polymerase w/ σ factor to bind to DNA using
CAP
7) Transcription occurs, creating RNA transcript with genes needed to make proteins, allowing lactose to
be transported into cell/broken down into glucose
8) Cyclic AMP generation reduces as glucose meets all cell energy requirements
9) Cycle restarts when lactose/allolactose levels drop/Lac repressor binds to operator
Similar mechanism for tryptophan biosynthesis- high tryptophan levels acts as repressible
repressor/turns off Operon
High maltose levels binds maltose activator protein itself for gene expression for maltose metabolism.
Low levels reduce transcription/gene expression of operon
