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WorksheetsBSCI330
Total questions: 140
Worksheet time: 1hrs 11mins
Vesicles are a common feature of eukaryotic cells. Which of the is FALSE about vesicles:
they use cargo receptors to capture proteins being transported
coat proteins on vesicle bind t-snares on target organelle
they can be transported along microtubules using motor proteins
all of the above
none of the above
Vesicles are a common feature of eukaryotic cells. Which of the is FALSE about vesicles:
they use cargo receptors to capture proteins being transported
Coat proteins facilitate fusion with target membrane
they can be transported along microtubules using motor proteins
all of the above
none of the above
Simple diffusion and transport -mediated diffusion are two kinds of passive transport. Which of the following statements describes simple diffusion but NOT transporter-mediated diffusion?
Transporter kinetics shows a linear relationship with concentration
Transport can occur against a concentration gradient
Transport can be saturated
All of the above
Symporters are transporters that move:
A single substance against its concentration gradient
One substance up its concentration gradient and another substance down its concentration gradient
Two different substances in the same direction
Two different substances in opposite directions
Which of the following is TRUE about a nuclear import sequence?
It consists of at least 8 non-polar amino acids in a row
It consists of an amphiphatic alpha helix
It consists of at least 5 basic amino acids in a row
It uses the amino acid sequence lysine-aspartic acid-glutamine acid-leucine (KDEL)
The helicase is a crucial machine for DNA replication. Which of the following is true?
It hydrolyzes ATP to unzip DNA
It holds DNA polymerase on the template to ensure processivity
It seals the gaps between Okazaki fragments
It introduces a nick into DNA to relieve torsional stress
Which of the following statements about the genetic code is TRUE?
Some codons do not encode any amino acid
Most amino acids are encoded by more than one codon
The initiation codon establishes the reading frame for the ribosome
Every possible codon has some function in translation
All of the above
Which of the following is NOT catalyzed by an aminoacyl-tRNA synthetase?
Attachment of amino acid to AMP
Attachment of amino acid to tRNA
Proofreading to ensure the correct amino acid is attached to the tRNA
Fromation of a peptide bond between two amino acids
None of the above (i.e all are performed by the aminoacyl-tRNA synthetase)
Which of the following is TRUE about enzyme catalysis?
Enzymes do not change the ∆G for a chemical reaction
Enzymes increase the activation energy for a chemical reaction
Enzyme shift the equilibrium point to increase product concnetration
Enzymes increase the rate of the forward reaction but not the reverse reaction
All of the above
Many enzymes that perform redox reactions in cells require NAD+. The NAD+ would be considered
An allosteric regulator
A coenzyme
A chaperone
A motif
Which of the following components of the protein synthesis pathway does NOT hydrolyze either ATP or GTP hydrolysis as part of its function?
EF-Tu
Aminoacyl-tRNA synthetase
eIF2
Ribosome
One measure of the binding interaction between a protein and its ligand is the dissociation constant, Kd. Which of the following is true about this value?
The Kd, is equal to Koff/Kon
The lower the Kd, the weaker the binding
The higher the Kd, the faster the on rate for binding
The lower the Kd, the faster the off rate for dissociation
None of the above
Which of the following is NOT a property of the homeodomain DNA binding motif?
Contains 3 α-helices
Contains a structure very similar to a helix-turn-helix
Contains a zinc ion
Makes contacts in both major and minor grooves of DNA
Which of the following is NOT a reason for a molecular tunnel structure in an enzyme?
It prevents the reaction intermediates from diffusing away
It prevents reactive intermediate species from interacting with water
It isolates toxic intermediate products from harming the cell
It slows down the reaction to allow for greater regulation
None of the above
Vesicles are common feature of eukaryotic cells. Which of the following is TRUE about vesicles:
They use cargo receptors to capture proteins being transported
Coat proteins facilitate fusion with the target memebrane
The RAB GTPase family regulates assembly and disassembly of the protein coat
All of the above
None of the above
The SRP is important for which of the following processes
Alternative splicing of RNA
Gated transport of proteins
Co-translational transport of proteins
Regulation of actin polymerization
Rabs and SNAREs are important for vesicular transport. Which of the following statements about these proteins are true?
Rabs regulate coat protein disassembly and SNAREs regulate membrane fusion
Rabs regulate vesicle trafficking and SNAREs regulate membrane fusion
SNAREs regulate vesicle trafficking and Rabs regulation membrane fusion
SNAREs regulate coat protein disassembly and Rabs regulate vesicle trafficking
Phosphorylation of proteins is useful in regulation function because
It is readily reversible, allowing proteins to be turned on or off quickly
It can generate a new binding site for other proteins, allowing for new protein-protein interactions
It can cause large shape changes, even allowing for pumping action
All of the above
Retrograde transport
Is the transport or proteins from one side of a polarized cell to other side
Is used to transport proteins from the outer mitochondrial membrane to the inner mitochondrial membrane
Allows cargo receptors to be recovered from the Golgi and returned to the ER
Is the process used during exocytosis of secreted proteins
Degradation of proteins via the proteasome
Requires ATP hydrolysis because the cleavage of a peptide bond is energetically
Requires ATP hydrolysis to link ubiquitin to the target protein
Requires GTP hydrolysis as a proofreading step
All of the above
Kinesins are motor proteins that
Move from the plus end of the microfilaments towards the minus end
Move from the minus end of the microfilaments towards the plus end
Move from the plus end of the microtubules towards the minus end
Move from the minus end of the microtubules towards the plus end
What sets the limit of resolution for microscopy?
Wavelength of the light
Size of the lens
Both
Neither
Why does an electron beam give more resolution than light
The wavelength of an electron is much shorter than the wavelength of a photon
Electrons are matter, not energy, and so are intrinsically different from photons
Starch and cellulose are both polymers made up of glucose subunits. Why are we able to digest starch but not cellulose?
Because starch is an energy storage molecule, but cellulose is a structural molecule
We have enzymes that digest the α linkages of starch, but not the β linkages of cellulose
What do we actually mean by a “spontaneous” reaction?
A reaction that will occur without a net addition of energy
A reaction that occurs immediately when the reactants are mixed together
Both
Which of the following would you expect to diffuse freely through the plasma membrane?
Water molecule
Steroid hormones
Glucose
All of the above
Animal cells lack a cell wall. What will happen if animal cells are placed in a highly hypotonic environment?
They will shrink as water flows out
They will expand until they burst
Nothing - animal cells are capable of regulating water flow in and out
Prokaryotes do not contain a nucleus. What does that tell us about their DNA?
It floats around freely in the cytoplasm
There might be some organized nucleus-like structure but it is not bounded by a membrane
Which structure(s) would you expect to find in a prokaryotic chromosome?
Telomere
Centromere
Origin of Replication
All of the above
Does the Central Dogma apply to all cases of biological information?
Yes - as far as we know it is a universal law
No- there are well-known exceptions
What is a result of the "degenerate" nature of the genetic code?
For a given RNA sequence there may be more than one protein sequence
For a given protein sequence there may be more than one RNA sequence
Does an in-frame stop codon always terminate translation?
Yes - that is why they are called stop codons
No - there are circumstances where a stop codon is translated to insert an amino acid
You are studying a protein that is turned on by phosphorylation at a specific serine residue. What do you expect would happen if the serine is mutated to aspartic acid?
It would become impossible for the protein to be turned on
The protein will always be turned on
Which of the following represents the stronger protein-ligand interaction?
Antibody binding to bacterial toxin with a Kd of 10-12 M
Calmodulin binding to calcium with a Kd of 10-6 M
What has happening to an enzyme if the Km was reduced?
The amount of substrate required to half-saturate the enzyme was lowered
a
The binding interaction between the enzyme and substrate became stronger
Both
Neither
Which of the following inhibitors could be overcome by increasing the concentration of the enzyme’s usual substrate?
sarin gas – binds to the catalytic site of acetylcholinesterase and phosphorylates a critical serine residue, inhibiting the catalytic function
methotrexate – binds to the catalytic site of dihydrofolate reductase and inhibits folate from binding
both, since both work by binding to the catalytic site
Cell communication is like human communication. Which of the following is like paracrine signaling?
A telephone conversation
Talking with people at a cocktail party
A radio announcement
Talking to yourself
How many different sequences could be recognized by dimerization of a TF that has 3 different pairing partners, A, B, and C?
3
6
9
This type of reaction combines two smaller molecules (such as two amino acids) to form a larger one.
Condensation
Hydrolysis
Proteolysis
Isomerization
Which of the following is NOT a carbohydrate polymer?
Cellulose
Glycogen
Chitin
phosphatidylcholine
Which of these techniques has the HIGHEST level of resolution?
Visible light microscopy
Fluorescence Microscopy
Scanning electron microscopy
Confocal microscopy
This class of covalent bond links two nucleotides in a nucleic acid
Glycosidic Bond
Phosphodiester bond
Peptide bond
Nucleotic bond
Which of the following is NOT advantage of light microscopy over electron microscopy?
Ability to visualize in multiple colors
Ability to visualize living cells
Ability to visualize cells within intact tissue
Ability to determine structure of macromolecular complexes
DNA in the nucleus is packaged as chromatin. Which of the following statements about chromatin is FALSE?
The basic unit of chromatin, the nucleosome, contains DNA wrapped around a histone octamer core
he nuclear lamina serves as a scaffold for higher order chromatin structure
Euchromatin contains DNA sequences that are not expressed, including the centromeres.
Chromatin is a dynamic structure, which can condense and open as needed by the cell
Which of the following statements about the plasma membrane of animal cells is TRUE?
There is asymmetric distribution of phospholipids between the inner and outer leaflets
The membrane is supported by a cellulose meshwork
Sphingolipids are the most abundant type of lipids in the membrane
There is little or no lateral diffusion of lipids within a leaflet of the membrane
All of the above answers are true
This component of the plant cell wall forms a gel that provides resistance to compression.
Cellulose
Pectin
Lignin
Remodeling enzymes
Which of the following models describes the structure of the plasma membrane?
The endosymbiotic theory
The induced fit model
The central dogma
The fluid mosaic model
Which of the following statements about turgor pressure is FALSE?
It is highest when the extracellular environment is hypotonic
It relies on osmosis of water into the cell
It provides rigidity to animal cells
None of the above
Which of the following statements about the nuclear membrane is TRUE?
It is supported by the meshwork of the nuclear lamina
It is continuous with the endoplamic reticulum
It has a double-membrane (two lipid bilayers) structure
All of the above
None of the above
Which of the following does not result from the amphipathic nature of phospholipids?
Formation of lipid micelles
Formation of lipid bilayers
Formation of closed (e.g. spherical) membrane structures
Ability of charged molecules to readily diffuse through membranes
None of the above
Which of the following statements about nuclear pores is TRUE?
Ions and small molecules can diffuse freely through the pores, but larger molecules require active transport mechanisms to pass through the pores
The pores allow unrestricted access to all molecules, large and small
The pores are used to import substances into the nucleus, but export of materials out of the nucleus uses a different mechanism
Nuclear pores open and close in response to changes in voltage across the nuclear membrane
What is the function of the nucleolus?
Ribosome assembly
Protein translation
Initiation of DNA replication
Regulation of transport into and out of the nucleus
Which of the following statements about the genetic code is FALSE?
AUG, the start codon, codes for methionine
A three-base codon system contains 24 possible codons
Multiple codons can encode for the same amino acid
Stop codons do not code for amino acids
Which of the following statements about ribosomes is TRUE?
Ribosomes are surrounded by the ribosomal membrane
Bacterial ribosomes are larger and more complex than eukaryotic ribosomes
Ribosomes synthesize cytoplasmic proteins, but not secreted proteins
The individual ribosome subunits are assembled in the nucleolus, a substructure of the nucleus
Which of the following is NOT a function of the Golgi apparatus?
Modification of N-linked glycosylation on proteins
Attachment of O-linked glycosylation to proteins
Synthesis of carbohydrates
Sorting of proteins to other organelles
None of the above
Which of the following is a function of the 5' methylguanosine cap?
Protect the 5' end of the RNA from degradation in the cytosol
Serve as a binding site for the ribosome
Interact with the 3' poly-A tail to enhance translation
All of the above
Which of the following is a property of the inner mitochondrial membrane?
It is folded into cristae
It is rich in the unusual lipid cardiolipin
TheIt contains the electron transport chain
All of the above are true
None of the above are true
Which of the following is a property of RNA splicing?Splicing occurs in the cytosol after RNA is exported from the nucleus
Splicing occurs in the cytosol after RNA is exported from the nucleus
An RNA transcript can only be spliced in one way by any given cell type
Alternative splicing can generate different protein sequences from the same original RNA sequence
Most prokaryotic genes have introns that must be spliced out
How is tRNA charged?
It is covalently attached to AMP
It is covalently attached to an aminoacyl-tRNA synthetase
It is covalently attached to an amino acid
All of the above
Which of the following is true about the process of translation?
GTP is hydrolyzed at several important steps
The catalytic component of the ribosome is composed of RNA
The translation initiation complex contains a special initiator tRNA
All of the above
None of the above
Which of the following organelles is surrounded by a double-membrane (i.e. two complete lipid bilayers) structure?
Chloroplast
Endoplasmic reticulum
Golgi apparatus
Ribosome
Which of the following is a possible property of a prokaryotic cell
Proteins are synthesized by ribosomes
Proteins are sorted to different cellular locations by the Golgi apparatus
Cellular metabolism occurs in mitochondria
All of the above
The secondary structure of a protein is held together by which of the following?
Non-covalent interactions between R-groups
Peptide bonds between amino acids
Hydrogen bonds between carbonyl and amine groups in the peptide backbone
Disulfide bonds
Which of the following will occur when an enzyme binds a competitive inhibitor?
the Kd will increase but Vmax will not change
The Vmax will decrease but Kd will not change
Kd will increase and Vmax will decrease
There is not enough information to determine
How are molecular pump proteins able to generate directional motion, when protein shape changes are reversible?
By only moving substrates down a concentration gradient
By always moving one substrate in one direction, and a second substrate in the opposite direction
By coupling shape changes to ATP hydrolysis
None of the above
Which class of enzymes covalently add phosphate groups to proteins?
Phosphatases
Kinases
Phosphorylases
Tyrosinases
A protein domain that is found in many related proteins is called a(n)
motif
exon
Secondary structure
None of the above
Which of the following is true of enzyme catalysis?
Enzymes speed up reactions by decreasing the free energy of the products
Enzymes speed up reactions by decreasing the activation energy
Enzymes speed up reactions by destabilizing the intermediate states
All of the above are true
Which of the following describes an allosteric regulator?
Aspirin inhibits the enzyme COX-2 by covalently binding to the active site
cAMP activates protein kinase A by binding to a regulatory site distinct from the active site
cyanide inhibits cytochrome oxidase by binding to the active site
All of the above
None of the above
Which of the following is NOT a consequence of the domain structure of proteins?
Proteins may contain multiple independently functioning parts
Proteins are modular in nature
Protein structures are rigid and inflexible
All of the above
None of the above
Which of the following contributes to the affinity of protein binding to a ligand?
Charge-charge interactions
Having multiple contacts
Having complementary shapes
All of the above
Which of the following is NOT true about protein folding?
It occurs spontaneously
It results in the lowest energy state for the protein
It sometimes requires assistance from a chaperone protein
It always requires an input of energy
Which of the following occurs when an enzyme binds a non-competitive inhibitor?
The Kd will increase but Vmax will not change
The Vmax will decrease but Kd will not change
The Vmax will decrease but Kd will not change
There is not enough information
Which of the following statements about enzymes is FALSE
Enzymes do not change the ∆G for a chemical reaction
Enzymes cannot change the equilibrium ratio of reactants and products
Enzymes can convert a non-spontaneous reaction to a spontaneous reaction
All of the above
None of the above
An allosteric regulator of an enzyme
Binds to a site away from the active site
Causes a shape change in the enzyme that affects enzyme function
Binds non-covalently to an enzyme
All of the above
None of the above
Which of the following is FALSE about signaling molecules?
The effect of a signaling molecule depends on the cell type on which it is acting.
Cells typically need signals to stay alive.
The concentration of a signaling molecule is not important for the cellular response.
There are signaling molecules that can cross cell membranes.Microfibers
Which of the following is NOT a feature of G-protein-coupled receptor mediated signaling?
GPCRs bind to hydrophobic ligands and translocate to the nucleus
GPCRs contain transmembrane domains
Ligand binding on GPCRs causes exchange of GDP for GTP in trimeric G-proteins
Cyclic AMP may serve as a second messenger downstream of GPCRs
Which of the following accurately describes how signaling molecules act in autocrine signaling?
Signaling molecule acts on the same cell that secreted it
Signaling molecule acts on neighboring cells
Signaling molecule enters the bloodstream and acts on distant cells
None of the above
The second messenger inositol trisphosphate (IP3) causes calcium ions to:
Be pumped from the cytosol to the ER
Be secreted from the cell
Be released from the ER
None of the above
Which of the following is an advantage of a kinase cascade?
Amplifies signal during the process of transduction
Slows signal transduction to prolong signal
uses less energy than a non-cascade pathway
None of the above
Which of the following is a function of molecular tunnels in enzymes?
Helps prevent intermediate products from diffusing away
Prevents reactive intermediates from interacting with the aqueous environment
Ensures that multi-step reactions occur in the correct order
All of the above
None of the above
Steroid hormones
Signal via G-protein-coupled receptors
Bind cytosolic receptors and induce nuclear translocation
Are hydrophilic molecules that cannot cross the plasma membrane
All of the above
Which of the following is TRUE about zinc finger proteins?
Multiple zinc finger domains can be strung together to recognize a long sequence.
All zinc finger proteins recognize the same DNA sequence.
Some zinc finger proteins do not coordinate a zinc ion.
Zinc finger proteins generally bind carbohydrates.
True or False: Most gene regulatory proteins make contacts with the minor groove of DNA.
True
False
True or False: You can create a whole sheep from the nucleus of one of its skin cells by combining that nucleus with an egg cell without a nucleus.
Correct!
True
False
Regulation at the drosophila 'Eve' gene exemplifies complex control regions that:
Can be found in plants and animals
Can respond to many different inputs, and integrate this information
Can produce a complex spatial and temporal output as development proceeds
All of the above
Which of the following accurately describes how a cell can control the proteins it makes?
RNA processing
Transcriptional
Protein activity
All of the above
Which of the following does NOT accurately describe riboswitches:
Their function is enhanced by DNA polymerase
They are particularly common in bacteria
They are often located near the 5' end of mRNAs
They change their conformation upon binding small molecules
Which of the following is NOT a mechanism of epigenetic inheritance?
Methylation of DNA on CpG sequences
Positive feedback loop maintaining expression of a protein
Removal of introns during RNA splicing
Modification of chromatin structure by acetylation of histones
Which of the following is a function of an IRES?
Allows the ribosome to bind to an internal sequence instead of the 5' cap
Represses translation by preventing ribosome binding
Causes rapid protein degradation by the proteasome
inhibits translation by inactivating initiation factor eIF2
Which of the following is involved in the siRNA pathway but NOT the microRNA pathway?
Slicer
Dicer
RISC
RITS complex
The 5' UTR, but NOT the 3' UTR, may be involved in regulating translation.
True
False
Which of the following receptors is involved in retrograde transport from the Golgi to the ER?
KDEL receptor
Mannose 6-phosphate receptor
PIP-3 receptor
All of the above
None of the above
Which of the following is an example of transmembrane transport?
Transport of a protein from the cytosol to the nucleus
Transport of a protein from the cytosol to the ER
Transport of a protein from the Golgi apparatus to the endosomes
Transport of a protein from the ER to the Golgi apparatus
All of the above
Which of the following is required for transport of a protein from the cytosol into the mitochondrial matrix?
Signal recognition particle
COPII
TOM
Ran
Which of the following compartments is topologically similar to the ER?
Golgi apparatus
Lysosomes
Exterior of the cell
All of the above
None of the above
Which of the following is NOT true about an ER signal sequence?
It forms an amphipathic alpha helix
It contains at least 8 non-polar amino acids in a row
It is generally at the N-terminus of the protein
It is recognized by the SRP
Which of the following is NOT required for export of a protein from the nucleus to the cytosol?
Ran-GDP
Ran-GTP
Nuclear export receptor
None of the above
Which of the following is a role for v-SNARE?
Correct!
Interacts with t-SNARE on target membrane to initiate vesicle fusion
Interacts with t-SNARE on vesicle to initiate fusion with target membrane
Interacts with t-SNARE on plasma membrane to initiate endocytosis
All of the above
Which of the following is a feature of regulated secretion?
Concentration of cargo in a specialize vesicle
Vesicle fusion with plasma membraane
Secretion depends on signals from outside the cell
All of the above
None of the above
Antiporters are transporters that move:
Two different substances in the same direction
Two different substances in opposite directions
A single substance against its concentration gradient
A single substance down its concentration gradient
Which of the following molecules CANNOT simply diffuse across a lipid bilayer
O2
chloride ions
Cortisol
CO2
Which of the following statements about actin monomers is TRUE?
Actin monomers bind GTP
Actin monomers are composed of alpha and beta actin
Actin monomers are known as F actin
All of the above
None of the above
Which of the following statements about cytoskeletal proteins is FALSE?
The cytoskeleton is essentially static and does not change over the lifetime of a cell
The cytoskeleton provides structural support to the cell and its internal components
Cytoskeletal proteins like actin and tubulin are highly conserved over evolution
All of the above
None of the above
Which of the following is true of kinesins?
They move from minus end to plus end on microtubules
They move from minus end to plus end on microfilaments
They move from plus end to minus end on microtubules
They move from plus end to minus end on microfilaments
Which of the following is TRUE about DNA replication?
The lagging strand is synthesized as one continuous strand
The DNA helicase is loaded on the lagging strand template
Okazaki fragments are synthesized on the leading strand
Loading of the sliding clamp on DNA does not require ATP
The semiconservative nature of DNA replication means that some parts of a DNA molecule are replicated and other parts are not.
True
False
Which of the following does NOT contribute to reducing the error rate of DNA replication?
5' to 3' replication
strand-directed mismatch repair
nuclear membrane
3' to 5' exonucleolytic proofreading
Activation of the Rho GTPase leads to bundling of actin microfilaments into a structure called:
stress fibers
microfibers
microspikes
pseudofilaments
Which of the following is NOT a role for actin-myosin complexes?
Contractile ring in cytokinesis
Separation of chromosomes in mitosis
Muscle contraction
Movement of vesicles in the cytoplasm
None of the above (i.e. all are functions)
The addition of nucleotides by DNA polymerase during DNA synthesis requires a primer.
True
False
A question on beer: Which of the following is true about the production of alcohol by fermentation?
Glucose is converted to glycogen
Pyruvate is converted to ethanol
A net of 4 ATP is produced per glucose molecule
It only occurs in the presence of oxygen
All of the above
Which of the following is true of photosynthesis?
Light reactions lead to the production of ATP and NADPH
Dark reactions can only occur in the absence of light
Dark reactions can only occur in the absence of light
The reactions all occur in the thylakoid space
The reactions all occur in the thylakoid space
Which of the following is NOT an example of substrate-level phosphorylation?
Generation of ATP during glycolysis
Generation of GTP during the citric acid cycle
Generation of ATP by ATP synthase via chemiosmosis
None of the above (i.e. all are substrate-level phosphorylation)
True or false: Glycolysis occurs in mitochondria
True
False
Which of the following is a property of metabolic cycles (such as the citric acid cycle)?
Allow multiple points of entry, so a variety of substrates can be utilized
Allow multiple points of regulation
Generate new biomolecules that can be used by the cell
All of the above
Which of the following is NOT a common feature of glucose oxidation and photosynthesis?
Both use proton gradients to generate ATP
Both involve the reduction of NAD+ to NADH
Both utilize electron transport chains
Both use metabolic cycles
None of the above (i.e. all are common to both processes)
At what point in photosynthesis is water split?
During the light reactions, as the final electron acceptor for the first electron transport chain
During the light reactions, to replace the electrons lost by Photosystem II
During the dark reactions, to fix carbon dioxide
During the dark reactions, to oxidize NADPH
Which of the following metabolic steps requires the expenditure of energy?
Activating glucose by phosphorylation
Transporting pyruvate from the cytosol into the mitochondrion
Fixing carbon in the Calvin cycle
All of the above
What is the role of molecular oxygen during glucose metabolism?
Oxidation of glyceraldehyde 3-phosphate to generate NADH
Oxidation of pyruvate to generate acetyl CoA
Final electron acceptor for the electron transport chain
All of the above
Which of the following is the location of an electron transport chain?
Thylakoid membrane
Outer mitochondrial membrane
Mitochondrial matrix
Chloroplast stroma
All of the above
True or False - Ribosomal RNA acts as a ribozyme, catalyzing peptide bond formation in protein synthesis.
True
False
Which of the following is true of both ribozymes and proteins?
They often work by positioning metal ions at the active sites.
They can have secondary structure.
They can directly guide the formation of copies of their own sequence.
A & B
A, B and C
Which of the following is NOT a hypothesis of the origins of life?
Replication first
Compartmentalization first
Metabolism first
Everything first
None of the above
When miRNA or siRNA associate with the Argonaute proteins, which complex is generated?
A primer
A ribozyme
A guide RNA
None of the above
Which of the following is a potential outcome of homologous recombination?
Repair broken replication forks
Repair double-strand breaks
Cause chromosomal crossovers
All of the above
None of the above
DNA-only transposons require which enzyme(s) to move from one location to another?
integrase
transposase
DNA polymerase
All of the above
Which type of transposon(s) uses an endonuclease-nick mechanism to move?
DNA-only transposon
retrovirus-like retrotransposon
non-retrovirus-like retrotransposon
All of the above
Which is TRUE about both retroviral-like retrotransposons and nonretroviral retrotransposons?
They both have long terminal repeats (LTRs).
They both require integrase for movement.
They both move as DNA.
They both require reverse transcriptase for movement.
Which of the following may be a result of transposon activity?
Corn kernel color variegation
Spreading of bacterial antibiotic resistance
F1 hybrid sterility in fruit flies
All of the above
None of the above
Metastasis is a particularly difficult problem to tackle in cancers. Which of the following is NOT a characteristic of cancer metastases?
They can be detected using the fact that cancer cells consume more glucose than other cells in the vicinity.
Cells that metastasize use extracellular proteases to cut through the extracellular matrix as they move from one place to another.
They can move long distances through capillaries.
They always move to pre-designated places inside an organism
True/False – Even in the absence of any harmful agents, the longer we live the greater our chance of getting cancer.
True
False
True or False: Formation of the mitotic spindle is essential for chromosome segregation in eukaryotic cells.
True
False
Which of the following adhesion molecules is independent of calcium ions?
E-cadherin
L-selectin
LFA-1 (an integrin)
All of the above
None of the above
What kind of feedback loop ensures robust start of events during the cell cycle.
Circular
Negative
Positive
None fo the above
Polarized cells have defined apical and basolateral surfaces. Which type of junction prevents diffusion of proteins between these surfaces?
Desmosomes
Tight Junction
Gap Junctions
None of the above
Which of the following is a major regulatory transition or checkpoint that occurs during the cell cycle?
Metaphase to anaphase transition
G2/M checkpoint
Start Checkpoint
All of the above
Which of the following is frequently mutated in cancer?
Ras
LacZ
Rho
Both a and c
Which of the following kinds of mitotic microtubules bind to identical substrates at their plus ends?
Astral microtubules and kinetochore microtubules
Interpolar microtubules and astral microtubules
Kinetochore microtubules and interpolar microtubules
None of the above
True or false: Apoptosis, or 'programmed cell death' can be visualized in tissues using the TUNEL assay, which detects caspase activation.
True
False
