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1. Activated Opsin (Rh*) binds to Transducin and changes its shape.
2. The α-subunit of Transducin then binds GTP -- it is now activated.
3. The activated α-subunit separates from Transducin and binds to the γ-subunit of PDE.
4. The γ-subunit of PDE normally prevents the α- and β-subunits from functioning.
5. When activated α-subunit of Transducin binds to the γ-subunit of PDE, the shape of the γ-subunit is changed, allowing the rest of PDE to now function.
6. The activated PDE will convert cGMP to GMP. But the cGMP is needed to keep the sodium-calcium (Na+/Ca2+) ion channel open.
7. So activated PDE will reduce the levels of cGMP in the cell, which will result in closure of the channels. This closure results in a change in the balance of electrical charge across the cell membrane.
Uses sodium dodecyl sulfate (SDS)
Load proteins into SDS-PAGE wells
Electrostatic attraction and repulsion moves proteins. More negative go further
Rotate 90 degrees and run it again
Proteins separated on basis of charge and mass
Pulse-chase experiments can track the pathway ofprotein modification or movement within cells.
One of the purposes of protein glycosylation
in the Golgi complex is to
The function of an ARF-GEF is to
The function of AP1 in clathrin complexes can best be compared to which of the following in COPII complexes?
Which of the following chaperones pre-collagen
to the cis-Golgi network?
What happens after the N- and C-terminals
of collagen have been cleaved?
What is the relationship between genes and chromosomes?
a. They are synonymous.
b. Chromosomes can be found in genes.
c. Genes are found in the nucleus.
d. Chromosomes are transcribed from genes.
e. Genes are part of a chromosome.
Evolution predicts that
a. bacteria do not have true nuclei.
b. mitochondrial DNA in both bacteria and humans are similar in sequence.
c. all organisms are related by descent.
d. living things transform energy.
e. people are descendants of monkeys.
a. and Martha Chase established that DNA was the genetic material.
b. translated Alhazen’s Book of Optics from Arabic into Latin.
c. contributed to the formulation of the cell theory.
d. used radioactive phosphorus to experimentally label proteins.
e. was one of two researchers to “rediscover” Gregor Mendel’s paper in AD 1900.
What is the function of adenosine trisphosphate (ATP)?
a. electron carrier
b. short-term energy storage
c. stabilization of hydrogen bonds in DNA
d. activation of enzymes
Where in a molecule is the biologically usable energy stored?
b. lone pair in nitrogen atoms
c. covalent bonds
e. plasma membrane
The Gibbs free energy of a reaction is
a. the sum of usable and unusable energy
b. the difference between enthalpy and entropy
d. the energy that is required to move reactants into their transition states e. negative
Why might a cell synthesize phospholipids that have unsaturated fatty acids?
a. In order to store more energy per phospholipid molecule.
b. Because such molecules are better signaling molecules.
c. To depress its membrane freezing point.
d. So that protons can remain in the intermembranal space of mitochondria.
e. This will allow positively charged ions to pass through its plasma membrane.
The highest level of structure that is possessed by tRNA moleules is
The hydrolysis of ATP
a. is an endergonic reaction
b. helps to store energy that is obtained from glycolysis
c. can result in the production of pyrophosphate
d. occurs at the active site of a phosphatase enzyme
e. will reduce the total entropy of a system
The aggregation of phospholipids in water into bilayers can be ascribed to
a. the hydrolysis of ATP
b. enzymatic activity
c. an increase in usable energy d. the aggregative force
e. a favored increase in entropy
In gel filtration chromatography, what is the void volume?
a. the volume of the column
b. the volume of the solution that is added to the column
c. the volume of the space around the stationary phase
d. the volume of the protein marker
e. the volume of the space that is taken up by the beads
In spectrophotometry, what is the diagnostic wavelength that is used to detect DNA?
a. 200 nm
b. 260 nm
c. 320 nm
d. 380 nm
e. 440 nm
The Transmembrane (TM) domain of Epo-R
a. possesses kinase function
b. is composed of hydrophobic amino acids
c. binds to Epo
d. is located in the cytoplasm
e. is located in the extracellular space
Under normoxic conditions
a. HIF-α is constantly synthesized
b. PHD will methylate HIF-α
c. kidney cells will increase Epo synthesis and release d. the transcription level of the EPO gene will increase
e. PHD will hydroxylate VHL
Structural flexibility of a polypeptide
a. is an emergent property of the zinc-finger motif
b. is limited by the delocalization of electrons in peptide bonds
c. is the result of disulfide bonds
d. can occur because of rotation around phosphodiester bonds e. prevents phosphorylation
According to Frouin et al. (2003), what might be true?
a. The synthesome is inhibited by CDK2.
b. DNA is the genetic material.
c. PAP will cleave a pre-mRNA molecule.
d. eRF1 is required for initiation of eukaryotic translation.
e. The 43S complex requires GTP for its formation.
What function is served by the key amino acids of arginine and lysine in Proliferating Cellular Nuclear Antigen (PCNA)?
a. They allow RNA polymerase to recognize the start codon.
b. They remove erroneous nucleotides in a growing DNA strand.
c. They facilitate binding to DNA.
d. They recognize the 5’-flap of an existing RNA primer.
e. They form the exonuclease active site.
Franklin et al. (2010)
a. proved that behaviors that are learned by parents can be genetically transmitted to offspring
b. demonstrated that depressive-like behaviors affected females and males similarly
c. employed the open-field test to determine the response of mice to an outdoor environment
d. showed a correlation between apparently heritable behavior and DNA methylation patterns
e. reported that mice are good animal models for human depression
How do CFI and CFII “know” where to make the cut on a pre-mRNA molecule?
a. they are both synthesized from information that is contained in mRNA
b. they are first phosphorylated by a kinase
c. a transcription factor binds to them and the cut site
d. they are not targeted for degradation by the being ubiquitinated
e. they are able to recognize a target nucleotide sequence
In eukaryotes, how many GTP are required to generate the first dipeptide of a protein?
a. 1 b. 2 c. 3 d. 4 e. 5
Alternative splicing is a phenomenon that allows for
a. the replication of a haploid genome
b. the replication of more than one allele from a single genome
c. the synthesis of multiple protein isoforms from a single gene
d. the production of a single protein that has more than one possible configuration
e. the analysis of more than one protein via SDS-PAGE
In the Hsp70 cycle, which proteins must be present for ATP to be hydrolyzed?
a. Cdk8 and Hsp17
b. DnaJ and Hsp40
c. Epo and Grp5
d. Hsp90 and JAK2
e. GrpE and BAG1
The greatest improvement of confocal fluorescent microscopy over conventional fluorescent microscopy is that
a. fluorescent molecules will emit more photons
b. emitted light will be of a shorter wavelength than excitatory light
c. light from outside the focal plane is largely excluded from view
d. more kinds of fluorescent labels can be used
e. a circular barrier is placed into the center of the column of light
You are employing FRET to determine whether two endogenous proteins, X and Y, physically bind to each other in vivo. Protein X is covalently bound to CFP. Protein Y is covalently bound to YFP. You shine an excitatory wavelength of light (436 nm) onto your cells. If Proteins X and Y interact, then what kind of light should you see emitted?
a. blue b. cyan c. yellow d. green e. red
Which structure allows a confocal microscope to convey to the researcher only light from an “optical slice” of the specimen?
a. dichromatic mirror
b. excitation filter
c. emission filter
d. photomultiplier detector
What is a gene?
a. It controls the traits that organisms have.
b. A chromosome that is present in the nucleus.
c. Gemmules that are passed from parent to offspring.
d. A sequence of nucleotides that encodes a protein or a RNA.
e. One unit of DNA.
What is the normal function of the product of the LMNA gene?
a. It stabilizes ssDNA during replication.
b. It is a structural component of the nuclear lamina.
c. It holds small and large ribosomal subunits together during transcription.
d. It phosphorylates STAT5.
e. It is a transcription factor.
Yeast are better experimental models of human cells than those of green algae because
a. people and yeast share a more recent common ancestor.
b. yeast are more similar to our intestinal bacteria.
c. green algae are prokaryotes.
d. mitochondria are not present in photosynthetic algae.
e. yeast are facultative anaerobes.
One structural distinction between bacteria and eukaryotes is that
a. bacteria do not possess organelles.
b. ribosomes are not present in bacteria.
c. bacteria are diploid.
d. the external surface of a bacterial cilium is an extension of the plasma membrane.
e. the glycocalyx of eukaryotic cells is present on the inner surface of the plasma membrane
a. was codified by Charles Darwin based on his experimental work.
b. occurs when heritable traits of organisms are modified by usage.
c. predicts that all populations will survive, unless they exhibit variability.
d. results in equal outcome of competition among individuals.
e. states that more offspring are produced than will survive.
N-acetyl-glucosamine can be used by a cell to
a. reduce cytoplasmic pH
b. build glycogen
c. carry high-energy electrons
d. regulate protein activity
e. phosphorylate a target molecule
a. an aromatic compound
b. usually hydrolyzed by cells into glycerol and three (3) fatty acids
c. a subunit of a phospolipid
d. not normally found in healthy cells
e. an amphipathic molecule
When any two molecules bind to each other, they
a. change each other’s shape
b. increase transcription of RNA
c. are of like net charge
d. inhibit protein activity
e. alter membrane permeability
What is pH?
a. the presence of high salt concentration in a solution
b. the amount of energy that is carried by acids
c. pKa + pKeq
d. a measurement of the number of hydrogen bonds in a solution
e. the negative logarithm of proton concentration
Adenine and cytosine residues in a DNA molecule will likely not pair because
a. like charges in these residues will form hydrogen bonds
b. the two sugar-phosphate backbones would be pushed farther away from the center of the helix
c. adenine pairs with thymine
d. there is room for only four molecular ring structures within the inner volume of the helix
e. these residues have been methylated
a. uses a Sephadex solution
b. can be used to calculate molecular weights
c. generates a pellet of all proteins from your sample
d. usually employs a sucrose gradient
e. separates proteins based on size
What is the function of sodium dodecyl sulfate in SDS-PAGE?
a. to promote bonds between agarose fibers
b. to bind to polyacrylamide
c. to solubilize Sephadex
d. to denature proteins
e. to provide a positive charge that can be acted upon by the electric field
Western blotting tests for the presence of
d. disulfide bonds
e. phosphodiester bonds
The binding of Epo to Epo-R will directly result in
a. the translocation of STAT5 to the nucleus
b. the phosphorylation of Epo-R
c. the exposing of the JAK5 kinase domain
d. the binding of a phosphate group to a tyrosine residue
e. the dimerization of Epo-R
One of the functions of ubiquitin ligase is to
a. covalently attach ubiquitin to E1
b. covalently attach ubiquitin to E2
c. form an isopeptide bond
d. ubiquitinate E3
e. ensure post-translational folding of ubiquitin
Who first isolated the molecule that would become known as DNA?
a. Francis Crick
b. Charles Darwin
c. Alfred Hershey
c. Gregor Mendel
d. J. Friedrich Miescher
One of the functions of DNA polymerase III is to
a. proofread a growing new DNA strand
b. synthesize an RNA primer
c. add RNA nucleotides to the growing strand
d. transcribe a target gene
e. remove the RNA primer
In DNA replication, the “rolling loop” allows
a. the relief of supercoiling of DNA ahead of the replication fork
b. replication on both DNA strands to occur in the same direction as the movement of the fork
c. the separation of template strands in circular prokaryotic chromosomes
d. for the occurrence of conservative replication
e. the inhibition of the topoisomerase
What technique did Franklin et al. (2010) employ to introduce potentially heritable stress responses to the F1 generation of mice?
a. forced swim
b. free exploratory paradigm
c. maternal separation
d. open field
e. sucrose consumption
Which of the following steps is not accompanied by the hydrolysis of GTP?
a. attachment of 43S pre-initiation complex to mRNA
b. joining of large ribosomal subunit
c. release of eIF5B
d. initiation of codon recognition
e. ribosome translocation
What is the signaling sequence for the boundaries of an mRNA intron (5’3’)?
How is Epo signaling physically tied to oxygen levels?
a. HIF is dehydroxylated by O2
b. Epo binds directly to O2
c. STAT5 will dimerize when it binds to O2
d. PHD requires O2 in order to hydroxylate HIF
e. O2 is necessary for generation of erythrocytes
In bacteria, the binding of an unfolded protein in one chamber of GroEL is followed by
a. hydrolysis of TAP
b. interaction with GrpE and BAG1
c. ubiquitination of the unfolded protein
d. binding of ATP to GroEL
e. binding of GroES to opposite chamber
hase-contrast microscopy is achieved by
a. interposing a circular barrier in the column of light from the light source
b. using a condenser to focus light onto the specimen
c. reducing contrast in the light image
d. reducing the quantity of light with the iris diaphragm
e. employing fluorescent dyes
A transcriptional reporter for gene X can be built by
a. attaching promoter X to protein X
b. attaching GFP promoter to GFP protein
c. attaching promoter X to gene X
d. attaching promoter X to GFP gene
e. attaching promoter X to gene X and GFP gene