final bis 101 - cell bio

Polyclonal antibodies can be used to neutralize SARS-Cov 2 virus to treat virus-infected patients.

False, it's impossible to estimate the scope of polyclonal antibodies

The peptide motif "RGD or Arg Gly Asp" is present in _________(1) for its binding to ______(2). A. (1) cadherin, (2) fibronectin B. (1) integrin, (2) fibronectin C. (1) collagen, (2) elastin D. (1) fibronectin, (2) cadherin E. (1) fibronectin, (2) integrin

E. (1) fibronectin, (2) integrin

Which of the following proteins is/are associated with the plasma membrane directly as a result of lipid modification? A .Gα B .Gβ C .G𝜸 D. All of the above E. A and C

E. A and C

Which of the following proteins is/are packed in vesicles in the Golgi apparatus before arriving at its/their destinations? A. Platelet-derived growth factor (PDGF) receptor B. Ras GTPase C. Fibronectin D. Clathrin heavy chain E. A and C

E. A and C

When is ATP consumed? A. Spindle elongation during anaphase B B. Crossing the restriction point in G1 phase during the cell division cycle C. Disassembly of the nuclear lamina D. Chromosome alignment at prometaphase E. All of the above

E. All of the above

Where do you expect to find the substrate protein(s) of the M-CDK (CDK + Cyclin B; also known as MPF) during the cell division cycle? A. Golgi apparatus B. Chromosomes C. Nuclear lamina D. Mitotic spindle E. All of the above

E. All of the above

Which of the following proteins is/are nucleotide-binding protein(s)? A. Actin B. Ran for nuclear export/import C. Epidermal growth factor (EGF) receptor D. Myosin E. All of the above

E. All of the above

Which of the following pairs represents the signal-receptor relationship? A. Red light - phytochrome B. Blue light - cryptochrome C. Bacterial raxX peptide - rice Xa21 kinase D. Insulin - tyrosine kinase E. All of the above

E. All of the above Slide 19, lecture 10: phytochrome responds to red light Slide 20 lecture 10: cryptochrome responds to blue light Slide 30 lecture 10 raxX is a signal for XA21 protein Slide 22 lecture 10: tyrosine kinases make a type of insulin receptor (receives insulin signal)

What is/ are features of neurofilaments and keratin filaments? A. They both have diameters of 10μm B. They both have diameters of 10nm C. The two ends of the two filaments are identical D. The two ends of the two filaments are different E. B and C

E. B and C

Which of the following amino acids could be phosphorylated by the enzyme cyclin-dependent kinase or Cdk? A. tyrosine B. serine C. threonine D. proline E. B and C

E. B and C

Which of the following proteins is/are degraded by the proteasome after ubiquitylation? A. cohesin B. the tumor suppressor protein p53 C. securin D. all of the above E. B and C

E. B and C

Model systems like E. coli can teach us mechanisms that regulate sister chromatid segregation in our cells

False because E. coli are bacteria that don't have sister chromatid segregation

A microscope is equipped with a 40X objective lens with an NA of 0.65 and a 63X objective lens with an NA of 1.3. If the resolution limit of the 40X objective lens is 0.5 uM, what would the resolution limit of the 63X be under identical conditions?

0.25 uM d (40x) = 0.61(x)/NA 0.5 = 0.61*x/0.65 ⇒ x = 0.53 (wavelength) d (63x) = 0.61*0.53/1.3 ⇒ d = 0.25 uM

A 300-amino acid protein has a molecular mass close to

30 kDa.

How many polypeptides are required to make an intact mammalian immunoglobulin G (IgG)?

4 polypeptides

Which of the following molecules can enter the nucleus by simple diffusion?

ATP and histone H1- immunoglobulins are too big

Some lymphoma patients carry mutations in a gene encoding the protease MALT1 and the mutations lead to common amino acid substitutions in a few positions of the MALT1 polypeptide. Therefore, the MALT1 gene is most likely A. A proto-oncogene. B. A tumor suppressor gene. C. Either a proto-oncogene or a tumor suppressor gene.

A. A proto-oncogene.

Which of the following statements represents a unique feature of actin microfilaments that is not shared by other cytoskeletal filaments? A. Actin microfilaments are assembled by ATPase enzyme B. Actin microfilaments are assembled by GTPase enzyme C. Only actin microfilaments are polarized

A. Actin microfilaments are assembled by ATPase enzyme

Which of the following features is/are shared by Gɑ and Ras proteins? A. Both are anchored to the lipids in the plasma membrane B. Both bind to adenylyl cyclase when in the GTP bound form C. Both are inserted into the lipid bilayer during translation D. Both interact with receptor proteins upon receiving signals E. A and D

A. Both are anchored to the lipids in the plasma membrane Ras is a small MONOMERIC GTPase that in the GTP bound form turns on Map kinase cascades, GDP form is inactive. Ras activated Map kinases drive cell division in mammals, and mating pheromones in yeasts Ras is anchored to the plasma membrane on the cytosolic side, attached to some kinda other thing that's not labeled. Slide 2 and 3 lecture 9 Ras does not interact with the receptor domain. G-alpha is a subunit of a HETEROTRIMERIC g-protein (GTPase) which is anchored to the cytosol by the alpha and gamma subunits. GTP and GDP both bind to the G-alpha subunit.. Slide 5, 6 lecture 9. G alpha appears to interact with the receptor domain (?) slide 9 lecture 9 G proteins activate adenyl cyclase but no mention of binding.

Which of the following proteins contains a DNA-binding domain? A. Cortisol receptor. B. Adenylyl cyclase. C. The mating pheromone receptor Ste11 in budding yeast. D. The chloride channel protein CFTR. E. The IP3 receptor.

A. Cortisol receptor.

Cyclin A and cyclin D are degraded by the 26S proteosome after being ubiquitylated. Which of the following statements is/ are true? A. Cyclin A and cyclin D are conjugated with the same ubiquitin polypeptide B. Cyclin A and cyclin D are conjugated with different ubiquitin polypeptides C. Cyclin A and cyclin D are ubiquitylated by the same E3 ubiquitin ligase D. Cyclin A and cyclin D are ubiquitylated by different E3 ubiquitin ligases.

A. Cyclin A and cyclin D are conjugated with the same ubiquitin polypeptide D. Cyclin A and cyclin D are ubiquitylated by different E3 ubiquitin ligases.

Where do you expect to find the MAP kinase kinase kinase Raf? A. Cytosol B. Vesicles C. Endoplasmic reticulum D. Nucleus E. Extracellular matrix

A. Cytosol

The G-protein coupled receptors are in favor of interacting with heterotrimeric G proteins when their Gα subunit is in the A. GDP bound form B. GTP bound form C. Both D. Neither

A. GDP bound form

When Sar1, a dominant negative (DN) mutant form of the Sar1 GTPase that only binds to GDP, but not GTP, is induced to be expressed at 50 times as much as the wild type protein, what happens to mannosidase II which is typically found in the golgi apparatus? A. More mannosidase II is found in the ER B. More mannosidase II is found in ER derived vesicles C. More mannosidase II is found in Golgi apparatus D. More mannosidase II is found in the Golgi-derived vesicles E. More mannosidase II is secreted outside the cell

A. More mannosidase II is found in the ER GTP bound is the active form, so if it is inactive in the GDP form manosidase II will stay in the ER and not enter the Golgi.

After actin polymerization reaches the equilibrium in a test tube, the unpolymerized actin monomers reaches to a stable concentration. The addition of profilin and formin to the test tube will cause: A. Increase of actin microfilaments B. Decrease of actin microfilaments C. Increase of the unpolymerized actin D. Decrease of the unpolymerized actin

A. Increase of actin microfilaments D. Decrease of the unpolymerized actin

What is/ are the statements below speak(s) for the enzyme caspase? A. The is a cysteine residue in the catalytic domain of caspase B. There is an aspartic acid residue in the catalytic domain of caspase C. There is a cysteine residue in the cleavage site recognized by caspase D. There is an aspartic acid residue in the cleavage site recognized by caspase

A. The is a cysteine residue in the catalytic domain of caspase D. There is an aspartic acid residue in the cleavage site recognized by caspase

Which of the following are features shared by Ras, Ran, and Rab? A. They all can hydrolyze GTP B. They are all associated with the plasma membrane C. They are all targeted by their respective GTPase activating proteins only when in their GDP bound states D. They are all targeted by their respective GEFs (guanine nucleotide exchange factors) when in the GTP bound state E. They all bind to their respective effector proteins when associated with GDP

A. They all can hydrolyze GTP Ran- nuclear import and export Ras- map kinase activation (dephosphorylate several times, has to do w cell division in mammals and mating pheromones in yeast) Rab- g protein is on the cargo, snare on the cargo connects to snare on membrane. Rab protein on the cargo transport vesicle

Different cells often produce different acetylcholine receptors. What are the common features shared by these receptor proteins? A. They all present an acetylcholine binding site when folded B. They all activate common signaling proteins after binding to acetylcholine C. They all have transmembrane domains

A. They all present an acetylcholine binding site when folded C. They all have transmembrane domains These receptors sit on the membrane on transmembrane domains and have specific binding sites

Which of the following cell-cell junctions is essential for polarized distributions of membrane proteins like receptors in different regions of the plasma membrane in an epithelial cell? A. Tight junction. B. Gap junction. C. Desmosome. D. Adherens junction. E. Adhesive junction.

A. Tight junction.

When tubulins are added to polymerized microtubules, under certain salt conditions, newly added tubulins tend to decorate the microtubule wall as "hooks" as shown in the figure from a cross section of the microtubules. The orientation of the hooks reflects the polarity of the microtubules. Based on the pattern in the picture, the microtubules are oriented with: A. Uniform polarities B. Mixed polarities

A. Uniform polarities This is uniform because all of the hooks curve in the same clockwise direction.

Alpha mannosidase II is an enzyme found in the Golgi apparatus. Which of the following statements is true?

Alpha mannosidase is packaged in a vesicle before arriving in the Golgi apparatus.

What would be the lengths combined of fully stretched chromatin DNA of a diploid human cell and a metaphase chromosome of a metaphase human cell? A. 3 m and 2 mm B. 3 m and 2 um C. 3cm and 2 mm D. 3mm and 2 nm E. 3um and 2 nm

B. 3 m and 2 um

When the Rb (retinoblastoma) protein's Cdk phosphorylation sites of Serine or Threonine all mutated into alanines, what would be the consequence in the cell division cycle? A. Cell division cycle would continue as usual B. Cell division cycle would be blocked at G1 phase C. Cell division cycle would be blocked at S phase D. Cell division cycle would be blocked at G2 phase E. Cell division cycle would be blocked at M phase

B. Cell division cycle would be blocked at G1 phase

Some people cannot detect a particular color, but can detect others. Which of the following proteins is most likely defective in these people? A. Gɑ subunit of heterotrimeric G-protein B. A GPCR (G protein coupled receptor) C. Adenylyl cyclase D. Protein kinase A E. Ras GTPase

B. A GPCR (G protein coupled receptor) Sight was discussed briefly when we were discussing signal transduction w rhodopsin. This was under a greater umbrella topic of PKA activation (protein kinase A). slide 12, lecture 9. A signal molecule activates a GPCR in the membrane, which activates adenylyl cyclase and alpha subunit of stimulatory G protein (heterotrimeric), which leads to Activating PKA. active PKA enters the nucleus via nuclear pore and binds to CREB which activates it and activates gene expression. I know that different receptors respond to different light wavelengths (colors) and that there are different types of receptors in the eye to see the different colors. In this case, rhodopsin's signal molecule is actually light photons. So it would make sense that some of the receptors are broken and cant respond to some color photons. SO that would be the GPCR of some color receptors.

After actin polymerization reaches the equilibrium in a test tube, the unpolymerized actin monomers reach a stable concentration. The addition of profilin alone to the test tube will cause: A. An increase of the actin microfilaments B. A decrease of the actin microfilaments C. An increase of the unpolymerized actin D. A decrease of the unpolymerized actin

B. A decrease of the actin microfilaments C. An increase of the unpolymerized actin

3. After polymerization reached the equilibrium phase in a test tube, a limited amount of tubulin dimers were added to the test tube. What would happen next? A. A new lag phase would start B. A new growth phase would start C. No changes will take place D. Treadmilling would start E. Tubulin polymers will remain unchanged

B. A new growth phase would start If it is in equilibrium, it is growing and shrinking at the same rate, however if we add more dimers, there is more material to allow the chain to keep growing.

Among actin microfilaments, intermediate filaments and microtubules, which ones exhibit treadmilling phenomenon when their respective subunits/proteins are provided at certain concentrations? A. Intermediate filaments B. Actin microfilaments C. Microtubules

B. Actin microfilaments C. Microtubules

The growth factor EGF (epidermal growth factor) stimulates proliferation of cultured rat cells. The receptor that binds EGF is a tyrosine kinase called EGFR. Which of the following mutations in the EGFR gene would be most likely to prevent receptor dimerization? A. Amino acid substitution near the SH2 domain B. Amino acid substitution in the EGF binding site C. Amino acid substitution in the SH2 domain D. Amino acid substitution in the ATP binding site

B. Amino acid substitution in the EGF binding site Tyrosine kinases appear to be two part receptors that dimerize when the signaling molecule(s) bind to the binding site and activate the pathway. So, if there was a mutation in the site of the EGF receptor that binds EGF, no dimerization would be possible. SLides 7 and 9 lecture 10 Slide 26 lecture 9 has more info on SH2 and SH3

Which of the following membrane compartments are used for delivering collagens? A. COPI coated vesicles B. COPII coated vesicles C. Clathrin coated vesicles D. Lysosomes

B. COPII coated vesicles

Which of the following proteins contains a transmembrane domain? A. Collagens B. Cadherins C. Integrins D. Fibronectins

B. Cadherins C. Integrins

Where is the inhibitory protein of steroid hormone receptors localized? A. Plasma membrane B. Cytoplasm C. Nuclear envelope D. Nucleoplasm E. Chromatin

B. Cytoplasm Slide 12 and 13, lecture 10. Steroid hormone receptor is bound to a transcription activating domain in the cytosol in an inactive form. There are inhibitory proteins that block the ligand binding domain (steroid receptor). Once the ligand (steroid hormone) is present, the receptor will bind to the steroid, and the unit will enter the nucleus ( receptor with transcription domain and the attached steroid ligand) to activate gene expression like increasing blood sugar or repressing the immune system.

Flavr Savr tomato shows deficiency in ethylene biosynthesis but not in ethylene signal transduction. After the green Flavr Savr tomato fruits are harvested, what would happen to the cells when ethylene is applied? A. The genome of the fruit cells will be edited/modified B. Genes encoding enzyme amylases and hydrolases will be expressed C. The expression of transcription factor EIN3 will be turned off D. EIN3 will be phosphorylated for degradation E. The expression of genes encoding the enzymes in the ethylene biosynthesis will be turned off

B. Genes encoding enzyme amylases and hydrolases will be expressed

Flowering plants have genes encoding retinoblastoma-related proteins (RBR) that function like Rb in mammals. Overexpression of the RBR protein in the meristem will likely A. Induce stem cell division. B. Inhibit stem cell division. C. Cause ubiquitylation of cyclin A. D. Cause ubiquitylation of cyclin B. E. Cause phosphorylation of the E2F transcription factor.

B. Inhibit stem cell division.

Which of the following events is required for contraction of smooth muscle cells? A. Phosphorylation of myosin heavy chain B. Phosphorylation of myosin light chain C. Phosphorylation of calmodulin D. Phosphorylation of actin E. All of the above

B. Phosphorylation of myosin light chain

Phosphorylation of which of the following proteins leads to the INACTIVATION of its function? A. PDGF receptor B. Retinoblastoma (Rb) C. Condensin D. MAP kinase E. Glycogen phosphorylase

B. Retinoblastoma (Rb)

In this graph, which cell cycle phase(s) does area 2 represent? A. G1 B. S C. G2 D. S and G2 E. G2 and M.

B. S

Compared to prometaphase when spindle assembly checkpoint proteins like MAD2 are detected at kinetochores that have not been attached to spindle microtubules, kinetochores in a metaphase have these proteins removed towards spindle poles in a microtubule-dependent manner. The removal of MAD2 is most likely carried out by __________. A. The ATPase Kinesin-5. B. The ATPase cytoplasmic dynein. C. The GTPase dynamin. D. Microtubule polymerization at the kinetochores. E. Microtubule depolymerization at the kinetochores.

B. The ATPase cytoplasmic dynein.

Apoptotic protease activating factor 1, or Apaf-1 which forms the apoptosome, sometimes is found to be inactivated in malignant melanoma. What happens when cytochrome C is artificially injected into such Apaf-1 negative melanoma cells? A. The cells will be induced to undergo programmed cell death/apoptosis. B. The cells will not be induced to undergo programmed cell death/apoptosis. C. The initiator but not executioner caspases will be activated. D. The executioner but not initiator caspases will be activated. E. The Bcl2 protein will enter the mitochondria.

B. The cells will not be induced to undergo programmed cell death/apoptosis.

In sarcomeres, actin filaments are arranged with their (-) ends facing A. The middle of the thin filaments B. The center of sarcomere C. The edge of sarcomere D. The Z disc E. C and D

B. The center of sarcomere

When cytochrome c is injected into the cytoplasm of tissue cultured mammalian cells, what would most likely be the consequence? A. The injected cells would enter S phase of cell division cycle B. The injected cells would be triggered would be triggered to undergo programmed cell death C. The bcl2 gene would be expressed in the injected cells D. The cytochrome c would enter the mitochondria in injected cells

B. The injected cells would be triggered would be triggered to undergo programmed cell death

Actin microfilaments are organized in different arrays upon the activation of Rho, Rac, or Cdc42 GTPase enzyme. These phenomena suggest that A. The three G proteins have common effector proteins that regulate the organization of actin microfilaments. B. The three G proteins have different effector proteins that regulate the organization of actin microfilaments. C. The three G proteins have G-actin as their effector protein so that actin microfilaments became organized differently.

B. The three G proteins have different effector proteins that regulate the organization of actin microfilaments.

In fission yeast, the cdc100 mutation was found dominant to the wild type allele and causes cell cycle arrest at G2 phase. To clone Cdc100 gene, which of the following approaches would most likely work? A. To rescue the cdc100 mutant by transformation with the genes derived from wild type cells B. To transform the wild type cells with the genes derived from the cdc100 mutant cells and to demonstrate the phenotype C. Either method would work

B. To transform the wild type cells with the genes derived from the cdc100 mutant cells and to demonstrate the phenotype

5. Ethylene is a common plant hormone which promotes fruit ripening. When it is applied to recently harvested fruit, what will happen to fruit cells? A. Genome of fruit cells would be edited/ modified B. Transcription factor EIN3 would become stable to induce gene expression C. The expression of the transcription factor EIN3 would be turned off D. The transcription factor EIN3 would be phosphorylated for degradation E. The expression for genes encoding ethylene biosynthesis would be turned off

B. Transcription factor EIN3 would become stable to induce gene expression EIN3 is a transcription factor that is bound to a complex system. When ethylene is present and read by the ethylene receptor in the cell membrane, EIN3 becomes released from its complex and can go to the nucleus to act as a TF that will allow transcription of ethylene responsive genes which include enzymes that ripen the fruit. Slide 8 lecture 8

Which of the following is the size of a sarcomere? A. 10 nm B. 50 nm C. 2 μm D. 20 μm E. 1 nm

C. 2 μm

The ratio of cell numbers in areas 1, 2, and 3 are 9:6:5. It was found that 5% of the cells were in the M phase. It was also learned that the doubling time of this cell culture was 20 hours. Determine the length of the G2 phase under this condition. A. 2 hours. B. 3 hours. C. 4 hours. D. 5 hours. E. 6 hours.

C. 4 hours.

When listeria bacteria present the ActA protein on its surface, which of the following proteins most likely is activated in order to promote actin polymerization? A. Profilin B. Capping protein C. ARP2/3 complex D. Actin E. Myosin II

C. ARP2/3 complex

When the ARP2/3 and ɣ-tubulin complexes are added to the polymerization of actin filaments and microtubules, respectively, what is considered to be similar? A. Both protein complexes associate with the polymerizing (+) ends of the respective filaments B. Both protein complexes associate with the depolymerizing (+) ends of the respective filaments to stop depolymerization C. Both protein complexes would decrease the critical concentration required for polymerization for respective filaments D. Both protein complexes associate with the microtubule-organizing center (MTOC) like the centrosome in animal cells to organize the respective cytoskeletal arrays E. Both protein complexes sever (break) the respective cytoskeletal filaments so that long filaments become shorter

C. Both protein complexes would decrease the critical concentration required for polymerization for respective filaments Slide 23, lecture 11: ARP2/3 complex starts a new (-) end, triggers polymerization of a new filament. When active, it binds to actin monomers and starts the new (-) end. By stabilizing the (-) end, ARP2/3 reduces the critical concentration for polymerization. It makes branches off of a preexisting actin filament. Slide 17 lecture 12: gamma tubulins make a ring complex with accessory proteins at the (-) end of a microtubule. Microtubules grow from the gamma tubulin ring with the (+) growing away from it as a branch off a preexisting microtubule. (slide 20 L 12) creates a "docking site" template. Microtubules do originate from the MTOC (textbook pg991). The textbook (991) doesnt specifically mention lowering the critical concentration, but it does mention that a high concentration of tubulin subunits is required to do spontaneous microtubule polymerization, so other factors like gamma, beta, and alpha tubulins help.

Which of the following motor proteins would likely contribute to the transport of secretory granules towards the centrosome in the cytotoxic T lymphocyte? A. Kinesin-5 B. Kinesin-13 C. Cytoplasmic dynein D. Dynamin E. Myosin-II

C. Cytoplasmic dynein

Mature mRNA molecules are produced in the nucleus and transported to the cytosol through nuclear pores. Which of the following statements is correct? A. Mature mRNA contains the nuclear export signal. B. Mature mRNA export is a passive diffusion process. C. Mature mRNA export is dependent on the nuclear export receptor or exportin. D. Mature mRNA is transported together with assembled ribosomes. E. Mature mRNA is transported together with the nuclear import receptor or importin when importin leaves the nucleoplasm.

C. Mature mRNA export is dependent on the nuclear export receptor or exportin.

The monomeric GTPase Ras is frequently linked to cancers. Which of the following exhibits the strongest binding to the Ras GAP (GTPase-activating Protein)? A. Ras without nucleotide B. Ras-GDP C. Ras-GTP D. Ras GEF (guanin nucleotide exchange factor) E. MAP kinase kinase kinase Raf

C. Ras-GTP

The protein kinase Raf acts as an effector protein of the Ras GTPase. The Q61K mutation in Ras makes it in the GTP locked form. When the cultured rat cells expressing this Q61K form of Ras, what would happen to the cells? A. The cells would be triggered to actively divide only in the absence of growth factor B. The cells will be triggered to divide only in the presence of growth factor C. The cells will be triggered to actively divide regardless of if a growth factor is present or not

C. The cells will be triggered to actively divide regardless of if a growth factor is present or not GTP form is activated. Ras will do its thang regardless of whether a signal is there

What proteins would likely be the targets of the Gi form of heterotrimeric G proteins? A. Adenylyl cyclase B. Guanylyl cyclase C. cAMP phosphodiesterase D. cGMP phosphodiesterase

C. cAMP phosphodiesterase D. cGMP phosphodiesterase

Which is/are typical amino acid residue(s) that is/are phosphorylated by the cytosolic kinase Src? A. Serine B. Threonine C. Tyrosine D. A and B E. All of the above

C. Tyrosine

Yeasts often are used as model systems to study autophagy. Which of the following conditions would most likely trigger yeast cells to produce autophagosomes that are dependent on ATG proteins? A. When yeast cells are cultured in the dark B. When yeast cells received pheromones C. When yeast cells consumed all glucose (their carbon source) in the medium D. When yeast cells were transferred to the new culture medium E. When yeast cells were cultured at lower temperatures when their growth rate dropped

C. When yeast cells consumed all glucose (their carbon source) in the medium Cells use autophagy when they are starving! And they'll sacrifice their own unnecessary cell components. Damaged organelles, unwanted organelles SLIDE 4 LECTURE 8

When scientists screened for mutations in genes regulating pheromone signaling in budding yeast, what of the following temperature sensitive phenotypes would be caused by such mutations? A. Yeast cells failed to enter cell division cycle B. Yeast cells failed to secrete carbohydrates C. Yeast cells failed to undergo sexual reproduction D. Yeast cells failed to make buds E. All of the above

C. Yeast cells failed to undergo sexual reproduction Slide 5 lecture 10. MAP kinase cascade in yeast pheromone response. In mammals, the MAP kinase cascade leads to cell proliferation (division), but in budding yeast, the MAP kinase cascade activates mating pheromones. So, if this was mutated, there would be difficulty with sexual reproduction in yeasts.

Cytoplasmic concentrations of different ions, from lowest to highest,

Ca2+ < Na+ <K+ KANAC!

Clathrin is assembled by clathrin light chain (CLC) of 40-kDa and clathrin heavy chain (CHC) of 200-kDa. In cultured mammalian cells, CLC was expressed in the form of a green fluorescent protein (GFP of 27-kDa) fusion protein as the only form of CLC. When CLC-GFP was purified from the cells by affinity chromatography using a GFP antibody, what would you expect to detect by an SDS-PAGE gel after the gel is stained by Coomassie blue? A. A 67-kDa band B. A 200-kDa band C. A 267-kDa band D. A 67- and a 200-kDa bands E. A 25- and a 50-kDa bands

D. A 67- and a 200-kDa bands

Lou Gehrig had the neuromuscular disorder known as Amyotrophic Lateral Sclerosis (ALS) or Lou Gehrig's disease. Which of the following defects would likely cause ALS? A. The loss of a gene encoding a neurofilament protein B. A low expression level of a gene encoding a neurofilament protein C. Neurofilaments in the motor axon cannot be polymerized quickly enough D. Abnormally assembled neurofilaments blocked transport along microtubules in the motor neuron E. Neurofilaments lost their polarity

D. Abnormally assembled neurofilaments blocked transport along microtubules in the motor neuron Slide 10 lecture 11. ALS is caused by abnormal assembly of neurofilaments so that axonal transport (microtubule dependent) is blocked.

Which of the following cells form the microtubule organizing center (MTOC)? A. Intestinal epithelial cells B. Plant epidermal cells C. Neurons D. All of the above

D. All of the above

Which of the following proteins bind(s) to calcium directly? A. Troponin B. Cadherin C. Calmodulin D. All of the above E. A and C

D. All of the above

Which of the following signaling molecules have receptors on the plasma membrane? A. Insulin B. Acetylcholine C. Ethylene D. All of the above

D. All of the above

In typical cultured mammalian cells, the Golgi apparatus is concentrated near the centrosome and the endoplasmic reticulum (ER) is placed away from the centrosome or towards the cell periphery. Vesicular transports between the ER and Golgi apparatus take place along microtubules. Based on the knowledge of vesicle coats, microtubule polarity, and transport directionality, select the best answer. A. COPII-coated vesicles are transported by diffusion in these cells. B. COPII-coated vesicles are transported by a myosin in these cells. C. COPII-coated vesicles are transported by a kinesin in these cells. D. COPII-coated vesicles are transported by a dynein in these cells. E. COPII-coated vesicles are transported by a dynamin in these cells.

D. COPII-coated vesicles are transported by a dynein in these cells.

The chaperone protein BiP assists the folding of proteins like immunoglobulins. Where is BiP localized? A. Nucleus B. The TGN (Trans Golgi Network) C. Vesicles produced by the TGN D. Endoplasmic reticulum E. Lysosome

D. Endoplasmic reticulum

When cells undergo apoptosis, one of the features is the enrichment of phosphatidylserine (PS) in the outer leaflet of the lipid bilayer in the plasma membrane. However, PS is typically enriched in the inner leaflet of the lipid bilayer in healthy cells. Which of the following actions most likely causes the change? A. New synthesis of PS on the plasma membrane. B. Phosphorylation of phospholipids by kinases. C. Frequent phospholipid flip-flop phenomenon between the inner and outer leaflets. D. Flipping of PS by specialized enzymes like flippases to the outer leaflet from inner leaflet. E. Activation of receptor tyrosine kinase by binding to its ligand.

D. Flipping of PS by specialized enzymes like flippases to the outer leaflet from inner leaflet.

Which of the following proteins would be a potential target protein that is activated after insulin binds to its receptor? A. Transducin B. RanGAP C. IP3 receptor D. Glucose transporter E. CFTR (cystic fibrosis transmembrane conductance regulator)

D. Glucose transporter

Which of the following amino acids and derivatives is frequently found in collagens? A. Tyrosine B. Serine C. Phosphoserine D. Glycine

D. Glycine

Which of the following proteins contain(s) at least 1 transmembrane domain? A. G𝜸 subunit of heterotrimeric G proteins B. Calmodulin C. Ras GTPase D. IP3 receptor E. All of the above

D. IP3 receptor

Novozymes wants to produce large quantities of the human golgi localized mannosidase II enzymes using a mold as host. Which of the following features most likely has to be removed in order to have an active enzyme derived from this mannosidase II secreted by the fungus? A. Its C-terminal SKL peptide B. Its C-terminal KDEL peptide C. Its N-terminal signal peptide D. Its C-terminal transmembrane domain E. Its positively charged 5 amino acid peptide in the middle.

D. Its C-terminal transmembrane domain

The G proteins Ran, Rab, Sar1 are activated by GEF (guanine exchange factor). Which of the following statements is true? A. The G proteins are activated by a common GEF at same subcellular location B. The G proteins are activated by a common GEF at different subcellular location C. The G proteins are activated by a different GEF at same subcellular location D. The G proteins are activated by different GEFs ar different subcellular locations

D. The G proteins are activated by different GEFs ar different subcellular locations

in fluorescence microscopy, the ___ reflects excitation light but passes emission light (beam splitter)

Dichroic mirror

What is/ are the shared features of lysosomal proteases and lysosomal phosphatases? A. They all undergo post translational modification of having the GPI (glycosylphosphatidylinositol) linkage B. They all are synthesized in the cytosol before being imported into the lysosome through protein translocation across the lysosomal membrane C. They all contain glycosylation sites D. They all are synthesized in the rough ER E. C and D

E. C and D These lysosomal enzymes have a particular glycosylated modification. All enzymes and proteins are synthesized in the ER The purpose of glycosylation is to promote protein folding. It helps make folding intermediates more soluble, preventing them from aggregating, and the glyco-code marks the progression of protein folding. These are used by chapera=ones in the ER to guide protein folding and degradation in guiding from ER to golgi transport. Glycoproteins are more resistant to digestion by enzymes, this was maybe an ancestral protective coat.

The M cyclins like Cyclin B contain that is called a destruction box which interacts with E3 ubiquitin ligase. When a truncated Cyclin B missing this destruction box is expressed in actively dividing cells, what would be the consequence? A. Cell division cycle continues as normal B. Cell division cycle would be blocked at G1 phase C. Cell division cycle blocked at S phase D. Cell division cycle blocked at G2 phase E. Cell division cycle blocked at M phase

E. Cell division cycle blocked at M phase

Lysosomal acid phosphatase contains two asparagine (N) residues which serve as the only possible glycosylation sites. When a mutant form of this enzyme that has both N residues mutated to alanine (A) is expressed in mouse cells, where is the mutant protein localized? A. The ER B. The golgi C. TGN D. Lysosome E. Extracellular space

E. Extracellular space Enzymes need to be secreted but they need to be glycosylated first.

Which of the following proteins contains at least 1 transmembrane domain? A. G beta subunit of heterotrimeric G protein B. Calmodulin C. Ras GTPase D. IP3 E. IP3 receptor

E. IP3 receptor

4. How would you determine the critical concentration of tubulin dimers for polymerization under this condition? A. By measuring the concentration of unpolymerized tubulin dimers at the end of the lag phase B. Measuring the concentration of unpolymerized tubulin dimers in the middle of the growth phase C. Measuring concentration of unpolymerized tubulin dimers at the equilibrium phase only before more dimers were added D. Measuring the concentration of unpolymerized tubulin dimers at the equilibrium phase only after more dimers were added E. Measuring concentration of unpolymerized tubulin dimers at the equilibrium phase either before or after the dimer addition

E. Measuring concentration of unpolymerized tubulin dimers at the equilibrium phase either before or after the dimer addition The critical concentration for polymerization is the monomer concentration at a steady state, when subunits are coming on and off. Polymerization properties: when concentration is greater than the (-) end CC, both ends polymerize. When concentration is less than the (+) end CC, both ends depolymerize. When the concentration is between the (+) end CC and the (-) end CC, treadmilling occurs, where subunits are added to the + end and removed from the - end, leading to a flux of subunits, with no net change in length. Slide 18-20 Lecture 11

Chromosome translocation can cause gene fusions. If such a gene fusion event leads to the production of a fusion protein between FGF (fibroblast growth factor) receptor (FGF-R) and a protein dimerization domain, what would happen to the fibroblasts? A. FGF-R loses its kinase activity B. FGF-R loses its binding activity to FGF C. The kinase activity of FGF-R is turned on only in the presence of FGF D. The kinase activity of FGF-R is turned on only in the absence of FGF E. The kinase activity of FGF-R is turned on regardless of the presence or absence of FGF

E. The kinase activity of FGF-R is turned on regardless of the presence or absence of FGF

What is the approx. molecular mass of the heavy chain of human immunoglobulins?

Heavy chain = 440 amino acids, 1 amino acid = 110 daltons. Therefore 1 heavy chain is 48400 daltons, or approximately 48.4 kDa.

Which of the following organelles contain(s) double membrane?

Mitochondria and chloroplasts

Which of the following posttranslational modifications would mask the nuclear localization signal from being recognized by importins?

Phosphorylation

Phosphorylation of a protein is catalyzed by

Protein kinases

Reverse reaction of phosphorylation, or dephosphorylation, is mediated by

Protein phosphatases

Ray wishes to discover novel genes responsible for the production of unsaturated fatty acid tails in order to have the corresponding enzymes introduced in oil crops like soybeans. Which of the following organisms would most likely have such a gene?

Pseudomonas bacteria found in Antarctica- the harsher cold the environment this organism is in, the more likely it is to produce this enzyme, as unsaturated fatty acids have kinks, allowing fluidity in the membrane so it doesn't freeze as easily

You are given a mouse monoclonal IgG antibody against tubulin, and a rabbit polyclonal antibody IgG antibody against the centromere protein CENP-A. Which of the following secondary antibody combinations would allow you to separately detect spindle microtubules (made of tubulin) and centromeres in cultured cells?

Red goat anti-mouse IgG and green goat anti-rabbit IgG

In FRAP (fluorescence recovery after photobleaching) experiments, the recovery of fluorescent signals to a bleached region indicates

Replacement of fluorescent proteins in the bleached region

For cancer immunotherapy, like treating breast and brain cancers using Herceptin and Nivolumab, these engineered antibodies were targeted at

cell surface receptors

In eukaryotic cells, mRNA is made in the nucleoplasm after splicing, but functions in the cytoplasm. Which of the following molecules is most likely to contain a nuclear export signal for it to be exported from the nucleus to the cytosol?

mRNA binding protein. (Can't be mRNA itself, the signal must be a protein)