Final Flashcards
(143 cards)
1
Q
The DNA sequence to which an RNA polymerase binds to initiate transcription of gene is called a(n)
a. Enhancer
b. Promoter
c. Polymerase-binding element
d. Origin of transcription
A
B. promoter
2
Q
Transcriptional _____________ bind to regulatory DNA sequences and stimulate transcription. these factors have two independent domains. one region binds DNA to other stimulates transcription by interacting with other proteins such as mediator.
a. Promoters
b. Activators
c. Carboxyl terminal domains
d. TFIIE factors
A
B. Activators
3
Q
The role of the sigma (S) Factors in prokaryote transcription is to
a. Terminate transcription
b. Direct RNA polymerases to bind to different transcription start sites under different condition
c. Recognize the splicing site of tRNA
d. All of the above
A
b. Direct RNA polymerases to bind different transcription start sites under different conditions
4
Q
RNA synthesis continues until the polymerase encounters a stop signal. The most common stop signal of prokaryotes is
a. Formation of DNA methylation
b. Binding of Rho protein to the end of the mRNA
c. Binding of a sigma () factor to the end of the mRNA
d. Inverted repeat of GC-rich sequence followed by seven A residues
A
d. Inverted repeat of GC-rich sequence followed by seven A residues
5
Q
Eukaryotic RNA polymerase I genes code for __________.
a. mRNAs
b. tRNAs
c. snRNAs and scRNAs
d. 45S pre-ribosomal RNAs
A
d. 45S pre-ribosomal RNAs
6
Q
Processing of pre-tRNAs to produce tRNAS involves the following except ___________.
a. Cleavage of the pre-tRNA by the enzyme RNase P
b. Addition of CCA terminus to the 3’ end
c. Modification of base at specific positions
d. Methylation of lysine and arginine residues and phosphorylation of serine residues
A
d. Methylation of lysine and arginine residues and phosphorylation of serine residues
7
Q
Processing of RNA transcripts occurs __________.
a. Only in eukaryotic cells
b. Only with mRNA transcripts
c. Only with rRNA and tRNA transcripts
d. With tRNA, rRNA, and mRNA transcripts
A
d. With tRNA, rRNA, and mRNA transcripts
8
Q
Splicing of pre-mRNA takes place in large complexes, called spliceosomes, which have five types of __________.
a. Small cytoplasmic RNAs
b. Small nuclear RNAs (snRNA)
c. microRNAs
d. siRNAs
A
b. Small nuclear RNAs (snRNA)
9
Q
Which of the following is not an example of a transcription factor DNA-binding domain?
a. Helix-turn-helix
b. Acidic-basic
c. Helix-loop-helix
d. Zinc finger
A
b. Acidic-basic
10
Q
In eukaryotes, pre-mRNA are extensively modified before export form the nucleus. The 5’ end of the transcript is modified by __________?
a. Acetylation
b. Adding a poly-A tail
c. Adding a 7-methylguanosine cap
d. Adding the CCA sequence
A
c. Adding a 7-methylguanosine cap
11
Q
Promoters contain several different sequence elements surrounding their transcription sites. The ________ resembles the -10 sequence of bacterial promoters.
a. TATA box
b. AAAAAA
c. Polymerase II
d. Mediator
A
a. TATA box
12
Q
Eukaryotic gene repressor proteins are thought to act by __________.
a. Binding to DNA sites in competition and prevent binding of activators to the DNA
b. Interacting with mediator, inhibiting transcription
c. Interacting with transcription factors, inhibiting transcription
d. All of the above
A
d. All of the above
13
Q
Processing of pre-tRNAs to produce tRNAs involves _________.
a. Cleavage of the pre-tRNAs by the enzyme RNase P
b. Addition of CCA terminus to the 3’ end
c. Modification of bases at specific positions
d. All of the above
A
d. All of the above
14
Q
Eukaryotic RNA polymerase II genes code for __________.
a. mRNAs
b. tRNAs
c. snRNAs and scRNAs
d. ribosomal RNAs
A
a. mRNAs
15
Q
Aminoacyl tRNA synthetases are enzymes that __________.
a. Synthesize transfer RNAs and microRNA
b. Attach amino acids to specific transfer RNAs
c. Connect nucleotides while they are held in place on ribosomes by transfer RNAs
d. Attach the terminal CCA sequence to transcription factor
A
b. Attach amino acids to specific transfer RNAs
16
Q
Ribosomes are named according to their sedimentation rates in ultra-centrifugation. The combined sizes of prokaryotic and eukaryotic ribosomes are ________.
a. The same
b. 30S and 50S, respectively
c. 40S and 60S, respectively
d. 70S and 80S, respectively
A
d. 70S and 80S, respectively
17
Q
During translation, the codons on the mRNA are recognized by complementary base pairing to the anticodon on the ___________.
a. Ribosome
b. Transfer RNA
c. Small cytoplasmic RNA
d. Aminoacyl tRNA synthetase
A
b. Transfer RNA
18
Q
Translation occurs in 3 stages. Which one is NOT one of these stages?
a. Initiation
b. Elongation
c. Epigenetic modification
d. Termination
A
c. Epigenetic modification
19
Q
The ribosome has three binding sites. Which one is incorrect?
a. T (termination)
b. P (peptidyl)
c. A (aminoacyl)
d. E (exit) sites
A
a. T (termination)
20
Q
The elongation factor that bring the aminoacyl tRNA to the eukaryotic ribosome and then releases it with GTP hydrolysis following the correct codon-anticodon base pairing is _________.
a. eIF-1
b. eRF-1
c. eIF-2
d. eEF-1alpha
A
d. eEF-1alpha
21
Q
In eukaryotes, translation always starts with ___________.
a. Any amino acid
b. Glutamine
c. Methionine
d. Arginine
A
c. Methionine
22
Q
Elongation continues until a stop codon is translocated into the A site. __________ recognizes the signals and terminate protein synthesis.
a. Any tRNA
b. Release factors
c. eIF5
d. Methionyl tRNA
A
b. Release factors
23
Q
The amount of a protein in a cell is regulated by the rate of ___________.
a. Transcription of its gene
b. Translation of it mRNA
c. Degradation of the protein
d. All of the above
A
d. All of the above
24
Q
Which one is incorrect about Small interfering RNAs (siRNAs)?
a. siRNA is produced from double-stranded RNAS by the nuclease Dicer
b. One strand of siRNA is incorporated into an RNA-induced silencing complex (RISC)
c. siRNAs generally pair with their targets and induce cleavage of the mRNA
d. Most siRNAs form mismatches their targets and repress translation
A
d. Most siRNAs form mismatches their targets and repress translation
25
Phosphorylation of eukaryotic initiation factors 2 (eIF2) and 2B (eIF2B) by regulatory protein kinases ____________.
a. Allows them to elongate transcription
b. Allow them to initiate translation
c. Blocks their exchange of bound GDP to GTP, inhibiting initiation of translation
d. Block the termination of translation
c. Blocks their exchange of bound GDP to GTP, inhibiting initiation of translation
26
Proteins that facilitate the folding of other proteins are called _________.
a. Foldases
b. Binding proteins
c. Chaperone
d. Escorts
c. Chaperone
27
___________ catalyzes disulfide bond formation. It is abundant in the ER, where an oxidizing environment allows (S—S) linkages.
a. Acetyltranferases (HAT)
b. Peptidyl prolyl isomerase
c. HSP
d. Protein disulfide isomerase (PDI)
d. Protein disulfide isomerase (PDI)
28
A __________ removes a signal sequence from a polypeptide chain after it passes through a channel into the rough ER
a. Signal peptidase
b. RFI
c. Chaperonin
d. HSP70
a. Signal peptidase
29
Cells can regulate the amount of the activities of their proteins by the following mechanisms.
a. Regulation by small molecules
b. Phosphorylation
c. Protein-protein interactions
d. A and C
e. All of the above
e. All of the above
30
Proteins are often regulated by phosphorylation by enzymes called _________.
a. Protein phosphatases
b. Phosphoproteases
c. Protein phosphorylases
d. Protein kinases
d. Protein kinases
31
In a major protein degradation pathway, a short polypeptide called ________ is attached to a protein to target it for destruction.
a. Glutathione
b. Ubiquontone
c. Ubiquitin
d. KDEL
c. Ubiquitin
32
The signals that identify initiation codons are different in prokaryotic and eukaryotic cells. Initiation codons in bacterial mRNAs are preceded by __________ that aligns the mRNA on the ribosome.
a. Apo-B100
b. 5’ methylguanosine cap
c. The Shine-Dalgarno sequence
d. Elongation factor
c. The Shine-Dalgarno sequence
33
cAMP activates cAMP-dependent protein kinase by _____________.
a. Stimulating its phosphorylation
b. Stimulating the dimerization of kinase subunits
c. Stimulating the release of a translational inhibitory protein bound to its mRNA
d. Binding regulatory subunits and inducing their release form the catalytic subunits
d. Binding regulatory subunits and inducing their release form the catalytic subunits
34
Eukaryotic ribosomes recognize and initially bind to what structure on the mRNA?
a. A Shine-Dalgarno sequence
b. The 7-methylguanosine cap
c. An operon sequence
d. A CCAAT sequence
b. The 7-methylguanosine cap
35
Entry of cells into mitosis is controlled in part by cyclin ________, a regulatory subunit for Cdk1 protein kinase.
a. A
b. B
c. C
d. D
b. B
36
________ is activated in nutrient starvations, allowing cells to degrade intracellular nonessential proteins and organelles and reutilize the components.
a. Autophagy
b. Endocytosis
c. Pinocytosis
d. Phagocytosis
a. Autophagy
37
The eukaryotic 45S pre-rRNA transcript codes for the ________.
a. 28S rRNA
b. 28S and 18S rRNAs
c. 28S, 18S, and 5.8S rRNAs
d. 28S, 18S, 5.8S, and 5S rRNAs
c. 28S, 18S, and 5.8S rRNAs
38
Processing of pre-tRNAs to produce tRNAs involves _________.
a. Cleavage of the pre-tRNAs by the enzyme RNase P
b. Addition of CCA terminus to the 3’ end
c. Modification of bases at specific positions
d. All of the above
d. All of the above
39
The factor that escorts the aminoacyl tRNA to the eukaryotic ribosome and then releases it with GTP hydrolysis following the correct codon-anticodon base pairing is _______.
a. eIF-1
b. eRF-1
c. eIF-2
d. eEF-1alpha
d. eEF-1alpha
40
During translation, the codons on the mRNA are recognized by complementary base pairing to the anticodon on the __________.
a. Ribosome
b. Transfer RNA
c. Small cytoplasmic RNA
d. Aminoacyl tRNA synthetase
b. Transfer RNA
41
The amount of a protein in a cell is regulated by the rate of __________.
a. Transcription of its gene
b. Translation of its mRNA
c. Degradation of the protein
d. All of the above
d. All of the above
42
In the cotranslational translocation, as they emerge from the ribosome, signal sequences are recognized and bound by a(n) __________.
a. tRNA
b. signal peptidase
c. signal recognition particle
d. miRNA
c. signal recognition particle
43
Some proteins have a targeting sequence (KDEL or KKXX) at the carboxy terminus that __________.
a. hold the proteins in the rough ER
b. hold the proteins in the smooth ER
c. hold the proteins in both the smooth ER and rough ER and prevent their transport to the Golgi apparatus
d. direct the proteins from the Golgi apparatus back to the ER
d. direct the proteins from the Golgi apparatus back to the ER
44
Protein folding in the ER is assisted by a chaperone called _________.
a. BiP
b. PiP
c. Hsp60
d. Hsp90
a. BiP
45
Formation of disulfide bonds is important in protein folding. In the ER, an ____________ environment promotes disulfide (S—S) bond formation, facilitated by protein disulfide isomerase.
a. reducing
b. oxidizing
c. both reducing and oxidizing
d. either reducing or oxidizing
b. oxidizing
46
Which of the following classes of lipids is synthesized in the Golgi apparatus?
a. Phosphatidylcholine
b. Glycolipids
c. Cholesterol
d. Ceramide
b. Glycolipids
47
Many proteins are inserted directly into the ER membrane by __________. These sequences are recognized by SRP, but not cleaved by signal peptidase.
a. glycosylation sites
b. internal signal sequences
c. phosphorylation sites
d. sulfation sites
b. internal signal sequences
48
New phospholipids are added only to the cytosolic half of the ER membrane. Some must be transferred to the other half. This requires passage of polar head groups through the membrane, facilitated by membrane proteins called ___________.
a. flippases
b. signal peptidase
c. chaperone
d. MPP
a. flippases
49
If an excess of unfolded proteins accumulates, a signaling pathway called the __________ is activated.
a. ER-associated degradation (ERAD)
b. unfolded protein response (UPR)
c. regulated secretory pathways
d. clathrin-coated vesicles transport
b. unfolded protein response (UPR)
50
Vesicles that carry proteins from the rough ER to the Golgi apparatus bud off as _________ vesicles.
a. uncoated
b. clathrin-coated
c. COPI-coated
d. COPII-coated
d. COPII-coated
51
The major model of vesicle fusion holds that actual fusion of a vesicle with its target membrane is driven by the interaction of pairs of proteins called vesicle and target _________.
a. SNAREs
b. SNEPs
c. COPs
d. Tethers
d. Tethers
52
```
Lysosomes contain about 60 different degradative enzymes. Mutations in genes that encode these enzymes result in lysosomal storage diseases – undegraded material accumulates in the lysosomes of affected individuals. The enzyme deficiency in _________ prevents the hydrolysis of glucosylceramide to glucose and ceramide.
a. Multiple sclerosis
b. Leber’s disease
c. Crohn’s disease
d. Gaucher disease
```
d. Gaucher disease
53
The inner compartment of mitochondria is called the ___________.
a. stroma
b. outer membrane space
c. inner membrane space
d. matrix
d. matrix
54
Which of the following is a product of glycolysis that is transported into the mitochondria?
a. Pyruvate
b. Glucose
c. Lactic acid
d. Citric acid
a. Pyruvate
55
The outer mitochondria membrane __________.
a. is NOT permeable to small molecules
b. contains porins which form channels to allow the free diffusion of small molecules
c. contains a high percentage of proteins involved in oxidative metabolism and transport
d. is the principle site of ATP generation
b. contains porins which form channels to allow the free diffusion of small molecules
56
The process by which mitochondria are thought to have arisen during evolution is called ____________.
a. symbiosis
b. phagocytosis
c. endosymbiosis
d. pinocytosis
c. endosymbiosis
57
Most mitochondrial genomes consist of ____________.
a. a single linear DNA molecule
b. several linear DNA molecules
c. several circular DNA molecules
d. a single circular DNA and a linear DNA molecules
c. several circular DNA molecules
58
Mitochondria contain ___________.
a. no genes of their own
b. genes for only mitochondrial proteins
c. gene for only mitochondrial rRNAs
d. genes for mitochondrial proteins, rRNAs, and tRNAs
d. genes for mitochondrial proteins, rRNAs, and tRNAs
59
The proteins encoded by the human mitochondrial genome function in ___________.
a. Cytosolic ribosomes synthesis
b. DNA duplication
c. respiratory complexes and oxidative phosphorylation
d. phospholipid synthesis in ER
c. respiratory complexes and oxidative phosphorylation
60
Tim and Tom are _________.
a. twin brothers with the same mitochondrial disease
b. chaperones
c. protein translocators in mitochondrial membranes
d. transporters of small molecules across the mitochondrial membranes
c. protein translocators in mitochondrial membranes
61
The mitochondrial proteins presequence is cleaved off by a protease called _________.
a. collagenase
b. presequence protease
c. ubiquitin-targeting protease
d. matrix processing peptidase (MPP)
d. matrix processing peptidase (MPP)
62
Electron transport occurs in the mitochondrial __________.
a. outer membrane
b. intermembrane space
c. inner membrane
d. matrix
c. inner membrane
63
The transport of proteins across the outer and inner chloroplast membranes occurs through complexes called __________.
a. Time and Tome
b. Tic and Toc
c. Sec and Tat
d. import complexes
b. Tic and Toc
64
The _________ is equivalent in function to the mitochondrial matrix. It contains the genetic system and metabolic enzymes, including those needed to convert CO2 to carbohydrates during photosynthesis.
a. intermembrane space
b. stroma
c. thylakoid lumen
d. thylakoid membrane
b. stroma
65
All plastids, including chloroplasts, develop from ________.
a. Chromoplasts
b. Etioplasts
c. Elaioplasts
d. Proplastids
d. Proplastids
66
In terms of its role in the generations of metabolic energy, the inner membrane in mitochondria is equivalent to which of the following in chloroplasts?
a. The inner membrane
b. The thylakoid membrane
c. The outer membrane
d. The stroma
b. The thylakoid membrane
67
Many proteins are synthesized on free ribosomes and imported into chloroplasts as completed polypeptides. The N-terminal __________ direct translocation across the two membranes of the envelope and are then removed by proteolytic cleavage.
a. Phospholipid transfer proteins
b. Poly AAA
c. Telomere
d. Transit peptides
d. Transit peptides
68
What triggers lipid-containing etioplasts to undergo complete development into chloroplasts?
a. Light
b. Glucose
c. Darkness
d. Pigment
a. Light
69
The cytoskeleton is composed of three main types of protein filaments. Which one is not cytoskeleton?
a. Actin filaments
b. Microtubules
c. Intermediate filaments
d. Laminin
d. Laminin
70
Actin exists in cells in two major forms called _____________.
a. -tubules and -tubules
b. -actin and -actin
c. G actin and D actin
d. G actin and F actin
d. G actin and F actin
71
Branching of actin filaments can be initiated by _________.
a. Arp 2/3
b. Formin
c. ADF/cofilin
d. Fimbrin
a. Arp 2/3
72
__________ bind at ATP-actin and nucleate initial polymerization of long unbranched actin filaments.
a. Spectrin
b. Formin
c. ADF/cofilin
d. Fimbrin
b. Formin
73
Actin filaments are bound into bundles of parallel filament by the protein’s _________.
a. filamin and cofilin
b. troponin and tropomyosis
c. profilmin and thymyosin
d. alpha-actinin and fimbrin
d. alpha-actinin and fimbrin
74
In actin filament assembly, the process in which ATP-actin monomers are added to the barbed end of the filament while at the same time ADP-actin monomers are dissociating from the points end of the filament is referred to as _________.
a. equilibrium
b. dynamic instability
c. treadmilling
d. balancing
c. treadmilling
75
During muscle contraction, the A band _________.
a. stays the same width, and the I band and H zone shorten
b. and H zone stay the same width, and the I bands shorten
c. shortens, and the I bands and H zone stay the same
d. and H zone shorten, and the I band stay the same
a. stays the same width, and the I band and H zone shorten
76
In nonmuscle cells and smooth muscle, contraction is regulated primarily by phosphorylation of a myosin light chain, which is catalyzed by myosin light chain kinase (MLCK), which is regulated by the Ca2+-binding protein _________.
a. Akt
b. calmodulin
c. integrin
d. collagen
b. calmodulin
77
Myosin _______ is present in muscle sarcomeres.
a. I
b. II
c. III
d. IV
b. II
78
Microtubules are assembled from __________.
a. alpha-tubulin dimers
b. beta-tubulin dimers
c. altering alpha-tubulin dimers and beta-tubulin dimers
d. dimers of alpha- and beta-tubulin
d. dimers of alpha- and beta-tubulin
79
Which nucleotide triphosphate is hydrolyzed during a cycle of microtubule assembly and disassembly?
a. ATP
b. TTP
c. CTP
d. GTP
d. GTP
80
The microtubule behavior in which some microtubules are rapidly depolymerizing and some are growing is called __________.
a. an equilibrium state
b. dynamic instability
c. treadmilling
d. balancing
b. dynamic instability
81
The major microtubule-organizing center in most animal cells is the __________.
a. kinetochore
b. polar microtubules
c. centrosome
d. centromere
c. centrosome
82
The microtubes that overlap in the center of the mitotic spindle are called __________ microtubules.
a. astral
b. chromosomal microtubules
c. kinetochore
d. polar
d. polar
83
Coflin plays a role in ___________.
a. severing actin filaments
b. stimulation of actin filament formation
c. nucleation of microfilaments
d. disassembly of microtubules
a. severing actin filaments
84
Actin may be cross-linked into either parallel or _________ bundles.
a. antiparallel
b. contractile
c. networks
d. orthogonal filament
b. contractile
85
The basis for muscle contraction is the _____________.
a. rotation of myosin fibers around actin fibers
b. expansion of the sarcomere
c. sliding of myosin and actin fibers past each other
d. movement of the Z discs away from each other
c. sliding of myosin and actin fibers past each other
86
Like myosins, kinesin and dyneins are both proteins. Which of the following statements is true of all kinesins and dyneins?
a. They are microtubule-dependent motors
b. They are both minus-end-directed motors
c. They are neither minus-end-directed nor plus-end-directed motors
d. They are both plus-end-directed motors
a. They are microtubule-dependent motors
87
Cell division follow mitosis. A contractile ring of _________ and myosin II is assembled by membrane-bound myosin just beneath the plasma membrane.
a. collagen
b. actin
c. intermediate filament
d. fibronectin
b. actin
88
Collagen commonly contain the three repeating amino acids: _______, proline, and ________.
a. glutamine; proline
b. glycine; hydroxyproline
c. glycine; arginine
d. glutamine; lysine
b. glycine; hydroxyproline
89
Adherens junctions are linked to cytoplasmic _________.
a. actin filaments
b. intermediate filaments
c. microtubules
d. myosin filaments
a. actin filaments
90
Desmosomes are linked to cytoplasmic _________.
a. collagen
b. intermediate filaments
c. microtubules
d. myosin filaments
b. intermediate filaments
91
The plasma membrane function as a __________.
a. Selective barrier to the passage of molecules
b. Site for the uptake of macromolecules into the cell
c. Site for cell-cell interactions
d. All of the above
d. All of the above
92
In animal cell plasma membrane, sphingomyelin are __________.
a. Exclusively in the inner leaflet
b. Mainly in the outer leaflet
c. Equally distributed between the inner and outer leaflets
d. Only on the basal surface of epithelia
b. Mainly in the outer leaflet
93
The two erythrocyte proteins, glycophorin and band 3, are example of _________.
a. Peripheral proteins
b. Transmembrane proteins
c. Cytoskeletal proteins
d. beta-barrel proteins
b. Transmembrane proteins
94
Facilitated diffusion differs from passive diffusion in that facilitated diffusion is _______.
a. Mediated only by a protein channel
b. Mediated only a protein carrier
c. Mediated by a protein carrier or channel
d. Against the concentration gradient
c. Mediated by a protein carrier or channel
95
Channels that open in response to neurotransmitter or other signal molecules are called ________ channels.
a. Voltage-gated
b. Ligand-gated
c. Signal-gated
d. Ion
b. Ligand-gated
96
In a typical mammalian cell, the concentration of ________ is higher on the inside, and the concentration of _______ is higher on the outside.
a. Na+ and K+; Ca2+
b. Na+; K+
c. K+; Na+
d. Na+ and Cl-; K+
c. K+; Na+
97
The resting potential of a typical eukaryotic cell is _________ mV.
a. 0
b. -60
c. +30
d. -100
b. -60
98
Which one is wrong about active transport?
a. Active transport is in an energetically unfavorable direction
b. Energy is provided by a coupled reaction such as ATP hydrolysis
c. Molecules are transported against their concentration gradients
d. Active transport is determined by concentration gradient and is in an energetically favorable direction
d. Active transport is determined by concentration gradient and is in an energetically favorable direction
99
The Na+ and K+ ion gradient across the plasma membrane are produced primarily by the _________.
a. Permeability of these ions across the lipid bilayer
b. Ratio of these ion in the blood
c. Action of the Na+-K+ pump
d. Flow of these ion through voltage-gated channels
c. Action of the Na+-K+ pump
100
Coupled transport of glucose and Na+ into the intestinal epithelial cell is an example of ________.
a. Facilitated diffusion
b. Symport
c. Antiport
d. Endocytosis
b. Symport
101
The functioning of the Na+-Ca2+ transported in the plasma membrane is an example of ________.
a. Facilitated diffusion
b. Symport
c. Antiport
d. Endocytosis
c. Antiport
102
Which of the following statement about ion channels is true?
a. They are opened either by the binding of ligand or by changes in electrical potential across the membrane
b. They require ATP
c. They are open most of the time
d. Glucose transporter is on type of channel proteins
a. They are opened either by the binding of ligand or by changes in electrical potential across the membrane
103
The pH of endosomes and lysosomes is _______.
a. Acidic
b. Alkaline
c. Neutral
d. Unknown
a. Acidic
104
Members of the Bcl-2 family of proteins are ________.
a. All caspases
b. All proapoptotic
c. All antiapoptotic
d. Either antiapoptotic or proapoptotic
e. Neither antiapoptotic or proapoptotic
c. All antiapoptotic
105
Which of the following cells cannot develop form hematopoietic stem cells?
a. Erythrocytes
b. Platelets
c. B lymphocytes
d. Sebaceous cells
d. Sebaceous cells
106
Intestinal stem cells may give rise to which of the following terminally differential cell type in the intestinal epithelium?
a. Absorptive epithelial cells
b. Goblet cells
c. Enteroendocrine cells
d. All of the above
e. None of the above
d. All of the above
107
Intestinal epithelial stem cells are located ______ the crypt.
a. At the top of
b. At the bottom of
c. At the sides of
d. Throughout
e. Next to but not part to
b. At the bottom of
108
The stem cells of skeletal muscles are called __________.
a. Myoblast
b. Myocytes
c. Satellite cells
d. Myo-stem cells
e. None of the about; no stem cells are found in skeletal muscle
c. Satellite cells
109
Mouse embryonic stem cells can proliferate but remain undifferentiated in the presence of the growth factor called ________.
a. Dif
b. LIf
c. EGF
d. Wnt
e. Scf
b. LIf
110
The ability to reprogram somatic cells into other types of differentiated cells (other than induced pluripotent stem cells) is referred to as ____________.
a. Transduction
b. Transfection
c. Transdifferentiation
d. Translocation
e. Transdevelopment
c. Transdifferentiation
111
The most lethal forms of cancer in the united states is _______ cancer.
a. Breast
b. Prostate
c. Lung
d. Colon
e. Skin
c. Lung
112
A tumor of an epithelial cell is a ________.
a. Carcinoma
b. Sarcoma
c. Leukemia
d. Lymphoma
a. Carcinoma
113
Tumor initiation occurs in a _______.
a. Single protein molecule
b. Single cell
c. Few cells
d. Single tissue
e. Single organ
b. Single cell
114
Which of the following is a common difference between normal cells and cancer cells?
a. Density-dependent inhibition of proliferation
b. Contact inhibition of migration
c. Growth factor requirements
d. Cell adhesion
e. All of the above
e. All of the above
115
Carcinogens are substances that cause cancer. The carcinogens include ________.
a. Solar ultraviolet radiation
b. Aflatoxin
c. Chemicals in tobacco smoke include benzo(a)pyrene, dimethyl nitrosamine, and nickel compounds
d. A and B
e. All of the above
e. All of the above
116
As they emerge from the ribosome, signal sequences are recognized and bound by a(n) _________.
a. tRNA
b. Signal peptidase
c. Signal recognition particle (SRP)
d. SRP receptor
e. Translocon
c. Signal recognition particle (SRP)
117
Most cellular lipids are synthesized in _______.
a. Fat droplets
b. Mitochondria
c. The endoplasmic reticulum
d. Secretory vesicles
c. The endoplasmic reticulum
118
Vesicles that carry proteins from the rough ER to ERGIC and on to the Golgi Apparatus bud off as _____ vesicles.
a. Uncoated
b. Clathrin-coated
c. COPI-coated
d. COPII-coated
e. SNAP-coated
d. COPII-coated
119
Disulfide bonds within or between proteins form easily in which of the following?
a. Both the cytosol and the ER
b. Neither the cytosol nor the ER
c. The cytosol but not the ER
d. The ER but not the cytosol
e. The mitochondria
d. The ER but not the cytosol
120
Which of the following lipids is/are synthesized in the Golgi Apparatus?
a. Phospholipids
b. Cholesterol
c. Ceramide
d. Glycolipid
d. Glycolipid
121
The major model of vesicles fusion that the specificity of a vesicles fusing with its target membrane lies in the interaction of pairs of proteins called v- (vesicle) and t- (target) _________.
a. SNAREs
b. SNAPs
c. COPs
d. NSFs
a. SNAREs
122
The process by which cells degrade their own components by enclosing them in a cytosolic membrane is ________.
a. Autophagy
b. ER-mediated endocytosis
c. Phagocytosis
d. Pinocytosis
a. Autophagy
123
Which of the following contain their own genome?
a. Mitochondria, but not chloroplasts, and peroxisomes
b. Chloroplasts, but not mitochondria and peroxisomes
c. Mitochondria and chloroplasts, but not peroxisomes
d. Peroxisomes, but not mitochondria and chloroplasts
c. Mitochondria and chloroplasts, but not peroxisomes
124
The process by which mitochondria are thought to have arisen during evolution is called _________.
a. Symbiosis
b. Phagocytosis
c. Endosymbiosis
d. Autophagocytosis
e. Pinocytosis
c. Endosymbiosis
125
Electron transport and oxidative phosphorylation are performed by protein complexes in the mitochondrial ________.
a. Outer membrane
b. Intermembrane space
c. Inner membrane
d. Matrix
e. Both A and C
c. Inner membrane
126
The transport of proteins across the outer and inner chloroplast membranes occurs through complexes called _________.
a. Import complexes
b. Tic and Toc
c. Sec and Tat
d. All of the above
b. Tic and Toc
127
The light-dependent generation of ATP in photosynthesis occurs in the __________.
a. Outer membrane
b. Inner membrane
c. Thylakoid membrane
d. The stroma
c. Thylakoid membrane
128
In terms of its role in the generation of metabolic energy, the inner membrane in mitochondria is equivalent to which of the following in chloroplasts?
a. The inner membrane
b. The thylakoid membrane
c. The outer membrane
d. The stroma
b. The thylakoid membrane
129
Light is capture by ________ different photosystems associated with the thylakoid membranes of chloroplasts.
a. Two
b. Four
c. Five
d. Ten
a. Two
130
Which of the following are integral membrane proteins that do not contain transmembrane alpha-helix?
a. Band 3
b. Glycophorins
c. Glycosylphosphatidylinositol (GPI)-anchors proteins
d. None of the above
c. Glycosylphosphatidylinositol (GPI)-anchors proteins
131
Which of the following statements about ion channels is true?
a. They are opened either by the binding of ligands or by changes in electric potential across the membrane
b. They require ATP
c. They are open most of the time
d. The rate of transport is slow compared to the rate of transport via carrier proteins
a. They are opened either by the binding of ligands or by changes in electric potential across the membrane
132
Clusters of sphingolipids, cholesterol, and membrane proteins that move together laterally in the plane of the plasma membrane are called lipid ________.
a. Boats
b. Barrels
c. Rafts
d. Barges
e. Patches
c. Rafts
133
Channels that open in response to neurotransmitters or other signal molecules are called _________ channels.
a. Voltage-gated
b. Ligand-gated
c. Signal-gated
d. Ion
e. Transporter
b. Ligand-gated
134
The Na+ and K+ ion gradient across the plasma membrane are produced primarily by the __________.
a. Permeability of these ions across the lipid bilayer
b. Ration of these ions in the blood
c. Action of the Na-K+ pump
d. Flow of these ions through voltage-gated channels
e. Passive flow of these ions through channels
c. Action of the Na-K+ pump
135
The functioning of the Na+-Ca2+ transporter in the plasma membrane is an example of _________.
a. Facilitated diffusion
b. Symport
c. Antiport
d. Transcytosis
e. Endocytosis
c. Antiport
136
Cholesterol is taken up into most cells of the body by ___________.
a. Pinocytosis
b. Receptor-mediated endocytosis
c. Simple diffusion
d. Active transport
e. Caveolae formation
b. Receptor-mediated endocytosis
137
Signaling by cadherins is an example of _______ signal.
a. Autocrine
b. Endocrine
c. Paracrine
d. Direct cell-to-cell
e. Electrical
d. Direct cell-to-cell
138
The G protein that activates adenylyl cyclase is a ________.
a. Monomeric G protein in the Ras family that bind GTP
b. Dimeric G protein that separates into alpha and beta
c. Heterotrimeric G protein that separates into alpha and beta gamma
d. Heterotrimeric G protein that separates into alpha beta and gamma
e. Tetrameric G proteins that separates into alpha beta and
c. Heterotrimeric G protein that separates into alpha and beta gamma
139
Most growth factor receptors are ___________.
a. G protein-linked
b. Protein-tyrosine kinases
c. Serine-threonine protein kinases
d. Intracellular receptors
e. Nuclear receptors
b. Protein-tyrosine kinases
140
The first step in growth factor pathway activation is ________.
a. Ras activation
b. Receptor phosphorylation
c. Receptor dimerization
d. The binding of SH2-containing proteins
e. The release of G protein
c. Receptor dimerization
141
Which of the following is considered a second messenger?
a. cAMP
b. IP3
c. Calcium
d. Both A and B
e. All of the above
e. All of the above
142
MAP kinase signal cascades are often organized into functional groups or cassettes by _______.
a. Scaffold proteins
b. Binding of SH2 domains to each other
c. Lipid rafts
d. Binding MAP kinase-responsive genes
e. Binding of the nuclear envelope
a. Scaffold proteins
143
Calcium stimulates many cellular enzymes by binding to a calcium-binding protein called ________.
a. Calcineurin
b. Calcinectin
c. Calmodulin
d. Calbindin
e. Cadherin
c. Calmodulin
