Exam 2 Problem Roulette Flashcards
Two sugars that differ only in their configuration about a single carbon atom are called?
Epimers
Which of the following bonds links the monosaccharides in amylose, causing this molecule to naturally form a coil?
Alpha 1 ->4
What is a lectin?
Proteins that bind specific carbohydrates
What describes a glycoprotein?
A transmembrane protein that is covalently linked to a unique series of carbohydrates that specifies the cell type
Which of the following are true about the reactions between monosaccharides and larger polysaccharides?
During starch synthesis, additional monosaccharides are added to amylose via a oxidative reduction reaction
Disaccharide formation proceeds via a condensation reaction that liberates water
A non-reducing sugar has no anomeric carbon available to react
In a glucose disaccharide, the reducing sugar exists in a stable anomeric configuration
Both amylose and amylopectin tend to adopt a coiled tertiary structure
The main factor that contributes to the stability of chitin is the acetylated amino group
-Disaccharide formation proceeds via a condensation reaction that liberates water
-A non-reducing sugar has no anomeric carbon available to react
-Both amylose and amylopectin tend to a adopt a coiled tertiary structure
Which molecule below is not a glycoconjugate
Heparan Sulfate
Lipopolysaccharides
Hyaluronate
DNA
Integrins
DNA
What statement about the position of the oxygen atom attached to C5 in monomeric Alpha-D-glucose is correct?
The C5 oxygen is on the same face of the ring as the C6 carbon.
The C5 oxygen is on the opposite face of the ring as the C6 carbon.
None of the other choices is correct
The C5 oxygen is part of an acetal functional group
The C5 oxygen is part of a hemiacetal functional group
The C5 oxygen is part of a hemiacetal functional group
Which of the following does NOT describe a general function of carbohydrates?
Metabolic energy source in biological systems.
Post-translational modifications of extra-cellular proteins.
Signaling hormone
Structural component of bacterial cell walls.
Headgroup component of certain membrane lipids.
Signaling hormone
Which of the following about cellulose and chitin is FALSE?
The strands stack very tightly, excluding the absorption of water
They are both linear homopolymers
They contain the same kind of glycosidic linkages
The higher order structures for both exclusively comprises parallel strands
The higher order structures for both exclusively comprises parallel strands
In which of the following locations would you expect to find a high concentration of peptidoglycans?
In starch granules
In the extracellular matrix
In the hard exoskeletons of certain insects
In eukaryotic cell membranes
In gram-positive bacterial cell walls
In gram-positive bacterial cell walls
Proteoglycans, Glycoproteins, and Glycolipids are collectively known as which of the following?
Glycans
Peptidoglycans
Dextrans
Glycoconjugates
Glycosaminoglycans
Glycoconjugates
Which of the following Weak Interactions is most important or most influential for homopolysaccharide folding?
Van der Waal’s interactions
Hydrophobic interactions
Hydrogen Bonding
Ionic interactions
Hydrogen Bonding
Which statement about glycogen is FALSE?
Glycogen is a linear storage molecule used by mammals
Glycogen contains (α1→6) linkages
Glycogen contains (α1→4) linkages
Glycogen is a homopolymer of glucose
Glycogen has many non-reducing ends for each reducing end
Glycogen is a linear storage molecule used by mammals
When two monosaccharides join to form a disaccharide which of the following is true?
An anhydride is converted to a hydride.
A water molecule is released as an additional product for this reaction.
An acetal is converted to an hemiacetal.
The resulting disaccharide is not a reducing sugar.
The resulting disaccharide is a reducing sugar.
A water molecule is released as an additional product for this reaction.
Some sugars, such as glucose, which can reduce metals such as iron or copper are called:
Metalloglycosides
Anomeric Sugars
Glycans
None of the above
Reducing Sugars
Reducing Sugars
An aldohexose that forms a five-membered ring is then called which of the following?
A glucopyranose
A pyranose
An aldopentose
A furanose
A furanose
Which of the following does NOT describe a lectin?
A toxin that reversibly binds to complex carbohydrates on the surface of eukaryotic cells
A plant protein with that specifically binds a fungal glycoconjugate
Viral proteins that adhere to sialic acid on the host cell surface
A protein that interacts with the extracellular matrix by hydrogen bonding to specific glycans
A polytopic membrane protein with N-linked glycosylation
A polytopic membrane protein with N-linked glycosylation
Starch and Cellulose are two of the most abundant polysaccharides in nature. They are both composed of glucose subunits, but with very different structures. Which linkage(s) below is/are present in Starch?
α1 →4 linkages
α1 →6 branches
β1→4 linkages
A and B only
B and C only
A and B only
From the abbreviated name of the compound Gal(alpha1->1beta)Glc, Which of the following is NOT true? (Gal = galactose, Glc = glucose)
the glucose residue is the beta anomer.
two anomeric carbons were linked to form this compound
the compound is a reducing sugar
there are no hemiacetal groups in this compound
C-1 of glucose is joined to C-1 of galactose by a glycosidic bond.
the compound is a reducing sugar
What term refers to the interconversion of the alpha and beta anomers of glucose in solution?
Mutarotation
Oxidation/Reduction
Glycosidation
Epimerization
Racemization
Mutarotation
Which of the following is a purine linked to a phosphate group and a sugar?
Thymidine
Cyclic 3’,5’-cytosine phosphate
Deoxycytidine
Deoxyguanylate
Uridine
Deoxyguanylate
Which of the following does NOT contribute favorably to the energetics of forming a DNA double helix?
Hydrogen bonds between pairs of nitrogenous bases
Ionic interactions involving the phosphoribose backbone
van der Waals interactions between stacked bases
Cooperativity of the two strands annealing
Bases are hydrophobic relative to the phosphoribose backbone
Ionic interactions involving the phosphoribose backbone
Which of the following describes a general biological function of nucleotides?
Donor of phoshoryl groups (phosphates) for post-translation protein modification (including regulation).
Component of many important enzyme cofactors
Building block of DNA and RNA
General energy-carrying molecule in biological systems
All these answers are functions of nucleotides.
All these answers are functions of nucleotides.
Which of the following structures is NOT a permanent change to chromosomal DNA?
Denaturation
Mutation
Thymine-Thymine (cyclobutane) dimer
Deamination
Depurination
Denaturation
DNA hairpins located exactly opposite each other and on different strands of DNA are called which of the following?
H-DNA
Inverted repeat
Palindrome
Cruciform
Mirror repeat
Cruciform
Which of the following is primarily responsible for holding the two DNA strands together in a helix?
Disulfide linkages
Hydrophobic interactions
Phosphodiester bonds
Hydrogen bonds
Glycosidic linkages
Hydrogen bonds
Which of the following is on the 3’ end of a DNA sequence?
Amino group
Carboxyl of a sugar
Hydroxyl of a sugar
Phosphate
Base
Hydroxyl of a sugar
Which of the following is NOT an example of DNA damage?
Cytosine deamination
Thymidine dimer formation
Guanosine depurination
Cytosine methylation
Cytosine methylation
Which of the following are most likely to lead to triplex DNA?
Cytosine deamination
Wobble base pairing
Low pH causing cytosine protonation
Palindromic sequences
High guanosine content
Low pH causing cytosine protonation
Which of the following is FALSE about phosphodiester linkages?
They join the 3’ hydroxyl of one nucleotide to the 5’ hydroxyl of the next.
They are more stable in RNA than in DNA
They form the backbone of double helical structure.
They are present in both DNA and RNA
They are negatively charged at neutral pH
They are more stable in RNA than in DNA
Nucleic acids are characterized by which of the following?
Ring resonance that causes absorption of light near 260 nm
Formation of helices by DNA but not by RNA
A-T rich regions melting at higher temperatures than G-C rich regions
Formation of a hairpin by a Palindrome on two strands
Sugar and phosphate residues located near the center of the molecule after refolding in aqueous media
Ring resonance that causes absorption of light near 260 nm
Which of the following is on the 5’ end of a DNA sequence?
Carboxyl of a sugar
Base
Amino group
Hydroxyl of a sugar
Phosphate
Phosphate
Which of the following is NOT a common feature of DNA binding proteins?
alpha helices fit perfectly in the major groove
DNA binding proteins can recognize specific DNA sequences that are visible within the major groove
Slide along the DNA until they find the correct binding site
Preferentially recognize single-stranded DNA
Tend to have a lot of arginines and lysines
Preferentially recognize single-stranded DNA
Which statement is FALSE?
Different fragments of DNA would be expected to have different melting temperatures
Depurination and deamination are non-enzymatic mutations
RNA and DNA both form Hairpin structures and double-helices
Partially denatured DNA could have G-C rich regions that have broken Hydrogen bonds while the A-T regions are intact
All of the statements above are TRUE
Partially denatured DNA could have G-C rich regions that have broken Hydrogen bonds while the A-T regions are intact
Which of the following statements about nucleic acid double-helices is FALSE?
RNA and DNA adopt essentially identical structures.
G-C base pairs are more stable than A-T base pairs.
Bases are stabilized in part by aromatic (pi-pi) stacking.
The major groove is large enough to accommodate protein secondary structure elements.
Negatively charge phosphates are solvent exposed on the outsides of the helix.
RNA and DNA adopt essentially identical structures.
Which of the following is NOT consistent with the Watson-Crick model for the DNA double helix?
Base stacking helps stabilize the double helix
The two strands run antiparallel to one another.
The composition of bases obeys Chargaff’s rules
Guanosine residues can form tetraplex structure.
The sequence of one strand provides a template for duplication of the second strand
Guanosine residues can form tetraplex structure.
You perform a Sanger sequencing reaction. The template strand is:
5’ ATCGAAC 3’
However, you make a mistake and forget to add any dGTP. What is the most likely outcome?
You will get a single band representing a 3-nucleotide product in the G lane.
You will get a single band representing a 7-nucleotide product in the G lane.
You will get two bands representing 1- and 5-nucleotide products in the G lane.
You will get a single band representing a 1-nucleotide product in the G lane.
You will get no bands in the G lane.
You will get a single band representing a 1-nucleotide product in the G lane.
Consider the following two segments of RNA. Which of the following describes a secondary structure that is likely to be formed?
5’ AUCGCG 3’
5’ CGCAGAU 3’
Bulge
These two segments are not expected to form base pair interactions
B-form double helix
Hairpin
Cruciform
Bulge
Which statement about transcription factor binding to its cognate DNA target is likely true?
The minor groove of non-distorted DNA can easily accommodate an alpha-helix for sequence recognition.
The transcription factor likely has a significant, positively charged region in its surface which can bind DNA in a NON sequence specific manner.
Charge-charge interactions directly between Asp/Glu residues and the phosphate backbone likely contribute to protein-DNA interactions.
Recognition of the base pairs by amino acids such as Leu/Ile likely contributes to binding at the correct sequence
The transcription factor likely has a significant, positively charged region in its surface which can bind DNA in a NON sequence specific manner.
What bonds are broken in order to partially Denature double-stranded DNA?
Hydrophobic
Didulfide
Glycosidic
Phosphodiester
Hydrogen
Hydrogen
Which of the following is NOT an example of RNA secondary structure?
Hairpin
Internal Loop
Palindrome
Cruciform
Bulge
Palindrome
Which weak interaction is most important in maintaining DNA as a double-helix?
Hydrogen bonds
Van der Waal’s interactions
Ionic interactions
Phosphodiester linkages
Hydrophobic interactions
Hydrogen bonds
Which of the following is a covalent bond that links elements of the DNA “backbone”?
Phosphodiester
Ether
Peptide
Glycosidic
Hydrogen
Phosphodiester
What parts of DNA are considered the “backbone”?
Nucleoside base
Sugar
Phosphate
A and B
B and C
B and C
Movement of water across membranes is facilitated by proteins called _____________, movement of water is allowed by ____________ amino acids in the pore, and selectivity is enforced by the presence of _____________ amino acids at the selectivity filter.
hydropermeases, polar, basic
annexins, polar, acidic
aquaporins, polar, basic
aquaporins, polar, acidic
aquaporins, hydrophobic, basic
aquaporins, polar, basic
Which of the following principles is consistent with the physical properties of membranes?
Lipids in membranes generally move freely (fluidly), both laterally and across the membrane
Peripheral proteins associate non-covalently with the polar head groups of lipids
Integral proteins span the membrane and associate with only the acyl chains of phospholipids, which stabilizes the proteins in a hydrophobic environment
Proteins in membranes are spaced symmetrically between the two layers of the bilayer, but in a manner that varies between membrane types
Peripheral proteins associate non-covalently with the polar head groups of lipids
Which of the following is FALSE concerning the lipids in membranes?
Since white blood cells and red blood cells are exposed to essentially the same environment, their membranes would have the same lipid constituents in the same relative proportions. Function, not location.
The inner leaflet and the outer leaflet of plasma membranes both contain phospholipids
Carbohydrate groups of glycolipids always face the extracellular surface of the plasma membrane
Flipases can alter the distribution of lipids on the outer versus inner membrane leaflets
Since white blood cells and red blood cells are exposed to essentially the same environment, their membranes would have the same lipid constituents in the same relative proportions. Function, not location.
Which factor(s) affect the direction in which an ion moves through an ion channel in a membrane?
I. the concentration differential across the membrane
II. the size and shape of the channel
III. the ion selectivity of the channel.
IV. the voltage differential across the membrane
II and III
I and IV
I and II
All of these
I, III and IV
I and IV
Which small molecule is NOT made during an amplification process in cell signaling?
diacylglycerol (DAG)
cAMP
Inositol 1,4,5-trisphosphate (IP3)
cGTP
Steroid hormone
Steroid hormone
Which of the following proteins that we discussed in class can be studied using patch clamp electrophysiology:
Aquaporin
GPCR
ABC transporter
GLUT1
CFTR
CFTR
Which of the following receptors that we discussed in class could be studied using patch clamp electrophysiology?
Estrogen receptor
Phospholipase C
Nicotinic acetylcholine receptor
Insulin receptor tyrosine kinase
GPCR
Nicotinic acetylcholine receptor
Which of the following is NOT a major component of biological membranes?
Carbohydrates
All other choices are all major components of biological membranes
Polar Lipids
Cholesterol
Integral proteins
All other choices are all major components of biological membranes
Lateral diffusion rates on cell surfaces can be measured by:
glucose transport measurements
FRAP experiments
single particle tracking of fluorescent lipids
patch clamp experiments
FRAP and single particle tracking of fluorescent lipids
FRAP and single particle tracking of fluorescent lipids
Which of the following molecules is the least oxidized:
Fatty acid
Carboxylic acid
Glycogen
Glucose
Carbon dioxide
Fatty acid
The fluidity of a lipid bilayer will be increased by which of the following?
Increasing the temperature
Substituting Stearic acid (18:0) for Linoleic acid (18:2)
Decreasing the number of unsaturated fatty acids
Decreasing the temperature
Adding alkyl side chains that are longer
Increasing the temperature
Which of the following transport mechanisms permits solute transport down a concentration gradient AND requires a conformational change to translocate each substrate across the membrane?
Simple diffusion
Ion channel
Secondary active transport
Facilitated diffusion
Primary active transportv
Facilitated diffusion
What is the purpose of the Hydropathy Index (or Plot)?
Predicts the charge required to open and close voltage-gate channels.
Predicts segments of globular proteins that would fold to the inside to avoid interactions with water.
Predicts if channels are Symports or Antiports based on delta E.
Predicts the number of solute molecules that pass through a membrane channel per unit of time.
Predicts that a segment of a protein may be transmembrane.
Predicts the number of solute molecules that pass through a membrane channel per unit of time.
Which of the following cellular processes typically does NOT involve membrane fusion?
Fertilization of an egg by sperm
Endocytosis
You getting infected with a Fall flu virus
Glucose transport into blood from the intestinal lumen
Exocytosis (i.e. secretion)
Glucose transport into blood from the intestinal lumen
Match the following cell signaling example with the feature it best exemplifies:
Hydrolysis of GTP by Gqa
Specificity
Modularity
Localization
Termination
Amplification
Termination
A researcher is investigating a potential inhibitor of the GLUT1 glucose transporter protein.
They determine that the Vmax for transport is the same with and without the inhibitor present, but the KT for transport is 5 mM glucose without the inhibitor, and 50 mM glucose with the inhibitor.
Which statement is most likely true about this inhibitor?
None of these other statements is plausible
The inhibitor binds GLUT1 in a different location from glucose
The inhibitor binds GLUT1 only in the presence of glucose
The inhibitor binds covalently to GLUT1
The inhibitor binds GLUT 1 in the same location as glucose
The inhibitor binds GLUT 1 in the same location as glucose
Which of the following membrane processes is responsible for steroid hormone signal transduction across the plasma membrane?
Primary active transport
Receptor enzymes
Gated ion channel
Simple diffusion
Carrier molecules
Simple diffusion
____________ membrane proteins ___________________ and can be removed from the membrane without disrupting the membrane, while ______________ membrane proteins require detergents and/or organic solvents to remove from the membrane.
Peripheral
may have functional units on both sides of the membrane
integral
Integral
penetrate deeply into the lipid bilayer
peripheral
Integral,
are usually denatured when released from membranes,
peripheral
Amphitropic,
are generally noncovalently bound to membrane lipids,
peripheral
Peripheral,
are generally noncovalently bound to membrane lipids,
integral
Peripheral,
are generally noncovalently bound to membrane lipids,
integral
Which statement about sterols is FALSE?
Cholesterol is the principal membrane sterol.
Sterols are soluble in water, but less so in organic solvents such as chloroform.
The sterol backbone is the basis for a number of hormones
Sterols are found in the plasma membranes of eukaryotic cells.
All sterols share a fused-ring structure with four rings.
Sterols are soluble in water, but less so in organic solvents such as chloroform.
You have raised two groups of tadpoles: one group at 15° C, and the second group at 30° C. You then compare the lipid composition of the plasma membranes for the two groups of tadpoles. Which of the following statements best describes the membranes of these tadpoles:
The group raised at 15° C has more unsaturated fatty acids, and the group raised at 30° C has more saturated fatty acids.
The two groups of tadpoles have identical lipid compositions, but the membranes of the group raised at 30° C are less fluid.
The group raised at 30° C has more unsaturated fatty acids, and the group raised at 15° C has more saturated fatty acids.
The two groups of tadpoles have identical lipid compositions, but the membranes of the group raised at 15° C are less fluid.
The group raised at 15° C has more unsaturated fatty acids, and the group raised at 30° C has more saturated fatty acids.
What group of lipids serves as the basis for the ABO blood group system?
Ether Lipids
Sphingomyelins
Glycerophospholipids
Triglycerides
Glycosphingolipids
Glycosphingolipids
Which statement is FALSE regarding the Oleic acid hydrocarbon [18:1(Δ9)]?
It has a much lower melting point than steric acid (18:0)
All of the above are true statements
It can pack tighter together than steric acid due to the higher relative flexibility of its structure
It can be classified as an unsaturated lipid molecule
There is a single double bond between carbons 9 and 10
It can pack tighter together than steric acid due to the higher relative flexibility of its structure
Triacylglycerols
Can sometimes be substituted with a carbohydrate group
Are usually planar molecules, which permits their tight packing in cells
Provide a means in which to store energy and act as insulators
Are composed of a glycerol backbone and 2 fatty acids plus a third group (usually an alcohol)
Are the main component of membrane lipids
Provide a means in which to store energy and act as insulators
Match the following cell signaling example with the feature it best exemplifies:
Use of SH2 domains to bind phosphotyrosine residues
Amplification
Integration
Modularity
Termination
Specificity
Modularity
Signal amplification is an important feature of many, but not all, signaling events. Which of the following signaling events do not include amplification?
A nuclear hormone receptor that turns gene expression off
Ligand binding triggers opening of a calcium channel
The insulin receptor signaling cascade
I and II only
I and III only
I only
All three signaling pathways include an amplification event
I, II, and III
I only
Phospholipases
Can produce fatty acids by hydrolysis of an ester bond in a phospholipid
Are named according to the specific bond they hydrolyze and not by their substrates
Can cleave fatty acids from gangliosides by hydrolysis of diester linkages
A and B are both true statements
A and C are both true statements
A and B are both true statements
Consider the membrane potential of a typical metabolizing cell. Which of the best mechanisms is the best strategy for the cell to export ammonium (NH4+)? (Assume the concentration of ammonium is equal inside and outside the cell).
Simple diffusion
H+/ammonium symport
H+/ammonium antiport
Uniport
Ion channel
H+/ammonium antiport
Phospholipase C can use phosphatidylinositol 4,5-bisphosphate (PIP2) as a substrate to produce which of the following molecules that directly causes the release of intracellular calcium?
I. Adenosine 3’,5’-cyclic monophosphate (cAMP)
II. Diacylglycerol (DAG)
III. Inositol 1,4,5-trisphosphate (IP3)
IV. Protein Kinase C (PKC)
I only
IV only
II and III
II only
III only
III only
Which of the following is NOT an example of signal termination?
GAPs strongly stimulate GTPase activity causing hydrolysis of the GTP bound to the trimeric G-protein
Estrogen production decreases below Kd of its receptor
The gate of the nicotinic acetylcholine receptor closes while nicotine remains bound
A cell takes up signaling peptides by endocytosis and sends them to the lysosome for degradation
Acetylcholine esterase hydrolyzes all of the acetylcholine in the gap junction
The gate of the nicotinic acetylcholine receptor closes while nicotine remains bound
An incorrect feature of G-proteins (Guanine Nucleotide Binding Proteins) is that:
They include heterotrimeric proteins as a major subclass
They are kinases.
They inactivate themselves by hydrolyzing GTP.
They include low molecular weight proteins as a major subclass
They are active in their GTP bound state.
They are kinases.
Which of the following are structurally most closely related to cholesterol?
Tocopherols, like Vitamin E
Steroid hormones
Eisosanoids
Phosphatidylinositols
Retinoids, like Vitamin A derivatives
Steroid hormones
What specific class of enzymes hydrolyze the ester bonds of glycerophospholipids?
Protein Kinases
Sialidases
Phosphorylases
Phospholipases
Phosphatases
Phospholipases
What is the abbreviated nomenclature for a polyunsaturated 22-carbon omega-3,6 fatty acid that contains no other double bonds?
22:2(Δ 16,19)
22:1(Δ 19)
22:2(Δ 13,19)
22:1( Δ 16)
22:2(Δ 13,16)
22:2(Δ 16,19)
Which of the following does NOT describe signal termination?
beta-arrestin binds to a GPCR and prevents a trimeric G-protein from accessing its binding site on the GPCR
The pancreas stops secreting the insulin, and the level of this hormone in the blood stream drops below the binding constant of the receptor
Acetylcholine esterase hydrolyzes acetylcholine in the synaptic cleft
Phospholipase C is inactivated and enzymes convert the remaining diacylglycerol to phosphatidic acid
GAPs stimulate the trimeric G-protein’s GTPase activity, causing GTP hydrolysis
beta-arrestin binds to a GPCR and prevents a trimeric G-protein from accessing its binding site on the GPCR
Which of the following are phospholipids that contain an ether-linked alkyl group?
Cerebrosides
Glycosphingolipids
Globosides
Plasmalogens
Sphingomyelins
Plasmalogens
Which of the following statements is FALSE regarding the insulin receptor?
Insulin binding causes autophosphorylation on Tyr residues
Activated receptors can induce transcription
Several steps of the signaling cascade involve phosphorylation, and amplification of the first signal at each step, so there is no requirement for either class of G-protein
The receptor changes conformation upon binding of its ligand (insulin).
It is a member of the Receptor Enzyme class
Several steps of the signaling cascade involve phosphorylation, and amplification of the first signal at each step, so there is no requirement for either class of G-protein
An example of signal termination is when:
Your eyes adjust to a brightened room
B-arrestin binds a receptor, leading it to be endocytosed
The concentration of the signaling molecule drops below the Kd of the receptor
All of these
The signal is amplified until there are no more enzymes in the cascade to phosphorylate
The concentration of the signaling molecule drops below the Kd of the receptor
Which of the following is important in developing an electrochemical gradient?
Membrane Potential (Vm)
Concentration gradient
Ka, the Acid-Base Constant
A and B only
A, B and C are all important in developing an electrochemical gradient
A and B only
What is the accepted minimum number of amino acids required for a portion of a protein to span the lipid bilayer of a membrane?
20
50
100
5
Varies with the size of the R-group, so there is no accepted minimum
20
A process not involving the fusion of two membranes or two regions of the same membrane is:
fertilization of an oocyte by a sperm cell.
propagation of the membrane voltage potential in neurons
creation of pores between adjacent cells
entry of enveloped viruses into cells.
release of neurotransmitters at a synapse.
propagation of the membrane voltage potential in neurons
What specific group of lipids have the following properties: long-chain (C14-C36) fatty acids bonded to long-chain (C16-C30) alcohols, chains are usually saturated and unsaturated?
Cerebrosides
Glycosphingolipids
Triacylglycerols
Globosides
Waxes
Waxes
steroid hormone receptors are different than the other signal transduction mechanisms we talked about because:
Their response time is hours-to-days
The signal molecules pass through the plasma membrane
All of these
They don’t make use of second messengers
All of these
We can calculate the energy required to move a charged solute, like bicarbonate, across a membrane using the transport formula, it relates the Transport Constant (GT) to some electrical measurements and the ratio of solute concentrations on either side of the membrane. Which of the following other constants and abbreviations is NOT in that formula?
Faraday’s Constant
Δψ, in volts
Gas Constant
Z, the charge of the ion
n, the number of ions moved
n, the number of ions moved
Which of the following statements about receptor enzymes is FALSE?
Receptor enzyme signaling cascades may include G proteins
Some receptor enzymes have tyrosine kinase activity
Receptor enzymes may directly catalyze the synthesis of second messengers
Receptor enzymes are typically polytopic membrane proteins
Integral membrane adenylyl kinases are examples of receptor enzymes
Integral membrane adenylyl kinases are examples of receptor enzymes
Which of the following can induce membrane curvature?
The ratio of saturated versus unsaturated fatty acids
Peripheral membrane proteins such as BAR domains
Monotopic membrane proteins such as caveolin
II only
II and III only
I, II, and III
III only
I only
II and III only
Which of the following amino acids are likely to contribute to the ligand binding site of a glycerol transporter:
Ser, Asn
Trp, Tyr
Gly, Ala
Asp, Arg
Ile, Val
Ser, Asn
Which of the following could describe the composition of globoside:
1 sphingosine, 2 fatty acids, 1 glucose
1 Sphingosine, 1 fatty acid, 1 glucose
1 sphingosine, 1 fatty acid, 2 glucose
1 sphingosine, 2 fatty acids, 2 glucose
1 sphingosine, 1 fatty acid, 2 glucose
Many diverse signaling pathways use cAMP as a second messenger. This is an example of the following principle:
Modularity
Localization
Integration
Desensitization
Termination
Modularity
Which of the following statements is FALSE concerning biological membranes?
Aquaporin is a good example of a protein involved in Passive Transport
The Chloride-bicarbonate exchanger is best classified as a Symport
The inner and outer leaflets of the plasma membrane have different lipids
One difference between Primary and Secondary Active Transport is the number of different molecules transported
The lipid composition of the plasma membrane is usually significantly different than any intracellular membrane
The Chloride-bicarbonate exchanger is best classified as a Symport
Independently, both insulin and epinephrine signaling lead to an increase in blood glucose levels. However, if both signaling cascades are activated at the same time, insulin signaling decreases epinephrin signaling to prevent blood glucose levels from becoming too high. This is an example of:
Modularity
Specificity
Amplification
Termination
Integration
Integration
Which of the following is NOT a feature that directly contributes to the Transition Temperature of lipids in membranes?
The relative concentration of saturated fatty acids
The relative concentration of sterols
The relative polarity of fatty acids
Only A and B above relate to the Transition Temperature of membrane lipids
A, B, and C above all relate directly to the Transition Temperature of membrane lipids
Only A and B above relate to the Transition Temperature of membrane lipids
Which statement about membranes is FALSE?
Lipids can freely pass from one leaflet to another in membranes
The inner and outer leaflets of membranes differ in lipid and protein compositions.
The lipid:protein ratio varies between tissues and organisms.
Transport of many solutes requires the action of integral membrane proteins.
Individual lipids can move freely in a lateral direction in membranes.
Lipids can freely pass from one leaflet to another in membranes
A cerebroside includes
A globoside with 3 or more esterified sugars
A phosphate group on carbon 3
A monosaccharide on ceramide
Sphingosine plus a long alcohol
A repeated disaccharide linked by a short peptide
A monosaccharide on ceramide
Match the following cell signaling example with the feature it best exemplifies:
Cyclization of ATP to cAMP
Amplification
Localization
Specificity
Termination
Modularity
Amplification
Adenylyl cyclase catalyzes the formation of cAMP in direct response to
An extracellular messenger
Hydrolysis of GTP by a bound G-protein
Binding of a GDP-bound G-protein
Binding of a GPCR
Binding of a GTP-bound G-protein
Binding of a GTP-bound G-protein
Which of the following sphingolipids is not also a glycolipids
Ganglioside
Globoside
Cerebroside
Sphingomyelin
Sphingomyelin
Which statement concerning membranes architecture is FALSE?
The inner and outer plasma membrane bilayers have an asymmetric distribution of phospholipids
Peripheral membrane proteins can be removed without damaging membrane integrity and without removing integral membrane proteins
Membranes are impermeable to simple diffusion of charged solutes
Carbohydrates are located only on the outer face of the plasma membrane
All internal membranes of Eukaryotic cells have the same relative proportions of the various phospholipids
All internal membranes of Eukaryotic cells have the same relative proportions of the various phospholipids
