Chem 3330 Which of the following structure is composed of a single layer of lipi
ID: 526964 • Letter: C
Question
Chem 3330
Which of the following structure is composed of a single layer of lipid molecules?
A) Plasma membrane of a plant cell
B) Plasma membrane of an animal cell
C) Plasma membrane of a bacterial cell
D) Liposome
E) Micelle
Which of the following is not a lipid membrane enclosed cellular compartment?
A) Endoplasmic reticulum
B) Nucleus
C) Chromosome
D) Mitochondria
E) Secretory granule
Which of the following is not a function performed by the cell membrane?
A) ATP synthesis
B) Signal transduction
C) Import and export materials
D) Storage potential energy in the form of a proton gradient. E) DNAreplication
What is the thickness of a typical lipid bilayer membrane?
A) 5×10-3m B) 5×10-6m C) 5×10-9m D) 5×10-10m E) 5×10-12m
Which of the following statements about the fluid mosaic model of membranes is true?
A) Integral proteins can be removed easily from the membrane.
B) Peripheral proteins can be covalently attached to the membrane lipid.
C) Cholesterol is found only on the outer leaflet of the lipid bilayer.
D) Glycolipids contain deoxyribonucleic acids.
E) Glycoproteins are composed of amino acids and lipids.
Which of the following is not a common feature found in most receptor molecules?
A) Each receptor binds a wide variety of signaling molecules.
B) They amplify the signals that they receive.
C) They promote protein phosphorylation.
D) They become desensitized to the signal after a period of time.
E) They often undergo conformational change.
Which of the following molecules are used for signaling?
A) adrenaline
B) heparin
C) insulin
D) epinephrine
E) All of the above.
Which of the following statements regarding GPCRs is correct?
A) They are integral membrane proteins.
B) They are heterotrimeric.
C) They contain a GTP binding site.
D) They are mainly made up of beta sheets.
E) They provide a tunnel through which signaling molecules can traverse the cell
membrane.
What is your body’s physiological response to epinephrine?
A) You feel sleepy.
B) You feel hungry.
C) You feel alert.
D) You feel relaxed.
E) You feel sad.
10. Which of the following molecules make direct contact with the GPCR during epinephrine signaling?
A) adenylyl cyclase
B) G-protein
C) ATP
D) GTP
E) cAMP
Explanation / Answer
1. Which of the following structure is composed of a single layer of lipid molecules? Ans E Micelle
A) Plasma membrane of a plant cell - phopholipid bilayer
B) Plasma membrane of an animal cell - phopholipid bilayer
C) Plasma membrane of a bacterial cell - phopholipid bilayer
D) Liposome - Lipid Bilayer
E) Micelle - Monolayer
2. Which of the following is not a lipid membrane enclosed cellular compartment? C chromosome
A) Endoplasmic reticulum - enclosed
B) Nucleus - enclosed
C) Chromosome - not enclosed with lipid membrane
D) Mitochondria - enclosed
E) Secretory granule - enclosed vesicles
3. Which of the following is not a function performed by the cell membrane? Ans E DNA replication
A) ATP synthesis - ATP synthase present on the membrane
B) Signal transduction - Glycoprotiens on the cell membrane
C) Import and export materials - endo/exo cytosis
D) Storage potential energy in the form of a proton gradient - Na/K Pump
E) DNAreplication - In the nucleus
What is the thickness of a typical lipid bilayer membrane? Ans C
A) 5×10-3m B) 5×10-6m C) 5×10-9m D) 5×10-10m E) 5×10-12m
Polar heads = 0.6-2 nm depending on hydration
Hydrophobic tails = 2.5-3.5 nm depending on the double bond "kink"
Other proteins, glycoprotiens etc = 1 nm
Bilayer = 5-10 nm
Which of the following statements about the fluid mosaic model of membranes is true? Ans B
A) Integral proteins can be removed easily from the membrane. False
B) Peripheral proteins can be covalently attached to the membrane lipid. True
types of interactions : 1. interaction by an amphipathic -helix parallel to the membrane plane (in-plane membrane helix) 2. interaction by a hydrophobic loop 3. interaction by a covalently bound membrane lipid (lipidation) 4. electrostatic or ionic interactions with membrane lipids (e.g. through a calcium ion)
C) Cholesterol is found only on the outer leaflet of the lipid bilayer. False (found on both layers)
D) Glycolipids contain deoxyribonucleic acids. False, they only contain sugar and lipid molecules
E) Glycoproteins are composed of amino acids and lipids. False ,sugar and lipid
Which of the following is not a common feature found in most receptor molecules? A
A) Each receptor binds a wide variety of signaling molecules. receptors are protien specific
B) They amplify the signals that they receive. G Protein-Coupled Receptors
C) They promote protein phosphorylation. - Receptor Protein-Tyrosine Kinases
D) They become desensitized to the signal after a period of time. - Homologous desensitization
E) They often undergo conformational change. - G Protein-Coupled Receptors
Which of the following molecules are used for signaling? E All the above
A) adrenaline - fight of flight
B) heparin - promotes platlet response
C) insulin - alters glucose uptake
D) epinephrine - Adrenaline
E) All of the above.
Which of the following statements regarding GPCRs is correct? A
A) They are integral membrane proteins. True
B) They are heterotrimeric. False G protiens are heteromeric
C) They contain a GTP binding site. False - G protiens have the site
D) They are mainly made up of beta sheets.False GPCR has seven-transmembrane -helix structure
E) They provide a tunnel through which signaling molecules can traverse the cell
membrane.False
What is your body’s physiological response to epinephrine? C
A) You feel sleepy.
B) You feel hungry.
C) You feel alert. - True Fight or flight response
D) You feel relaxed.
E) You feel sad.
10. Which of the following molecules make direct contact with the GPCR during epinephrine signaling? B
A) adenylyl cyclase
B) G-protein
C) ATP
D) GTP
E) cAMP
The first step in epinephrine signaling occurs when the hormone binds to an GPCR on the cell surface. The hormone triggers the receptor to change shape, converting the receptor to its active form.
The activated receptor triggers a cascade of events within the cell to activate G protein. The G protein then binds to the activated receptor, releases GDP, and takes up a molecule of GTP.
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