Quiz
Ch 12
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Perguntas do quiz (60)
1Membrane characteristics
- ASheet like structures, two molecules thick, form closed boundaries
- Bcomposed of lipids and proteins,
- Cnoncovalent assemblies
- Dcovalent assesmblies
- Eare fluid structures
- Fare fatty structures
- GMost are electrically polarized
2Membranes are asymmetric in that the outer surface is always different from the inner surface
- AVerdadeiro
- BFalso
3Membrane lipids are
- Asmall amphipathic molecules that form closed bimolecular sheets that prevent the movement of polar or charged molecules.
- Blarge amphipathic molecules that form closed bimolecular sheets that prevent the movement of polar or charged molecules.
- Csmall amphipathic molecules that form closed molecular sheets that prevent the movement of polar or charged molecules.
- Dlarge amphipathic molecules that form closed molecular sheets that prevent the movement of polar or charged molecules.
4Proteins serve to mitigate the impermeability of membranes and
- Aallow movement of molecules and information across the cell membrane
- Bdon't allow movement of molecules and information across the cell membrane
5Fatty acid names are based on their parent hydrocarbons
- AVerdadeiro
- BFalso
6Fatty acids
- Aare chains of hydrogen bearing carbon atoms that have a carboxylic acid at one end and a methyl group at the other end
- Bare chains of hydrogen bearing carbon atoms that have a ketone at one end and a methyl group at the other end
- Cmay be saturated or unsaturated
- Dusually numbered beginning with the carboxyl terminal carbon atom
- EWhen double bonds present, they are commonly in the cis position
- FProperties are dependent on chain length and degree of unsaturation
7Fatty acids can also be numbered from the methyl carbon atom which is called the omega (ω) carbon.
- AVerdadeiro
- BFalso
8Carbon atoms [blank_start]2[blank_end] and [blank_start]3[blank_end] are also referred to as α and β, respectively.
- A2
- B3
9Fatty acids in biological systems usually contain an [blank_start]even[blank_end] number of carbon atoms, with the [blank_start]16[blank_end]- and [blank_start]18[blank_end]-carbon atom chains the most common.
- Aeven
- Bodd
- C16
- D15
- E18
- F17
10In polyunsaturated fatty acids, the double bonds are separated by at least one
- Amethylene group
- Bcarboxylic acid
- Cketone
- Daldehyde
11Long chain length and the presence of cis double bonds enhances the fluidity of fatty acids
- AVerdadeiro
- BFalso
12What are the major class of membrane lipids
- APhospholipids
- BGlycolipids
- CCholesterol
13Phospholipids are composed of four components:
- Afatty acids (1 or more), a platform, a carbon, and an alcohol.
- Bfatty acids (1 or more), a platform, a phosphate, and an alcohol.
- Cfatty acids (1 or more), a platform, a phosphate, and an nitrogen.
14Two common platforms are [blank_start]glycerol[blank_end] and [blank_start]sphingosine[blank_end]
- Aglycerol
- Bglycogen
- Csphingosine
- Dsphinose
15Phospholipids with a glycerol platform are called
- Aphosphoglycerides
- Bphosphoglycerols
- Cphosphoglycogen
16The common types of membrane lipids are
- APhospholipids
- BGlycolipids
- CCholesterol
- DCarbohydrates
17The major phospholipids are derived from
- APhosphatidate (diacylglycerol 3-phosphate)
- BPhosphatidate (diacylglycerol 2-phosphate)
18Phosphoglycerides are derived from phosphatidate by the formation of an ester bond between the phosphate and an alcohol
- AVerdadeiro
- BFalso
19Glycolipids are
- Acarbohydrate-containing lipids derived from sphingosine.
- Bcarbohydrate-containing lipids derived from glycerol.
20The carbohydrate in the glycolipid is linked to the secondary alcohol of sphingosine
- AVerdadeiro
- BFalso
21What are the simplest glycolipids, containing only a single sugar
- ACerebrosides
- BGangliosides
- CMonosaccharides
22Gangliosides contain a branched chain of as many as
- Aseven sugar molecules
- Bfive sugar molecules
- Cthree sugar molecules
- Deight sugar molecules
23The [blank_start]carbohydrate[blank_end] components of glycolipids are on the [blank_start]extracellular[blank_end] surface of the cell membrane, where they play a role in cell-cell recognition
- Acarbohydrate
- Blipid
- Cextracellular
- Dintracellular
24Cholesterol is a lipid based on a steroid nucleus
- AVerdadeiro
- BFalso
25Cholesterol is a
- Aa steroid that is modified on both ends by the attachment of a fatty acid chain and at the other end by a methyl group
- Ba steroid that is modified on one end by the attachment of a fatty acid chain and at the other end by a hydroxyl group
26In membranes, the hydroxyl group interacts with phospholipid head groups
- AVerdadeiro
- BFalso
27A membrane lipids is an
- Aan amphipathic molecule containing a hydrophilic and hydrophobic moiety
- Ban amphipathic molecule containing a hydrophilic moiety
- Can amphipathic molecule containing a hydrophobic moiety
28The fatty acid components provide the
- Ahydrophobic properties
- Bhydrophilic properties
29The alcohol and phosphate components are called the
- Apolar head group, hydrophilic properties
- Bpolar head groups, hydrophobic properties
30Phospholipids and Glycolipids Readily form Bimolecular sheets in Aqueous Media
- AVerdadeiro
- BFalso
31Membrane formation is a consequence of the amphipathic nature of the constituent lipid molecules.
- AVerdadeiro
- BFalso
32Phospholipids are
- Atoo large to form micelles
- Btoo small to form micelles
- Clike glycolipids spontaneously form lipid bilayers in aqueous solutions
- Dlike glycolipids nonspontaneously form lipid bilayers in aqueous solutions
33The hydrophobic effect powers membrane formation, and van der Waals interactions between the [blank_start]hydrophobic[blank_end] tails stabilize membranes
- Ahydrophobic
- Bhydrophillic
34Integral membrane proteins
- Acomposed of β strands that form a pore in the membrane.
- Bcomposed of α helices that form a pore in the membrane
35What is an example of β strand–rich integral membrane protein.
- Abacterial protein porin
- BMembrane spanning
36The [blank_start]outside[blank_end] surface of porin, which interacts with the [blank_start]hydrophobic[blank_end] interior of the membrane, is composed of [blank_start]hydrophobic[blank_end] amino acids. The [blank_start]inside[blank_end] is [blank_start]polar[blank_end] and filled with water.
- Aoutside
- Binside
- Chydrophobic
- Dhydrophillic
- Ehydrophobic
- Fhydrophillic
- Ginside
- Houtside
- Ipolar
- Jnonpolar
37Membrane-spanning α helices are a common structural feature of integral membrane proteins.
- AVerdadeiro
- BFalso
38Bacteriorhodopsin, a light-powered proton pump, is an integral membrane protein composed of eight membrane- spanning helices.
- AVerdadeiro
- BFalso
39Only a portion of the enzyme prostaglandin H2 synthase-1 is embedded in the membrane.
- AVerdadeiro
- BFalso
40The cyclooxygenase (COX) activity of prostaglandin H2 synthase-1 is dependent on a channel connecting the [blank_start]active site[blank_end] to the membrane interior.
- Aactive site
- Bterminator site
41What inhibits cyclooxygenase activity by obstructing the channel
- AAspirin
- BXanax
- CKlonopin
- DNaproxen
42Hydrophobic proteins can be made to associate with the membrane by attaching a hydrophillic group.
- AVerdadeiro
- BFalso
43The fluid mosaic model allows
- Alateral movement but not rotation through the membrane
- Brotation through the membrane
- Cvertical movement
44The fluid mosaic model describes
- Amembranes as two-dimensional solutions of oriented lipids and globular proteins
- Bmembranes as two-dimensional solutions of oriented lipids and quartnary proteins
- Cmembranes as two-dimensional solutions of oriented lipids and primary proteins
45The lipids serve as a solvent and a permeability barrier
- AVerdadeiro
- BFalso
46Lipids rapidly diffuse vertically in membranes, although transverse diffusion or flip-flopping is very rare without the assistance of enzymes
- AVerdadeiro
- BFalso
47The prohibition of [blank_start]transverse[blank_end] diffusion accounts for the stability of membrane asymmetry.
- Atransverse
48Membrane fluidity is controlled
- Aby fatty acid composition and carbohydrate content
- Bby fatty acid composition and cholesterol content
- Cby fatty acid composition and amino acid content
49Cholesterol helps to maintain proper membrane fluidity in membranes in animals
- AVerdadeiro
- BFalso
50 No Biological membranes are asymmetric
- AVerdadeiro
- BFalso
51The Na+-K+ pump illustrates
- Athe principle of membrane asymmetry.
- BPumps 3 Na+ out of the cell and 2 K+ into the cell by hydrolyzing ATP on the intracellular side of the membrane
- CPumps 2 Na+ out of the cell and 3 K+ into the cell by hydrolyzing ATP on the extracellular side of the membrane
52Some bacteria are enclosed by a single membrane surrounded by a cell wall.
- AVerdadeiro
- BFalso
53Other bacteria are surrounded by two membranes, with a cell wall lying between them
- AVerdadeiro
- BFalso
54Other bacteria are surrounded by two membranes, with a cell wall lying between them.The space between the two membranes is called the
- Aperiplasm
- Bcytoplasm
- Cmitochondria
55With exception of plants, what cells do not have cell walls and area surrounded by a single membrane, the plasma membrane
- AEukaryotic cells
- BProkaryotic cells
56Cells can acquire molecules from their environment by receptor-mediated endocytosis.
- AVerdadeiro
- BFalso
57The protein clathin helps to
- Ainternalize receptors bound to their cargo
- Breceptor-mediated endocytosis
- Cfacilitate membrane fusion by forming tightly coiled four-helical bundles
58Fusion of internal membranes with the plasma membrane allows the [blank_start]release[blank_end] of molecules, such as [blank_start]neurotransmitters[blank_end], from the cell
- Arelease
- Babsorabance
- Cneurotransmitters
- Dserotonin
599. The internalization of iron-bound transferrin in association with the transferrin receptor is a example of
- ASNARE proteins
- Breceptor-mediated endocytosis
- Cprotein clathrin
60[blank_start]SNARE[blank_end] proteins facilitate membrane fusion by forming tightly coiled four-helical bundles.
- ASNARE
Informações
- Descrição
- biochem
- Autor
- Amy Arce
- Idioma
- English
- Visualizações
- 57
- Etiquetas
- Avaliação
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