Question 1
Question
Membrane characteristics
Answer
-
Sheet like structures, two molecules thick, form closed boundaries
-
composed of lipids and proteins,
-
noncovalent assemblies
-
covalent assesmblies
-
are fluid structures
-
are fatty structures
-
Most are electrically polarized
Question 2
Question
Membranes are asymmetric in that the outer surface is always different from the inner surface
Question 3
Question
Membrane lipids are
Answer
-
small amphipathic molecules that form closed bimolecular sheets that prevent the movement of polar or charged molecules.
-
large amphipathic molecules that form closed bimolecular sheets that prevent the movement of polar or charged molecules.
-
small amphipathic molecules that form closed molecular sheets that prevent the movement of polar or charged molecules.
-
large amphipathic molecules that form closed molecular sheets that prevent the movement of polar or charged molecules.
Question 4
Question
Proteins serve to mitigate the impermeability of membranes and
Question 5
Question
Fatty acid names are based on their parent hydrocarbons
Question 6
Answer
-
are chains of hydrogen bearing carbon atoms that have a carboxylic acid at one end and a methyl group at the other end
-
are chains of hydrogen bearing carbon atoms that have a ketone at one end and a methyl group at the other end
-
may be saturated or unsaturated
-
usually numbered beginning with the carboxyl terminal carbon atom
-
When double bonds present, they are commonly in the cis position
-
Properties are dependent on chain length and degree of unsaturation
Question 7
Question
Fatty acids can also be numbered from the methyl carbon atom which is called the omega (ω) carbon.
Question 8
Question
Carbon atoms [blank_start]2[blank_end] and [blank_start]3[blank_end] are also referred to as α and β, respectively.
Question 9
Question
Fatty 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.
Question 10
Question
In polyunsaturated fatty acids, the double bonds are separated by at least one
Answer
-
methylene group
-
carboxylic acid
-
ketone
-
aldehyde
Question 11
Question
Long chain length and the presence of cis double bonds enhances the fluidity of fatty acids
Question 12
Question
What are the major class of membrane lipids
Answer
-
Phospholipids
-
Glycolipids
-
Cholesterol
Question 13
Question
Phospholipids are composed of four components:
Answer
-
fatty acids (1 or more), a platform, a carbon, and an alcohol.
-
fatty acids (1 or more), a platform, a phosphate, and an alcohol.
-
fatty acids (1 or more), a platform, a phosphate, and an nitrogen.
Question 14
Question
Two common platforms are [blank_start]glycerol[blank_end] and [blank_start]sphingosine[blank_end]
Answer
-
glycerol
-
glycogen
-
sphingosine
-
sphinose
Question 15
Question
Phospholipids with a glycerol platform are called
Answer
-
phosphoglycerides
-
phosphoglycerols
-
phosphoglycogen
Question 16
Question
The common types of membrane lipids are
Answer
-
Phospholipids
-
Glycolipids
-
Cholesterol
-
Carbohydrates
Question 17
Question
The major phospholipids are derived from
Question 18
Question
Phosphoglycerides are derived from phosphatidate by the formation of an ester bond between the phosphate and an alcohol
Question 19
Question 20
Question
The carbohydrate in the glycolipid is linked to the secondary alcohol of sphingosine
Question 21
Question
What are the simplest glycolipids, containing only a single sugar
Answer
-
Cerebrosides
-
Gangliosides
-
Monosaccharides
Question 22
Question
Gangliosides contain a branched chain of as many as
Answer
-
seven sugar molecules
-
five sugar molecules
-
three sugar molecules
-
eight sugar molecules
Question 23
Question
The [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
Answer
-
carbohydrate
-
lipid
-
extracellular
-
intracellular
Question 24
Question
Cholesterol is a lipid based on a steroid nucleus
Question 25
Question
Cholesterol is a
Answer
-
a steroid that is modified on both ends by the attachment of a fatty acid chain and at the other end by a methyl group
-
a steroid that is modified on one end by the attachment of a fatty acid chain and at the other end by a hydroxyl group
Question 26
Question
In membranes, the hydroxyl group interacts with phospholipid head groups
Question 27
Question
A membrane lipids is an
Answer
-
an amphipathic molecule containing a hydrophilic and hydrophobic moiety
-
an amphipathic molecule containing a hydrophilic moiety
-
an amphipathic molecule containing a hydrophobic moiety
Question 28
Question
The fatty acid components provide the
Answer
-
hydrophobic properties
-
hydrophilic properties
Question 29
Question
The alcohol and phosphate components are called the
Answer
-
polar head group, hydrophilic properties
-
polar head groups, hydrophobic properties
Question 30
Question
Phospholipids and Glycolipids Readily form Bimolecular sheets in Aqueous Media
Question 31
Question
Membrane formation is a consequence of the amphipathic nature of the constituent lipid molecules.
Question 32
Question
Phospholipids are
Answer
-
too large to form micelles
-
too small to form micelles
-
like glycolipids spontaneously form lipid bilayers in aqueous solutions
-
like glycolipids nonspontaneously form lipid bilayers in aqueous solutions
Question 33
Question
The hydrophobic effect powers membrane formation, and van der Waals interactions between the [blank_start]hydrophobic[blank_end] tails stabilize membranes
Question 34
Question
Integral membrane proteins
Question 35
Question
What is an example of β strand–rich integral membrane protein.
Answer
-
bacterial protein porin
-
Membrane spanning
Question 36
Question
The [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.
Answer
-
outside
-
inside
-
hydrophobic
-
hydrophillic
-
hydrophobic
-
hydrophillic
-
inside
-
outside
-
polar
-
nonpolar
Question 37
Question
Membrane-spanning α helices are a common structural feature of integral membrane proteins.
Question 38
Question
Bacteriorhodopsin, a light-powered proton pump, is an integral membrane protein composed of eight membrane- spanning helices.
Question 39
Question
Only a portion of the enzyme prostaglandin H2 synthase-1 is embedded in the membrane.
Question 40
Question
The 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.
Answer
-
active site
-
terminator site
Question 41
Question
What inhibits cyclooxygenase activity by obstructing the channel
Answer
-
Aspirin
-
Xanax
-
Klonopin
-
Naproxen
Question 42
Question
Hydrophobic proteins can be made to associate with the membrane by attaching a hydrophillic group.
Question 43
Question
The fluid mosaic model allows
Question 44
Question
The fluid mosaic model describes
Answer
-
membranes as two-dimensional solutions of oriented lipids and globular proteins
-
membranes as two-dimensional solutions of oriented lipids and quartnary proteins
-
membranes as two-dimensional solutions of oriented lipids and primary proteins
Question 45
Question
The lipids serve as a solvent and a permeability barrier
Question 46
Question
Lipids rapidly diffuse vertically in membranes, although transverse diffusion or flip-flopping is very rare without the assistance of enzymes
Question 47
Question
The prohibition of [blank_start]transverse[blank_end] diffusion accounts for the stability of membrane asymmetry.
Question 48
Question
Membrane fluidity is controlled
Answer
-
by fatty acid composition and carbohydrate content
-
by fatty acid composition and cholesterol content
-
by fatty acid composition and amino acid content
Question 49
Question
Cholesterol helps to maintain proper membrane fluidity in membranes in animals
Question 50
Question
No Biological membranes are asymmetric
Question 51
Question
The Na+-K+ pump illustrates
Answer
-
the principle of membrane asymmetry.
-
Pumps 3 Na+ out of the cell and 2 K+ into the cell by hydrolyzing ATP on the intracellular side of the membrane
-
Pumps 2 Na+ out of the cell and 3 K+ into the cell by hydrolyzing ATP on the extracellular side of the membrane
Question 52
Question
Some bacteria are enclosed by a single membrane surrounded by a cell wall.
Question 53
Question
Other bacteria are surrounded by two membranes, with a cell wall lying between them
Question 54
Question
Other bacteria are surrounded by two membranes, with a cell wall lying between them.The space between the two membranes is called the
Answer
-
periplasm
-
cytoplasm
-
mitochondria
Question 55
Question
With exception of plants, what cells do not have cell walls and area surrounded by a single membrane, the plasma membrane
Answer
-
Eukaryotic cells
-
Prokaryotic cells
Question 56
Question
Cells can acquire molecules from their environment by receptor-mediated endocytosis.
Question 57
Question
The protein clathin helps to
Answer
-
internalize receptors bound to their cargo
-
receptor-mediated endocytosis
-
facilitate membrane fusion by forming tightly coiled four-helical bundles
Question 58
Question
Fusion 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
Answer
-
release
-
absorabance
-
neurotransmitters
-
serotonin
Question 59
Question
9. The internalization of iron-bound transferrin in association with the transferrin receptor is a example of
Question 60
Question
[blank_start]SNARE[blank_end] proteins facilitate membrane fusion by forming tightly coiled four-helical bundles.