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Ch 12

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biochem
Amy Arce
Quiz por Amy Arce, atualizado more than 1 year ago
Amy Arce
Criado por Amy Arce mais de 8 anos atrás
12
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Resumo de Recurso

Questão 1

Questão
Membrane characteristics
Responda
  • 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

Questão 2

Questão
Membranes are asymmetric in that the outer surface is always different from the inner surface
Responda
  • True
  • False

Questão 3

Questão
Membrane lipids are
Responda
  • 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.

Questão 4

Questão
Proteins serve to mitigate the impermeability of membranes and
Responda
  • allow movement of molecules and information across the cell membrane
  • don't allow movement of molecules and information across the cell membrane

Questão 5

Questão
Fatty acid names are based on their parent hydrocarbons
Responda
  • True
  • False

Questão 6

Questão
Fatty acids
Responda
  • 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

Questão 7

Questão
Fatty acids can also be numbered from the methyl carbon atom which is called the omega (ω) carbon.
Responda
  • True
  • False

Questão 8

Questão
Carbon atoms [blank_start]2[blank_end] and [blank_start]3[blank_end] are also referred to as α and β, respectively.
Responda
  • 2
  • 3

Questão 9

Questão
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.
Responda
  • even
  • odd
  • 16
  • 15
  • 18
  • 17

Questão 10

Questão
In polyunsaturated fatty acids, the double bonds are separated by at least one
Responda
  • methylene group
  • carboxylic acid
  • ketone
  • aldehyde

Questão 11

Questão
Long chain length and the presence of cis double bonds enhances the fluidity of fatty acids
Responda
  • True
  • False

Questão 12

Questão
What are the major class of membrane lipids
Responda
  • Phospholipids
  • Glycolipids
  • Cholesterol

Questão 13

Questão
Phospholipids are composed of four components:
Responda
  • 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.

Questão 14

Questão
Two common platforms are [blank_start]glycerol[blank_end] and [blank_start]sphingosine[blank_end]
Responda
  • glycerol
  • glycogen
  • sphingosine
  • sphinose

Questão 15

Questão
Phospholipids with a glycerol platform are called
Responda
  • phosphoglycerides
  • phosphoglycerols
  • phosphoglycogen

Questão 16

Questão
The common types of membrane lipids are
Responda
  • Phospholipids
  • Glycolipids
  • Cholesterol
  • Carbohydrates

Questão 17

Questão
The major phospholipids are derived from
Responda
  • Phosphatidate (diacylglycerol 3-phosphate)
  • Phosphatidate (diacylglycerol 2-phosphate)

Questão 18

Questão
Phosphoglycerides are derived from phosphatidate by the formation of an ester bond between the phosphate and an alcohol
Responda
  • True
  • False

Questão 19

Questão
Glycolipids are
Responda
  • carbohydrate-containing lipids derived from sphingosine.
  • carbohydrate-containing lipids derived from glycerol.

Questão 20

Questão
The carbohydrate in the glycolipid is linked to the secondary alcohol of sphingosine
Responda
  • True
  • False

Questão 21

Questão
What are the simplest glycolipids, containing only a single sugar
Responda
  • Cerebrosides
  • Gangliosides
  • Monosaccharides

Questão 22

Questão
Gangliosides contain a branched chain of as many as
Responda
  • seven sugar molecules
  • five sugar molecules
  • three sugar molecules
  • eight sugar molecules

Questão 23

Questão
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
Responda
  • carbohydrate
  • lipid
  • extracellular
  • intracellular

Questão 24

Questão
Cholesterol is a lipid based on a steroid nucleus
Responda
  • True
  • False

Questão 25

Questão
Cholesterol is a
Responda
  • 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

Questão 26

Questão
In membranes, the hydroxyl group interacts with phospholipid head groups
Responda
  • True
  • False

Questão 27

Questão
A membrane lipids is an
Responda
  • an amphipathic molecule containing a hydrophilic and hydrophobic moiety
  • an amphipathic molecule containing a hydrophilic moiety
  • an amphipathic molecule containing a hydrophobic moiety

Questão 28

Questão
The fatty acid components provide the
Responda
  • hydrophobic properties
  • hydrophilic properties

Questão 29

Questão
The alcohol and phosphate components are called the
Responda
  • polar head group, hydrophilic properties
  • polar head groups, hydrophobic properties

Questão 30

Questão
Phospholipids and Glycolipids Readily form Bimolecular sheets in Aqueous Media
Responda
  • True
  • False

Questão 31

Questão
Membrane formation is a consequence of the amphipathic nature of the constituent lipid molecules.
Responda
  • True
  • False

Questão 32

Questão
Phospholipids are
Responda
  • 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

Questão 33

Questão
The hydrophobic effect powers membrane formation, and van der Waals interactions between the [blank_start]hydrophobic[blank_end] tails stabilize membranes
Responda
  • hydrophobic
  • hydrophillic

Questão 34

Questão
Integral membrane proteins
Responda
  • composed of β strands that form a pore in the membrane.
  • composed of α helices that form a pore in the membrane

Questão 35

Questão
What is an example of β strand–rich integral membrane protein.
Responda
  • bacterial protein porin
  • Membrane spanning

Questão 36

Questão
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.
Responda
  • outside
  • inside
  • hydrophobic
  • hydrophillic
  • hydrophobic
  • hydrophillic
  • inside
  • outside
  • polar
  • nonpolar

Questão 37

Questão
Membrane-spanning α helices are a common structural feature of integral membrane proteins.
Responda
  • True
  • False

Questão 38

Questão
Bacteriorhodopsin, a light-powered proton pump, is an integral membrane protein composed of eight membrane- spanning helices.
Responda
  • True
  • False

Questão 39

Questão
Only a portion of the enzyme prostaglandin H2 synthase-1 is embedded in the membrane.
Responda
  • True
  • False

Questão 40

Questão
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.
Responda
  • active site
  • terminator site

Questão 41

Questão
What inhibits cyclooxygenase activity by obstructing the channel
Responda
  • Aspirin
  • Xanax
  • Klonopin
  • Naproxen

Questão 42

Questão
Hydrophobic proteins can be made to associate with the membrane by attaching a hydrophillic group.
Responda
  • True
  • False

Questão 43

Questão
The fluid mosaic model allows
Responda
  • lateral movement but not rotation through the membrane
  • rotation through the membrane
  • vertical movement

Questão 44

Questão
The fluid mosaic model describes
Responda
  • 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

Questão 45

Questão
The lipids serve as a solvent and a permeability barrier
Responda
  • True
  • False

Questão 46

Questão
Lipids rapidly diffuse vertically in membranes, although transverse diffusion or flip-flopping is very rare without the assistance of enzymes
Responda
  • True
  • False

Questão 47

Questão
The prohibition of [blank_start]transverse[blank_end] diffusion accounts for the stability of membrane asymmetry.
Responda
  • transverse

Questão 48

Questão
Membrane fluidity is controlled
Responda
  • by fatty acid composition and carbohydrate content
  • by fatty acid composition and cholesterol content
  • by fatty acid composition and amino acid content

Questão 49

Questão
Cholesterol helps to maintain proper membrane fluidity in membranes in animals
Responda
  • True
  • False

Questão 50

Questão
No Biological membranes are asymmetric
Responda
  • True
  • False

Questão 51

Questão
The Na+-K+ pump illustrates
Responda
  • 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

Questão 52

Questão
Some bacteria are enclosed by a single membrane surrounded by a cell wall.
Responda
  • True
  • False

Questão 53

Questão
Other bacteria are surrounded by two membranes, with a cell wall lying between them
Responda
  • True
  • False

Questão 54

Questão
Other bacteria are surrounded by two membranes, with a cell wall lying between them.The space between the two membranes is called the
Responda
  • periplasm
  • cytoplasm
  • mitochondria

Questão 55

Questão
With exception of plants, what cells do not have cell walls and area surrounded by a single membrane, the plasma membrane
Responda
  • Eukaryotic cells
  • Prokaryotic cells

Questão 56

Questão
Cells can acquire molecules from their environment by receptor-mediated endocytosis.
Responda
  • True
  • False

Questão 57

Questão
The protein clathin helps to
Responda
  • internalize receptors bound to their cargo
  • receptor-mediated endocytosis
  • facilitate membrane fusion by forming tightly coiled four-helical bundles

Questão 58

Questão
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
Responda
  • release
  • absorabance
  • neurotransmitters
  • serotonin

Questão 59

Questão
9. The internalization of iron-bound transferrin in association with the transferrin receptor is a example of
Responda
  • SNARE proteins
  • receptor-mediated endocytosis
  • protein clathrin

Questão 60

Questão
[blank_start]SNARE[blank_end] proteins facilitate membrane fusion by forming tightly coiled four-helical bundles.
Responda
  • SNARE

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