2693649
Descripción
Test por acbridges91, actualizado hace más de 1 año
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Creado por acbridges91
hace más de 9 años
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Pregunta 1
Pregunta
Which of these classes of biological molecules does NOT include polymers?
Respuesta
-
nucleic acids
-
proteins
-
carbohydrates
-
lipids
Pregunta 2
Pregunta
What is the difference between an aldose sugar and a ketose sugar?
Respuesta
-
the position of the carbonyl group
-
the number of carbons
-
the position of the hydroxyl groups
-
one is a ring form, the other is a linear chain
Pregunta 3
Pregunta
What is the major structural difference between starch and glycogen?
Respuesta
-
The amount of branching that occurs in the molecule
-
the types of monosaccharide subunits in the molecules
-
the types of glycosidic linkages in the molecule
-
whether glucose is in the alpha or beta form
Pregunta 4
Pregunta
Which polysaccharide is an important component in the structure of many animals and fungi?
Respuesta
-
cellulose
-
chitin
-
amylose
-
amylopectin
Pregunta 5
Pregunta
What does the term insoluble fiber refer to on food packages?
Respuesta
-
amylopectin
-
cellulose
-
polypeptides
-
starch
Pregunta 6
Pregunta
A molecule with the chemical formula C6H12O6 is probably a _____.
Respuesta
-
polysaccharide
-
fatty acid
-
hexose
-
monosaccharide
Pregunta 7
Pregunta
Lactose, a sugar in milk, is composed of one glucose molecule joined by a glycosidic linkage to one galactose molecule. How is lactose classified?
Respuesta
-
polysacchardie
-
disaccharide
-
hexose
-
monosaccharide
Pregunta 8
Pregunta
Starch and cellulose ____.
Respuesta
-
used for energy storage in plants
-
are cis-trans isomers of each other
-
are structural components of the plant cell wall
-
are polymers of glucose
Pregunta 9
Pregunta
Phospholipids and triglycerides both ____.
Respuesta
-
Have three fatty acids
-
have a phosphate
-
contain serine or some other organic compound
-
have a glycerol backbone
Pregunta 10
Pregunta
Which of the following is the best explanation for why vegetable oil is a liquid at room temperature while animal fats are solid?
Respuesta
-
animal fats have no amphipathic character
-
vegetable oil has longer fatty-acid tails than animal fats have
-
vegetable oil has fewer double bonds than animal fats
-
vegetable oil has more double bonds than animal fats
Pregunta 11
Pregunta
Saturated fatty acids ____.
Respuesta
-
have double bonds between carbon atoms of the fatty acids
-
are the principal molecules of lard and butter
-
are usually liquid at room temperature
-
are usually produced by plants
Pregunta 12
Pregunta
Steroids are considered to be lipids because they _____.
Respuesta
-
contribute to atherosclerosis
-
are essential components of cell membranes
-
are not soluble in water
-
are made of fatty acids
Pregunta 13
Pregunta
The molecule illustrated in the accompanying figure ____.
Respuesta
-
Will be liquid at room temperature
-
is a carbohydrate
-
stores genetic information
-
is a saturated fatty acid
Pregunta 14
Pregunta
A glycosidic linkage is analogous to which of the following proteins?
Respuesta
-
an amino group
-
beta-pleated sheet
-
a peptide bond
-
a disulfide bond
Pregunta 15
Pregunta
Which one of the following is NOT a component of each monomer used to make proteins?
Respuesta
-
phosphorus atom, P
-
side chain, R
-
amino functional group, NH2
-
carboxyl group, COOH
Pregunta 16
Pregunta
What component of amino acid structure varies among dfifferent amino acids?
Respuesta
-
the components of the R-group
-
the presence of a central C atom
-
the long carbon-hydrogen tails of the molecule
-
the glycerol molecule that forms the backbone of the amino acid
Pregunta 17
Pregunta
You disrupt all hydrogen bonds in a protein. What level of structure will be preserved?
Respuesta
-
primary structure
-
secondary structure
-
tertiary structure
-
quaternary structure
Pregunta 18
Pregunta
All of the following contain amino acids EXCEPT ____.
Respuesta
-
hemoglobin
-
enzymes
-
insulin
-
cholesterol
Pregunta 19
Pregunta
Which level of protein structure do the α-helix and the β-pleated sheet represent?
Respuesta
-
primary
-
secondary
-
tertiary
-
quaternary
Pregunta 20
Pregunta
Misfolding of polypeptides is a serious problem in cells. Which of the following diseases are associated with an accumulation of misfolded polypeptides?
Respuesta
-
diabetes mellitus only
-
Parkinson's only
-
Alzheimer's only
-
Alzheimer's and Parkinson's only
Pregunta 21
Pregunta
What is the term used for a protein molecule that assists in the proper folding of other proteins?
Respuesta
-
denaturing protein
-
chaperonin
-
renaturing protein
-
tertiary protein
Pregunta 22
Pregunta
Nucleic acids are polymers made up of which of the following monomers?
Respuesta
-
sugars
-
amino acids
-
nitrogenous bases
-
nucleotides
Pregunta 23
Pregunta
Which of the following includes all of the pyrimidines found in RNA and DNA?
Respuesta
-
cytosine, uracil, and guanine
-
cytosine and uracil
-
cytosine, uracil, and thymine
-
cytosine and thymine
Pregunta 24
Pregunta
One of the primary functions of RNA molecules is to _____.
Respuesta
-
transmit genetic information to offspring
-
make a copy of itself, thus ensuring genetic continuity
-
function in the synthesis of proteins
-
act as a pattern or blueprint to form DNA
Pregunta 25
Pregunta
Which of the following descriptions best fits the class of molecules known as nucleotides?
Respuesta
-
a nitrogenous base, a phosphate group, and a sugar
-
a nitrogenous base and a sugar
-
a nitrogenous base and a phosphate group
-
a sugar and a purine or pyrimidine
Pregunta 26
Pregunta
The smallest cell structure that would most likely be visible with a standard (not super-resolution) research-grade light microscope is a _____.
Respuesta
-
ribosome
-
microfilament
-
mitochondrion
-
microtubule
Pregunta 27
Pregunta
The advantage of light microscopy over electron microscopy is that _____.
Respuesta
-
light microscopy provides for higher resolving power than electron microscopy
-
light microscopy provides higher contrast than electron microscopy
-
light microscopy allows one to view dynamic processes in living cells
-
light microscopy provides for higher magnification than electron microscopy
Pregunta 28
Pregunta
What technique would be most appropriate to use to observe the movements of condensed chromosomes during cell division?
Respuesta
-
transmission electron microscopy
-
standard light microscopy
-
scanning electron microscopy
Pregunta 29
Pregunta
A newspaper ad for a local toy store indicates that an inexpensive toy microscope available for a small child is able to magnify specimens nearly as much as the more costly microscope available in your college lab. What is the primary reason for the price difference?
Respuesta
-
The toy microscope does not have the same fine control for focus of the specimen.
-
The college microscope produces greater contrast in the specimens.
-
The toy microscope usually uses a different wavelength of light source.
-
The toy microscope magnifies a good deal, but has low resolution and therefore poor quality images.
Pregunta 30
Pregunta
All of the following are part of a prokaryotic cell EXCEPT _____.
Respuesta
-
a cell wall
-
an endoplasmic reticulum
-
a plasma membrane
-
ribosomes
Pregunta 31
Pregunta
Cell size is limited by _____.
Respuesta
-
the size of the endomembrane system
-
the surface area of mitochondria in the cytoplasm
-
the number of proteins within the plasma membrane
-
surface to volume ratios
Pregunta 32
Pregunta
Which of the following is a major difference between prokaryotic cells and eukaryotic cells?
Respuesta
-
Prokaryotes have cells while eukaryotes do not.
-
Eukaryotic cells have more intracellular organelles than prokaryotes.
-
Prokaryotes are not able to carry out aerobic respiration, relying instead on anaerobic metabolism.
-
Prokaryotes are generally larger than eukaryotes.
Pregunta 33
Pregunta
Prokaryotes are classified as belonging to two different domains. What are the domains?
Respuesta
-
Bacteria and Protista
-
Bacteria and Archaea
-
Bacteria and Eukarya
-
Archaea and Protista
Pregunta 34
Pregunta
Which structure is common to plant and animal cells?
Respuesta
-
central vacuole
-
centriole
-
mitochondrion
-
chloroplast
Pregunta 35
Pregunta
Which of the following is present in a prokaryotic cell?
Respuesta
-
ER
-
mitochondrion
-
chloroplast
-
ribosome
Pregunta 36
Pregunta
Which of the following macromolecules leaves the nucleus of a eukaryotic cell through pores in the nuclear membrane?
Respuesta
-
amino acids
-
mRNA
-
DNA
-
phospholipids
Pregunta 37
Pregunta
Large numbers of ribosomes are present in cells that specialize in producing which of the following molecules?
Respuesta
-
glycogen
-
proteins
-
nucleic acids
-
lipids
Pregunta 38
Pregunta
A cell with a predominance of free ribosomes is most likely _____.
Respuesta
-
enlarging its vacuole
-
primarily producing proteins for secretion
-
constructing an extensive cell wall or extracellular matrix
-
primarily producing proteins in the cytosol
Pregunta 39
Pregunta
Which organelle often takes up much of the volume of a plant cell?
Respuesta
-
vacuole
-
lysosome
-
peroxisome
-
Golgi apparatus
Pregunta 40
Pregunta
A cell with an extensive area of smooth endoplasmic reticulum is specialized to _____.
Respuesta
-
import and export protein molecules
-
synthesize large quantities of lipids
-
play a role in storage
-
actively export protein molecules
Pregunta 41
Pregunta
Which structure is NOT part of the endomembrane system?
Respuesta
-
Golgi apparatus
-
chloroplast
-
plasma membrane
-
nuclear envelope
Pregunta 42
Pregunta
Which structure is the site of the synthesis of proteins that may be exported from the cell?
Respuesta
-
plasmodesmata
-
free cytoplasmic ribosomes
-
Golgi vesicles
-
rough ER
Pregunta 43
Pregunta
The liver is involved in detoxification of many poisons and drugs. Which of the following structures is primarily involved in this process and, therefore, abundant in liver cells?
Respuesta
-
Golgi apparatus
-
nuclear envelope
-
rough ER
-
smooth ER
Pregunta 44
Pregunta
Which of the following produces and modifies polysaccharides that will be secreted?
Respuesta
-
lysosome
-
Golgi apparatus
-
mitochondrion
-
peroxisome
Pregunta 45
Pregunta
What is the most likely pathway taken by a newly synthesized protein that will be secreted by a cell?
Respuesta
-
Golgi → ER → lysosome
-
ER → Golgi → nucleus
-
ER → lysosomes → vesicles that fuse with plasma membrane
-
ER → Golgi → vesicles that fuse with plasma membrane
Pregunta 46
Pregunta
Which organelle is the primary site of ATP synthesis in eukaryotic cells?
Respuesta
-
mitochondrion
-
lysosome
-
peroxisome
-
Golgi apparatus
Pregunta 47
Pregunta
Thylakoids, DNA, and ribosomes are all components found in _____.
Respuesta
-
lysosomes
-
mitochondria
-
nuclei
-
chloroplasts
Pregunta 48
Pregunta
Suppose a young boy is always tired and fatigued, suffering from a metabolic disease. Which of the following organelles is most likely involved in this disease?
Respuesta
-
mitochondria
-
ribosomes
-
lysosomes
-
Golgi apparatus
Pregunta 49
Pregunta
Motor proteins provide for molecular motion in cells by interacting with what types of cellular structures?
Respuesta
-
cellulose fibers in the cell wall
-
free ribosomes and ribosomes attached to the ER
-
components of the cytoskeleton
-
membrane proteins of the inner nuclear envelope
Pregunta 50
Pregunta
Vinblastine, a drug that inhibits microtubule polymerization, is used to treat some forms of cancer. Cancer cells given vinblastine would be unable to _____.
Respuesta
-
migrate by amoeboid movement
-
form cleavage furrows during cell division
-
separate chromosomes during cell division
-
maintain the shape of the nucleus
Pregunta 51
Pregunta
For a protein to be an integral membrane protein, it would have to be _____.
Respuesta
-
exposed on only one surface of the membrane
-
hydrophobic
-
amphipathic, with at least one hydrophobic region
-
hydrophilic
Pregunta 52
Pregunta
According to the fluid mosaic model of cell membranes, phospholipids _____.
Respuesta
-
frequently flip-flop from one side of the membrane to the other
-
can move laterally along the plane of the membrane
-
have hydrophilic tails in the interior of the membrane
-
occur in an uninterrupted bilayer, with membrane proteins restricted to the surface of the membrane
Pregunta 53
Pregunta
The membranes of winter wheat are able to remain fluid when it is extremely cold by _____.
Respuesta
-
cotransport of glucose and hydrogen
-
decreasing the number of hydrophobic proteins in the membrane
-
increasing the percentage of cholesterol molecules in the membrane
-
increasing the percentage of unsaturated phospholipids in the membrane
Pregunta 54
Pregunta
Some regions of the plasma membrane, called lipid rafts, have a higher concentration of cholesterol molecules. At higher temperatures, these regions _____.
Respuesta
-
are more fluid than the surrounding membrane
-
have higher rates of lateral diffusion of lipids and proteins into and out of these regions
-
are less fluid than the surrounding membrane
-
detach from the plasma membrane and clog arteries
Pregunta 55
Pregunta
An animal cell lacking oligosaccharides on the external surface of its plasma membrane would likely be impaired in which function?
Respuesta
-
attaching the plasma membrane to the cytoskeleton
-
transporting ions against an electrochemical gradient
-
establishing a diffusion barrier to charged molecules
-
cell-cell recognition
Pregunta 56
Pregunta
Which of these are NOT embedded in the hydrophobic portion of the lipid bilayer at all?
Respuesta
-
peripheral proteins
-
integral proteins
-
transmembrane proteins
-
All of these are embedded in the hydrophobic portion of the lipid bilayer.
Pregunta 57
Pregunta
Which component is a peripheral protein?
Respuesta
-
A
-
B
-
C
-
D
Pregunta 58
Respuesta
-
B
-
C
-
D
-
E
Pregunta 59
Pregunta
Which component is a protein fiber of the extracellular matrix?
Respuesta
-
A
-
B
-
C
-
E
Pregunta 60
Pregunta
Which component is a microfilament (actin filament) of the cytoskeleton?
Respuesta
-
A
-
B
-
C
-
D
Pregunta 61
Respuesta
-
A
-
B
-
C
-
E
Pregunta 62
Pregunta
The presence of cholesterol in the plasma membranes
Respuesta
-
enables the membrane to stay fluid more easily when cell temperature drops
-
enables the membrane to stay more rigid when cell temperature increases (or body temperature)
-
enables the cell to add hydrogen atoms to unsaturated phospholipids
-
a and b
Pregunta 63
Pregunta
What kinds of molecules pass through a cell membrane most easily?
Respuesta
-
large and hydrophobic
-
large polar
-
small and hydrophobic
-
ionic
Pregunta 64
Pregunta
Which of the following most accurately describes selective permeability?
Respuesta
-
Only certain molecules can cross a cell membrane.
-
There must be a concentration gradient for molecules to pass through a membrane.
-
Lipid-soluble molecules pass through a membrane.
-
An input of energy is required for transport.
Pregunta 65
Pregunta
Which of the following would likely move through the lipid bilayer of a plasma membrane most rapidly?
Respuesta
-
glucose
-
an amino acid
-
CO2
-
K+
Pregunta 66
Pregunta
Which of the following allows water to move much faster across cell membranes?
Respuesta
-
ATP
-
peripheral proteins
-
the sodium-potassium pump
-
aquaporins
Pregunta 67
Pregunta
Diffusion _____.
Respuesta
-
is a passive process in which molecules move from a region of higher concentration to a region of lower concentration
-
requires an expenditure of energy by the cell
-
is very rapid over long distances
-
requires integral proteins in the cell membrane
Pregunta 68
Pregunta
Which of the following processes includes all others?
Respuesta
-
osmosis
-
facilitated diffusion
-
passive transport
-
transport of an ion down its electrochemical gradient
Pregunta 69
Pregunta
Celery stalks that are immersed in fresh water for several hours become stiff. Similar stalks left in a 0.15 M salt solution become limp. From this we can deduce that the fresh water_____.
Respuesta
-
is hypertonic and the salt solution is hypotonic to the cells of the celery stalks
-
and the salt solution are both hypertonic to the cells of the celery stalks
-
is hypotonic and the salt solution is hypertonic to the cells of the celery stalks
-
is isotonic and the salt solution is hypertonic to the cells of the celery stalks
Pregunta 70
Pregunta
What will happen to a red blood cell (RBC), which has an internal ion concentration of about 0.9 percent, if it is placed into a beaker of pure water?
Respuesta
-
The cell will remain the same size because the solution outside the cell is isotonic.
-
The cell would swell because the water in the beaker is hypotonic relative to the cytoplasm of the RBC.
-
The cell would shrink because the water in the beaker is hypertonic relative to the cytoplasm of the RBC.
-
The cell would shrink because the water in the beaker is hypotonic relative to the cytoplasm of the RBC.
Pregunta 71
Pregunta
The sodium-potassium pump is called an electrogenic pump because it _____.
Respuesta
-
ionizes sodium and potassium atoms
-
is used to drive the transport of other molecules against a concentration gradient
-
contributes to the membrane potential
-
pumps equal quantities of Na+ and K+ across the membrane
Pregunta 72
Pregunta
The voltage across a membrane is called the _____.
Respuesta
-
membrane potential
-
chemical gradient
-
electrochemical gradient
-
osmotic potential
Pregunta 73
Pregunta
Ions diffuse across membranes through specific ion channels down _____.
Respuesta
-
their chemical gradients
-
their electrochemical gradients
-
the electrical gradients
-
their concentration gradients
Pregunta 74
Pregunta
Which of the following would increase the electrochemical gradient across a membrane?
Respuesta
-
a proton pump
-
a sucrose-proton cotransporter
-
a potassium channel
-
both a proton pump and a potassium channel
Pregunta 75
Pregunta
The force driving simple diffusion is _____, while the energy source for active transport is _____.
Respuesta
-
phosphorylated protein carriers; ATP
-
the concentration gradient; ADP
-
transmembrane pumps; electron transport
-
the concentration gradient; ATP
Pregunta 76
Pregunta
In eukaryotic cells, chromosomes are composed of _____.
Respuesta
-
DNA and RNA
-
DNA only
-
DNA and phospholipids
-
DNA and proteins
Pregunta 77
Pregunta
What is the final result of mitosis in a human?
Respuesta
-
genetically different 2n somatic cells
-
genetically identical 2n somatic cells
-
genetically identical 2n gamete cells
-
genetically identical 1n somatic cells
Pregunta 78
Pregunta
Starting with a fertilized egg (zygote), a series of five cell divisions would produce an early embryo with how many cells?
Respuesta
-
32
-
64
-
16
-
8
Pregunta 79
Pregunta
If there are 20 duplicated chromosomes in a cell, how many centromeres are there?
Respuesta
-
30
-
20
-
40
-
10
Pregunta 80
Pregunta
Scientists isolate cells in various phases of the cell cycle. They find a group of cells that have 1.5 times more DNA than G1 phase cells. The cells of this group are _____.
Respuesta
-
in the G2 phase of the cell cycle
-
in the S phase of the cell cycle
-
between the G1 and S phases in the cell cycle
-
in the M phase of the cell cycle
Pregunta 81
Pregunta
The first gap in the cell cycle (G1) corresponds to _____.
Respuesta
-
normal growth and cell function
-
the phase between DNA replication and the M phase
-
the beginning of mitosis
-
the phase in which DNA is being replicated
Pregunta 82
Pregunta
The microtubule-organizing center found in animal cells is an identifiable structure present during all phases of the cell cycle. Specifically, it is known as the _____.
Respuesta
-
centrosome
-
microtubulere
-
kinetochore
-
centromere
Pregunta 83
Pregunta
The mitotic spindle is a microtubular structure that is involved in _____.
Respuesta
-
separation of sister chromatids
-
dissolving the nuclear membrane
-
triggering the compaction and condensation of chromosomes
-
splitting of the cell (cytokinesis) following mitosis
Pregunta 84
Pregunta
Metaphase is characterized by _____.
Respuesta
-
splitting of the centromeres
-
cytokinesis
-
separation of sister chromatids
-
aligning of chromosomes on the equator
Pregunta 85
Pregunta
At which phase are centrioles beginning to move apart in animal cells?
Respuesta
-
prophase
-
metaphase
-
prometaphase
-
anaphase
Pregunta 86
Pregunta
Taxol is an anticancer drug extracted from the Pacific yew tree. In animal cells, Taxol disrupts microtubule formation. Surprisingly, this stops mitosis. Specifically, Taxol must affect _____.
Respuesta
-
anaphase
-
chromatid assembly
-
the structure of the mitotic spindle
-
formation of the centrioles
Pregunta 87
Pregunta
The beginning of anaphase is indicated by which of the following?
Respuesta
-
Spindle microtubules begin to polymerize.
-
Cohesin attaches the sister chromatids to each other.
-
Chromatids lose their kinetochores.
-
Cohesin is cleaved enzymatically.
Pregunta 88
Pregunta
During which phase of mitosis do the chromatids become chromosomes?
Respuesta
-
telophase
-
anaphase
-
prophase
-
metaphase
Pregunta 89
Pregunta
Which of the following does NOT occur during mitosis?
Respuesta
-
separation of the spindle poles
-
condensation of the chromosomes
-
spindle formation
-
replication of the DNA
Pregunta 90
Pregunta
The drug cytochalasin B blocks the function of actin. Which of the following aspects of the cell cycle would be most disrupted by cytochalasin B?
Respuesta
-
cleavage furrow formation and cytokinesis
-
spindle formation
-
cell elongation during anaphase
-
spindle attachment to kinetochores
Pregunta 91
Pregunta
Motor proteins require which of the following to function in the movement of chromosomes toward the poles of the mitotic spindle?
Respuesta
-
a microtubule-organizing center
-
intact centromeres
-
synthesis of cohesin
-
ATP as an energy source
Pregunta 92
Pregunta
Neurons and some other specialized cells divide infrequently because they _____.
Respuesta
-
can no longer bind Cdk to cyclin
-
no longer have active nuclei
-
show a drop in MPF concentration
-
have entered into G0
Pregunta 93
Pregunta
MPF is a dimer consisting of _____.
Respuesta
-
ATP synthetase and a protease
-
cyclin and tubulin
-
a growth factor and mitotic factor
-
cyclin and a cyclin-dependent kinase
Pregunta 94
Pregunta
What happens if MPF (mitosis-promoting factor) is introduced into immature frog oocytes that are arrested in G2?
Respuesta
-
The cells enter mitosis.
-
Cell differentiation is triggered.
-
Nothing happens.
-
The cells undergo meiosis.
Pregunta 95
Pregunta
The M-phase checkpoint ensures that all chromosomes are attached to the mitotic spindle. If this does not happen, cells would most likely be arrested in _____.
Respuesta
-
prophase
-
telophase
-
metaphase
-
prometaphase
Pregunta 96
Pregunta
Which of the following is released by platelets in the vicinity of an injury?
Respuesta
-
PDGF
-
MPF
-
cyclin
-
Cdk
Pregunta 97
Pregunta
Which of the following is a protein synthesized at specific times during the cell cycle that associates with a kinase to form a catalytically active complex?
Respuesta
-
PDGF
-
cyclin
-
MPF
-
Cdk
Pregunta 98
Pregunta
Which of the following is a protein maintained at steady levels throughout the cell cycle that requires cyclin to become catalytically active?
Respuesta
-
Cdk
-
PDGF
-
cyclin
-
MPF
Pregunta 99
Pregunta
The cyclin component of MPF is destroyed toward the end of which phase?
Respuesta
-
G2
-
M
-
S
-
G1
Pregunta 100
Pregunta
Besides the ability of some cancer cells to overproliferate, what else could logically result in a tumor?
Respuesta
-
lack of appropriate cell death
-
changes in the order of cell cycle stages
-
inability to form spindles
-
inability of chromosomes to meet at the metaphase plate
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