The Cell Flashcards
(145 cards)
1
Q
how many cells in a prokaryote?
A
single-celled
2
Q
how many cells in a eukaryote?
A
can be unicellular or multicellular
3
Q
do prokaryotic cells contain a nucleus?
A
no
4
Q
do eukaryotic cells contain a nucleus?
A
yes, enclosed in a membrane
5
Q
why are most organelles in eukaryotic cells membrane-bound?
A
to allow for compartmentalization of functions
6
Q
which bilayer do membranes of eukaryotic cells consist of?
A
phospholipid bilayer
7
Q
are the membrane surfaces of eukaryotes hydrophilic or hydrophobic?
A
hydrophilic
8
Q
why are membrane surfaces of eukaryoties hydrophilic?
A
to electrostatically interact with the aqueous environment inside and outside the cell
9
Q
is the membrane inner portion of eukaryotes hydrophilic or hydrophobic?
A
hydrophobic
10
Q
why is the membrane inner portion of eukaryotes hydrophobic?
A
to provide a highly selective barrier between the interior of cell and external environment
11
Q
what is the cytosol?
A
allows for diffusion of molecules throughout the cell
12
Q
where is the genetic material encoded in DNA?
A
nucleus
13
Q
what is the DNA organized into?
A
chromosomes
14
Q
what is mitosis?
A
how eukaryotic cells are reproduced, allowing for formation of two identical daughter cells
15
Q
what is the nucleus surrounded by?
A
nuclear membrane or envelope
16
Q
what is the envelope?
A
a double membrane that maintains a nuclear environment separate and distinct from the cytoplasm
17
Q
where are nuclear pores located?
A
in the nuclear membrane
18
Q
what is the purpose of nuclear pores?
A
to allow selective two-way exchange of material between the cytoplasm and the nucleus
19
Q
what are genes?
A
coding regions contained by the genetic material (DNA)
20
Q
what are histones?
A
linear DNA
21
Q
what are chromosomes?
A
linear strands
22
Q
what is the nucleolus?
A
a subsection of the nucleus where ribosomal (rRNA) is synthesized
23
Q
what is the mitochondria?
A
powerhouse of the cell that is important for metabolic functions
24
Q
how many layers does the mitochondria contain?
A
two layers (inner and outer membranes)
25
what is the purpose of the outer membrane of the mitochondria?
it serves as a barrier between the cytosol and the inner environment of the mitochondria
26
what does the cristae contain?
the molecules and enzymes of the electron transport chain
27
what does the cristae increase for the electron transport chain enzymes?
the surface area available
28
what is the intermembrane space of the mitochondria?
the space between the inner membrane and outer membrane
29
what is the mitochondrial matrix?
the space inside the inner membrane
30
what is apoptosis?
the space inside the inner membrane cell death
31
how does mitochondria kill cells?
by releasing enzymes from the electron transport chain
32
what are lysosomes?
membrane-bound structures that break down substrates
33
what kind of enzymes do lysosomes contain?
hydrolytic enzymes
34
what is the purpose of endosomes?
to transport, package and sort cell material traveling to and from the membrane
35
what is autolysis?
released enzymes directly leading to degradation of cellular components
36
does the rough ER contain ribosomes?
yes
37
does the smooth ER contain ribosomes?
no
38
what is the rough ER primarily used for?
translation of proteins
39
what is the smooth ER primarily used for?
lipid synthesis
40
from where to where does the SER transport proteins?
from the RER to the golgi apparatus
41
what is the golgi apparatus primarily do?
modify cellular products through the introduction of signal sequences, which direct the delivery of the product to a specific cellular location
42
what is exocytosis?
the process of which the secretory vesicles emerge with the cell membrane and its contents
43
what do peroxisomes contain?
hydrogen peroxide
44
what is the primary function of peroxisomes?
breakdown of very long chain fatty acids via beta-oxidation
45
in which type of synthesis do peroxisomes participate in?
in the synthesis of phospholipids
46
what is the function of the cytoskeleton?
provide structure to the cell and help maintain its shape
47
what are the three components of the cytoskeleton?
microfilaments, microtubules, intermediate filaments
48
what are microfilaments made up of?
actin
49
what is the purpose of actin filaments?
provide protection for the cell
50
what do actin filaments use ATP for?
to generate force for movement by interacting with myosin
51
what is an example of actin interacting with myosin?
muscle contraction
52
what is cytokinesis?
the division of materials between daughter cells
53
what are microtubules?
polymers of tubular proteins that provide primary pathways along which motor proteins carry vesicles
54
what are the motile structures for the microtubules?
cilia and flagella
55
what are cilia?
projections of the cell involved in movement of materials along the surface of the cell
56
what is an example of cilia moving materials along the surface of the cell?
cilia line the respiratory tract and are involved in movement of mucus
57
what are flagella?
involved in the movement of the cell itself
58
what is an example of flagella moving the cell itself?
the movement of sperm cells through the reproductive tract
59
how many microtubules are the cilia and flagella both composed of?
nine pairs of microtubules, forming an outer ring
60
what are centrioles?
found in the region of the centrosomes, they organize centers for microtubules
61
how many microtubules are centrioles composed of?
nine triples of microtubules
62
what are intermediate filaments?
group of filamentous proteins
63
what re intermediate filaments involved in?
cell-cell adhesion and maintenance of overall integrity of cytoskeleton
64
what do intermediate filaments anchor?
the organelles, including the nucleus
65
what are the four tissue types?
epithelial, connective, nervous, muscle
66
where are epithelial tissues located?
cover the body and lines its cavities
67
what do epithelial tissues protect against?
pathogen invasion and desiccation
68
what do epithelial tissues constitute?
the parenchyma
69
what is the parenchyma?
the functional parts of the organ?
70
what are examples of parenchyma?
nephrons in the kidney, hepatocytes in the liver, acid-producing cells in the stomach
71
what is simple epithelia?
have one layer of cells
72
what is stratified epithelia?
have multiple layers of cells
73
what is pseudostratified epithelia?
appear to have multiple layers due to differences in cell height, but are really only one layer
74
what is the purpose of connective tissues?
support the body and provide a framework for epithelial cells to carry out their function
75
what is the biggest difference between epithelial tissues and connective tissues?
epithelial cell contribute to the parenchyma (functional part of the organ) and connective tissues contribute to the stroma (support structure)
76
what are examples of connective tissues?
bone, cartilage, tendons, ligaments, adipose tissue, blood
77
do prokaryotes include all bacteria?
yes
78
do prokaryotes contain membrane-bound organelles?
no
79
what is the genetic material organized into in prokaryotes?
into a single circular molecule of DNA
80
what are the three domains of life?
archaea, bacteria, eukarya
81
how many cells in archaea?
single-celled
82
how do archaea divide?
by binary fission or budding
83
what is the overall structure of archaea similar to?
bacteria
84
do bacteria contain cell membranes and cytoplasm?
yes
85
what are mutualistic symbiotes?
where both humans and bacteria benefit from the relationship
86
what are the three shapes of bacteria?
spherical (cocci), rod-shaped (E.coli), spiral-shaped (syphilis)
87
what are obligate anaerobes?
bacteria that require oxygen for metabolism
88
what are anaerobes?
bacteria that use fermentation, or other form of metabolism that does not require oxygen
89
what are obligate anaerobes?
anaerobes that cannot survive in an oxygen-containing environment
90
what are facultative anaerobes?
when bacteria toggle between aerobic and anaerobic metabolism
91
what are aerotolerant anaerobes?
unable to use oxygen for metabolism, but could survive in oxygen-containing environment
92
what is the biggest difference in structure between prokaryotes and eukaryotes?
prokaryotes do not have a nucleus and membrane-bound organelles
93
what is the purpose of the cell wall in bacteria
it forms the outer barrier of the bacterial cell
94
what is the purpose of the cell wall?
to provide structure and control movement of solutes into and out of bacterium
95
what are the two types of cell walls?
gram positive and gram negative
96
what is the type of cell wall determined by?
by the gram staining process (crystal violet stain)
97
what happens is the envelope absorbs the crystal violet stain?
it appears purple and the cell wall is gram positive
98
what happens if the envelope does not absorb the crystal violet stain?
it appears pink-red and the cell wall is gram negative
99
what do gram-positive cell walls consist a thick layer of?
peptidoglycan
100
do gram-negative cell walls contain peptidoglycan?
yes, but in much smaller amounts that gram-positive cell walls
101
what is chemotaxis?
the ability of a cell to detect chemical stimuli and move toward or away from them
102
what is binary fission?
a simple form of asexual reproduction in prokaryotes
103
why does binary fission proceed more rapidly than mitosis?
because binary fission requires fever events than mitosis
104
what are plasmids?
extrachromosomal material that carry genes that impart some benefit to the bacteria, such as antibiotic resistance or virulence factors
105
what is transformation?
results from the integration of foreign genetic material into the host genome
106
what is conjugation?
the bacterial form of mating (sexual reproduction)
107
what is the conjugation bridge?
used in conjugation for the transfer of genetic material
108
is the transfer in conjugation unidirectional or multidirectional?
unidirectional; from donor male (+) to the recipient female (-)
109
what is transduction?
the only genetic recombination process that requires a vector
110
what is a vector?
a virus that carries genetic material from one bacterium to another
111
can viruses reproduce outside of a host cell?
no
112
what does it mean when viruses are obligate intracellular pathogens?
they cannot reproduce outside of a host cell
113
what are bacteriophages?
viruses that infect bacteria
114
what are transposons?
genetic elements capable of inserting and removing themselves from the genome
115
are transposons only seen in prokaryotes?
both prokaryotes and eukaryotes
116
how do bacteria reproduce?
via binary fission
117
bacteria grow in a series of what?
series of phases?
118
what is the lag phase of the growth of bacteria?
when bacteria first adapt to the new local conditions
119
what is the exponential phase of the growth of bacteria?
when the rate of division increases, causing an exponential increase in number of bacteria in the colony
120
what is the exponential phase in the growth of bacteria also known as?
the log phase
121
what is the stationary phase of the growth of bacteria?
the reduction of resources, caused by the increase of bacteria in the colony, which slows reproduction
122
what is the death phase of growth of bacteria?
depletion of resources
123
what is the protein coat of a virus also known as?
capsid
124
what is the capsid?
the protein coat of a virus
125
what is the capsid of a virus surrounded by?
an envelope composed of phospholipids and virus-specific proteins
126
why are viruses considered obligate intracellular parasites?
because they cannot reproduce independently
127
why must viruses replicated within a host cell?
because they are obligate intracellular parasites and lack ribosomes to carry out protein synthesis
128
what are virions?
viral progeny
129
what are bacteriophages?
viruses that target and infect bacteria
130
do bacteriophages actually enter bacteria?
no; they just inject their genetic material
131
132
what is the tail sheath of a bacteriophage?
acts like a syringe: injects genetic material into bacterium
133
what is the tail fiber of bacteriophage?
help the bacteriophage recognize and attach to the correct host cell
134
can single-stranded RNA viruses be either positive or negative sense?
yes
135
what is positive sense?
genome may be translated to functional proteins by the ribosomes of the host cell, just like mRNA
136
what is the negative sense?
acts as a template for synthesis of a complementary strand, which can then be used as a template for protein synthesis
137
what type of viruses are retroviruses?
single-stranded RNA viruses
138
what do the virion in retroviruses contain?
two identical RNA molecules
139
what do retroviruses carry?
an enzyme known as reverse transcriptase, which synthesizes DNA from single-stranded RNA
140
can viruses infect all cells?
no; only specific cells with the proper receptors
141
what does the bacteriophage do during the lytic cycle?
it maximizes the use of the cell’s machinery with little regard for the survival of the host cell
142
what does the virus do in the lysogenic cycle?
the virus will be replicated as the bacterium reproduces because it is now a part of the host’s genome
143
what are prions?
infections proteins that are non living things
144
how do prions cause disease?
by triggering and misfolding of other proteins, through the conversion of a protein from an alpha-helical structure to a beta-pleated sheet
145
what are viroids?
small pathogens that infect plants
