Ch. 4 A Tour of the Cell Flashcards
(146 cards)
1
Q
cell
A
fundamental unit of life
2
Q
all organisms are made of
A
cells
3
Q
cells are related by
A
descent from earlier cells
4
Q
most cells are too small to be seen so scientists use
A
microscopes
5
Q
light microscope
A
visible light is passed through a specimen then through glass lenses, which refract the light so that the image is magnified
6
Q
magnification
A
ratio of an object’s image size to its real size
7
Q
resolution
A
measure of the clarity of an image, or the minimum distance between two distinguishable points
8
Q
contrast
A
difference in brightness between the light and dark areas of the image
9
Q
light microscopes can magnify the image up to
A
1,000 times
10
Q
light microscopy is not able to see
A
subcellular structures
11
Q
2 types of electron microscopes can be used to see subcellular structures
A
scanning electron microscopes and transmission electron microscopes
12
Q
scanning electron microscope
A
focuses beam of electrons onto surface of specimen, producing images that look 3-dimensional
13
Q
transmission electron microscope
A
focuses a beam of electrons through a specimen, used mostly to study internal structures of cells
14
Q
2 types of cells
A
eukaryotic and prokaryotic
15
Q
prokaryotic cells
A
domain archaea and bacteria
16
Q
eukaryotic cells
A
protists, fungi, animals, and plants
17
Q
plasma membrane (cell membrane)
A
selective barrier that allows passage of oxygen, nutrients, and waste to service the volume of every cell
18
Q
general structure of plasma membrane
A
phospholipid bilayer
19
Q
cytosol
A
semifluid substance surrounding organelles
20
Q
cytoplasm
A
includes cytosol and organelles bound by plasma membrane
21
Q
chromosome
A
long molecule of DNA that carries genetic information, associated with proteins
22
Q
ribosome
A
uses information from DNA to make proteins
23
Q
differences between prokaryotic and eukaryotic cells
A
nucleus/nucleoid, size, membrane bound organelles
24
Q
eukaryotic cells have DNA in
A
nucleus
25
prokaryotic cells have DNA in
nucleoid
26
nucleoid
an unbound region of prokaryotic cells where DNA is found
27
organelle
extensive internal membrane that divides the cell into compartments
28
plasma membrane and organelle membranes participate directly with
cell's metabolism
29
eukaryotic cell size
10μm-100μm
30
prokaryotic cell size
1μm-5μm
31
nucleus
an organelle in eukaryotic cells that is bounded by a double membrane and contain's most of the cell genes
32
nuclear envelope
encloses the nucleus, separating it from the cytoplasm
33
nuclear envelope consists of
an inner and outer membrane
34
nuclear pores
ringed by protein particles, regulates entry and exit of molecules
35
nuclear lamina
composed of protein filaments and maintains shape of nucleus, lines the inner surface of the nuclear envelope (nuclear envelope inner membrane)
36
chromatin
uncondensed DNA + proteins of chromosomes that serves as blueprint for controlling cell's function and making more cells
37
as cell prepares to divide, chromatin
condenses
38
nucleolus
located within the nucleus as site of ribosomal RNA (rRNA) synthesis
39
ribosome
complexes of ribosomal RNA and proteins that carry out protein synthesis in two locations
40
2 locations of ribosomes
free ribosomes in the cytosol, bound ribosomes on the outside of the endoplasmic reticulum or the nuclear envelope
41
ribosome is made up of
large and small subunit
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endomembrane system
nuclear envelope, endoplasmic reticulum, golgi apparatus, lysosomes, vacuoles, plasma membrane
43
components of endomembrane system are
either continuous or connected through transfer by vesicles
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vesicle
small structures within a cell consisting of fluid enclosed by a lipid bilayer
45
vesicles are involved in
transport, buoyancy control, and enzyme storage
46
endoplasmic reticulum
series of interconnecting flattened tubular channels continuous with the nuclear envelope, accounts for more than half of the total membrane
47
two distinct regions of the endoplasmic reticulum
rough endoplasmic reticulum, smooth endoplasmic reticulum
48
functions of smooth endoplasmic reticulum
synthesizes lipids, metabolizes (processes) carbohydrates, detoxifies drugs and proteins, stores calcium ions
49
functions of rough endoplasmic reticulum
secretes glycoproteins for use in the cell (extracellular matrix), transports proteins in transport vesicles created from budding to golgi apparatus or other places in/out of cell, creates membranes for use in the cell
50
smooth endoplasmic reticulum
lacks ribosomes
51
rough endoplasmic reticulum
has bound ribosomes which secrete glycoproteins and distributes transport vesicles
52
transitional endoplasmic reticulum
the exit site of proteins leaving the rough endoplasmic reticulum destined to enter the golgi apparatus for modification, packaging, shipping
53
cisternae
flattened membrane vesicle that synthesizes glycoproteins and complex polysaccharides, included in the endoplasmic reticulum
54
endoplasmic reticulum lumen
the area enclosed by the endoplasmic reticulum membrane where proteins are folded to produce their important structure
55
golgi apparatus
consists of flattened membranous sacs called cisternae
56
through budding off of its ends, the golgi apparatus makes
lysosomes, other specialized vesicles, and vacuoles
57
functions of golgi apparatus
modifies products of endoplasmic reticulum, manufactures certain macromolecules, sorts and packages materials into transport vesicles sent to other places inside/outside the cell
58
transport vesicles (holding proteins) take products from endoplasmic reticulum to
golgi apparatus
59
the golgi apparatus helps to process
protein and lipid molecules, especially proteins to be sent out of cell
60
glycoprotein
protein covalently bonded to carbohydrate
61
transport vesicle
membrane surrounded protein that separates from ends of the rough endoplasmic reticulum and carries protein to golgi apparatus or other place inside/outside the cell
62
cis face of golgi apparatus
receiving side of golgi apparatus where transport vesicles go to form new cis golgi cisternae
63
trans face of golgi apparatus
shipping side of golgi apparatus where transport vesicles are sent out
64
cisternal maturation
occurs when golgi cisternae move in cis-to-trans direction
65
lysosome
membranous sac of hydrolytic (breaking apart) enzymes that are necessary for the intercellular digestion of macromolecules and to degrade worn out organelles
66
lysosomes are made in
endoplasmic reticulum (formation of enzymatic proteins) and golgi apparatus (budding to form vesicle)
67
lysosomal enzymes work best in
acidic environment of the lysosome
68
the 3-dimensional shape of lysosomes protects them from
digestion by lysosomal enzymes
69
products of lysosomal degradation can
be reused in the cell
70
phagocytosis (cellular eating)
the process by which a cell engulfs another cell and forms a food vacuole
71
autophagy
the process by which a lysosome uses enzymes to recycle the cell's own organelles and macromolecules (cleaning out damaged cells in order to regenerate newer, healthier cells)
72
difference between phagocytosis and autophagy
phagocytosis engulfs extracellular particles while autophagy occurs with original cell materials that aren't needed anymore
73
vacuole
large vesicle derived from endoplasmic reticulum and golgi apparatus, vacuole solution differs from cytosol
74
food vacuole
formed by phagocytosis between engulfed cell and regular cell
75
contractile vacuole
found in many freshwater protists and pumps excess water out of cells
76
certain vacuoles in plants and fungi hold reserves of inorganic compounds (break down macromolecules into monomers) through the use of
enzymatic hydrolysis (like lysosomes)
77
central vacuole
found in many mature plant cells and serves as a repository for inorganic ions, including potassium and chloride
78
plasma membrane
thin, partially semi-permeable membrane essential in controlling exchange between cell and its environment
79
efficient barrier that allows controlled traffic of materials in both directions, allows some materials to pass but not others
plasma membrane
80
exocytosis
the process by which contents of vacuole are released to exterior of cell when vacuole membrane fuses with cell membrane
81
mitochondria
site of cellular (aerobic) respiration and major energy production center in both plant and animal cells
82
cellular respiration
a metabolic process that uses oxygen to generate ATP by extracting energy from sugars, fats, and other fuels
83
chloroplast
site of photosynthesis found in both plants and algae
84
peroxisome
oxidative organelle responsible for protecting the cell by ridding the body of toxic substances (hydrogen peroxide) and breaking down lipids, specialized metabolic compartment bounded by a single membrane
85
peroxisomes produce
hydrogen peroxide and then convert it to water
86
peroxisomes in liver
detoxify alcohol and other harmful compounds
87
endosymbiont theory
theory that mitochondria and chloroplasts were once prokaryotic bacteria that were engulfed by larger bacteria due to similarities between mitochondria and chloroplasts
88
mitochondria and chloroplast similarities
enveloped by double membrane, contain ribosomes and multiple circular DNA molecules, grow and reproduce somewhat independently in cells
89
mitochondria is found in
all eukaryotic cells (plant/animal)
90
cristae
folds in the inner membrane of mitochondria surrounded by smooth outer membrane
91
folds of cristae enhance ATP production because
they present a larger surface area for synthesization
92
inner membrane with cristae folds creates 2 compartments
intermembrane space and mitochondrial matrix
93
intermembrane space
enclosed by the outer and inner membrane of mitochondria as tiny compartment of cell
94
mitochondrial matrix
holds free ribosomes, DNA, and enzymes where some metabolic steps of cellular respiration are catalyzed
95
chloroplasts contain
green pigment chlorophyll, as well as enzymes and other molecules that function in photosynthesis
96
chloroplasts are found in
leaves and other green organs of plants and in algae
97
chloroplast structure includes
thylakoid, granum, and stroma
98
thylakoid
flattened, interconnected sac in a chloroplast's membranous system
99
granum
vertical stack of thylakoids
100
grana
multiple stacks of thylakoids (granum)
101
stroma
internal fluid of chloroplast, found outside of the chloroplast filing the inner membrane
102
the chloroplast is part of a group of plant organelles called
plastids
103
plastid
organelles containing pigment/food in the cytoplasm of plant cells
104
cytoskeleton
network of fibers extending throughout the cytoplasm that organizes the cell's structure and activities
105
functions of cytoskeleton
helps to support cell and maintain shape, provides anchorage for many organelles and molecules, interacts with motor proteins (powered by ATP) to produce motility
106
motor protein
a protein that interacts with cytoskeletal elements and other cell components, producing movement of the whole cell or parts of the cell
107
3 main types of fibers make up the cytoskeleton for support, structure, and movement
microtubules (thickest), microfilaments (thinnest, 2 thin strands of actin filament coiled), intermediate filaments (middle diameter, fibrous proteins coiled into cables)
108
microtubule
hollow rod constructed from globular protein dimers called tubulin
109
functions of microtubules
shape and support the cell, guide movement of organelles through organelles' motor proteins, separate chromosomes during cell division
110
centrosome
organelle that serves as main microtubule organizing center for animal cells
111
centrosomes are made up of a pair of
centrioles, each with 9 triplets of microtubules arranged in a ring, along with proteins that help additional microtubules to form
112
microtubules control beating of
cilium and flagella, microtubule containing extensions projecting from some cells
113
cilia
minute, hair like organelles involved in movement of mucus out of lungs and egg in fallopian tube
114
flagella
similar to cilia but longer and typically found on sperm
115
cilia and flagella differ in
quantity and beating patterns
116
common structure of cilia and flagella
group of microtubules sheathed by plasma membrane with 9 + 2 arrangement of microtubules, dynein arms, basal body
117
9 + 2 arrangement of microtubules
contains 9 fused pairs of microtubules (microtubule doublets) on the outside of the cylinder and 2 unfused microtubules in the center (central microtubules)
118
microtubules in 9 + 2 arrangement are connected by
flexible cross-linking proteins and the radial spoke
119
dynein arms
attached to outer ring of microtubules use motor proteins to control the beating of cilia and flagella
120
basal body
microtubule based organelle which anchors and assembles the cilium or flagellum
121
dynein motor proteins use microtubule doublet arms to
alternatively contact, move, and release the outer microtubules, movement causes cilium/flagellum to bend
122
microfilament (actin filament)
thin, solid rod built from molecules of globular actin filaments
123
microfilament (actin filament) functions
structural role to bear tension (resisting pulling forces) and make up the core of microvilli of intestinal cells
124
microfilaments can bear tension when
certain proteins bind along the side of the microfilament which allows new filament to extend as a branch
125
microvilli
bundle of microtubules with thin projections on the surface of a cell that increase surface area without a big increase in volume
126
microfilaments that function in cellular motility interact with the motor protein
myosin, which works with actin filaments to cause muscle contraction, amoeboid movement of white blood cells, and cytoplasmic streaming in plant cells
127
intermediate filament
filament larger than microfilament but smaller than microtubule that is only found in the cells of some animals, including vertebrae
128
intermediate filament functions
reinforce cell shape and fix organelles in place
129
compared to microtubules and microfilaments, intermediate filaments are
a more permanent structure of the cytoskeleton
130
cell wall
extracellular structure that distinguishes plant cells from animal cells
131
functions of cell wall
protects plant cell, maintains shape, and prevents excessive uptake of water
132
plant cell walls have multiple layers
primary cell wall, middle lamella, secondary cell wall
133
primary cell wall
relatively thin and flexible
134
middle lamella
thin layer between primary walls of adjacent cells
135
secondary cell wall (only in some cells)
added between the plasma membrane and the primary cell wall, usually thicker layer
136
animal cells lack walls but are covered by
an extracellular matrix
137
extracellular matrix
a large network of proteins and other molecules that surround, support, and give structure to cells and tissues in the body
138
extracellular matrix is made up of
glycoproteins such as collagen, proteoglycans, and fibronectin
139
extracellular matrix functions
attach to and communicate with other cells and plays an important role in cell growth, movement, and functions
140
proteins of extracellular matrix bind to
cell-surface receptor proteins in the plasma membrane called integrins
141
integrin
principal receptor used by animal cells to bind to the extracellular matrix
142
several types of intercellular junctions that facilitate interactions between cells (especially common in epithelial tissue)
plasmodesmata, tight junctions, desmosomes, gap junctions
143
plasmodesmata
membrane lined channels that are filled with cytosol and perforate plant cell walls, allow water and small solutes (+ proteins, RNA) to pass from cell to cell
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tight junctions
plasma membranes of neighboring cells pressed very tightly together, bound by specific proteins that prevent leakage of extracellular fluid across a layer of epithelial cells
145
desmosomes
anchoring junctions that function like rivets, fastening cells together into strong sheets
146
gap junctions
communicating junctions that provide cytoplasmic channels from one cell to adjacent cell (only in animal cells, similar to plant cell plasmodesmata)
