Cliff's - Chapter 2 - Cells Flashcards
1
Q
cell
A
basic functional unit of all living things
2
Q
plasma membrane (cell membrane)
A
bounds cell
encloses nucleus and cytoplasm
3
Q
cytoplasm consists of
A
organelles suspended in fluid matrix, cytosol
4
Q
organelles
A
specialized bodies
5
Q
cytosol
is
consists of
A
fluid matrix,
water, dissolved substances - proteins + nutrients
6
Q
plasma membrane
function
A
- separates internal metabolic events from external environment
- controls movement of materials into and out of cell
7
Q
plasma membrane
composition
A
- double phospholipid membrane
- (liquid bilayer)
- polar hydrophlic heads form two outer surfaces
- nonpolar hydrophobic tails point inwards
8
Q
Peripheral proteins
A
attach loosely to inner or outer surface of membrane
9
Q
integral proteins
A
extend into membrane
10
Q
transmembrane proteins
A
type of integral protein
span across membrane (surface to surface)
11
Q
integral proteins
form
A
amphipathic
12
Q
amphipathic
A
hydrophobic + hydrophilic regions
13
Q
fluid mosaic model
A
mosaic
scattered proteins within flexible matrix of phospholipid molecules
14
Q
phospholipid membrane is selectively permeable
only these may freely pass:
A
small, uncharged, polar molecules
e.g. H2O, CO2
hydrophobic molecules
e.g. nonpolar mlc like O2, lipid-soluble mlc like hydrocarbons
15
Q
phospholipid membrane
impermeable molecules:
A
large polar molecules
e.g. glucose
all ions
16
Q
Channel proteins
(plasma membrane)
A
certain hydrophilic (water-soluble) mlc
polar + charged molecules
17
Q
Ion channels
(plasma membrane)
A
ions
18
Q
gated channels
A
ion channels in nerve and muscle cells
open and close in response to chem or electric stimuli
passge of specific ions (K+, Na+)
19
Q
Porins
(plasma membrane)
A
certain ions
small polar molecules
20
Q
aquaporins
(plasma membrane of certain cells)
A
e.g. kidney, plant roots
dramatically increase flow of H2O
21
Q
Carrier proteins
(plasma membrane)
A
bind to specific mlc
mlc transferred across membrane after carrier proteins change shape
e.g. glucose via carrier protein
22
Q
Transport proteins
(plasma membrane)
A
use ATP (energy)
active transport
e.g. Na+-K+ pump
23
Q
active transport
A
ATP used to transport materials
24
Q
Na+-K+ Pump
A
uses ATP to maintain higher conc of Na+ and K+ on opp. sides of plasma membrane
25
recognition proteins
function
(plasma membrane)
give each cell type unique ID
rec b/w self types
self cells vs. foreign cells
normal cells vs. infected cells (viruses)
26
recognition protein
(plasma membrane)
form
glycoproteins
oligosaccharide attached
oligosaccharide extends away from surface of membrane
27
oligosaccharide
short polysaccharide chains
28
glycoproteins
proteins with oligosaccharides covalently bonded to polypeptide side chains
29
adhesion proteins
| (plasma membrane)
attach cells to neighboring cells
or
provide anchors for internal filmanets and tubules of cell
30
internal filaments and tubules of cell provide...
stability to cell
31
receptor proteins
| (plasma membrane)
binding sites for hormones, trigger mlc
32
when hormones, trigger mlc bind to receptor proteins..
specific cell response activated
33
Cholesterol mlc distributed throughout plasma membrane provide
rigidity to membrane (animal cells)
34
sterols
function as cholesterol in plasma membrane in plant cells
provide rigidity to membrane
35
glycocalyx
def and function
carb coat
covers outer face of cell wall (bacteria)
covers outer face of plasma membrane (animal)
36
glycocalyx
form
oligosaccharides attached to glycolipids and proteins
37
glycolipids
membrane phospholipids
38
glyocalyx
depending upon cell, may provide (3):
adhesive capabilities
barrier to infection
markers for cell-cell recognition
39
Organelles
bodies within cytoplasm
serve to physically separate various metabolic reactions
40
nucleus bouned by
nuclear envelope
41
nuclear envelope consists of
two phospholipid bilayers (sim. to plasma membrane)
42
DNA form
spread out within nucleas in form of chromatin
43
when cell begins to divide, chromatin...
condenses into chromasomes
44
before dividing, chromosomes made up of
two long DNA molecules
various histone molecules
45
histones
protein
organize - coil DNA into nucleosomes
46
nucleoli
in nucleus
concentrations of DNA
manufacture subunits of ribosomes
47
during cell division, chromsomes separate in the
nucleus
48
ribosome
made up of...
RNA molecules and protein
2 subunits
49
ribosome subunits and unification
40S + 60S
manufactured in nucleoli
subunits move nuclear envelope ---\> cytoplasm
combine --\> 80S in cytoplasm
50
ribosome function
in cytoplasm - help assemble amino acids ---\> proteins
51
S Value
| (Svedberg unit)
how readily product forms sediment in centrifuge
larger values = heavier products
52
Endoplasmic Reticulum
(ER)
form
2 types
stacks of flattened sacs
cross section: series of maze-like channels
rough (with ribosomes)
smooth (without ribosomes)
53
ER
function (general)
production of various materials
54
rough ER
has ribosomes on surface
creates glycoproteins
55
how does rough ER create glycoproteins?
attaches polysaccharide groups to polypeptides as they are assembled by ribosomes
56
smooth ER
function
various activities
synthesis of lipids and hormones
esp in cells that produce these for export from cell
57
smooth ER in liver cells
breakdown of toxins
drugs
toxic by-products from cellular rxns
58
Golgi apparatus
(golgi complex, golgi body)
form
group of flattened sacs
arranged like stack of bowls
59
gogli
fxn
modify and pack proteins and lipids into vesicles
60
vesicles
form
small
spherically shaped sacs
bud from outside surface of golgi
61
vesicles
fxn
merge with plasma membrane
release contents to outside of cell
62
Lysosomes
form
vesicles from golgi that
contain digestive enzymes
63
lysosomes
fxn
break down food
cellular debris
foreign invaders (bacteria)
64
lysosomes
characteristics (pH)
low pH (favorable to enzymes)
65
lysosomes occur in
animal cells
NO plant cells
66
if an enzyme escapes from lysosome
it will be inactive in neutral pH of cytosol
67
Peroxisomes
fxn
break down various substances
e.g. H2O2, fatty acids, amino acids
68
peroxisomes are common in these kinds of cells
liver and kidney
69
peroxisomes fxn in liver and kidney cells
break down toxic substances
70
peroxisomes in plant cells
modify by-products of photorespiration
71
photorespiration
CO2 diverted from use in photosynthesis
72
glyoxysomes
peroxisomes in germinating seeds
break down fatty acids ---\> energy for growth
73
Mitochondria
carry out aerobic respiration
74
aerobic respiration
energy (ATP) obtained from carbs
75
chloroplasts
carry out photosynthesis
76
photosynthesis
plant process
incorporate energy from sunlight into carbohydrates
77
three protein fibers, in decreasing diameter
microtubules
intermediate filaments
microfilaments
78
microtubules
intermediate filaments
microfilaments
protein fibers involved in shaping or coordinating movements of cytoskeleton
79
cytoskeleton
internal structure of cytoplasm
80
microtubules made of
protein tubulin
81
microtubules
fxn
support and motility for cellular activities
82
microtubules found in
spindle apparatus
flagella
cilia
83
spindle apparatus
guides movement of chromosomes during cell division
84
flagella and cilia
project from plasma membrane
provide motility to cell
85
intermediate filaments
maintain shape of cell
86
microfilaments made of
protein actin
87
microfilaments involved in
cell motility
88
microfilaments found in
1. muscle cells
2. cells that move by changing shape
e.g. phagocytes
89
phagocytes
white blood cells
wander through body attacking bacteria and other foreign invaders
90
flagella and cilia
protrude from cell membrane
make wavelike movements
91
flagella
long, few
move in snakelike motion
92
cilia
short, many
move with back and forth motion
93
propels sperm
single flagellum
94
line respiratory tract and sweep away debris
numerous cilia
95
structure of flagella and cilia
microtubules arranged in 9+2 array
9 doublets of microtubules arranged in a circle around a pair of microtubules
96
Centrioles and basal bodies act as
microtubule organizing centers (MTOCs)
97
both centrioles and basal bodies are made up of
nine triplets of microtubules arranged in a circle
98
a pair of centrioles are enclosed in the
centrosome
99
centrioles in centrosome located outside nuclear envelope gives rise to...
microtubules that make up spindle apparatus (used during cell divison)
100
at the base of each flagellum and cilium are
basal bodies
101
basal bodies at the base of each flagellum and cilia
fxn
organize development of flagellum and cilia (microtubules)
102
cenrioles are not present in
plant cells
103
only lower plants
e.g. mosses and ferns
with motile sperm have these
(re: microtubules)
flagella and basal bodies
104
Vacuoles and vesicles are
fluid-filled, membrane-bound bodies
105
transport vesicles
fxn
move materials
bw organelles
bw organelles and plasma membrane
106
food vacuoles
temporary receptacles of nutrients
107
food vacuoles often merge with
lysosomes
108
digestive enzymes in lysosomes...
| (fxn re: food vacuoles)
break down the food transported from food vacuoles
109
storage vacuole store:
| (plants)
starch
pigments
toxic substances (e.g. nicotine)
110
central vacuoles
form + location
(plants)
large bodies
occupy most of interior of certain plant cells
111
central vacuoles
fxn
exert turgor (when fully filled) on cell walls ---\> maintain rigidity of cell
store nutrients
carry other fxns of lysosomes (animal cells)
112
turgor
pressure
113
contractile vacuoles
found in
single celled organisms
114
contractile vacuoles
fxn
collect + pump excess water out of cell
(single celled organisms)
115
extracellular region
area outside plasma membrane
116
cell walls found in
plants
fungi
protists
bacteria
117
cell walls
location
outside plasma membrane
in extracellular region
118
composition of cell wall in plants
cellulose
119
composition of cell wall in fungi
cellulose
or
chitin
120
cellulose
polysaccharide
beta-glucose
121
chitin
modified polysaccharide
differs from cellulose - one OH replaced by N-group
122
extracellular matrix found in
| (organism)
animals
123
extracellular matrix found in
| (area)
space bw adjacent cells
(beyond plasma membrane and glycocalyx)
124
extracellular matrix
composition
fibrous structural proteins
adhesion proteins
polysaccharides secreted by cells
125
extracellular matrix
fxn
mechanical support
helps bind adjacent cells together
126
most common substance in extracellular matrix
collagen
127
cell junctions
anchor cells to one another
or
passageway for cellular exchange
128
types of cell junctions
3
anchoring junctions
tight junctions
communicating junctions
129
anchoring junctions
protein attachments between adjacent cells
in animals
130
desmosome
anchoring junction
keratin + other proteins
bind adjacent cells together
provide mechanical stability to tissues
associated with protein filaments that extend into interior of cell and hold cellular structures together (pg 37)
131
tight junctions
tighty stitched seams bw cells
animal
completely encircles each cell
acts as seal - prevents passage of materials bw cells
132
tight junctions characteristic of cells that
line digestive tract:
materials req'd to pass through cells to penetrate blood stream
pass through cells as opposed to intercellular space!!
133
Communicating Junctions
passageways bw cells
transfer chemical or electrical signals
134
2 types of communicating junctions
gap junctions
plasmodesmata (plural)
plasmodesma (singular)
135
gap junctions
narrow tunnels bw cells
animals
136
gap junctions consist of
proteins - connexins
137
connexins prevent/allow
| (gap junctions)
prevent: cytoplasms of each cell from mixing
allow: passage of ions and small molecules
138
gap junctions allow for communication bw cells via
exchange of material
transmission of electrical impulses
139
gap junctions are like ____ of two adjacent cells
channel proteins
140
gap junctions
namesake
proteins of each cell extend beyond plasma membrane before they meet
small gap occurs bw two plasma membranes
141
plasmodesmata
| (singular: plasmodesma)
narrow channels
plant cells
142
plasmodesmata
fxn
desmotubule (narrow tube of ER), surrounded by cytoplasm and plasma membrane, passes through channel
143
material exchange through plasmodesma occurs through
cytoplasm surrounding desmotubule
144
plant cells
| (3 defining characteristics)
cells walls
chloroplasts
central vacuoles
145
animal cells
3 definining characteristics
lysosomes
centrioles
cholesterol
146
eukaryotes include all organisms except
bacteria
cyanobacteria
archaebacteria
147
prokaryotes include
bacteria
cyanobacteria
archaebacteria
148
prokaryotes lack all organelles except
(5)
plasma membrane
DNA molecule
ribosomes
cytoplasm
cell wall (often)
149
prokaryotes do not have a
| (vs. euk)
nucleus
150
hereditary material in prokaryotes exists as
(vs. euk)
single DNA molecule
no proteins (as in DNA of eukaryotic chromosomes)
151
prokaryotic ribosomes are
| (vs euk)
smaller
70S
subunits: 50S + 30S
152
eukaryote ribosomes
(composition)
(vs. prok)
80S
subunits:
60S + 40S
larger than prokaryotes
153
cell walls of bacteria and cyanobacteria
(when present)
constructed from
(vs euk)
peptidoglycans
154
peptidoglycan
polysaccharide protein molecule
155
cell walls of archaebacteria contain
do not contain
(vs. euk)
various polysaccharides
no:
peptidoglycans
cellulose (plants)
chitin (fungi)
156
flagela
when present in prokaryotes
are not constructed of
(vs. euk)
microtubules
157
selectively permeable membrane
| (movement of substances)
allows only specific substances to pass
e.g. plasma membrane
158
solvent
| (movement of substances)
substance whose movement is being described
159
solute
| (movement of substances)
substance dissolved in solvent
160
hypertonic solute
higher concentration of solutes
161
hypotonic solute
lower concentration of solutes
162
isotonic solute
| (relative to another region)
equal concentration of solutes
163
hypertonic solute
higher concentration of solutes
164
movement of substances may be ___ or \_\_\_\_
passive or active
165
active movement of substances requires \_\_\_\_
and usually \_\_\_\_
expenditure of energy
occurs up a gradient
166
Bulk flow
collective movement of substances in same direction
due to force or pressure
167
e.g. of bulk flow
blood moving through vessel
168
passive transport
movement of substances
higher conc. ---\> lower conc.
down conc. gradient
does not require expenditure of energy
169
simple diffusion
aka diffusion
(passive transport)
**net** movement of substances from higher conc. --\> lower conc
result of:
all mlc (atoms, ions) in random and constant motion
motion independent of other mlc
some mlc against gradient, some down gradient (random)
net = overall result of movement
170
ultimate result of diffusion
| (passive transport)
equilibrium
mlc uniformly distributed but continue to move randomly
171
osmosis
| (passive transport)
diffusion of water mlc across selectively permeable membrane
172
when water moves into body by osmosis ____ may build up inside body
hydrostatic pressure (osmotic pressure)
173
turgor pressure
osmotic pressure
water enters cells of plants and microorganisms
174
dialysis
| (passive transport)
diffusion of solutes across selectively permeable membrane
\*term usually used when:
different solutes separated by selectively permeable membrane
175
plasmolysis
| (passive transport)
water out of cell (osmosis)
results in collapse of cell
176
plasmolysis esp common in
plant cells
w/ central vacuoles
177
facilitated diffusion
| (passive transport)
diffusion of solutes or water through channel proteins in plasma membrane
\*water can pass through plasma membrane w/o aid, but aquaporins increase rate of transfer
178
\_\_\_ release rate of transfer of water across selectively permeable membranes
type of channel protein
(facilitated diffusion - passive transport)
aquaporins via facilitated diffusion
179
countercurrent exchange
| (passive transport)
diffusion of substances bw two regions
substances moving by bulk flow in opposite directions
180
e.g. countercurrent exchange
* direction of water flow through gills of fish opposite flow of blood in blood vessels
* diffusion of oxygen from water --\> blood maximized because
1. relative motion of mlc bw two regions increased
2. conc. gradients bw two regions remain constant along area of contact
181
Active transport
movement of solutes against gradient
requires expenditure of energy (usually ATP)
182
transport proteins in plasma membrane transfer solutes via
active transport
183
transport proteins transfer these solutes across plasma membrane
small ions (Na+, K+, Cl-, H+)
amino acids
monosaccharides
184
Vesicular Transport
uses vesicles or other bodies in cytoplasm to move macromolecules or large particles aross plasma membrane
185
types of passive transport
| (6)
1. simple diffusion (diffusion)
2. osmosis
3. dialysis
4. plasmolysis
5. facilitated diffusion
6. countercurrent exchange
186
types of vesicular transport
1. exocytosis
2. endocytosis
187
types of endocytosis
| (vesicular transport)
1. phagocytosis
2. pinocytosis
3. receptor-mediated
188
exocytosis
vesicles fusing with plasma membrane
releasing contents to outside of cell
189
exocytosis common when
cell produces substances for export
190
endocytosis
* plasma membrane merges to engulf substance outside of cell
* substance enters cytoplasm enclosed in a vesicle
191
phagocytosis
(endocytosis)
"cellular eating"
occurs when
undissolved material enters cell
192
phagocytosis
mechanism
plasma membrane wraps around solid material
engulfs it
forms phagocytic vesicle
e.g. white blood cells (phagocytes) attack and engulf bacteria
193
pinocytosis
(endocytosis)
"cellular drinking"
occurs when
dissolved substances enter cell
194
pinocytosis
mechanism
plasma membrane folds inward to form channel allowing liquid to enter
plasma membrane closes off channel
encircling liquid inside of vesicle
195
receptor-mediated
(endocytosis)
occurs when
specific molecules in fluid surrounding cell bind to specialized receptors that concentrate in coated pits in plasma membrane
196
receptor mediated endocytosis
mechanism
membrane pits, receptors, specific molecules (ligands)
fold inward --\> formation of vesicle
197
e.g. receptor mediated endocytosis
proteins that transport cholesterol in blood (LDL)
certain hormones
target specific cells via rme
198
LDL
low-density lipoproteins
199
receptor mediated endocytosis is a type of
pinocytosis
200
