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exam 3 Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

what and where are proteins polymerized by

A

ribosomes- in cytosol or attached to rough er

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2
Q

what kind of proteins are made in cytosol

A

soluble

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3
Q

where do proteins made in cytosol go

A

-some stay in cytosol
-actively imported to an organelle (fold or unfolded)

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4
Q

what are the unfolded and folded proteins into an organelle

A

unfolded- mitochondria, chloroplasts, peroxisomes
folded- nucleus

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5
Q

proteins made on the rough er may

A

-cross membrane and enter lumen
(endomembrane system, secretion)
-Stick in er membrane
(go to plasma membrane, or stay in ems membrane)

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6
Q

proteins that do not stay in the cytosol have a

A

signal sequence

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7
Q

what do proteins that have a signal sequence do

A

direct polypeptides to destination

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8
Q

what is a signal sequence

A

amino acids that are recognized by protein receptors that guide a new polypeptide to destination

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9
Q

endomembrane system structure

A

membrane compartments linked together by ontogeny and function

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10
Q

er membrane thickness vs plasma membrane

A

5nm
8nm

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11
Q

what is the smooth er function

A

steroid biosynthesis
assembly of glycerolipids
stores ca2+, triaglycerols

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12
Q

structure of smooth er

A

lacks ribosomes
cisternae are tubular

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13
Q

rough er function

A

biosynthesis and processing of proteins for secretion and ems

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14
Q

structure of rough er

A

receptors for ribosomes
cisternae are flattened
lumen accumulates secretory proteins

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15
Q

what directs a ribosome to the er membrane

A

signal sequence and a signal recognition particle

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16
Q

glycosylation of membrane proteins and lipids begins where

A

in the er- assembled on cytosolic face ( bound to dolichol phosphate

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17
Q

in glycosylation what moves oligosaccharides to lumen side of membrane

A

flippase, then transferred to protein or lipid

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18
Q

what does asparagine have to do with glycosylation

A

many proteins are glycosylated on it while in the er

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19
Q

importance of protein modifications in er and golgi apparatus

A

each chunk does a different modification

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20
Q

golgi apparatus structure

A

flattened cisternae in stacks
cis-golgi= faces er
trans= faces plasma membrane
medial=middle

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21
Q

functions of golgi apparatus

A

chemical modification of proteins and lipids
-glycosylation, methylation, phophorylation

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22
Q

how does the golgi apparatus sort proteins and target them to specific destinations

A

membrane thickness-traps IMPs
pH and ca2+ -aggregate some secretory proteins
mannose-6-P- targets to lysosomes
KDEL- targeting sequence (a.a)
(ALL RELY ON CHEMICAL AND PHYSICAL PROPERTIES)

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23
Q

what are lysosomes

A

organelle that digest biological macromolecules and organelles
-acidic considering digestive enzymes

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24
Q

early endosomes mature with addition of more ____ from golgi and become what

A

enzymes/vesicles, late endosomes

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25
Q

late endosomes which are more ____ develop into

A

acidic, lysosomes

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26
Q

where would hydrolytic enzymes be found in ems and why

A

lysosomes because they are only active under acidic conditions

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27
Q

vacuoles in plants are similar to what in animals

A

lysosomes

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28
Q

nuclear envelope in relation to ems

A

fused with the er
gets lipids and proteins from er/golgi

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29
Q

vesicle structure/ coated vesicles

A

proteins that bind to membrane surface and direct vesicle formation

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30
Q

type of protein coat- clathrin characteristics

A

-inside pm
-form at trans golgi and pm, go to endosomes, then lysosomes
-link together by overlapping arms
-“triskelion” subunits, 6 polypeptides each

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31
Q

clathrin molecules form _______ cages that help ____ membranes into vesicles

A

basketlike, shape

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32
Q

calthrin-coated vesicles use what type of endocytosis

A

receptor-mediated ENDOCYTOOSIS

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33
Q

how does clathrin use receptor-mediated endocytosis

A

cargo binds receptor protein in pm then is brought into the cell

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34
Q

different proteins form ___ at other membranes in the ___,
____ may dissociate after budding of ____ or may stay on _____ until fusion with target ____

A

coats, ems
coat, vesicle, membrane

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35
Q

trafficking in the ems =

A

directed movement of vesicles among compartments

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36
Q

snare hypothesis in vesicle binding and fusion

A

proteins protruding from vesicle surface and target membrane link and pull the 2 membranes together

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37
Q

describe the 3 steps in the snare hypothesis

A

-recognition: by tethering complexes of proteins on target membranes
-these then bind the incoming vesicle and pull it to the membrane surface
-SNARES then link

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38
Q

what helps direct transport vesicles to their target membranes

A

Rab proteins, tethering proteins, and SNARES

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39
Q

secretion and exocytosis

A

fusion of vesicle with plasma membrane and release contents out of cell

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40
Q

vesicle movement occurs along cytoskeleton, using

A

motor proteins

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41
Q

what is oxidative phosphorylation

A

making atp from energy derived by oxidation of molecules

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42
Q

what is oxidative metabolism

A

pathways that catabolize organic molecules to retrieve energy

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43
Q

electrons are carried to the electron transport chain in the

A

inner mito membrane

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44
Q

as electrons move through the electron transport chain, energy ____ is used to set up H+ ___ across membrane

A

released, gradient

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45
Q

after H+ gradient is established across mito membrane, that proton gradient ____ energy that is then used by _____ Factor( F-type ATPase) to make ___

A

stores, coupling, atp

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46
Q

in summary what are the 4 steps of oxidative metabolism

A
  1. electrons move down free energy through the e.t.c to O2
  2. O2 is reduced to H2O
  3. establish proton gradient
  4. gradient stores energy then is used up by F-type ATPase to make ATP
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47
Q

where is the electron transport chain

A

the inner mitochondrial membrane

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48
Q

what does the etc do

A

sets up proton gradient for chemiosmotic ATP synthesis

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49
Q

activated carriers generated during the citric acid cycle power the production of

A

atp

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50
Q

what are the four separate compartments of the mitochondrion

A

matrix, outer membrane, inner membrane, and the folds

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51
Q

where are porins present in the mitochondria

A

the outer membrane

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52
Q

inner mito membrane and cristae

A

curved folded surface (cristae) -high surface area
protein; lipid ratio high

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53
Q

what is cardiolipin

A

lipid unique to mitochondria- relates to lipid composition, low sterols, high PE

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54
Q

cardiolipid is ___ weight percent of inner mito membrane lipids

A

20

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55
Q

what may enable high curvature of cristae

A

cardiolipin - may trigger apoptosis

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56
Q

what is the mitochondrial matrix

A

innermost space, protein rich solution
enzymes fro citric acid cycle, b-oxidation

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57
Q

intermembrane space

A

between intermembrane mito membrane and outer
-continuous with cytosol via porins

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58
Q

intracristal space

A

within tubules and folds of cristae
-where H+ accumulates during electron transport
-limited connection to intermembrane space

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59
Q

where does oxidative phosphorylation occur

A

cristae membrane of eukaryotes
plasma mebrane of aerobic prokes

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60
Q

5 steps of oxidative phosphorylation

A
  1. e.t.c lets electrons flow down gradient from NADH to FADH2 to O2
  2. electron transport is coupled to the active transport of H+ out of the matrix to intracristal space
  3. proton gradient across cristal membrane stores potential energy
  4. energy released, protons diffused back into matrix
  5. energy can be used to fuel ATP synthesis when protons move through FoF1 coupling complex in cristae
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61
Q

electron carriers are _____, mostly attached to ____ membrane proteins in respiratory complexes

A

cofactors, integral

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62
Q

what is an example of an integral membrane protein

A

cytochrome c

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63
Q

coenzyme Q -lipid soluble electron carrier can be found where

A

in core of cristal membrane

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64
Q

what are respiratory complexes

A

groups of integral membrane proteins with attached cofactors

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65
Q

high energy electrons are transferred through ___ respiratory enzyme complexes in the ____ mitochondrial membrane

A

3, inner

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66
Q

each complex is doing what by pumping protons

A

work- active transport

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67
Q

what are the 2 major entry points of the three respiratory complexes and what are the names

A

complex 1- NADH dehydrogenase complex
complex 2- cytochrome c reductase

68
Q

what is the major endpoint in oxidative phosphorylation

A

complex 4- cytochrome c oxidase

69
Q

what does complex 2 not do

A

pump protons, not much work being done, succinate FADH not NADH

70
Q

what is bound to complex 2

A

FADH- succinate in

71
Q

electrons move ___ redox potential gradient but ____ free energy gradient

A

up, down

72
Q

all complexes feed to what

A

coenzyme Q

73
Q

oxidative metabolism- endergonic or exergonic

A

exergonic

74
Q

electron carriers - nucleotide based

A

NADH/NAD+ water soluble, carries e- to e.t.c
FAD/FADH
FMN/FMNH2 -bound to flavoproteins

75
Q

what are cytochromes and what complexes

A

proteins with a heme prosthetic group
complexes 3 and 4

76
Q

how do hemes differ from one another

A

by side groups- makes different cytochromes

77
Q

one cytochrome will be a _____ protein others are all parts of _____ membrane proteins

A

peripheral, integral

78
Q

where does redox occur in cytochromes

A

Fe ion, alternating between +2 and +3 states

79
Q

what are the most common protein bound carriers in mito e.t.c

A

Fe-S centers

80
Q

other examples of carriers in oxidative phosphorylation

A

Cu centers and Cu cytochromes
-alternating between +1 and +2 states
Cu center- aa side chains
cytochrome-has Cu and Fe in heme

81
Q

what is the last example of a carrier in oxidative phosphorylation

A

quinones; ubiquinone,, coenzyme Q
Lipid soluble- isprenoid chain
can diffuse across 1,2,and 3

82
Q

where does coenzyme Q carry electrons from in the complexes

A

from complex 1 and 2 to complex 3

83
Q

where does coenzyme Q carry protons from

A

across the inner mito membrane from matrix to intercristal space

84
Q

electrons move from ____ to carrier, always moving to a ____ with a higher ____ potential (greater ____ for e-)

A

carrier, carrier, redox, affinity
-downhill towards O2

85
Q

what if there is no oxygen to accept in oxidative phosphorylation

A

whole system will become reduced

86
Q

how do electrons flow when talking about numbers- redox potentials

A

smallest to biggest
negative to positive

87
Q

does NADH or FADH pump more protons to O2

A

NADH- 10
FADH-6

88
Q

protons are pumped out of matrix in which complexes

A

1,3,4

89
Q

what does the proton gradient across the inter mito membrane depend on

A

membrane potential and pH gradient -proton motive froce pulls H+ back into matrix

90
Q

atp synthase acts like a ____ to convert the ____ of protons flowing ____ their free energy gradient to ____ bond atp

A

motor, energy, down, chemically

91
Q

characteristics of F1 knob

A

has 3a and 3b subunits
sticking outside-big
3b subunits have active sites with atpase activity

92
Q

characteristics of Fo knob

A

integral to membrane
“a” subunit is stationary, passes H+ across inner mito membrane
10 “c” subunits form rotating ring next to “a”

93
Q

conformational changes and atp synthase in F1 are driven by what

A

H+ flux through Fo

94
Q

uncoupling atp synthesis from H+ flux and electron transport characteristics

A
  1. energy released as heat
  2. occurs when proteins move through uncoupling proteins or cross membrane liked to chemical
  3. can occur if electron transport does nit set up proton gradient
95
Q

cytoskeleton consists of ___ throughout cell
what do these do?

A

protein fibers
give form strength, and help in movement

96
Q

what are the 3 types of protein fibers

A

microfilaments, microtubules, and intermediate filaments

97
Q

diameter of each of the protein fibers

A

microfilaments- 7nm
microtubules- 25nm
intermediate filaments- 8-12nm

98
Q

intermediate filaments characteristics

A

hold cell together in pictures
provide mechanical strength to cells and tissues
mostly in animals

99
Q

intermediate filaments _____ cells against _____ stress

A

strengthen, mechanical

100
Q

what is the intermediate filament structure made of

A

“ropes” made of long, twisted fibrous proteins
alpha helix
twist=strength
-hydrogen bonds

101
Q

microtubules are _____ tubes with structurally ____ ends

A

hollow, distinct

102
Q

the ____ is the major microtubule-_____ center in animal cell

A

centrosome, organizing

103
Q

mictrotubules display _____ instability

A

dynamic

104
Q

dynamic instability is driven by ____ hydrolysis

A

GTP

105
Q

microtubule _____ can be _____ by drugs

A

dynamics, modified

106
Q

motor proteins drive _______ transport

A

intracellular

107
Q

what are the motor proteins in microtubules and microfilaments

A

microtubules- kinesin and dynein
micofilaments- myosin

108
Q

______ and motor proteins _____ organelles in the ____

A

microtubules, position, cytoplasm

109
Q

_____ and flagella contain stable ____ moved by ____

A

cillia, microtubules, dynein

110
Q

microtubules polymers of protein is called

A

tubulin

111
Q

cytoplasmic microtubules or intracellular

A

mitotic spindle
vesicle trafficking - walking traffic pattern in the endomembrane system

112
Q

why are cytoplasmic microtubules important

A

help organize and maintain cell structure

113
Q

structure of cytoplasmic and axonemal microtubules

A

axonemal- highly structured -doublet ring- cilia and flagella-causes movement
cytoplasmic- loosely organized and dynamic

114
Q

tubulin is a family of

A

globular proteins

115
Q

eahc tubulin is about how many amino acids

A

450

116
Q

profilaments are polymers of ___-tubulin heterodimers which causes _____ in microtubules

A

ab
polarity

117
Q

how many protofilaments form tubule

A

about 13

118
Q

where is the microtubule organizing center aka site where most microtubules initiate polymerization

A

basal bodies or centrosomes

119
Q

where are centrosomes located in animal cells

A

near nucleus

120
Q

what is y-tubulin

A

rings of this isoform are only found in centrosomes
anchor minus end of microtubule

121
Q

centrosomes contain 2 _____ and rings of _____

A

centrioles
y tubulin

122
Q

what are basal bodies

A

organize axonemal microtubules of cilia and flagella

123
Q

the centriole _____ microtubule doublets that form _____. This is located at ______ membrane

A

nucleates, axoneme, plamsa

124
Q

microtubules that constantly assemble and disassemble is called what

A

dynamic instability

125
Q

what drives dynamic instability

A

GTP

126
Q

steps of polymerization/dynamic instability

A
  1. GTP binds to each subunit of heterodimer
  2. GTP on B-tubulin is hydrolyzed to GDP
  3. GTP- tubulin stabilizes microtubule-polymerization
  4. GDP-tubulin destabilizes microtubule-depolymerization
  5. when rate of GTP hydrolysis exceeds rate of dimer addition, microtubules rapidly depolymerize
127
Q

what are the motor microtubule proteins

A

kinesin and dynein

128
Q

what do the non motor MAPs do

A

some stabilize microtubules
some promote polymerization
some cross link and bundle microtubules

129
Q

what are the ways that microtubules are involved in motility

A

intracellular vesicle trafficking
cilia and flagella
spindle formation and mitotic division of chromosomes

130
Q

intracellular motility is mediated by what

A

motor proteins
-in microtubules kinesin and dynein
in microfilaments- myosin

131
Q

organelles and vesicles attach to ____ protein and are ___ along microtubule

A

motor, walked

132
Q

what motor proteins are on each end of the microtubule

A

kinesin is on plus end
dynein on minus end

133
Q

what is kinesin important for

A

the binding and hydrolysis of ATP

134
Q

what are cilia and flagella and what do they use to cause motion

A

extensions of cell that beat to move cell
dynein (no kinesin)

135
Q

size difference in cilia and flagella

A

cilia -5-25 micrometers long
flagella- 50-75 micrometers long

136
Q

what is primary cilia

A

used in sensory structures, important during development- non motile

137
Q

what is a axoneme

A

core of cilium -9+2 arrangement of microtubules
2= singlet microtubules
primary cilia lack central pair

138
Q

dynein crawls along ______ and makes microtubules ____ along each other to cause ____ of cilia and flagella

A

microtubule, slide, beating

139
Q

what is the mitotic spindle

A

separates chromosomes during mitosis, formed of microtubules

140
Q

mitotic spindle steps

A
  1. organize chromatids. separate during mitosis
  2. centrosome is duplicated prior to mitosis
  3. centrosomes separate at start of prophase, opposite sides of nucleus
  4. centrosomes nucleate the formation of mitotic spindle as prophase begins
  5. cytoplasmic microtubules mostly depolymerize
141
Q

what is the kinetochore

A

binds spindle microtubules, link them to chromosomes

142
Q

many proteins bind to ____ and modify its properties

A

actin

143
Q

actin and ____ polymerize by similar mechanisms

A

tubulin

144
Q

cell crawling depends on what

A

cortical actin -actin and myosin working together pushing and pulling

145
Q

actin-binding proteins ____ the type of _____ formed at the leading ____

A

influence, protrusions, edge

146
Q

a cortex rich in ____ microfilaments underlies the ____ membrane of most eukaryotic cells

A

actin, plasma

147
Q

extracellular signals can ____ the arrangement of ____ microfilaments

A

alter, actin

148
Q

microfilaments are polymers of protein called what

A

actin

149
Q

types of movements in microfilaments

A

cell crawling, amoeboid motion
muscle contraction
cleavage furrow -animal cells

150
Q

cell shape and structure of microfilaments

A

cell cortex= dense network of microfilaments below plasma membrane
microvilli core is bundle of actin microfilaments

151
Q

actin microfilaments ____ animal cells to ____ a variety of shapes and _____ a variety of function

A

allow, adopt, perform

152
Q

microfilaments have binding sites for

A

atp/adp
myosin
other proteins

153
Q

polymerization in microfilaments

A
  1. pool of actin monomers in cytosol polymerize to form actin filaments
  2. polarity- plus end polymerizes more quickly
154
Q

actin monomers mus bind ____ to polymerize

A

ATP

155
Q

in microfilaments ____ is hydrolyzed after actin _____

A

ATP, polymerization

156
Q

actin binding proteins control the ___ of actin filaments

A

behavior

157
Q

what does the dense cortex beneath the plasma membrane that microfilaments form contain

A

actin and myosin
can change shape using contractile forces
generates motile surface projections

158
Q

what movement does myosin cause in microfilaments

A

-muscle contraction
-cytoplasmic streaming
-amoeboid motion
-cytokinesis

159
Q

what does myosin require

A

ATP

160
Q

the extracellular matrix is the structure ____ cells, to which cells ____, that gives form and _____ to tissues and ____

A

surrounding, adhere, function, organs

161
Q

function of extracellular matrix

A

support -strength
regulation of development -cell division
physical barriers to movement of molecules,cells, and pathogens- filter

162
Q

extracellular matrices have ____ fibrous molecules in a ____ of cushioning ____

A

strong, network, molecules

163
Q

animals versus plants extracellular matrices

A

animals - fibers of collagen(main structural protein) in a network of proteoglycans
-proteins and polysachharides
plants- fibers of cellulose (or elastin) in a network of pectin
-both polysachharides

164
Q

what is cellulose

A

beta 1-4 linked glucose polymer

165
Q
A

cell biology (4 decks)

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