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exam 3 Flashcards

1
Q

in order for multicellular organisms to communicate you need _______ cell and a _______ cell

A

signaling

target

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2
Q

target cells need _____ proteins to detect the signal

A

receptor

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3
Q

the extracellular signal is converted into a intracellular signal, which is a process known as ____________

A

transduction

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4
Q

_______ has a variety of functions, depending on the cell that receives the signal

A

acetylcholine

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5
Q

intracellular signal molecules generally influence transcription and bind to a member of the nuclear receptor ______________

A

superfamily

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6
Q

these relays involve ___________ signaling pathways, that can operate in the following ways

A

intracellular

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7
Q

_______ of these proteins is typically done by phosphorylation, while ______ is typically done by dephosphorylation

A

activation

deactivation

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8
Q

Many pathways involve several kinases activating the next kinase in the pathway, which activates the next kinase; these are referred to as phosphorylation ______

A

cascades

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9
Q

CPCRs span the plasma membrane back and forth ___ times

A

7

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10
Q

the α subunit has an affinity for ____ when it is ______

A

GDP

inactive

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11
Q

when a signal molecule binds to the GPCR, it causes the αsubunit to exchange the GDP for a _____ (it is now ________)

A

GTP

active

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12
Q

eventually, the α subunit will _______ its GTP to GDP, which will ‘turn off’ the system and restore the G protein to its inactive state

A

hydrolyze

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13
Q

the response of skeletal muscle to __________ is an excellent example of a cAMP pathway

A

adrenaline

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14
Q

________ filaments have a diameter between that of microtubules and actin

A

intermediate

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15
Q

the main purpose of these filaments is to provide _____ strength, which prevents the overstretching of cells

A

tensile

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16
Q

eight of these tetramer ropes come together to form a

single filament, which is made up of a total of __ subunits

A

32

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17
Q

Because of the α and β arrangements of the tubulin subunits, the microtubules have _____ (the α being the - negative end, and the β being the + positive end).

A

polarity

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18
Q

microtubules show _________ instability

A

dynamic

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19
Q

growing microtubules end up with a ‘GTP ____’

A

cap

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20
Q

__________ proteins can help anchor microtubules onto the plasma membrane

A

capping

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21
Q

______ proteins help direct movement in the cell

A

motor

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22
Q

they use the energy of ____ to drive their incremental movement along filaments

A

ATP

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23
Q

there are many other actin-binding proteins that help control the behavior of actin filaments, including capping proteins (prevent depolymerization) and ____________ proteins (provide a starting point for filament growth)

A

nucleating

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24
Q

“cell crawling” is mediated by _______ filaments, where the extending protrusions are driven by actin polymerization at the cell surface (i.e. the growth of actin filaments ‘pushes’ out a cellular protrusion)

A

actin

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25
Common protrusions driven by actin are ______ ("false feet") of amoebas
pseudopods
26
myosin involved in muscle contraction belongs to the ___________ subfamily
myosin-II
27
myosin-II molecules are _________ of myosin molecules, with each dimer having two heads and a rod-like tail
dimers
28
bundles of actin and myosin filaments can therefore generate a _____________ force seen in muscle cells
contractile
29
muscle fibers are made of several __________, which are composed of contractile units called ____________
myofibrils | sarcomeres
30
when a muscle cell is excited via T _________, Ca2+ is released from the sarcoplasmic reticulum (modified ER)
tubules
31
in the absence of Ca2+, a rod-shaped protein filament called ______________ blocks the actin/myosin binding sites, which prevents muscle contraction
tropomyosin
32
when Ca2+ is available, it binds to _____________, which in turn shifts the position of tropomyosin to expose the actin binding sites
troponin
33
the remaining three phases (G1, S and G2) together are referred to as ____________
interphase
34
the G phases are also times for important ___________
checkpoints
35
if the G1 conditions are not met, the cell enters into a specialized __________ phase known as G0, which can last for the lifetime of the cell in some cases
resting
36
__________ can arise from G1 misregulation - where cells divide without any checks and balances
cancer
37
studying the cell cycle control system has occurred with ________ primarily since the proteins involved are highly conserved in all eukaryotic organisms
yeast
38
proteins called ________ activate enzymes known as cyclin-dependent protein kinases (CDKs) by forming complexes
cyclins
39
cyclin-CDK is inactive until it is finally turned on by a _______________ (i.e. it is turned on by the loss of a -PO4)
phosphatase
40
the concentration of a cyclin depends on ___________
proteolysis
41
when cyclins reach a certain level, they are tagged with __________, which sends them to the proteasome
ubiquitin
42
at the end of M phase, the cell is split in two in a process known as ___________
cytokinesis
43
cleavage begins with a ____________ furrow (near the end of anaphase) perpendicular to the axis of the mitotic spindle
cleavage
44
variations in the position of the mitotic spindle can create ____________ division (important for embryogenesis)
asymmetric
45
a ______________ ring composed of actin and myosin filaments causes the contraction (the same proteins that allow muscle contraction)
contractile
46
a _________________ structure is formed, which attracts Golgi vesicles full of polysaccharides and glycoproteins (young cell wall components)
phragmoplast
47
___________ ("rebar" made of glucose strands) and _________ (polyphenolic "glue") are added to complete the new cell wall
cellulose | lignin
48
programmed cell death is known as ________________
apoptosis
49
cells that die from injury is called ___________
necrosis
50
the cell surface is also changed to attract ________________, which engulf the cell before it bursts open
macrophages
51
during apoptosis, enzymes called ____________ initiate an irreversible pathway of cell death (once it starts it can't be undone)
caspases
52
growth and division of cells of multicellular organisms rely on __________ proteins
signal
53
____________ factors act by binding to cell-surface receptors, which then regulate the Bcl2 family of proteins
survival
54
____________ act by cell-surface receptors, which initiate pathways that lead to release of "molecular brakes" that prevent cells from entering S phase from G1 phase
mitogens
55
well-known mitogen is platelet-derived growth factor(PDGF), which is released from ____________ at the site of a wound; PDGF then stimulates cell proliferation of surviving cells at the wound site, which leads to healing
platelets
56
when the liver is injured or wounded, _____________ growth factor helps to promote cell division among the surviving liver cells
hepatocyte
57
__________ factors operate through cell-surface receptors and stimulate pathways that lead to increased protein production and/or decreased protein degradation
growth
58
__________ is an example of signal proteins that prevent cell growth
myostatin
59
there are two main stages involved in generating chemical energy via membranes (called _______________ coupling)
chemiosmotic
60
with mitochondria, a single glucose molecule produces __ ATP
36
61
the _______ membrane contains transport proteins called ________ that allow relatively small molecules (5 kDa or less) to pass through easily
outer | porins
62
the ________ membrane is less permeable, and contains ATP synthase and the proteins required for the electron transport chain; it is also convoluted, forming infolds called ____________ that help to increase the surface area within the mitochondria
inner | cristae
63
the _________ is the large internal space of the mitochondria that is bordered by the inner membrane
matrix
64
the _______________ space is the space between the inner and outer membrane
intermembrane
65
the space contained by the inner membrane is called the _________
stroma
66
these enzymes are found in the _____________ membrane of disc-like sacs called thylakoids, that exist in stacks called ________
thylakoid | grana
67
chloroplasts contain multi-protein complexes called ________________ embedded in the thylakoid membrane
photosystems
68
the antenna complex contains hundreds of _______________ and other pigment molecules that are able to funnel energy toward the reaction center
chlorophyll
69
when a special chlorophyll molecule (_______) in the reaction center of photosystem II (PSII) is excited by energy from
P680
70
the electron is then replaced by the oxidative splitting (____________) of a water molecule, which also generates O2
photolysis
71
these protons are then pumped across the thylakoid membrane by ATP synthases, which generate ATP in the stroma in a process known as __________________________
photophosphorylation
72
The special chlorophyll (_______) of photosystem I (PSI) also absorbs light energy and loses an electron in the same way as photosystem II
P700
73
the ATP and NADPH produced from the light reactions are used for carbon __________
fixation
74
the most important enzyme in the Calvin cycle is ___________
Rubisco
75
breaking down compounds is referred to as _____________
catabolism
76
______________ ("sugar splitting") occurs in the cytoplasm of cells and does not require oxygen
glycolysis
77
for each glucose consumed, two ATP are consumed and four are produced - resulting in a net gain of _ ATP
2
78
his production of ATP without the mitochondria is known as ___________-level phosphorylation
substrate
79
after glycolysis, pyruvate enters the _______________ where it is converted to acetyl CoA
mitochondria
80
a process called _____________ involves the production of more complex molecules from simple ones
anabolism
81
notice how glycolysis and the citric acid cycle are central to ___________________
metabolism
82
what are the 2 processes that use actin and myosin to generate a contractile force
Muscle contraction | Cytokinesis
83
What are the different strategies between a plant and animal cell for cytokinesis?
plant walls are rigid whereas animal cells are squishy
84
What is the difference between apoptosis and necrosis?
Apoptosis is a planned and organized cell death | Necrosis is a unplanned and messy cell death
85
what are the 2 main types of receptors?
cell-surface receptors | intracellular receptors
86
What are the 2 common enzymes targeted by G-protein subunits?
Adenylyl cyclase | Phospholipase C
87
What are the 2 main types of motor proteins that move along microtubules?
Kinesins (move away from the organizing center) toward positive end Dynein's (move toward the organizing center) toward the negative end
88
Give 2 ways actin and microtubules are similar
both have polarity | both made of subunits
89
Give 2 ways actin and microtubules are different
microtubules are hollow actin is not hollow | actin uses ATP to grow microtubules use GTP to grow
90
What are 2 ways mitochondria and chloroplasts are the same
Both have inner membrane | Both have outer membrane
91
What are 2 ways mitochondria and chloroplasts are different
Chloroplasts have 3 membranes while mitochondria only have 2 | Chloroplast membranes are much larger than mitochondria
92
What are the 3 main types of phosphorylation
Oxidative Photo phosphorylation substrate level

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