cell bio final Flashcards

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1
Q

only _______ actin is expressed in muscle cells

A

alpha

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2
Q

what are the three mechanisms of active transport?

A
  1. coupled transport
  2. ATP pumps
  3. light/redox reactions
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3
Q

where does the final shape of collagen happen

A

outside the cell

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4
Q

what kind of membranes do autophagosomes have?

A

double membranes

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5
Q

a two headed phospholipid exclusively present in the mitochondrial membranes. It is found in many bacterial membranes.

A

cardiolipin

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6
Q

kinesin walks towards which end of microtubules

A

plus end

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7
Q

two functions of integrins

A

adhesion (cell to ECM linkage) and signalling

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8
Q

what are the three phases of actin polymerization (ACTIN GROWTH/formation)

A
  1. nucleation/lag phase
  2. elongation/growth phase
  3. steady state/equilibrium phase
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9
Q

enzymes activated by extracellular signals to cleave specific phospholipids to release short- lived intracellular messages (aka second messengers)

A

phospholipases

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10
Q

how is mitochondrial DNA inherited

A

from mother to child

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11
Q

what do cilia and flagella contain (2)

A

dynein (motor protein) and microtubules

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12
Q

highly polar and negatively charged, has a strong tendency in attracting water molecules that give the matrix a gel-like composition

A

GAGs

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13
Q

what are cell junctions

A

cell - cell interations!

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14
Q

what are the three protein extraction methods?

A
  1. detergent based lysis
  2. osmotic shock
  3. changes in pH
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15
Q

connects actin filament bundle in one cell with that in the next one

A

adherens junction

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16
Q

what is the largest GAG

A

hyaluronic acid

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17
Q

movement of substances across the membrane using energy

A

active transport

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18
Q

cell eating

A

phagocytosis

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19
Q

nucleates microtubule branching

A

augmin

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20
Q

chemical bond forming reactions that generate ATP and membrane transport processes

A

chemiosmotic coupling

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21
Q

describes the structure of the plasma membrane as a mosaic of components including phospholipids, cholesterol, proteins, and carbohydrates

A

fluid mosaic model

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22
Q

what are the soluble subunits of intermediate filaments

A

dimers and tetramers

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23
Q

major sterol found in animal cells

A

Cholesterol

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24
Q

what links cells with the ECM

A

inegrins (proteins)

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25
Q

during apoptosis PS is externalized to the outer leaflet by

A

scramblases

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26
Q

where are microtubules nucleated

A

microtubule organizing center (MTOC)

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27
Q

how does collagen formation start

A

with a triple helix molecule (3 molecules of collagen form homo or heterotrimers)

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28
Q

what are cytoskeletal filaments made of

A

big picture: large helical insoluble filaments
zoom in: each filament is made of soluble monomers

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29
Q

The inner mitochondria membrane forms numerous folds which extend into the interior of the organelle, what are the folds called

A

cristae

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30
Q

are actin-based motor proteins that generates force by coupling ATP hydrolysis to conformational changes

A

Myosin proteins

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31
Q

what pump uses ATP hydrolysis to drive H + transport

A

V-type pump

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32
Q

the y tubulin ring complex in microtubules is similar to what in actin filaments

A

Arp2/3 complex (both nucleation complexes)

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33
Q

how can we visualize actin cytoskeleton in vivo?

A

incorporating fluorescently labeled actin
ex. staining F-actin in vivo with SiR- Actin, a cell-permeable noncytotoxic compound

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34
Q

yellow or orange pigments

A

carotenoids

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35
Q

anchors actin filaments in cell to extracellular matrix

A

focal adhesions/actin-linked cell matrix junction

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36
Q

Anchors intermediate filaments in cell to extracellular matrix

A

hemidesmosome

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37
Q

cell crawling relies on the

A

actin cytoskeleton

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38
Q

cell migration in response to soluble factors (concentration gradients of extracellular signals)

A

chemotaxis

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39
Q

why does the matrix have a slightly higher pH than the cytosol

A

cristae traps the proton because of its shape, this lets the protons stay close to the ATP synthase and makes synthesis of ATP more effective

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40
Q

encloses the matrix and contains all the protein complexes involved in the electron transport chain and the ATP synthase

A

inner mitochondrial membrane

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41
Q

cell drinking

A

pinocytosis

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42
Q

where photosynthesis and the synthesis of ATP takes place

A

Thylakoid membrane

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43
Q

WHO use the energy stored in concentration gradients to couple the uphill transport of one solute across the membrane to the downhill transport of another

A

couple transporters

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44
Q

channels only use what kind of transport

A

passive transport

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45
Q

Four ways of immobilizing specific membrane proteins through protein-protein interactions

A
  1. By forming large self-assembled protein aggregates
  2. By tethering(restricting) them to macromolecular assemblies outside the cell
  3. By tethering(restricting) them to macromolecular assemblies inside the cell
  4. By interacting with proteins on the surface of another cell
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46
Q

actin-based structures that act as platforms for the localized release of lytic enzymes that degrade the extracellular matrix (matrix degrading structures)

A

podosomes and invadopodia

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47
Q

which mitochondrial membrane contains B barrel proteins

A

outer mitochondrial

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48
Q

virus that uses dynein (and dynactin) and microtubules only

A

influenza

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49
Q

what are the three functions of accessory proteins in the cell cytoskeleton?

A
  1. assembly and disassembly of filaments
  2. link filaments to cells structures and between each other
  3. act as a bridge between the cytoskeleton and intra/extracellular signals
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50
Q

dynein walks towards which end of microtubules

A

minus end

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51
Q

movement of substances across the membrane without the expenditure of cellular energy

A

passive transport

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52
Q

why does the inner mitochondrial membrane have many pumps, channels and transporters

A

because it is almost impermeable, hard to cross

53
Q

the most abundant glycolipids, affect the electrical environment of the cell membrane

A

gangliosides

54
Q

intercellular adhesion complexes of claudin and occludin proteins that control paracellular permeability

A

tight junctions

55
Q

In most transmembrane proteins, the polypeptide chain crosses the lipid bilayer in an ________ conformation

A

a-helical

56
Q

a fungal toxin that binds and stabilizes F-actin and effectively prevents the depolymerization of actin fibers, toxic for the cell

A

phalloidin

57
Q

in microtubules at which ends are alpha and beta tubulins exposed

A

alpha : minus end
beta: plus end

58
Q

phospholipids have a _______ head and ______ tails, they are ___________

A

hydrophilic head (water loving head), polar
hydrophobic tails (water fearing tails), non-polar

they are amphiphilic

59
Q

bind to and stabilizes microtubules causing a net increase in tubulin polymerization

A

taxol

60
Q

name 4 parts of the basal lamina

A

proteoglycans, nidogen, collagen, laminin

61
Q

a phospholipid that interacts with proteins involved in oxidative phosphorylation and the transport of ATP, in cristae its disposition supports membrane curvature

A

cardiolipin

62
Q

what are the three major protein filaments in the cell cytoskeleton

A

actin filaments, microtubules, intermediary filaments

63
Q

what couples uphill transport to the hydrolysis of ATP

A

ATP-driven pumps

64
Q

connects intermediate filaments in one cell to those in the next

A

Desmosome

65
Q

Approximately 50% of the dry mass of the plasma membrane

A

membrane proteins (protein channels, globular protein, peripheral protein, glycoprotein, integral protein, surface protein, a-helix protin)

66
Q

Contains two central microtubules that are surrounded by an outer ring of nine doublet microtubules

A

axoneme (core of cilia and flagella)

67
Q

small and transient (short lived) regions of the plasma membrane (microdomains) enriches in cholesterol and sphingolipids

A

lipid rafts

68
Q

true or false
to study cell migration in the lab we use 2D models

A

false, we use 3D models

69
Q

the thylakoid membrane corresponds to what in the mitochondria

A

cristae

70
Q

The switch from polymerization to shrinkage is called a

A

Catastrophe

71
Q

what cytoskeltal filament is abundant in an animal cell nucleus

A

intermediate filaments

72
Q

what is the thickness of the plasma membrane

A

5 to 10 nm

73
Q

what is the function of the plasma membrane

A
  1. encloses the cell
  2. defines the cells boundaries
  3. maintains differences between cytosol and extracellular environment
  4. mediates cell signalling
  5. controls passage of molecules in and out of the cell
74
Q

the stroma is similar to what part of the mitochondira

A

matrix

75
Q

what technique can we use to detect PS on death cells

A

flow cytometry

76
Q

what is the core of cilia and flagella called?

A

axoneme

77
Q

from what did mitochondria and chloroplasts originate

A

bacteria

78
Q

the majorly of y tubulin ring complex is found where

A

cytoplasm (centrosome is in the cytoplasm)

79
Q

which photosystem takes out electrons from water

A

photosystem II

80
Q

binds to B tubulin and disrupts microtubule assembly/disassembly dynamics, depolarization agent

A

nocodazole

81
Q

the structure of the lipid bilayer is

A

asymmetric

82
Q

what is the major microtubule organizing centre in animal cells

A

centrosome

83
Q

The electrons used in carbon fixation by chloroplasts ultimately come from:

A

WATER

84
Q

what does cytochrome b6f complex do in ETC of photosynthesis

A

pumps protons into the thylakoid space

85
Q

can act as a bridge to connect ECM and cells

A

glycoproteins…fibronectin

86
Q

Does not provide cell anchorage but allows direct communication via specialized intercellular channels

A

gap junctions

87
Q

most common protein found in ECM

A

collagen, fibrous protein

88
Q

normally keep PS inside the cell

A

flippases

89
Q

where do the protons go from water in photosynthesis

A

released into the thylakoid space by water oxidation

90
Q

leaves become yellow: defects in chlorophyll produce is the most common viral symptoms

A

Chlorosis

91
Q

harness energy to drive force and movement

A

motor proteins

92
Q

has ADP/ATP carrier proteins that carriers ADP in and produced ATP out

A

inner mitochondrial membrane

93
Q

The switch from shrinkage to polymerization

A

rescue

94
Q

what macromolecules are founded in the ECM

A
  1. protoglycans and GAGs
  2. fibrous proteins
  3. glycoproteins
95
Q

what are the subunits for the filaments in the cell cytoskeleton?

A
  1. actin filaments: actin subunits
  2. microtubules: tubulin subunits
  3. intermediary filaments: elongated and fibrous subunits
96
Q

where is chlorophyll located

A

within the thylakoid membrane

97
Q

what is the most abundant negatively charged phospholipid in eukaryotic membranes

A

PS = phosphatidylserine

98
Q

true or false:
healthy and damaged mitochondria CANNOT co-exist

A

FALSE
healthy and damaged mitochondria can co-exist

99
Q

the places where food-derived molecules are converted into energy (ATP)

A

matrix and cristae

100
Q

uptake of large amounts of fluids and nutrients (it can also involve the uptake of big particles)

A

macropinocytosis

101
Q

accessory protein that nucleates assembly and remains associated with the growing plus end of actin

A

formin

102
Q

what is dynamin involved in

A
  1. endocytosis
  2. phagocytosis
  3. mitochondria fission
103
Q

what is the structure of microtubules

A

two globular proteins (alpha and beta) in the form of a heterodimer

104
Q

binds ADP actin filaments, accelerates disassembly

A

cofilin

105
Q

whats bigger mitochondria or chloroplasts?

A

chloroplasts

106
Q

Conversion of light energy into chemical energy: occurs entirely within the

A

thylakoid membrane

107
Q

why do many many proteins need to be imported into the mitochondria

A

the mitochondria contains less than of the proteins that the mitochondria needs to funciton

108
Q

a rare inherited blood disease due to a group of metabolic disorders of the heme biosynthetic pathway (altered enzymatic activity)

A

Porphyria

109
Q

Cell migration depends on the

A

actin cortex

110
Q

thin membranous cytoplasmic protrusions to sample the extracellular environment

A

Filopodia

111
Q

how are anthocyanins formed

A

reaction between sugar and proteins in cell sap!
- sugar concentration must be high and it is since temperatures are cooled and this causes leaf veins to close, and sugars are stuck

112
Q

accessory protein that nucleates assembly to form a branches network and remains associated with the minus end of actin filaments

A

Arp/2/3 complex

113
Q

The removal of bad or damaged mitochondria by autophagy

A

mitophagy

114
Q

what at the cell cortex determines cell shape

A

actin

115
Q

stabilize microtubules by binding along sides

A

MAPs

116
Q

Play critical roles in cell recognition and help maintain the stability of the plasma membrane

A

glycolipids

117
Q

a hollow cylindrical structure built from 13 parallel protofilaments, each composed of alpha-beta tubulin heterodimers

A

microtubule

118
Q

at low concentrations it stops the growth of microtubules, while at high concentrations it promotes their depolarization

A

colchicine

119
Q

what three stimuli can open ion channels?

A
  1. Voltage gated: change in voltage
  2. Ligand gated:binding to extracellular or intracellular ligands
  3. mechanically gates: mechanical stress
120
Q

virus that uses dynein, kinesin, and microtubules

A

herpes

121
Q

what kind of charged molecules are favoured into the cell

A

positively charged molecules

WHY? because inner leaflet is negatively charged

122
Q

nucleates assembly and remains associated with the minus end of microtubules

A

y-TuRC

123
Q

is the carbohydrate-rich zone on the cell surface that protects the membrane from the harsh and dynamic microenvironment that could damage the lipids and proteins

A

glycocalyx

124
Q

building polymers from smaller parts called monomer

A

polymerization

125
Q

flat and wide cytoplasmic protrusions at the periphery of a migrating cell
- Protrusions are enriched with a branches network of actin filaments

A

lamellipodia

126
Q

involved in muscle contraction

A

myosin II

127
Q

what are the two main classes of membrane transport proteins

A

transporters and channels

128
Q

the principal sites
of intracellular digestion

A

lysosomes

129
Q
A