Exam 1: Cell Flashcards

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1
Q

3 Cellular consituents

A

Organelles
Inclusions
Cytoplasmic matrix (cytosol)

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2
Q

Cytoplasm

A

part of cell external to nucleus

suspends organelles and inclusions

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3
Q

Cytoplasmic matrix (cytosol)

A

cytoplasm devoid of organelles and inclusions

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4
Q

Inclusions

A

nonliving entities found in cytoplasm and nucleus

Stored food, pigments, and crystalline not bound by membrane

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5
Q

Stored foods

A

Glycogen - abundent in liver and skeletal and cardiac muscle cells
Lipid droplets - found in adipocytes, hepatocytes, muscle, and steroid secreting cells

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6
Q

Glycogen demonstrated by

A

PAS reaction

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7
Q

McArdle disease

A

genetic defect in skeletal muscle phosphorylase
Accumulations of glycogen under sarcolemma
Cramping, exercise intolerance, elevated myoglobin, creatine kinase elevated, venous lactate level does not increase with exercise

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8
Q

Exogenous Pigments

A

Carotene - yellow orange color
Carbon particles
Tattoo pigments - stored in macrophages of dermis

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9
Q

Anthracosis

A

accumulation of carbon particles in lungs and regional lymph nodes
Harmless

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10
Q

Endogenous pigments

A
Hemoglobin - cyanosis and myoglobin
Hemosiderin
Bilirubin
Melanin
Lipofuscin
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11
Q

Hemosiderin

A

Iron containing pigment
brown
spleen & liver
Hemosiderosis & Hemochromatosis - accumulation of iron

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12
Q

Melanin

A

Eumelanin - brown/black found in epidermis
Neuromelanin - found in neurons - substantia nigra
Parkinson’s disease depigmentation
Phaemelanin - red pigment of skin/hair

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13
Q

Plasmalemma (plasma membrane)

A
separates internal and external environment
lipid bilayer (contains phospholipids, glycolipids, cholesterol)
Cholesterol strengthens bilayer
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14
Q

Lipid rafts

A

areas in membrane where sphingolipids and cholesterol concentrated
Thicker
involved in cell signaling

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15
Q

simvastatin

A

cholesterol inhibitor that induces apoptosis by reduction in raft formation
down regulates cell survival signaling molecule, Akt

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16
Q

Integral proteins

A

some partially embedded, other extend across entire plasma membrane

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17
Q

Creutzfeldt-Jakob disease

A

normal prion protein is converted to abnormal variant.

Forms cross-linked filaments - resistant to proteolysis

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18
Q

Functions of proteins

A

Receptors, transporters, enzymatic control of chemical rxns, linker protein for structural support, cellular identification tags, anchor cell to extracellular matrix, intercellular junctional complexes

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19
Q

Carrier transport proteins

A

transport one or more chemicals in one direction or two chemicals in opposite direction without direct expenditure of energy

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20
Q

Pump transport proteins

A

require direct expenditure of energy

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21
Q

Na/K pump

A

cleaves ATP to transport 3 Na ions out of cell and 2 K ions into cell
regulate intracellular volume

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22
Q

Digoxin

A

partially inhibits Na/K pump

decrease in Ca/Na transporter = increase in sarcoplasmic Ca ion concentrations - improves cardiac pump performance

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23
Q

Na/K pump and cotransport of glucose and Na

A

secondary active transport
Na and glucose enter cell as Na moves down its concentration gradient
To maintain gradient Na is pumped out of cell by Na/K pump

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24
Q

Multidrug resistant transporters

A

primary transporter proteins that are ATPases
MDR-1 expressed in kidney, intestine, liver, and blood-brain barrier - Transports drugs
Overexpression can cause cancer cells to become resistant to cytotoxic drugs
MDR-2 transports conjugated bilirubin
MDR-3 expressed in liver, flippase of phosphatidylcholine

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25
Q

Pores

A

Aquaporins - channels for water

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26
Q

Vesopressin

A

causes translocation of aquaporin receptors to plasma membrane of collecting tubule cells

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27
Q

Dystrophin

A

provides structural ingetrigy
link plasma membrane to underlying cytoskeleton
brown ring

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28
Q

Role of carbohydrates in membrane

A

attach to lipids and proteins forming glycolipids and glycoproteins, net negative charge repels other negatively charged substances, react with regulatory molecules, play role in cell to cell and cell to matrix recognition, protection

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29
Q

Glycolipids

A

exclusively on noncytosolic lipid monolayer

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30
Q

Endocytosis

A

transport into cell

energy ATP and Ca required

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31
Q

Macropinocytosis

A

Actin-based, nonspecific ingestion

occurs in thyroid cells as they take up thyroglobulin and dendritic cells for immune surveillance

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32
Q

Clathrin-mediated endocytosis

A

occurs in clathrin coated pits
Dynamin (GTPase) is required to pinch of vesicle
receptor mediated - cholesterol, protein hormones

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33
Q

Phagocytosis

A
ingestion of large particles (cell eating)
mediated by receptors
dependent on actin
Phagosomes
fuse with lysosomes
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34
Q

Exocytosis (bulk secretion)

A

secretion of cellular synthetic products with secretory vesicles

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35
Q

Secretory vesicles

A

formed in Golgi complex
fuse with plasma membrane
intracellular trafficking orchestrated by COPs

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36
Q

Consitutive exocytosis

A

continuous secretory process

secretory product not stored in secretory granules

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37
Q

Regulated exocytosis

A

secretory product stored in secretory vesicles until signal causes product to be secreted

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38
Q

Porocytosis

A

quantal release of neurotransmitters

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39
Q

Ribosome

A

basophilic
small electron dense particles
subunits exported from nucleus to cytoplasm where assemeble when actively synthesizing proteins

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40
Q

Polyribosomes free in cytoplasm

A

create proteins to be used in cell

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41
Q

Polyriosomes attached to endoplasmic reticulum

A

create proteins to be secreted

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42
Q

rER

A

membranous organelle, basophilic

continuous with outer membrane of nuclear envelope

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43
Q

ER stress

A

accumulation of unfolded/misfolded proteins in ER cisterna
Chaperone synthesis increases, decreased protein synthesis, caspases activated, misfolded proteins tagged for degradation

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44
Q

Targeting signals

A

sequences of amino acids in protein

direct proteins to their target compartments by binding to receptors specific for the organelles

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45
Q

sER

A
lacks polyribosomes
acidophilic
continuous with rER
Cisternae more tubular
Cholesterol homeostasis, steroid synthesis, phospholipid synthesis, detoxification of drugs, storage & release of Ca in muscle
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46
Q

van Gierke disease

A

defect in glucose 6 phosphatase or transporter; sER unable to transport glycogen - glycogen accumulation in cytoplasm and nucleus
liver enlargement, hypoglycemia, increased lactate

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47
Q

Cholera toxin gains entry into the cell by using

A

a glycolipid

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48
Q

Non-coated mediated endocytosis

A

Cholera and Shiga toxins

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49
Q

Caveolae mediated endocytosis

A

Simian virus 40

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50
Q

cytochrome p450 and alcohol detoxification takes place in

A

sER

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51
Q

Synthesis of phospholipids occurs in the lipid monolayer in the

A

sER and rER

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52
Q

Alastin

A

involved in shaping the ER

Deficiency leads to fragmented ER & spastic paraplegia

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53
Q

Spastic paraplegia caused by

A

deficienty in atlastin (ER fragmented)

stiff leg & gait disturbances

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54
Q

Proteasomes

A

large complex protease

Proteolysis of regulating proteins, damaged proteins, and antigenic proteins (initiate immune response)

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55
Q

Proteasomes are dependent on

A

ubiquitin for degredation

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56
Q

Abnormal prion proteins inhibit

A

proteasomes

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57
Q

Defective ubiquination of proteins is implicated in

A

Parkinson’s disease, as well as a form of cystic fibrosis

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58
Q

Bortezomib

A

partially inhibits proteasomes

effective against multiple myeloma - promotes apoptosis of cancer cells

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59
Q

Golgi apparatus

A

Functions as major sorting and distribution center

Proteins packaged into vesicles and moved throughout cell

60
Q

Golgi apparatus lies between

A

nucleus and apical cytoplasm

61
Q

Negative Golgi image

A

Found in active protein secreting cells
Pale staining of cytoplasm that may be seen in H and E staining
Does not contain ribosomes

62
Q

Cis, convex, forming face Golgi

A

face presents towards transitional ER where transport vesicles forming
Transport vesicles carry newly synthesized proteins from ER to Golgi

63
Q

Trans, concave maturing face Golgi

A

face opposite of cis

Forms secretory granules (vesicles)

64
Q

Wilson’s disease

A

mutation in protein pump for copper in trans-Golgi network of liver cells

65
Q

Membrane protein-transporting vesicles containing dysferlin

A

repair microperforations formed in skeletal muscle plasma membranes
Patching is calcium dependent

66
Q

Mutations in dysferlin

A

muscular dystrophy

67
Q

Proinsulinemia

A

mutated proinsulin missorted into unregulated pathway without prohormone enzyme
Absence of prohormone converting enzyme activity in unregulated pathway

68
Q

Endosomes

A

sorting and identifying molecules for recycling or degradation by lysosomes
early, recycling, multivescular, and late

69
Q

Early and recycling endosomes

A

cell periphery

pH 6.2 to 6.5

70
Q

Multivesicular bodies

A
located between early and late endosomes
pH 5 - 6.2
large amounts of membrane and vesicles
fuse with late endosomes
Secretory role
71
Q

Late endosomes

A

located near nucleus
fuse with lysosomes
pH 5

72
Q

achondroplasia

A

FGFR3 is recycled instead of degraded, amplifying FGF signaling
abnormal bone growth leads to dwarfism

73
Q

Lysosomes

A

acidophilic

enzymes able to digest most biologic molecules

74
Q

Autophagolysosome (secondary lysosome)

A

primary lysosome + autophagosome
Macroautophagy - send structures to lysosome
Microautophagy - eliminates proteins and smaller molecules
Chaperone mediated direct transport

75
Q

Heterophagolysosome (secondary lysosome)

A

primary lysosome + heterophagosome

76
Q

Secondary lysosomes

A

are heterogeneous at EM level (light and dark regions)

77
Q

Type II Pompe’s disease

A

Glycogen accumulation in lysosome

alpha-1,4-Glucosidase deficiency

78
Q

Clathrin

A

used in endocytosis and at Golgi to create secretory vesicles

79
Q

COPII

A

anterograde transport from ER to cis Golgi network

80
Q

COPI

A

retrograde transport from cis Golgi network to ER

needed to return membrane, vSNARE proteins, and missorted ER proteins back to ER

81
Q

SNARE proteins

A

allow vesicle to recognize its target domain and dock
vesicle SNARES - on vesicle
Target SNARES on target membrane

82
Q

Neurotoxins of tetanus and botulism

A

enter nerve terminals and proteolyse SNARE proteins
prevent neurotransmitter vesicles from docking with nerve cell membrane and releasing neurotransmitter
Braking effect on motoneurons = paralysis

83
Q

Mitochondria

A

Acidophilic
Pleomorphic - change shape
Located in areas of high metabolic activity - increase in skeletal and cardiac muscle

84
Q

Outer mitochondrial membrane

A

permeable
large channel forming proteins (porins)
Translocator protein

85
Q

Inner mitochondrial membrane

A

selectively permeable
high concentration of phospholipid cardiolipin
enzymes for ETS

86
Q

Tubular Cristae

A

steroid-secreting cells

synthesize steroid hormones

87
Q

Cristae in cardiac and muscle cells

A

shelf like

88
Q

Mitochondrial matrix contains

A

Enzymes of Kreb cycle
Enzymes for fatty acid beta oxidation
Matrix granules

89
Q

Mutations in mitochondrial DNA are implicated in

A

diabetes, deafness, heart disease, Alzheimers, Parkinson, LHON

90
Q

MERRF (myoclonic epilepsy with ragged red bifers)

A

red appearing mitochondria seen with Gomori trichrome stain
at EM - parking lot inclusions
myoclonus, seizures, ataxia

91
Q

Peroxisomes

A

contain oxidative enzymes
enzymatically forms water and oxygen from hydrogen peroxide
enzymes for beta-oxidation of fatty acids
ingested ethanol oxidation
synthesis of plasmalogens

92
Q

Zellweger syndrome

A

peroxisomal enzymes not transported into peroxisome - defective import protein on unit membrane of peroxisome

93
Q

Import of peroxisomal proteins

A

Enzymes formed by free polyribosomes in cytoplasm, then transported into organelle
Phospholipid exchange proteins move phospholipids from ER membrane to peroxisomal membrane

94
Q

Antilipidemics

A

increased uptake of triglycerides and cholesterol by hepatic cells
Ramps up beta oxidation of fatty acids by mitochondria nd peroxisomes - peroxisomes increase in number

95
Q

Defects in synthesis of plasmalogens lead to

A

abnormalities in myelination of nerve cells

96
Q

Cytoskeleton

A

made of microtubules, microfilaments, thick filaments, & intermediate filaments

97
Q

Microtubules

A

13 longitudinally arranged protofilaments made of tubulin dimers

98
Q

Colchicine, vinblastine, and vincristine

A

inhibit polymerization of microtubules

99
Q

Taxol

A

inhibits depolymerization of microtubules

100
Q

Microtubules function to

A

support cytoplasm and organelle, cell division, motility of cilia and flagella, long-range transport of vesicles

101
Q

Kinesin

A

transport vesicles toward periphery (negative to positive)

102
Q

Defect in kinesin

A

decrease in transport of serotonin receptors - development of anxiety disorders

103
Q

Dynein

A

transport vesicles toward nucleus (positive to negative)

104
Q

Microtubule-associated proteins (MAPS)

A

stabilize microtubules

105
Q

Alzheimer’s results from

A

hyperphosphorylation of tau - leads to tangles

106
Q

Microfilaments

A

comprised of actin;

structural support, core of microvilli and stereocilia, movement, cytokinesis, formation of filopodia

107
Q

Cytochalasin B

A

prevents polymerization of actin - affects microfilaments

108
Q

Thick filaments

A

comprised of protein myosin;

mutation in gene coding for mysoin causes severe form of cardiomyopathy

109
Q

Intermediate filaments

A

Cytokeratin, Desmin, Vimentin, Neurofilaments, Glial fibrillary acidic protiens, Nuclear lamins

110
Q

Cytokeratin

A

in epithelial cells
forms tonofilaments
Mallory bodies - characteristic of alocholic liver disease
Epidermolysis bullosa simplex - skin becomes fragile and damaged

111
Q

Desmin

A

found in striated muscle and nonvascular smooth muscle

mutations involve cardiac and skeletal myopathies

112
Q

Vimentin

A

fibroblasts and chondroblasts

113
Q

Neurofilaments

A

most nerve cells, mutations associated with neuropathies

114
Q

Glial fibrillary acidic proteins (GFAP)

A
astrocytes
Alexander disease (degenerative disease of brain white matter), astrocytomas, chronic gliosis have aggregates of GFAP
115
Q

Function of Intermediate Filaments

A

structural support

116
Q

Centrosome

A

Microtubule-organizing Center (MTOC)
Specialized region near nucleus containing two centrioles
conductor of microtubule

117
Q

Centrioles

A

perpendicular to one another
microtubules arranged in 9x3
form mitotic spindle

118
Q

Nucleus

A

one per cell usually
Basophilic
Nuclear envelope, nuclear matrix, chromatin, nuclear bodies

119
Q

Cajal bodies

A

modifying and assembling molecules needed to splice pre-mRNA into mRNA
include snRNA, snoRNA, snRNPs

120
Q

Spinal muscular atrophy

A

muscle wasting
defective SMN protein localized to GEMS (resemble Cajal bodies)
death of motor neurons in gray horns of spinal cord

121
Q

Interchromatin granule clusters (speckles)

A

storage depots of snRNAs and proteins

can become engaged in pre-mRNA splicing

122
Q

Promyelocytic leukemia (PML) bodies

A

modify and assembeling proteins involved in DNA repair and triggering apoptosis

123
Q

Nuclear (fibrous) lamina

A

support inner membrane
Disassembly of nuclear envelope during prometaphase - lamins phosphorylated
Reassembly of nuclear envelope during telophase - lamins dephosphorylated

124
Q

Heterochromatin

A

coiled
transcriptionally inactive
Barr body - inactiated X chromosome in female

125
Q

Euchromatin

A

uncoiled

Synthetically active

126
Q

Nucleolus

A

not membrane bound
rich in rRNA and protein
3 components: Nucleolar-organizer DNA, Pars fibrosa, Pars granulosa

127
Q

Nucleolar-organizer DNA

A

contains sequence of bases that code for transcription of rRNA

128
Q

Pars fibrosa

A

Newly transcribed rRNA just beginning to become complexed with proteins

129
Q

Pars granulosa

A

Maturing subunits of ribosomes

130
Q

G1 (interphase)

A

replication of centrioles begins
Checkpoints for G1 DNA-damage
Restriction - point of no return

131
Q

S (synthesis) of interphase

A

DNA synthesis can occur

S DNA damage checkpoint

132
Q

G2 (interphase)

A
accumulate ATP for mitosis
synthesis of tubulin to form microtubules
centriole replication complete
Checkpoints:
Unreplicated DNA
G2 DNA damage
133
Q

G0

A

nondividing cells

Striated muscle, most neurons

134
Q

Prophase

A

chromatids condensed

centriolar pairs migrate to opposite ends of cell

135
Q

Prometaphase

A

nuclear envelope starts to disappear

136
Q

Metaphase

A

chromatids line up at equator of cell

Colchicine will arrest dividing cells at metaphase

137
Q

Anaphase

A

chromatids separate

138
Q

Telophase

A

nuclear envelope reforms

139
Q

M phase checkpoints

A

Spindle assembly

chromosome segregation

140
Q

Telomerase

A

maintains length of telomere sustaining capacity of cell to divide - expressed in most tumor cells & germinal cells

141
Q

Apoptosis

A

programmed cell death

Phosphatidylserine - translocated to extracellular monolayer - marks cell as dead

142
Q

Extrinsic pathway

A

Fas ligand and Fas receptor
Adaptor protein
caspase-8

143
Q

Intrinsic pathway

A

cell injury causes release of cytochrome c

activated caspase-9

144
Q

FasL counterattack

A

tumor cells evade immune attack by expressing FasL - destroy immune cells by triggering their elimination via apoptosis

145
Q

Estrogen

A

anti-apoptotic effect on osteoblasts