Cell Bio

Front 1

_______ form the spindle, bind chromosomes, and move them to daughter cells during mitosis.

Back 1

Microtubules (MTs)

Front 2

How do MTs generate bending movements in cilia?

Back 2

using dynein molecules

Front 3

Assembly and organization of microfilaments are controlled by _____________.

Back 3

microfilament (actin or MT) associated proteins

Front 4

What are lysosomes?

Back 4

acidic; hydroytic enzymes degrade

Front 5

What process can be exploited by viruses and bacteria to enter a cell?

Back 5

endocytosis

Front 6

Microtubules radiate from the cell center with their ___ ends projecting outward.

Back 6

+

Front 7

______________ are sphingomyelins with hydrophilic sugar groups on extracellular surface.

Back 7

Glycolipids

Front 8

How would you get multiple pass loops in a membrane protein?

Back 8

more start-stop signals (Beta adrenergic receptor has 7)

Front 9

Name 3 components of the plasma membrane.

Back 9

1) hydrophobic lipid bilayer
2) integral & peripheral proteins
3) carbohydrates (oligosaccharides) only on outside

Front 10

_________ filaments are structural and non-motile.

Back 10

Intermediate

Front 11

Improperly folded proteins are returned to __________ for degradation in __________.

Back 11

cytoplasm, proteosomes

Front 12

Name 2 types of aerobic metabolism that mitochondria does.

Back 12

1) TCA cycle
2) OxPhos

Front 13

What mediates separation of receptor and ligand in endosomal compartments?

Back 13

lowered pH

Front 14

What are lipid rafts?

Back 14

Cholesterol and sphingomyelin. Less fluid. Protein aggregate sites.

Front 15

Which type of chromatin is inactive?

Back 15

dark heterochromatin

Front 16

_________ seal apical borders b/t epithelial cells. Do they have associated filaments?

Back 16

tight junctions
no

Front 17

Can phospholipids flip-flop?

Back 17

no

Front 18

Name 2 types of glycolipids and their distinguishing features.

Back 18

1) cerebrosides - small uncharged sugar groups
2) gangliosides - large negatively charged sialic acid groups

Front 19

What are endosomes?

Back 19

Vesicles from cell surface that internalize extracellar material

Front 20

The extracellular, but not intracellular, domains of most integral proteins are _____________.

Back 20

glycosylated

Front 21

Which type of chromatin is active?

Back 21

light euchromatin

Front 22

Mitochondria may have evolved from ______ ______ ________. (3 words)

Back 22

ancient symbiotic bacteria

Front 23

Most proteins are made in the _____ on ________.

Back 23

cytoplasm on free ribosomes

Front 24

What is the process by which a vesicle is formed at one cell surface and re-released at another surface?

Back 24

transcytosis

Front 25

Actin subunits and filaments are in ____________________: filaments continually form, breakdown, and reorganize.

Back 25

DYNAMIC EQUILIBRIUM

Front 26

Actin filament organized into __________ or _________.

Back 26

meshworks or bundles

Front 27

________ hold nucleus in position.

Back 27

IMFs (just structural)

Front 28

mediate direct cell-cell communication by allowing exchange of small molecules

Back 28

gap junctions

Front 29

How does mitochondria get energy?

Back 29

Proton Motive Force (PMF)

Front 30

IMFs are relatively stable in organization, but do break down and reform during ________.

Back 30

mitosis

Front 31

What kind of tail does sphingomyelin have?

Back 31

ceramide tails

Front 32

What are rigid, hollow, polarized tubules providing structural support and movement?

Back 32

microtubules

Front 33

What are 2 diseases associated with peroxisomes?

Back 33

1) ALD - cannot oxidize long-chain fatty acids. (lethal).
2) Zellweger - peroxisomes empty. (lethal).

Front 34

Where is protein packaging done?

Back 34

Golgi

Front 35

Phospholipids are ___________, meaning they contain both hydrophobic and hydrophilic moities.

Back 35

AMPHIPATHIC

Front 36

actin subunits add at the _____ end and get removed at _____ end. This treadmilling means they're in ______________.

Back 36

add at +, remove at -
DYNAMIC EQUILIBRIUM

Front 37

What are the pathways of vesicles?

Back 37

microtubules

Front 38

What do mitochondria do in the liver?

Back 38

Beta oxidation of fatty acids

Front 39

Organization and behavior of microfilaments are controlled by _______________.

Back 39

actin-associated proteins.

Front 40

Can cholesterol flip flop? Why/why not?

Back 40

yes, adds membrane fluidity

Front 41

What's the IMF in nerve axons?

Back 41

neurofilaments

Front 42

Can integral proteins flip flop?

Back 42

no, they're stuck in the membrane, duh.

Front 43

Oligosaccharides only appear on the __________ surface of the plasma membrane.

Back 43

extracellular

Front 44

What attaches cell to matrix?

Back 44

integrin

Front 45

Name 3 filamentous structures of the cytoskeleton.

Back 45

1) actin filaments
2) microtubules
3) intermediate filaments

Front 46

In non-polarized cell, MTs anchored by their ____ ends at the _______.

Back 46

anchored by - ends at MTOC.

Front 47

Adhesion belt: 3 things

Back 47

cell-cell
cadherin
actin

Front 48

T/F: actin filaments are inserted into the membrane.

Back 48

FALSE. Integrins connect actin filaments to matrix at focal contact

Front 49

What's the IMF in epithelial cells?

Back 49

keratin

Front 50

How do MTs support uni-directional vesicle movement?

Back 50

using motor proteins kinesin and dynein

Front 51

Gangliosides are a type of ________________ that have ________________.

Back 51

glycolipids
negatively charged sialic acid groups

Front 52

desmosome: 3 things

Back 52

cell-cell
cadherin
IMF

Front 53

Cell migration: __________ extends edge, ____________ retracts tail.

Back 53

actin extends, actin and myosin retract tail

Front 54

99.99% of mitDNA comes from ________?

Back 54

the mother

Front 55

What's an autophagosome?

Back 55

When part of the ER wraps around an organelle and degrades it.

Front 56

What's the word for mitDNA variation?

Back 56

HETEROPLASMY

Front 57

What are contractile bundles?

Back 57

stress fibers at apex of epithelial cells, also constricts during cytokinesis

Front 58

The polar head group of glycerophospholipids is either ________ or ____________, which is a _______.

Back 58

AMINO ALCOHOL or
INOSITOL, which is a SUGAR.

Front 59

What attaches cell to cell?

Back 59

cadherin

Front 60

How are proteins inserted into membrane of ER?

Back 60

co-translationally inserted from ribosomes into ER membrane

Front 61

What are proteosomes?

Back 61

degrade ubiquinated proteins w/ protease activity in central cavity.

Front 62

Plasma membrane gets its structure by _____________ and ______________.

Back 62

phospholipids and cholesterol

Front 63

What do perioxisomes do?

Back 63

beta oxidation of fatty acids

Front 64

Extends the leading edge and retracts the tail of crawling cells.

Back 64

microfilaments

Front 65

Where does N-linked glycosylation occur? How?

Back 65

ER - high mannose oligosaccharides are attached to asparagine residues on peptides containing appropriate aa sequence

Front 66

MTs have ________ subunits that grow and shrink at __________ ends.

Back 66

TUBULIN
+

Front 67

Name 3 basic functions of the plasma membrane.

Back 67

1) transport of material in/out of cell
2) anchoring internal cytoskeleton, cell to extracellular matrix, cell to cell
3) receptors relay signals into the cell from external environment

Front 68

What's the IMF in nuclear envelope?

Back 68

nuclear lamins

Front 69

Where is ribosomal RNA synthesized?

Back 69

nucleOlus

Front 70

___________ junctions inhibit cell division;
____________ junctions promote cell division.

Back 70

cell-cell junctions inhibit division;
cell-matrix junctions promote cell division.

Front 71

IMFs are anchored to plasma membrane at ____________.

Back 71

desmosomes

Front 72

Explain the OxPhos hypothesis.

Back 72

b/c mitDNA has no introns, everything codes. It's particularly susceptible to ROS damage.
Mutations accumulate more with age.
Mitochondria segregate randomly to daughter cells, so the mtDNA genotype can fluctuate. So you have mutant and normal mtDNA = HETEROPLASMY.

Front 73

Form contractile ring that separates mitotic daughter cells.

Back 73

MFs (microfilaments)

Front 74

What's ONLY on the outside (extracellular side) of plasma membrane? 2 things...

Tell what property this gives the membrane:

Back 74

1) oligosaccharides
2) cross-linked sulfhydryl groups (S-S)

ASYMMETRY!

Front 75

_____________ underlie and strengthen plasma membrane.

Back 75

MF (microfilament) MESHWORKS

Front 76

Name 5 metabolic activities of the cytoplasm.

Back 76

1) glycolysis - anaerobic break down of glucose into 2 ATP
2) fatty acid synthesis - long chains for lipids
3) protein synthesis - mRNA, tRNA, ribosomes
4) proteolysis - protein degradation
5) maintain reducing env't - via glutathione

Front 77

hemidesmosome: 3 things

Back 77

cell-basal lamina
integrin
IMF

Front 78

What provides motive force for bending of cilia and flagella?

Back 78

dyneins and MTs

Front 79

Name the 2 types of phospholipids.

Back 79

1) glycerophospholipids (most) [KINK]
2) sphingomyelin [CERAMIDE TAILS]

Front 80

Which phospholipid group adds to membrane fluidity and why?

Back 80

glycerophospholipids b/c cis-double bond kink

Front 81

Microfilament assembly is ___________ and under the influence of _____________.

Back 81

dynamic
actin-associated proteins

Front 82

What's the IMF in muscle cells?

Back 82

desmin

Front 83

How are microtubules anchored in cell?

Back 83

by their minus (-) ends in an organizing center (MTOC)

Front 84

What forms a gap junction?

Back 84

2 connexons

Front 85

Microvilli have __________, cilia have _________.

Back 85

actin, MTs

Front 86

What happens with accumulated mitDNA mutations?

Back 86

reduced ATP production

Front 87

focal adhesion: 3 things

Back 87

cell-matrix
integrin
actin filaments

Front 88

How do mitochondria produce ATP? (2 ways) What else do they do in liver?

Back 88

1) Krebs cycle
2) OxPhos
break down fatty acids

Front 89

Name 3 peripheral membrane proteins and their functions.

Back 89

1) cytoskeletal - anchored to inner surface
2) signal transduction complexes - relay signals to interior
3) extracellular matrix - (laminin, collagen, fibronectin) anchor cells to surroundings

Front 90

Name 5 IMFs and where they're found.

Back 90

1) KERATIN- epithelial
2) VIMENTIN- mesenchymal (connective tissue)
3) DESMIN- muscle
4) NEUROFILAMENTS- nerve axons
5) NUCLEAR LAMINS- nuclear envelope

Front 91

What are start transfer sequences?

Back 91

ER: bound by signal receptor protein (SRP), which stops translation until ribosome binds to SRP receptor on ER. Now translation is unblocked and peptide can go in ER.

Front 92

Hydrolytic enzymes destined for degradation in lysosomes are tagged with ________ that is recognized by receptors in _____________.

Back 92

mannose 6 phosphate (M6P)
trans Golgi

Front 93

High _________ component of oligosaccharide is transported to Golgi, removed in ____ Golgi, then __________ is added in _____ Golgi.

Back 93

mannose
cis
-chg. sialic acid
trans

Front 94

Proteins destined for the mitochondria are targeted by _______________.

Back 94

amino-terminal sequence
(NH3)

Front 95

Name 6 functions of cytoskeleton filaments

Back 95

1) maintain cell shape
2) support projections (cilia & microvilli)
3) position organelles
4) mvmt of organelles
5) contract microfilament bundles
6) cell migration

Front 96

What is at the polar head of sphingomyelin?

Back 96

phosphorylcholine

Front 97

Which protein is most abundant in cells?

Back 97

actin

Front 98

______________ separates daughter cells after mitosis by "purse string" contraction of ____________.

Back 98

cytokinesis
MFs (microfilaments)

Front 99

kinesin moves along MTs toward _____ ends.
dynein moves toward _____ ends.

Back 99

Kinesin toward +
Dynein toward -

Front 100

Name 2 types of secretory vesicles.

Back 100

transport from Golgi to cell surface
1) regulated
2) constitutive (always on)

Front 101

Where is location of translational material for mRNA?

Back 101

nucleus in spaces b/t chromosomal domains

Front 102

____________________ anchored to plasma membrane stabilize cell shape.

Back 102

Contractile bundles (stress fibers) of microfilaments

Front 103

Name 2 ER cisternae and their functions.

Back 103

1) rough - docking ribosomes,
secretory protein synthesis
2) smooth - membrane lipid synthesis,
drug detox,
Ca2+ storage,
glycogen synthesis

Front 104

Cerebrosides are under the category of ____________, and cerebrosides have _______________.

Back 104

glycolipids
uncharged sugar residues

Front 105

Name 4 adhesions junctions. Tell what they do.

Back 105

1) adhesion belt: cell-cell, cadherin, actin.
2) desmosome: cell-cell, cadherin, IMF.
3) hemidesmosome: cell-basal lamina, integrin, IMF.
4) focal adhesion: cell-matrix, integrins, actin.

Front 106

How does N-linked glycosylation occur?

Back 106

co-translationally via transfer from dolichol carrier

Front 107

Proteins made in cytoplasm that lack a targeting signal go where?

Back 107

remain in the cytoplasm

Front 108

The presence of ___________ in nascent peptides determines that they will be integral proteins in ER membrane, not lumen.

Back 108

stop-transfer sequences

Front 109

What's the IMF in mesenchymal cells (connective tissue)?

Back 109

vimentin

Front 110

How is mitochondrial DNA different from other DNA?

Back 110

no introns. it all codes.

Front 111

Where are ATP synthase particles bound?

Back 111

inner membrane of mitochondria

Front 112

Which adds more membrane fluidity to the membrane, glycerophospholipids or sphingomyelin, and why?

Back 112

glycerophospholipid b/c cis-double bond kink

Front 113

Can receptors be recycled?

Back 113

yes - to cell surface except growth factor receptors

Front 114

Where does Golgi get proteins from? What does it do with them?

Back 114

ER
POLARIZED cis-trans processing, sorting, packaging, export.

Front 115

Which tissues are particularly susceptible to OxPhos damage?

Back 115

muscle and nerve

Front 116

The nuclear envelope is continuous with _____.

Back 116

ER

Front 117

The inner membrane of mitochondria folds to form __________.

Back 117

cristae

Front 118

What is transcytosis? Give example.

Back 118

Uptake at one cell surface, release at another.
maternal to placental; liver; skin

Front 119

Glycerophosphoipids have __________ tails with ______.

Back 119

fatty acid tails with cis-double bond kink

Front 120

Can phospholipids laterally diffuse?

Back 120

yes

Front 121

The cytoplasm is a _________ environment. Therefore we only find __________________ on the cytoplasmic domains. But ___________ are an important structural determinant of extracellular domains.

Back 121

reducing,
free sulfhydryl groups,
interchain disulfide bonds

Front 122

Why does 99.99% of mitDNA come from one parent? Which one?

Back 122

mother b/c sperm contributes no cytoplasm

Front 123

What defines the cytoplasmic compartment?

Back 123

plasma membrane

Front 124

How are the lipids in the plasma membrane organized?

Back 124

hydrophobic bilayer

Front 125

Which chaperones bind to protein destined for mitochondria?

Back 125

Hsp70 - keep it unfolded so it can pass thru membrane

Front 126

What keeps nascent, unfolded proteins from being hydrolyzed?

Back 126

chaperones like Hsp70 (sm) and Hsp60 (lg)

Front 127

Where do you find glycolipids? Why? Name the 2 types while you're at it...

Back 127

on extracellular surface b/c sugar residues
1) cerebrosides (uncharged)
2) gangliosides (- chg. sialic acid)

Front 128

What modulates membrane fluidity more than anything else?

Back 128

cholesterol

Front 129

Where does the TCA cycle happen?

Back 129

matrix of mitochondria

Front 130

What is N-linked glycosylation and where does it take place?

Back 130

mannose-rich sugar is assembled onto a membrane lipid in the lumen of the ER and transferred to ASN.

Front 131

What is O-linked glycosylation and where does it take place?

Back 131

oligosaccharides attach to serine and threonine residues only in Golgi.

Front 132

What happens to N-linked glycosylated stuff in the Golgi?

Back 132

processed by removing mannose and adding - chg. sialic acid

Front 133

From Golgi, stuff either goes to ____________ or _____________.

Back 133

cell surface (secretory vesicles)
lysosomes (to get degraded)

Front 134

How do lysosomes work?

Back 134

Hydrolytic enzymes are recognized in the cis-Golgi, and their N-linked oligosaccharides from ER are phosphorylated to produce mannose-6-phosphate. The M6P receptor in the trans-Golgi recognizes it. Both the receptor and ligand are packaged and sent to a late endosome/multivesicular body forming an endolysosome. The low pH causes the receptor to be released and recycled. The pH slowly drops until pH 4.5 forming a lysosome that degrades its contents.

Front 135

What is Tay-Sachs disease?

Back 135

Absence of a lysosomal B-hexosaminidase leads to indigestible ganglioside in neurons leading to juvenile death

Front 136

How do proteosomes work?

Back 136

Proteins are tagged with ubiquitin and are recognized by barrel-shaped proteasomes (related to HSP 60) for degradation. The broken down protein fragments are imported to the ER and are attached to major histocompatibility (MHC) proteins on the ER membrane. These complexes routinely go from the ER to the Golgi and then to the cell surface. Foreign fragments are recognized by the immune system.

Front 137

What is pinocytosis?

Back 137

The formation of small vesicles from indentations from the cell
surface. The pits may be coated with CLATHRIN that helps to
round the pit and pinch it off.

Front 138

Mitochondrial genes code only for proteins in what important metabolic process?

Back 138

glucose metabolism (making ATP)
also does aerobic metabolism (TCA and OxPhos)

Front 139

After an activated G-alpha subunit of a trimeric complex binds and activates its target, what's the effect of the target protein on the G-alpha subunit?

Back 139

make cAMP, hydrolyze GTP-->GDP, dissociates and rebinds beta/gamma, thus inactivating enzyme.

Front 140

2 pathways in cytoplasm activated by receptor tyrosine kinases:

Back 140

1) ras (thru intermediate proteins)
2) kinase cascade

Front 141

What does Cdk1/cyclin B do to promote onset of mitosis?

Back 141

1) phosphoryl nuclear lamins and nuclear envelope breakdown
2) phosphoryl condensin to condense chromosomes
3) reorganize MTs for spindle formation

Front 142

What is the role of cyclinE/cdk2 at G1 to S transition?

Back 142

phosphorylate Rb and CDK4/6-cyclin D. Internal feedback. activate DNA synthesis.

Front 143

*What is heteroplasmy in mitochondria?

Back 143

co-existance of normal and mutant mtDNA in a cell

Front 144

*Proteins that cannot fold properly are degraded within what structure?

Back 144

proteasomes

Front 145

*How are lysosomal hydrolases targeted for sorting to endosomes/lysosomes in the Golgi?

Back 145

Hydrolytic enzymes are recognized in the cis-Golgi, and their N-linked oligosaccharides from ER are phosphorylated to produce mannose-6-phosphate. The M6P receptor in the trans-Golgi recognizes it. Both the receptor and ligand are packaged and sent to a late endosome/multivesicular body forming an endolysosome. The low pH causes the receptor to be released and recycled. The pH slowly drops until pH 4.5 forming a lysosome that degrades its contents

Front 146

*Identify 2 different pathways that can be activated by G-protein linked stimulation.

Back 146

1) increase cAMP
2) increase Calcium
BOTH INCREASE GLUCOSE

Front 147

*How does phosphoryl of Rb promote onset of DNA synthesis?

Back 147

activated CDK4/6-cyclin D hyper-phosphorylates Rb. Rb releases E2F, which triggers last step of DNA synthesis

Front 148

*What are the 4 types of signal receptors that ligands bind?

Back 148

1) contact-dependent
2) paracrine
3) synaptic
4) endocrine

Front 149

*What's enzyme-linked?
(receptor tyrosine kinase)

Back 149

turned on when ligand dimerizes receptors (autoPO4). binds PLCgamma, cleaves PIP2 into IP3 & DAG. RTKs bind adaptor proteins (GEFs) that activate ras. Ras activates kinase cascade, nuclear transcription factors, gene expression. opposed by phosphotases

Front 150

*What's G-protein linked?
(adenyl cyclase)

Back 150

cAMP activates PKA, more glucose.

G-protein activates PLCbeta, cleaves PIP2 into IP3 & DAG. IP3 releases Ca+ from ER. Ca+ activates calmodulin. Calmodulin breaks down glycogen. DAG activates PKC (ser/thr kinase).

Front 151

Cytokine receptor pathways

Back 151

can overlap w/ RTK pthways through ras. Both activate nuclear transcription factors

Front 152

Integrin pathway

Back 152

cell-matrix jcn permissive for cell growth. activates ras and signals to nucleus

Front 153

Cadherin receptors - permissive for cell division or not?

Back 153

NOT b/c cell-cell jcns. Beta catenin links filaments to cell-cell jcns, but can also enter nucleus to promote cell division. APC inhibits cell division by keeping B-catenin out of the nucleus.

Front 154

What's the "go to lysosome" signal?

Back 154

M6P

Front 155

What's the "go to proteasome" signal?

Back 155

ubiquitin

Front 156

What's the "ER is the place to be" signal?

Back 156

start-transfer sequence
recognized by SRP (signal recognition particle)

Front 157

Where can you get disulfide bonds inside the cell? I thought the cytoplasm was a reducing environment?

Back 157

it is. don't freak out. the lumen of the ER is not, however, so you can get disulfide bonds there.

Front 158

What is a model G-protein-linked receptor? What does it do?

Back 158

Beta-adrenergic. elevates glucose.
activated receptors -->
activate G-alpha -->
adenylate cyclase -->
cAMP -->
PKA -->
glucose

Front 159

What does the phosphorylating?
What are they opposed by?

Back 159

protein kinase
phosphotases

Front 160

Another G-linked pathway...what if ligand activates trimeric G protein?

Back 160

PLC-Beta-->
cleave PIP2 into IP3 (Ca+) & DAG-->
PKC-->
kinase cascade -->
transcription factors in nucleus

Front 161

What are the 2 ways we can increase glucose in the cell?

Back 161

increase cAMP or Ca+

Front 162

Why are cell-cell jcns inhibitory for cell division?

Back 162

beta catenin links cadherin receptors at cell-cell junctions; however, it can also enter the nucleus and promote cell division. APC inhibits cell division b/c it ties up B-catenin and keeps it out of the nucleus.

Front 163

How do cell-matrix jcns promote cell division?

Back 163

integrin binds focal adhesions or hemidesmosomes, activating ras, the kinase cascade, and transcription factors in the nucleus

Front 164

Go thru the RTK pathway.

Back 164

growth factor/ligand binds-->
activated RTKs dimerize, autophosphory-->
activate either PLC-gamma or ras (thru adaptor proteins) -->
kinase cascade --> nucleus.
*if PLC-gamma, cleaves PIP2 into IP3 (Ca+) & DAG (PKC, kinase cascade...)

Front 165

What's the word for different # of chromosomes in a cell?

Back 165

aneuploidy

Front 166

How can you look for appearance/quantity of DNA in stages of cell cycle?

Back 166

thymidine labeling and time (b/c they only take up thy during S phase)
also, could do cell sorter flourescence

Front 167

What happens if you fuse a mitotic cell with an S cell?

Back 167

induce mitosis b/c there's a MPF (mitosis promoting factor)

Front 168

What's the MPF?

Back 168

mitosis promoting factor
has 2 proteins:
CDK1 (induces mitosis)
cyclin B (activates CDK1)