Exam 1 9/6 Kingsley Flashcards

1
Q

Why is inner nuclear membrane important?

A

Meshwork of intermediate filaments; lamin A, B, C represses DNA expression of genes that are no longer needed

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2
Q

Chromosome compartmentalization within nucleus

A

Location of each portion of chromosome may allow for transcriptional activation or repression. Nuclear lamin-associated (border) less active due to more nucleosomes

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3
Q

Histones

A

DNA binding proteins

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4
Q

Components of nucleosome

A

2 copies of H2A, H2B, H3, H4. Forms octamer

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5
Q

dsDNA wound around histone octamer is called:

A

nucleosome

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6
Q

___ binds linker DNA between nucleosomes

A

H1

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7
Q

Histones can be:

A

acetylated, methylated, phosphorylated

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8
Q

Constitutive heterochromatin

A

closed

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9
Q

What DNA should be constitutive?

A

genes from embryonic development

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10
Q

Facultative heterochromatin

A

Can be open or closed

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11
Q

Euchromatin

A

Open

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12
Q

What DNA should be open?

A

things that we will always be making. ex: actin

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13
Q

Characteristics of constitutive chromatin

A

Closed, DNA methylated. More histone methylation on H3K9, H3K27

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14
Q

What opens DNA to be transcribed?

A

Acetylation

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15
Q

Euchromatin may be associated with:

A

histone acetylation

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16
Q

How does acetylation induce open DNA?

A

removes positive charge, decreases DNA affinity

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17
Q

Euchromatin has:

A

fewer histone methylations (H3K4me); less likely to have methylated DNA

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18
Q

Nucleolus

A

active site of transcription

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19
Q

Annulate lamella is present in:

A

cells with high mitotic index

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20
Q

True or false: most cells have annulate lamella

A

False. found in cells like cancer cells or stem cells

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21
Q

NLS

A

Nuclear localization signal; “importins”

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22
Q

NLS signal sequence is:

A

PKKKRKV

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23
Q

NES

A

Nuclear export signal; “exportins”

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24
Q

What binds exportins?

A

short hydrophobic sequence (leucine) or RNA. Both regulated by Ran or GTP binding proteins

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25
Q

SER another name

A

agranular reticulum

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26
Q

RER another name

A

granular reticulum

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27
Q

SRP

A

signal recognition peptide

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28
Q

What is SRP important for in RER?

A

essential for the targeting of proteins for secretion or membrane insertion; “docking”

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29
Q

RER is the site for:

A

protein synthesis, protein folding, post translational modification

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30
Q

What post-translational modifications occur in the RER?

A

core glycosylation, disulfide/hydrogen bonds, chaperone-mediated folds

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31
Q

Most proteins from RER are delivered to:

A

golgi

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32
Q

Golgi apparatus has __ faces, called:

A

2; cis (faces toward rER), trans (faces away from rER towards cell membrane)

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33
Q

What occurs in the golgi apparatus?

A

PTM; protein sorting

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34
Q

What component of the cell helps mediate bidirectional transport?

A

COP proteins

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35
Q

COP II is associated with what protein?

A

kinesin

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36
Q

COP I is associated with:

A

dynein

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37
Q

Can you name any cell types that use constitutive exocytosis?

A

salivary glands (euchromatin)

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38
Q

True or false: pinocytosis is specific regarding what molecules are brought into the cell

A

False - it is non-specific

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39
Q

True or false: potocytosis is clathrin dependent

A

False - clathrin independent

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40
Q

Types of intake in cells:

A

-pinocytosis
-potocytosis
-endocytosis
-phagocytosis

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41
Q

Pinocytosis is an important regulatory mechanism for:

A

regulating membranes; removal of excess cell membrane; balancing fluid content

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42
Q

Potocytosis is a type of:

A

receptor-mediated endocytosis

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43
Q

Potocytosis involves what protein?

A

caveola (caveolin protein)

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44
Q

Potocytosis causes parts of membrane to go directly to:

A

into cytosol and fuse with endosomes

45
Q

Folate uptake pathways

A
  1. anion exchange-mediated hRFCI (reduced folate carrier)
  2. FR or FOL (potocytosis)
46
Q

Phagocytosis

A

directed, specific cellular eating of larger molecules and structures (microbes)

47
Q

Phagocytosis is ______ mediated

A

receptor

48
Q

What cells do phagocytosis

A

neutrophils, macrophages

49
Q

Endocytosis is a ____ ____ mechanism

A

ligand specific (receptor mediated)

50
Q

Endosome serves as an:

A

intracellular sorting component

51
Q

SNARe protein stands for:

A

Soluble NSF Attachment Receptor

52
Q

M6P receptor is used to:

A

help package hydrolases into vesicles from TGN to endosomes, which develop into lysosomes

53
Q

Lysosomes have a unique lipid consituent called:

A

lysobisphosphatidic acid

54
Q

Specific features of lysosomes:

A
  • luminal glycosylation (interior is heavily glycosylated)
  • H+ pumps
  • transport proteins
55
Q

What is sarcoplasmic reticulum?

A

Specialized smooth ER found in muscle cells, sequesters Ca2+, helps muscles contract

56
Q

Peroxisomes contain:

A

MAVS (mitochondrial anti viral signaling adaptors)

57
Q

Folded inner membrane of mitochondria are _____ rich

A

cardiolipin

58
Q

Where is cardiolipin localized and synthesized?

A

inner mitochondrial membrane

59
Q

ATP synthase is found on:

A

inner mitochondrial membrane

60
Q

Where does energy generation occur in mitochondria?

A

inner mitochondrial membrane

61
Q

True or false: mitochondria has its own DNA

A

True - ds cDNA

62
Q

Plasmalemma structure

A

trilaminar structure; dense outer layer, clear staining middle, dark staining inner layer

63
Q

Plasmalemma is another name for:

A

plasma membrane

64
Q

The golgi serves as an intersection of what pathways?

A

secretory, lysosomal, endocytic pathways

65
Q

What is Rab GTPase responsible for?

A

associated with endosomes, controls all aspects of intracellular vesicle trafficking

66
Q

True or false: proteosomes are organelles

A

False - they are protein complexes that help degrade old/unneeded proteins, associated with ubiquitin

67
Q

DUBs

A

de-ubiquitinating enzymes - used by proteasomes to recycle ubiquitin to tag other proteins or components in the cell that need to be degraded

68
Q

What is the main function of smooth ER?

A

site for lipid metabolism

69
Q

Where does the citric acid cycle take place?

A

Inner mitochondrial membrane

70
Q

What are the leaflets of the plasmalemma?

A

Inner leaflet (Protoplasmic or P face); Outer leaflet (Ectoplasmic or E face)

71
Q

Describe phosphatidylserine and what its various locations mean in a cell

A

Important lipid on the P face of the cell; asymmetric; flips to E face (outside) thus becoming symmetrical –> signal that the cell is going to die

72
Q

Where does most protein activity take place (which leaflet)

A

P face

73
Q

Proteins found on P face leaflet

A

Phosphatidylserine (PS); Phosphatidylethanolamine (PE)

74
Q

What are signals that apoptosis is occurring in a cell?

A
  1. PS asymmetry is lost (PS externalized)
  2. flippase activity is lowered
75
Q

Apoptosis

A

programmed cell death

76
Q

What is observed in a cell that has undergone apoptosis on a gel electrophoresis?

A

compared to normal DNA, more DNA fragmentation is observed with several sized bands shown on an apoptosis cell

77
Q

Characteristics of necrosis versus apoptosis

A

Necrosis shows cell swelling, organelle rupture, and membrane rupture (popping open)

Apoptisis shows cell shrinkage, fragmentation, engulfment, and degradation

78
Q

What is an annexin assay and how does it work?

A

measures the real-time exposure of phosphatidylserine (PS) on the outer leaflet of cell membranes during the apoptotic process. PS is bound to fluorophore and visualized with microscopy –> apoptotic cells will glow

79
Q

What increases membrane fluidity?

A

fatty acyl tails

80
Q

Most voltage-gated ion channels are in what position?

A

Closed/Inactive

81
Q

True or false: voltage gated ion channels can quickly be opened after closing

A

False - there is a refractory period in which gate cannot be reopened

82
Q

What are some nucleotide-gated channels?

A
  1. cAMP in olfactory receptors
  2. cGMP in retinal receptors
83
Q

Which nucleotide-gated channel is associated with olfactory receptors?

A

cAMP

84
Q

Which nucleotide-gated channel is associated with retinal receptors?

A

cGMP

85
Q

Physical manipulation triggers opening of what kind of channel?

A

mechanically gated ion channel

86
Q

What is an example of a type of cell where mechanically-gated channels are found?

A

stereocilia in tectorial membrane

87
Q

Describe how stereocilia transmits information about sound to the brain

A
  1. sounds create mechanical vibration/movement in basilar membrane
  2. stereocilia bends
  3. ion channel opens
  4. depolarization occurs, causing nerve impulse
  5. nerve impulse translates sound to the brain
88
Q

What is a G-protein complex?

A

Heterotrimeric (three distinct subunits alpha, beta, gamma) GTP-binding G protein

89
Q

How many transmembrane domains are found in G-protein complex

A

Seven (intra/extracellular domains)

90
Q

How does signaling occur in G-protein to activate ion channels?

A
  1. extracellular ligand binds, changing conformation
  2. GTP replaces GDP, activating intracellular signaling
  3. Activated protein interacts to open ion channel
91
Q

Aquaporins are a family of:

A

multipass proteins

92
Q

Where are aquaporins involved?

A

kidney function/clearance

93
Q

AqpZ

A

passage of water

94
Q

GlpF function

A

passage of glycerol

95
Q

What are 3 types of carrier proteins?

A

uniport, symport, antiport

96
Q

Uniport

A

single molecule moving one direction

97
Q

Symport

A

coupled; two molecules moving one direction

98
Q

Antiport

A

coupled; two molecules moving opposite directions

99
Q

Example of uniport:

A

GLUT1

100
Q

GLUT1 uniport carrier is a type of ____ transport

A

facilitated transport

101
Q

True or false: GLUT1 moves against concentration gradient

A

False - moves along concentration gradient up to Vmax

102
Q

Symport example

A

SGLT (sodium-glucose linked transport)

103
Q

Where is SGLT found/its functions?

A
  1. proximal tubule of nephron –> renal glucose absorption
  2. mucosa (enterocytes) of small intestine; target for oral rehydration therapy to move sodium and water into enterocytes
104
Q

Example of antiport

A

TRP/LAT antiport carrier

105
Q

_____ has an increased expression in oral and pharyngeal cancers

A

TRP/LAT

106
Q

What does TRP/LAT do?

A

imports trytophan, exports kynurenine

107
Q

Why is TRP/LAT associated with oral/pharyngeal cancers?

A

increased expression increases the amount of kynurenine exported, increasing down regulation of CD8 and CTL cells (reducing anti-cancer immune response)

108
Q

Example of primary active transport antiport

A

sodium potassium pump

109
Q

Specific components of lysosomes

A
  1. lysobisphosphatidic acid
  2. Lysosome associated membrane proteins (LAMPs)
  3. lysosomal integral membrane proteins (LIMPs)
  4. lysosomal membrane glycoproteins (LGPs)