Exam 1 9/6 Kingsley Flashcards
(109 cards)
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
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
3
Q
Histones
A
DNA binding proteins
4
Q
Components of nucleosome
A
2 copies of H2A, H2B, H3, H4. Forms octamer
5
Q
dsDNA wound around histone octamer is called:
A
nucleosome
6
Q
___ binds linker DNA between nucleosomes
A
H1
7
Q
Histones can be:
A
acetylated, methylated, phosphorylated
8
Q
Constitutive heterochromatin
A
closed
9
Q
What DNA should be constitutive?
A
genes from embryonic development
10
Q
Facultative heterochromatin
A
Can be open or closed
11
Q
Euchromatin
A
Open
12
Q
What DNA should be open?
A
things that we will always be making. ex: actin
13
Q
Characteristics of constitutive chromatin
A
Closed, DNA methylated. More histone methylation on H3K9, H3K27
14
Q
What opens DNA to be transcribed?
A
Acetylation
15
Q
Euchromatin may be associated with:
A
histone acetylation
16
Q
How does acetylation induce open DNA?
A
removes positive charge, decreases DNA affinity
17
Q
Euchromatin has:
A
fewer histone methylations (H3K4me); less likely to have methylated DNA
18
Q
Nucleolus
A
active site of transcription
19
Q
Annulate lamella is present in:
A
cells with high mitotic index
20
Q
True or false: most cells have annulate lamella
A
False. found in cells like cancer cells or stem cells
21
Q
NLS
A
Nuclear localization signal; “importins”
22
Q
NLS signal sequence is:
A
PKKKRKV
23
Q
NES
A
Nuclear export signal; “exportins”
24
Q
What binds exportins?
A
short hydrophobic sequence (leucine) or RNA. Both regulated by Ran or GTP binding proteins
25
SER another name
agranular reticulum
26
RER another name
granular reticulum
27
SRP
signal recognition peptide
28
What is SRP important for in RER?
essential for the targeting of proteins for secretion or membrane insertion; "docking"
29
RER is the site for:
protein synthesis, protein folding, post translational modification
30
What post-translational modifications occur in the RER?
core glycosylation, disulfide/hydrogen bonds, chaperone-mediated folds
31
Most proteins from RER are delivered to:
golgi
32
Golgi apparatus has __ faces, called:
2; cis (faces toward rER), trans (faces away from rER towards cell membrane)
33
What occurs in the golgi apparatus?
PTM; protein sorting
34
What component of the cell helps mediate bidirectional transport?
COP proteins
35
COP II is associated with what protein?
kinesin
36
COP I is associated with:
dynein
37
Can you name any cell types that use constitutive exocytosis?
salivary glands (euchromatin)
38
True or false: pinocytosis is specific regarding what molecules are brought into the cell
False - it is non-specific
39
True or false: potocytosis is clathrin dependent
False - clathrin independent
40
Types of intake in cells:
-pinocytosis
-potocytosis
-endocytosis
-phagocytosis
41
Pinocytosis is an important regulatory mechanism for:
regulating membranes; removal of excess cell membrane; balancing fluid content
42
Potocytosis is a type of:
receptor-mediated endocytosis
43
Potocytosis involves what protein?
caveola (caveolin protein)
44
Potocytosis causes parts of membrane to go directly to:
into cytosol and fuse with endosomes
45
Folate uptake pathways
1. anion exchange-mediated hRFCI (reduced folate carrier)
2. FR or FOL (potocytosis)
46
Phagocytosis
directed, specific cellular eating of larger molecules and structures (microbes)
47
Phagocytosis is ______ mediated
receptor
48
What cells do phagocytosis
neutrophils, macrophages
49
Endocytosis is a ____ ____ mechanism
ligand specific (receptor mediated)
50
Endosome serves as an:
intracellular sorting component
51
SNARe protein stands for:
Soluble NSF Attachment Receptor
52
M6P receptor is used to:
help package hydrolases into vesicles from TGN to endosomes, which develop into lysosomes
53
Lysosomes have a unique lipid consituent called:
lysobisphosphatidic acid
54
Specific features of lysosomes:
- luminal glycosylation (interior is heavily glycosylated)
- H+ pumps
- transport proteins
55
What is sarcoplasmic reticulum?
Specialized smooth ER found in muscle cells, sequesters Ca2+, helps muscles contract
56
Peroxisomes contain:
MAVS (mitochondrial anti viral signaling adaptors)
57
Folded inner membrane of mitochondria are _____ rich
cardiolipin
58
Where is cardiolipin localized and synthesized?
inner mitochondrial membrane
59
ATP synthase is found on:
inner mitochondrial membrane
60
Where does energy generation occur in mitochondria?
inner mitochondrial membrane
61
True or false: mitochondria has its own DNA
True - ds cDNA
62
Plasmalemma structure
trilaminar structure; dense outer layer, clear staining middle, dark staining inner layer
63
Plasmalemma is another name for:
plasma membrane
64
The golgi serves as an intersection of what pathways?
secretory, lysosomal, endocytic pathways
65
What is Rab GTPase responsible for?
associated with endosomes, controls all aspects of intracellular vesicle trafficking
66
True or false: proteosomes are organelles
False - they are protein complexes that help degrade old/unneeded proteins, associated with ubiquitin
67
DUBs
de-ubiquitinating enzymes - used by proteasomes to recycle ubiquitin to tag other proteins or components in the cell that need to be degraded
68
What is the main function of smooth ER?
site for lipid metabolism
69
Where does the citric acid cycle take place?
Inner mitochondrial membrane
70
What are the leaflets of the plasmalemma?
Inner leaflet (Protoplasmic or P face); Outer leaflet (Ectoplasmic or E face)
71
Describe phosphatidylserine and what its various locations mean in a cell
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
Where does most protein activity take place (which leaflet)
P face
73
Proteins found on P face leaflet
Phosphatidylserine (PS); Phosphatidylethanolamine (PE)
74
What are signals that apoptosis is occurring in a cell?
1. PS asymmetry is lost (PS externalized)
2. flippase activity is lowered
75
Apoptosis
programmed cell death
76
What is observed in a cell that has undergone apoptosis on a gel electrophoresis?
compared to normal DNA, more DNA fragmentation is observed with several sized bands shown on an apoptosis cell
77
Characteristics of necrosis versus apoptosis
Necrosis shows cell swelling, organelle rupture, and membrane rupture (popping open)
Apoptisis shows cell shrinkage, fragmentation, engulfment, and degradation
78
What is an annexin assay and how does it work?
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
What increases membrane fluidity?
fatty acyl tails
80
Most voltage-gated ion channels are in what position?
Closed/Inactive
81
True or false: voltage gated ion channels can quickly be opened after closing
False - there is a refractory period in which gate cannot be reopened
82
What are some nucleotide-gated channels?
1. cAMP in olfactory receptors
2. cGMP in retinal receptors
83
Which nucleotide-gated channel is associated with olfactory receptors?
cAMP
84
Which nucleotide-gated channel is associated with retinal receptors?
cGMP
85
Physical manipulation triggers opening of what kind of channel?
mechanically gated ion channel
86
What is an example of a type of cell where mechanically-gated channels are found?
stereocilia in tectorial membrane
87
Describe how stereocilia transmits information about sound to the brain
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
What is a G-protein complex?
Heterotrimeric (three distinct subunits alpha, beta, gamma) GTP-binding G protein
89
How many transmembrane domains are found in G-protein complex
Seven (intra/extracellular domains)
90
How does signaling occur in G-protein to activate ion channels?
1. extracellular ligand binds, changing conformation
2. GTP replaces GDP, activating intracellular signaling
3. Activated protein interacts to open ion channel
91
Aquaporins are a family of:
multipass proteins
92
Where are aquaporins involved?
kidney function/clearance
93
AqpZ
passage of water
94
GlpF function
passage of glycerol
95
What are 3 types of carrier proteins?
uniport, symport, antiport
96
Uniport
single molecule moving one direction
97
Symport
coupled; two molecules moving one direction
98
Antiport
coupled; two molecules moving opposite directions
99
Example of uniport:
GLUT1
100
GLUT1 uniport carrier is a type of ____ transport
facilitated transport
101
True or false: GLUT1 moves against concentration gradient
False - moves along concentration gradient up to Vmax
102
Symport example
SGLT (sodium-glucose linked transport)
103
Where is SGLT found/its functions?
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
Example of antiport
TRP/LAT antiport carrier
105
_____ has an increased expression in oral and pharyngeal cancers
TRP/LAT
106
What does TRP/LAT do?
imports trytophan, exports kynurenine
107
Why is TRP/LAT associated with oral/pharyngeal cancers?
increased expression increases the amount of kynurenine exported, increasing down regulation of CD8 and CTL cells (reducing anti-cancer immune response)
108
Example of primary active transport antiport
sodium potassium pump
109
Specific components of lysosomes
1. lysobisphosphatidic acid
2. Lysosome associated membrane proteins (LAMPs)
3. lysosomal integral membrane proteins (LIMPs)
4. lysosomal membrane glycoproteins (LGPs)
