Exam 3 Flashcards

1
Q

What isotope indicates how old tissues are?

A

Carbon 14

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is Apoptosis

A

programmed cell death

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Does apoptosis cause damage to tissue?

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What cleans up cells which have undergone apoptosis?

A

Macrophages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

True of False?

Intracellular constituents are released into extracellular milieu durring apoptosis.

A

False

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What causes necrosis?

A

severe cell damage

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What does necrosis lead to or present as?

A

Inflimation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What happens to the intracellular contents during necrosis?

A

The are released into the extracellulara milieu

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How does apoptosis contribute to embryonic development?

A

Removes cells to sculpt the body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What causes a frog to loose its tail?

A

Induced apoptosis in the tail

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What common disease is apoptosis important for protecting against?

A

uncontrolled cell division, cancer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the function of apoptosis generally?

A

serve as a safety system for removing cells which have lost normal comunication and control

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the function of apoptosis in neuronal development?

A

it matches the number of developing nerve cells to the number of target cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

how do target cells match the correct number of nerve cells?

A

By releasing a limited amount of survival factor which prevents apoptosis of nerve cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what morphology changes occur during apoptosis?

A

mild convolution
chromatin compaction and margination
condensation of cytoplasm
breakup of nuclear envelope
nuclear fragmentation
blebbing
cell fragmentation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

True of False?

Asymmetric lypid distribution is maintained during apoptosis.

A

False
the negatively charged lipid phosphatidylserine (PS), which is usually only found on the inner side of the membrane, is exposed to the extracellular side of the membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what does phosphatidylserine (PS) do when exposed to the extracellular space?

A

signals macrophages to phagocytose the cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what do restriction enzymes do?

A

they cut DNA at specific sites

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How does agarose gel from gel electrophoresis seperate DNA?

A

size with the largest particles nearest to the well

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the negative side of agarose gel in gel electrophoresis?

A

the well side

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is the DNA stain used at the end of agarose gel electrophoresis?
what is needed to visualize the stained DNA?

A

ethidium bromide
UV-light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What does necrosis do to DNA on agarose gel electrophoresis?

A

creates a DNA smear

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What does apoptosis do with regards to DNA?

A

activates nucleases which cut the DNA between the nucleosomes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What executes apoptosis?

A

caspases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

what are caspases?

A

proteases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

what activates procaspases?

A

their prodomains are cleaved off

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

what do activated procaspases do?

A

dimerize to form on caspase molecule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

what will one molecule of active initiatior caspase do?

A

activate many executioner caspase Y

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What does executioner caspase y do?

A

cleave the nuclear lamin and activate many more executioner caspase Z

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

what does executioner caspase Z do?

A

cleaves cytosolic proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

How does the initiator caspase get activated?

A

the aggregation of procaspases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

what helps the procaspases agregate?

A

adaptor proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What do agregated procaspases do to each other and what is the result?

A

cleave each other resulting in the formation of active caspase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

True of False?

The active initiator caspase can cleave and activate many executioner caspases

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

how many different caspases do human cells express?

A

15

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

what is released from the mitochondria that initiates the apoptic pathway?

A

cytochrome C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

where is cytochrome C stored in the mitochondria?

A

intermembrane space

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What does cytochrome C bind to and activate in the apoptic pathway?
What do those activated things subsequently bind to?

A

adaptor proteins
other adaptor proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What are cyclized adaptor proteins called?

A

apoptosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

How does p53 activate apoptosis

A

it acitvates the Bax transport protein which releases Cytochrome C into the cytoplasm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What cells contain the fas ligand?

A

killer lymphocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

what doe the fas ligand bind to?

A

the fas receptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What happens once the fas lignad binds the fas receptor?

A

A DISC is fromed which initiates apoptosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What is a DISC?

A

the fas receptor bound to adaptor proteins which are bound on the other end to procaspase molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Describe how a virus infected cell gets delt with.

A

Virus infected cells present viral peptides at the cell surgace (antigen)
T Cell Receptors (TCR) recognize the antigen
this causes the fas ligand to bind the fas receptor and initiate apoptosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

How does the DISC initiate cell apoptosis?

A

By activating procaspases and helping them dimerize.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What are C. elegans?

A

Nematodes (round worms).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What are doomed cells?

A

cells that are genetically programmed to always undergoe apoptosis in the lifecylce of a multicellular organism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

How many doomed cells were identified in C. elegans?

A

131

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

What are the CED-3 and CED-4 genes required for?

A

apoptosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

What is the function of CED-9?

A

suppress apoptosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What is the vertebrate analog to C. elegans CED-9, CED-4, and CED-3?

A

Bcl-2, Apaf-1, and Casp9

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

Vertebrates require an aditional step to initate cell death when compared to C. elegans. What is it?

A

Casp9 needs to activate Casp3 in vertebrates
C. elegans undergo cell death after CED-3 (the Casp9 analog) is activated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

What are the different stem cell types and how are the different?

A

Embryonic (pluripotent) stem cells
Adult (somatic) stem cells
somatic maintain a specific tissue while pluripotent differentiate into various tissue types

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

Where do pluripotent stem cells come from?

A

the blastocyst

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

True of False?

C. elegans have somatic stem cell lines for most of their tissue types?

A

False
the only somatic stem cell lines in C. elegans are the germ line stem cells (GSCs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

What are the vili?

A

specialized epithelial areas of the gut that absorb nutrients

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

True of False?

The vili have a high turnover rate and must constantly be replaced.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
59
Q

Where do find vili?

A

Mammalian intestines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
60
Q

What is the tip of the vili called?

A

Villus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
61
Q

What is the basal cavity of a vili called?

A

the crypt

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
62
Q

What is the function of goblet cells in the vili?

A

mucus secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
63
Q

Where are new cells made for the vili?

A

at the bottom of the crypt

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
64
Q

where are old cells recycled in the vili?

A

at the villus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
65
Q

How long does it take a new cell in the crypt to navigate to the villus?

A

3 to 6 days

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
66
Q

How is the crypt structured?

A

The very bottom are dividing stem cells
middle half is dividing precursor cells (non-differentiated)
top portion is non-dividing, differentiated cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
67
Q

What are the cells types at the very bottom of the crypt in villi?

A

dividing stem cells
non-dividing terminally differentiated Paneth cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
68
Q

True of False?

Cells continue to divide in the villus?

A

false

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
69
Q

What are the two cell types of the villus?

A

secratory cells
absorbative cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
70
Q

Where are skin cells born?

A

The bottom of the epidermis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
71
Q

What happens to newly replicated skin cells?

A

They differentiate into keratin containing cells, die, and finally shed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
72
Q

What is the major layer below the epidermis?

A

The dermis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
73
Q

What sepperates the dermis from the epidermis?

A

The Basal Lamina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
74
Q

Define Tissues.

A

Tissues are groups of cells that act together to perform a specific function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
75
Q

What are groups of cells that perform specific functions called?

A

Tissues

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
76
Q

What are gap junctions?

A

Transmembrane proteins that link the cytoplasm of neighboring cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
77
Q

What is allowed to flow through gap junctions?

A

ions and small molecules.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
78
Q

Describe the morphology of gap junctions.

A

Six subunits cyclize to form a nm channel.
These macrounits are called connexons
Two connexons from different cells connect to form a gap junction.
The space between cells with gap junctions is 2-4 nm.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
79
Q

What are desmosomes?

A

Protein complexes that form strong physical connections between cells.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
80
Q

Describe the morphology of desmosomes.

A

Keratin filaments bind to cytoplasmic plaque.
Cytoplasmic plaque binds to transmembrane cadherin proteins.
Cadherin proteins of differnet cells interact to bind the cells together.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
81
Q

What is the cytoplasmic plaque made of?

A

intracellular linker proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
82
Q

In reference to the Extra Cellular Matrix (ECM) what facilitates a strong network between cells?

A

Secreted proteins and polysaccharides.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
83
Q

True or False?

Integrin links the cell to the collagen of the ECM?

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
84
Q

Where is integrin found?

A

The plasma membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
85
Q

What is vitamin C deficiency commonly known as and what does it do?

A

Scurvy
It weakens connective tissues (loss of ECM)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
86
Q

What is proline?

A

An amino acid.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
87
Q

What is hydroxylation?

A

The addition of an alcohol (hydroxyl) group

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
88
Q

What hydroxylizes proline?
What does this enzyme require as a co-factor?

A

procollagen-proline dioxygenase
vitamin C (ascorbate)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
89
Q

What is the Ascorbate also known as?

A

Vitamin C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
90
Q

What is vitamin C also known as?

A

Ascorbate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
91
Q

Describe the morphology of collagen fibers.

A

Amino acid chains containing proline fold into a-helical chains.
Three a-helical cahins form a collagen molecule.
Many collagne molecule form a collagen fibril (like rope).
Many fibrils form a collagen fiber (like a bigger rope).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
92
Q

True or False?

There are many distinct epithelial systems disconnected from one another.

A

False
There are many epithelial systems but they are all connected.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
93
Q

Describe the various functions of epithelial cells.

A

protection, secretion, absorption, excretion, filtration, diffusion, and sensory reception.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
94
Q

Describe where epithelial cells can be found.

A

All body surfaces, lining of cavities and hollow organs, and glands.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
95
Q

What is the major cell type found in glands?

A

epithelial

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
96
Q

What is the general category of disease caused by aging?
Name three specific examples.

A

damage-based diseases
cancer, diabetes, and alxheimer’s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
97
Q

How does aging affect telomeres?

A

Aging reduces telomere length.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
98
Q

How does aging affect dividing cells?

A

Aging causes a loss of dividng cells (stem cells).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
99
Q

About how many times can stem cells divide?

A

Aproximately 50

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
100
Q

What things accumulate with aging?

A

damaged cells and molecules as well as mutations in nuclear and mitochondrial DNA.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
101
Q

True or False?

Researchers originally thought yeast were immortal.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
102
Q

How many times can yeast divide before going into senescence?

A

about 25 to 30 times

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
103
Q

What is senescence?

A

G zero phase of the cell cycle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
104
Q

What is the replicative lifespan of yeast?

A

The time when yeast are actively replicating

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
105
Q

What is the chronological lifespan of yeast?
Aproximately how long is the chronological lifespan in yeast?

A

The survival of non-replicative yeast.
weeks to months

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
106
Q

True or False?

90% (aprox.) of a cells DNA and proteins are dedicated to regulation.

A

True, maybe
Babst made up the number

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
107
Q

True or False?

There is a corilation between complexity of organism and genes dedicated to regulation.

A

True
more complex = more regulation genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
108
Q

Name some cellular programs.

A

cell differentiation, cell cycle initiation, celly cycle exiting, apoptosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
109
Q

True or False?

Each step from brith to death of a protein can be regulated

A

True
and it usually is regulated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
110
Q

What does each type of regulation require?

A

A certain time to respond to a signal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
111
Q

What types of things are controlled via regulatory processes?

A

transcription, enzyme activity, protein stability, protein localization, cellular programs, RNA processing, mRNA transport and localization, mRNA degredation, translation, etc.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
112
Q

Why does regulation inhibit enzymes from creating their product?

A

an overaccumulation of product makes product synthesis inefficient.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
113
Q

Where is product inhibition (enzyme regulation) used commonly?

A

Metabolic pathways

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
114
Q

is feedback regulation (enzyme regulation) inhibitory or activating?

A

inhibitory

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
115
Q

What is feedback regulation (enzyme regulation) mainly used for?

A

regulating non-reversible reactions
regulating key steps in metabolic pathways

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
116
Q

describe feedback regulation (enzyme regulation).

A

A chemical affects the quantity or activity of an enzyme such that the chemicals synthesis is blocked. I.e. a chemical blocks a reaction upstream in the pathway that led to its synthesis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
117
Q

True or False?

Chemicals can only block one step/reaction in a cellular pathway (feedback regulation).

A

False

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
118
Q

What is aspartate transcarbamoylase?
What does it do?

A

An enzyme involved in the synthesis of the nucleotides CTP,UTP, and TTP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
119
Q

How does aspartate transcarbamoylase (asp-t) get regulated?
What kind of regulation is this?

A

A downstream product of asp-t, CTP, binds the regulatory site of asp-t and inactivates.
feedback regulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
120
Q

What does CTP bind and inactivate?

A

aspertate transcarbamoylase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
121
Q

When CTP bind aspertate transcarbamoylase what is CTP functioning as?

A

a regulatory ligand

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
122
Q

What do kinases do?

A

phosphorylate things

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
123
Q

What is phosphorylation?

A

The addition of a phosphate group to something via covalent bond

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
124
Q

Describe how covalent modifications can regulate proteins.

A

The presence of a phosphate group covalently bound to a protein can activate or inactivate the protein.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
125
Q

What do phosphotases do?

A

remove phosphate groups from proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
126
Q

What does acetylation do to lysine?

A

removes the posative charge by adding an acetyl group to the amine
R-NH3+ to R-NH-Acetyl

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
127
Q

True or False?

Ubiquitination is a form of protein regulation.

A

True
it is a form of regulation via covalent modification

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
128
Q

True or False?

p53 has a relatively simple regulation system.

A

False
it hase many phosphorylation, acetylation, and ubiquitination sites

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
129
Q

True or False?

p53 acts as a coincidence detector.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
130
Q

How does localization regulate proteins?

A

The presence of certain bound molecule affects the functionality of a protein.
Think when GTP is bound protein equals ON
When GDP is bound protein equals OFF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
131
Q

Describe how Sar1 is an example of protein regualtion via localization.

A

When Sar1 is bound to GDP it is inactivated and soluable
When the GDP is swapped for GTP by an exchange factor (GEF ) a hydrophobic tail is esposed on Sar1 allowing it to bind to a membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
132
Q

What does active, anchored Sar1 do?

A

initiates vesicle formation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
133
Q

What is an alternative name for protein regulation via assembly?

A

protein complex formation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
134
Q

What does the assembly of coat proteins and cargo receptors do?

A

drives vesicle formation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
135
Q

What are Sec23 and Sec24?

A

coat proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
136
Q

What form of regulation controls Actin and why?

A

assembly/disassembly and localization
the presence of ATP vs ADP changes what actin subunits can do. the synthesis or degredation of AF is what drives the functionality of AF

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
137
Q

What are the different types of protein regulation via proteins synthesis?

A

Regulation of transcription
Regulation of mRNA processing
Regulation of mRNA nuclear export
Regulation of mRNA stability
Regulation of translation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
138
Q

What are transcription factors?

A

DNA binding proteins that regualte transcription initiation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
139
Q

What are the two domains of transcription factors?

A

DNA binding domains and transcription regualtory domains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
140
Q

True or False?

Most transcription factors are monomers but some are dimers.

A

False
most are dimers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
141
Q

What do homeodomains do?

A

form hydrogen bonds with nucleobases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
142
Q

Where do homeodomains locate themselves when binding to nucleobases?

A

Mostly the major groove of DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
143
Q

True or False?

Homeodomain-DNA interactions are specific for certain DNA sequences.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
144
Q

What are homeodomains important for?

A

development in multicellular organisms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
145
Q

What are homeodomains?

A

The parts of transcription factors which bind to the DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
146
Q

What do homeodomain transcription factors do to increase specificity?

A

function together with other transcription factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
147
Q

How do leucine zipper transcription factors interact?

A

They form dimers

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
148
Q

Describe the leucine zipper transcription factor complex structure when bound to DNA.

A

Two a-helix cross and from an x shape reffered to as the leucine zipper. one groove of the x stratles DNA and the two legs bind the DNA on opposite sides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
149
Q

True or False?

Yeast are an example of simple eukaryotes.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
150
Q

what is the promoter region of a gene?

A

the region upstream of a transcription start site where transcription factors bind the DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
151
Q

What is an enhancer region of a gene?

A

a binding site for transcriptional activator proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
152
Q

Where are enhancer regions of genes located?

A

They can be upstream or downstream of the transcriptional start site

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
153
Q

In what type of eukaryote can transcriptional acitvators act far away from the transcription start site?

A

higher eukaryotes (more complex)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
154
Q

True or False?

Many transcription factors act together to regulate transcription.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
155
Q

How specific are transcription factor binding sites?

A

not that specific

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
156
Q

What is the mediator complex?

A

a protein complex that interacts with several transcription factors to regulate transcription initiation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
157
Q

How do transcription repressors do their job?

A

Physically compteing with activating transcription factors for DNA binding sites or suppressing transcription via the mediator complex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
158
Q

What is a transcription factor?

A

DNA binding protein that affects transcription initiation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
159
Q

How are transcription activators and repressors different?

A

activators increase transcription of a gene while repressors decrease transcription

160
Q

what is an enhancer?

A

DNA sequence that is recognized by a transcription activator

161
Q

what is a silencer?

A

DNA sequence that is recognized by a transcription repressor

162
Q

True or False?

Trancription activators and repressors are what we call transcription factors.

A

True

163
Q

Describe the promoter region.

A

DNA region usually upstream of the transcription start site with enhancer/silencer sequences and importantly an RNA polymerase binding site.

164
Q

What are the three states of the gal promoter?

A

repressed, de-repressed, and active

165
Q

What keeps the gal promoter repressed?

A

the presence of glucose

166
Q

In the absence of glucose and galactose what blocks the Gal4 activator?

A

Gal80

167
Q

What condition are needed for the total activation of Gal4?
How does this activation work

A

The presence of galactose and absence of glucose
the absence of glucose removes downstream inhibitory proteins
galactose then binds Gal3.
Gal3 binds to Gal80
Gal80 in turn unbinds Gal4 thus activating it.

168
Q

True or False?

Some transcription factors can affect the expression of hundreds of target genes.

A

True

169
Q

Describe how transcription factors affect cell identity.

A

Several transcription factors which control complex gene expression programs can lead to changes in gene expression patterns.

170
Q

Name the types of protein regulation covered.

A

feedback regulation
covalent modification regulation
localization regulation
assembly regualtion
synthesis regulation

171
Q

Which type of protein regulation has sub categories of regulation?

A

synthesis regulation

172
Q

How can trasncription factors influence transcription initiation through recruitment?

A

By recruiting histone modefying enzymes or chromatin remodeling proteins

173
Q

What is the consequence of histone acetylation?

A

It can help recruit transcription factors to the promoter region.

174
Q

How do chromatin remodeling proteins affect transcription?

A

They can increase access to trasnscriptional start sites

175
Q

What are epigenetics?

A

Heritable changes in gene function/activity that are not changes in DNA sequence

176
Q

What form do epigenetics mostly present as?

A

Changes in transcription

177
Q

**

What is the memory effect?

A

Epigenetic mechanism involved in cell fate determination and other long term changes in cell populations

178
Q

How clear is it that epigenetic changes propogate to daughter cells?
future generations of individuals?

A

clear (well known)
less clear

179
Q

What are the two major mechanisms of epigenetic changes?

A

histone modification
DNA methylation

180
Q

What is the enzyme group that does DNA methylation?

A

methyltransferases

181
Q

What gets methylated in DNA methylation?

A

cytosine

182
Q

What does DNA methylation do?

A

suppresses gene expression by recruiting/attracting transcription repressors

183
Q

True or False?

DNA methylation is forgotten by the second generation of following daughter cells.

A

False
The methylation pattern is maintained by daughter cells

184
Q

What does epigenetic histone modification do?

A

Changes the access to promoter regions

185
Q

True or False?

Histone modification can be inherited by the daughter cells.

A

True

186
Q

How are histones modifications different in the gametes?

in humans

A

They are mostly erased

187
Q

What is most of the genome dedicated to in higher eukaryotes?

A

regulatory RNA molecules (rRNA)

188
Q

What is the function of micro-RNAs (miRNA)?

A

trigger the degredation of mRNA or reduce their translation efficiency

189
Q

What is the function of small-interfering RNAs (siRNA)

A

they protect cells from foreign RNA

190
Q

What is a function of long non-coding RNAs?

A

regulation of gene expression

191
Q

What are the regulatory RNAs?

A

miRNA
siRNA

192
Q

Describe how miRNA leads to the degredation of mRNA.

A

Precursor miRNA is processed to form miRNA
single strand miRNA gets bound by RISC protien(RNA-induced silencing complex)
miRNA -RISC complex binds mRNA and the mRNA is degraded

193
Q

Besides mRNA degredation how do miRNAs affect gene expression?

A

interfering with translation

194
Q

What are siRNAs made of?
What binds a mature siRNA?

A

cleaved foreign RNA
RISC protein

195
Q

What do researchers use siRNAs for?

A

silence expression of a specific gene

196
Q

What is Gcn2?

A

a kinase

197
Q

What is elF2?

A

a Translation initiation factor

198
Q

What activates and thus causes Gcn2 to phosphorylate elF2?

A

uncharged t-RNA

199
Q

What does phosphorylated elF2 do?

A

blocks the guanidine-exchange factor (GEF) elF2B

200
Q

What does elF2B do?

A

activates elF2 by exchanging the GDP for GTP

201
Q

What does Gcn2 do in the big picture and why?

A

starvation conditions activate Gcn2 which blocks general translation.

202
Q

What is an example of protein regulation via protein degredation?

A

cyclins getting degraded at specific times in the cell cycle
p53 getting degraded constantly unless damaged DNA is detected

203
Q

True or False?

Many cell surface proteins get inactivated by endocytosis.

A

True

204
Q

What is the general way in which cell signaling works?

A

extracellular signal is sensed, signal gets sent inside the cell, and protein regulation changes as a result.

205
Q

What are the basic types of cell communication?

A

Contact dependent (cell-cell contact)
synaptic (directed)
paracrine (short distance)
endocrine (long distance)
Autocrine (self signaling)
gap junctions (cell connection)

206
Q

describe paracrine signaling.

A

signal A changes gene expression in neighboring cells resulting in secretion of signal B. Signal B induces changes in gene expression of neighbor cell which equals differentiation.

207
Q

True or False?

The cummulation of multiple signals is what tells the cell what to do.

A

True

208
Q

What do signaling scaffolds do?

A

increase speed, efficiency, and specificity of signal transduction

209
Q

What are the two types of signaling scaffolds?

A

preformed and post-activated

210
Q

what is the general structure of signaling scaffolds?

A

intracellular protein which binds on one end to a receptor protein
along the length of the scaffold other inracellular signaling proteins bind in order

211
Q

How does receptor down regulation work?
Why is this process important?

A

a signal molecule and its bound receptor is endocytosed and degraded in the lysosome
This process adjusts sensitivity to a signal (it can turn off a signal)

212
Q

What is are the two basic types of receptors? Which one is more common?

A

cell-surface (more common) and intracellular receptors

213
Q

Which signal receptor binds hydrophobic signals and which binds hydrophilic?

A

hydrophobic -> intracellular
hydrophilic -> cell-surface

214
Q

What is signal transduction?

A

The process of communicating an extracellular signal to intracellular components

215
Q

What do intracellular receptors typically function as?

A

transcriptional regulators

216
Q

What are nuclear hormone receptors?

A

lignad-regulated transcription factors

217
Q

How is signal transduction often mediated?

A

phosphorylation and small GTPases

218
Q

What are second messengers?

A

small moelcule or ions that relay the signal from the plasma membrane throughout the cell including the nucleus

219
Q

How are second messengers often used?

A

They are used for the amplification of a signal

220
Q

What are three cell surface receptor families?

A

G protein coupled receptors
receptor tryosine kinases
notch receptor

221
Q

What is the largest family of cell surface receptor proteins?

A

G protein coupled receptors (GPCRs)

222
Q

How many GPCRs are found in humans?
How many in yeast?

A

over 700
3

223
Q

How many transmembrane domains do GPCRs have?

A

7

224
Q

What is the G protein of GPCRs made of?

A

a trimer of the alpha, beta, and gamma subunits

225
Q

What G protein subunit acts like a small GTPase

A

the alpha subunit

226
Q

What does the activated GPCR act like?

A

a GEF (guanedine exchange factor)

227
Q

What happens once a GPCR gets activated?

A

It binds to a G protein complex
G alpha-GDP becomes G alpha-GTP
G alpha dissociates form G beta-gamma

228
Q

What are downstream targets usually called?

A

effectors

229
Q

G alpha-GTP does what?

A

interacts with effectors and triggers their activation

230
Q

What does trimerization do to G alpha and G beta-gamma complexes?

A

turns off their signaling

231
Q

What do high levels of cAMP cause?

A

lipolysis (breakdown of storage fat)

232
Q

True or False?

Adenylyl cyclase only gets activated by G proteins .

A

False
G proteins can activate and deactivate adenylyl cyclase depending on the type of g protein

233
Q

What are heart pacemaker cells?

A

neurons

234
Q

how does acetylcholine affect pacemaker cells?

A

Acetylcholine binds a GPCR
G protein trimer gets activated and alpha subunit seperates from beta-gamma
beta-gamma subunit binds and opens a potassium channel
potassium flux hyperpolarizezs the membrane potential which makes action potential harder to form
this slows down heart reat
hydrolysis of G alpha-GTP terminates this signal

235
Q

*

What is a Pl?

A

a phospholipd that plays an important role in cell signaling and protein trafficking

236
Q

True or False?

Pls have one phosphorylation site?

A

False

237
Q

What do the different phosphorylated versions of Pls do?

A

function as markers for different membranes in the cell

238
Q

What do Ptdlns do?

A

function as specific markers for organelles

239
Q

How many different binding domains do ptdlns have?

A

many, at least four

240
Q

What is the function of Ptdlns?

A

localize proteins to specific organelles or to activate signaling cascades

241
Q

Ptdlns4p is specific to where?

A

Golgi

242
Q

Ptdlns4,5P2 is specific to where?

A

plasma membrane

243
Q

Ptdlns3P is specific to where?

A

lysosomes

244
Q

Ptdlns3,5P2 is specific to where?

A

lysosomes

245
Q

How do Ptdlns direct trafficking?

A

Proteins bind the Ptdln that associates where they want to go

246
Q

**

What is the result of the inositol phopholipid pathway?

A

activated protein kinase C (PKC)

247
Q

What role does calcium2+ play in signaling?

A

it is a messenger

248
Q

describe how calcium2+ functions as a messenger.

A

very little calcium is in the cytoplasm so its release has profound impacts on the cell

249
Q

What is the sensitivit of human rod cells?

A

about five photons

250
Q

How do human rod cells work?

A

cation channels open in the dark resulting in depolarization
this leads to constant neurotransmitter secretion

251
Q

What closes the cation channels in rod cells?

A

light

252
Q

Where are rod cells found?

A

The back of the retina which is the back of the eye

253
Q

describe how light closes cation channels in rod cells.

A

light activates a GPCR which activates a G protein complex
the active A subunit acitvates a cGMP phosphodiesterase
the phosphodiesterase converts cGMP to GMP
lower cGMP means the cGMP gated channel gets closed

254
Q

What is retinal?

A

the light sensitive co-factor in rhodopsin

255
Q

What is rhodopsin?

A

opsin (GPCR) + retinal

256
Q

How many G proteins can be activated by rhodopsin which has absorbed only one photon?

A

500

257
Q

True or False?

One photon can casue a rod to send a signal to the brain.

A

True
The signal amplification system in rods can do this but typically you would want/need more photons for a signal to the brain

258
Q

How can the dark signals of rods (rhodopsin by proxy) be conveyed in light situations?

A

Rhodopsin kinase can use ATP to phosphorylate rhodopsin
this reduces G protein Alpha subunit from being activated

259
Q

if rhodpsin has been phosphorylated enough and there is still more light what happens?

A

arrestin can bind the phosphate groups and inactivate rhodopsin completely

260
Q

What does notch receptor signaling require?

A

direct cell contact

261
Q

When a notch receptor binds the substrate what happens?

A

The intracellular domain gets proteolyticaly celaved and the cleaved domain becomes a transcription activator

262
Q

What do notch receptors function in?

A

Multicellular organism development

263
Q

How many subfamilies are there of Receptor Tyrosine Kinases (RTKs)?

A

Seven

264
Q

What is the largest class of RTK?

A

Eph receptor

265
Q

What are the major morphological components of RTKs?

A

transmembrane domain
tyrosine-kinase domain (Cytosolic)
kinase insert region (Cytosolic)
Cysteine rich domain (Extracellular)
Immunoglobulin-like domain (Extracellular)
fibronectin type III like domain (Extracellular)

266
Q

What is the rarest type of kinase?

A

Tyrosine Kinase

267
Q

What is the energy source and source of phosphate for a Kinase?

A

ATP

268
Q

What are trophic factors?

A

Factors that tell the cell to live

269
Q

List the seven families of RTKs.

A

EGF receptor
insulin receptor, IFG-1 receptor
NGF receptor
PDGF receptor, M-CSF receptor
FGF receptor
VEGF receptor
Eph receptor

270
Q

What activate the EGF receptor?

A

Epidermal growth factor (EGF)

271
Q

What is EGF a potent promoter of?

A

cell survival, growth, and proliferation

272
Q

List some facts about EGF.

A

53 amino acid protein
3 intramolecular disulfide bridges (Cys-Cys)
Produced by several cell types notably epithelia cells
Almost all human cells respond to EGF

273
Q

What do most RTKs activate?

A

the small GTPase Ras

274
Q

What do RTK signaling molecules usually take the form of?

A

protein/peptide dimers

275
Q

When a signaling molecule binds RTKs what happens?

A

The RTKs dimerize

276
Q

What does RTK dimerization do?

A

Activates the tyrosine kinase

277
Q

What does the active tryosine kinase do?

A

phosphorylates the other RTK

278
Q

Once the RTK has been phosphorylated what happens next?

A

signaling protiens are recruited to the RTK in a scaffold like manner and they relay the signal to different effectors

279
Q

How does an active RTK interact with the Ras protein?

A

an adaptor binds the active RTK to Ras-GEF
the Ras-GEF exchanges the Ras GDP with GTP

280
Q

What is the on state of the Ras protein?

A

GTP bound

281
Q

When Ras gets activated What happens?

A

downstream signaling pathways are activated

282
Q

Where is Ras located?

A

the cytosolic side of the plasma membrane

283
Q

What is MAP KInase?

A

Mitogen Activated Protein Kinase

284
Q

What acitvates MAP kinase kinase kinase?

A

The active Ras protein

284
Q

What activates MAP kinase kinase?
What does this activate?

A

MAP kinase kinase kinase
MAP kinase

285
Q

What does MAP kinase activate?

A

many proteins involved in gene expression and protein control

286
Q

What kinds of signals can MAPKs interpret?

A

Chemical, enviromental, physical, etc.

287
Q

Describe the diversity of MAPks signaling response diversity.

A

everything from protein regulation to osmolarity control to cell locomotion

288
Q

What do we call a complex cellular response?

A

a cell program

289
Q

True or False?

Sexual reproduction is limmited to higher order eukaryotes.

A

False

290
Q

What is required for conjugation in yeast sexual reproduction.

think signaling

A

A pheromone pathway

291
Q

How do scaffold proteins contribute to signaling orginization?

A

They seperate and arange different signaling pathways.

292
Q

What receptor activates the Pl 3 kinase? What is the signal that binds this receptor?

A

RTKs
trophic factors

293
Q

Where is Ptdlns (3,4,5)P3?

A

the cytosolic side of the cell membrane

294
Q

What does the production of Ptdlns (3,4,5)P3 casue?

A

Protein kinases get recruited to the plasma membrane

295
Q

What do protein kinases bind to on Ptdlns (3,4,5)P3?

A

the phospho domains

296
Q

What does the inactive Akt kinase bind to?

A

the phospho domains of Ptdlns (3,4,5)P3

297
Q

What is Bcl2?

A

An apoptosis inhibitor

298
Q

What is the inactive Bcl2 protein bound to?

A

The Bad protein

299
Q

What phosphorylates Bad (protein)?

A

Akt Kinase

300
Q

When Bad gets phosphorylated what happens?

A

Bad becomes inactive
Bcl2 gets released and activated

301
Q

How does p53 activate apoptosis?

A

through the protein Bax

302
Q

what does Bax do?

A

release cytochrome c from the mitochondria

303
Q

How does Bcl2 inhibit apoptosis?

A

by supressing Bax and the relase of cytochrome c

304
Q

what is the function of apoptosis?

A

safety system to remove cells that losse normal communication and control

305
Q

True or False?

when cells do not receive trophic factors they stay in the state they are in.

A

False
the abscense of trophic factors leads to apoptosis

306
Q

What is uncontrolled cell division called?

A

cancer

307
Q

what does Tor stand for?

A

Target of Rapamycin

308
Q

what is Tor?

A

A kinase regulated by nutrient availability

309
Q

How do low nutrients affect Tor?

A

They block Tor activity

310
Q

What is the result of low Tor activity?

A

autophagy, blocked translation, and blocked cell cycle (starvation response)

311
Q

what drug blocks Tor?

A

rapamycin

312
Q

When injested what does rapamycin do to a cell?

A

induces the starvation response

313
Q

What is the pharmaceutical purpose of rapamycin?

A

used to prevent transplant organ rejection

314
Q

What activates Tor Kinase?

A

Akt

315
Q

What does activated Tor kinase do?

A

inhibits protein degredation and stimulates protein synthesis

316
Q

True or False?

Tor kinase acts as a coincidence detector.

A

True

317
Q

What are coincidence detectors?

A

proteins that integrate many intra and extracellular signals to determine cell fate
they take all the info available and make a decision

318
Q

True or False?

Signaling pathways are linear chains to definite responses.

A

False
lots of signaling pathways are linear but many also interconnect and the result is not always the stimulated cell program

319
Q

What is the significance of receptor desensitization?

A

Maintaining special and temporal specificity of signal

320
Q

How is the activated EGFR degraded?

A

rapidly via the MVB

321
Q

what activates the EGFR?

A

EGF binding it

322
Q

cellular-Cbl (c-Cbl) does what?

A

binds and ubiquinates activated EGFR

323
Q

what is c-Cbl?

A

a ubiquitin ligase

324
Q

how is v-Cbl differnet from c-Cbl?

A

v-Cbl was discovered first
v-Cbl was found in viruses
v-Cbl is shorter than c-Cbl
v-Cbl binds EGFR but does not ubiquinate it

325
Q

What is a micro-consequence of v-Cbl binding EGFR?

A

EGFR can not be ubiquinated

326
Q

What is the macro-consequence of v-Cbl being expressed in a cell?

A

Tumorigenesis

327
Q

what is an oncogene?

A

a gene which can stimulate transformation of a cell into a tumor cell when expressed

328
Q

True or False?

v-Cbl is a normal oncogene.

A

False
it is a potent oncogene

329
Q

True or False?

Many oncogenes are mutated tumor suppressors.

A

True

330
Q

Synonym for Tumorigenesis

A

oncogenesis

331
Q

Oncogenesis meaning

A

cancer forming process

332
Q

proto-oncogene meaning

A

a gene that when mutated promotes tumor formation

333
Q

True or False?

Proto-oncogenes and tumor supressor genes often function in cell cylce regulation, apoptosis, and/or cell signaling.

A

True

334
Q

What are the two defining charachteristics of cancer?

A

uncontrolled division
invasion into other tissues

335
Q

what is the most common type of cancer?
Where does it start?

A

carcinomas
eptithelia cells

336
Q

What is important to remember about cancer formation?

A

it requires an acumulation of a series of mutations

337
Q

True or False?

Cancer cells maintain their identity as the travel through the organism.

A

False
they loose their identity

338
Q

List some things required for tumorigenesis.

A

self-sufficient growth signaling
insensitivity to antigrowth signals
evasion of apoptosis
limitless replicative potential
tissue invasion and metastasis
sustained angiogenesis

339
Q

What is angiogenesis?

A

The formation of new blood vessels

340
Q

What things do cancer “evolution” require?

A

High mutation rate
high proliferation rate
TIME

341
Q

How does cancer loose regulatory systems?

A

through genetic mutations

342
Q

What are the mutations that lead to cancer?

A

mutations in coding regions
gene amplification
chromosome rearrangement

343
Q

why is genetic background (multi generational heredity of individuals) important to cancer?

A

mutations can be inherited form parents

344
Q

What is a dominant mutation?
What is a recessive mutation?

A

gaining a function
loosing a function

345
Q

What is an example of cancer exhibiting genetic instability?

A

higher mutation rate
chromosomal translocation (peices of chromosomes getting rearranged )

346
Q

Why are HeLA cells really bad for research?

A

The scrambled DNA changes the functionality of the cells compared to healthy cells

347
Q

What causes gentic instability?

A

external factors (x-rays, UV, radiation, chemicals) damage DNA
Oxygen radicals made by the mito. can react with DNA
DNA replication is not perfect

348
Q

Why does it make sense that most cancers are carcinomas?

A

they have lots of exposure and high chemical rates

349
Q

What causes the rapid acumulation of mutations in cancer cells?

A

the loss of DNA repair systems and DNA damage check points

350
Q

What percent of human cancers have mutations in p53?

A

50

351
Q

what is p53 in terms of cancer?

A

a tumor suppressor

352
Q

How does p53 work?

A

when dna damage is detected p53 is activated
p53 promotes the expresion of p21
p21 binds and inactivates Cdks thus stopping the cells cycle

353
Q

Why is angiogenesis necessary for cancer?

A

cancer needs nutrients to survive and grow

354
Q

What is the furthest any cell in the body will get away from a blood vessel?

A

about four cells

355
Q

What are many cancer cells required to do for energy?
Why is this?

A

they are forced to do fermentation for ATP
they are too far way from blood vessels and thus oxygen

356
Q

How do tumor cells upregulate glycolysis?

A

overexpression of glucose importers and glycotic enzymes

357
Q

What is APC

A

a ubiquitin ligase

358
Q

what tells cells in the crypt to proliferate

A

the wnt signaling pathway

359
Q

What turns off the wnt signaling pathway?

A

degredation of the transcription factor beta-catenin

360
Q

what degrades beta-catenin?

A

APC via ubiquitination and transport to the proteasome

361
Q

What is the other name for the E3 enzyme?

A

APC

362
Q

How can APC mutations lead to cancer?

A

They can lead to loss of proliferation control which could lead to cancer

363
Q

What is the rate fo breast cancer for women in the US?

A

about 1/8

364
Q

What are BRCA 1 and BRCA 2?

A

tumor supressor genes

365
Q

When BRCA 1/2 mutate what happens?

A

Risk of breast cancer increases dramatically

366
Q

What are BRCA 1/2 involved in?

A

repair of double stranded DNA breaks

367
Q

DNA double stranded break (DSB) repair by recombination is good becasue why?

A

the repair is error free

368
Q

How is DSB repair by DNA ligase differnet than by BRCA 1/2?

A

DNA ligase repair losses a few nucleotides near the break site
BRCA 1/2 looses no nucleotides near the repair site

369
Q

How do BRCA 1/2 repair DSBs?

A

by processing the broken ends and using undamaged DNA as a template

370
Q

True or False?

Cancer cells listen to the signals of surrounding cells?

A

False

371
Q

What is the morphology of breast cancer cells?

A

amorphous cell clusters

372
Q

What is metastasis?

A

cells of the primary tumor becoming mobile, invading other tissues, and forming secondary tumors

373
Q

Tumors that stay local and do not metastasize are called what?

A

Benign

374
Q

Tumors that metastasize are called what?

A

malignant

375
Q

For metastasis to happen what is required?

A

weakening of cell-cell interactions
more specifically weakening of the ECM

376
Q

what is the protein at the branching points of actin?

A

Arp 2/3

377
Q

Describe how blebbing works.
How do cancer cells use this for movement?

A

The cell membrane looses contact with the cortex
turgor pressure forces the membrane out into a bubble

The blebbed portion of cell membrane sticks to a new cell and the blebbed cell pulls itself in this direction

378
Q

How controlled is the movement of cancer cells?

A

uncontrolled and totaly random

379
Q

What does adenylyl cyclase do?

A

Produces cAMP

380
Q

What is the lipid that signals phagocytosis when exposed to the extracellular space?

A

phosphatidylserine (PS)

381
Q

What is the learned function of phosphatidylserine (PS)?
what is PSs charge?

A

signal phagocytosis when exposed to the extracellular space during apoptosis
negative

382
Q

What blocks aspartate trasncarbamoylase?
what kind of regulation is this?

A

CTP (a product of aspartate transcarbamoylase)
feedback regulation

383
Q

besides interacting with the mediator complex how else can transcription factors influence transcription initiation?

A

by recruiting histone modefying enzymes and chromatin remodeling proteins/complex

384
Q

What do histone modefying enzymes do?

A

acetylate histone
the acetyl group helps recruit transcription factors to the promoter region

385
Q

what is the name of the enzyme that acetylates histone (lysine side chains).

A

acetyltransferase

386
Q

How do chromatin remodeling complex affect transcription?

A

the physically increase access to the promoter region of a gene by spreading out nucleosomes

387
Q

What are the two epigenetic mechanisms?

A

histone modification and DNA methylation

388
Q

what enzyme methylates cytosine?

A

methyltransferase

389
Q

what does methylated cytosine do?

A

recruits transcription repressors

390
Q

what do general histone modifications do?

besided recruiting transcription factors.

A

they change access to the promoter region of a gene

391
Q

What does Ptdlns stand for?

A

phosphoinositides

392
Q

What is the abreviation for phosphatidylserine and phosphoinositides

A

PS and Ptdlns respeectiveyly

393
Q

Describe the inositol phospholipid pathway.

A

a signal binds a GPCR
active GPCR acts as a GEF for a G protein
the disosiated a subunit activates a phospholigase
the phospholigase cleaves the lipip portion of ptdnls4,5p2 from the inositiol
the lipid portion anchors protein kinase C (PKC)
the 1,4,5 inositol travels to the ER and binds as a ligand to a ligand gated claium channel
calium (Ca2+) is released into the cytoplasm and binds the PKC
the PKC is now active

394
Q

What is the final produc of the inositol phospholipid pathway?

A

protein kinase C