Week 7 Flashcards

1
Q

RAS proteins

A

essential for signaling cells to
divide and grow (proliferate)

  • mutated in 30% of human cancers
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2
Q

Mutant Ras protein

A

stimulates cell growth
and division even when there is no external
EGF binding to EGF-R

(However, microRNA Let-7 can block mutant
RAS)

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3
Q

when RAS RNA binds let-7

A

no translation by ribosome –> no RAS protein

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3
Q

how do microRNAs control gene expression

A

by blocking translation

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4
Q

ligand

A

external signal

lig (bind) as in “ligature”

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5
Q

simple chemical signalling model

A

external signal (ligand)
membrane receptor
internal signal transduction
internal response

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6
Q

Endocrine signalling

A

hormones…

gland secretion into blood

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7
Q

Paracrine signalling

A

chem signal secreted from neighbour cells

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8
Q

Autocrine signalling

A

chem signal secreted and acting on source cell

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9
Q

ATRA

A

all-trans retinoic acid

  • derived from vitamin A
  • binds receptors and activates genes needed for differentiation
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10
Q

steroid hormones

A

i.e. testosterone

promote growth and cell
division in some tissues

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11
Q

what gene mutations and mutation effects would benefit tumour development

A

dominant mutations
gain-of-function mutations
mutation that results in an overactive mitogen’
mutation that results in unregulated mitogen
mutation results in excessive mitogen synthesis

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12
Q

phagocytosis

A

process by which certain living cells called phagocytes ingest or engulf other cells or particles

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13
Q

cytochrome c released from cell

A

mitochondria into cytoplasm during apoptosis

  • stops ATP synthesis, stopping cell metabolism
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14
Q

cytochrome c purpose in normal cell

A

attached to inner membrane
It transfers electrons to molecules
(respiratory complexes) so they can
move protons needed for ATP
synthesis.

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15
Q

BAX

A

pro-apoptosis gene / “tumour suppressor” proteins

causes opening of outer membrane when activated

16
Q

caspases

A

proteins activated when cytochrome c is released

17
Q

clusters of large vesicles during apoptosis

A

degrading cytoplasm contents include protein
fragments

18
Q

If inhaled radon-222 gas

A

decays in lungs radioactive polonium metal is deposited.

  • Radioactive polonium and other metallic
    decay products remain in lungs emitting
    alpha or beta particles until non-radioactive
    lead is produced.
19
Q

Rob McIntosh

A

healthy and fit 31-year-old
non-smoker diagnosed with metastatic lung
cancer (p. 37, Sidebar 2.3), and died at 33.

  • believed radon in family home cause
20
Q

bcl2

A

production in larger amounts may keep cancer cells from dying

(survival signals)

21
Q

successful cancer cell

A

unregulated ability to grow and divide
no/only partial differentiation

  • mitogens : abundant, overactive, unregulated
  • antimitogens : suppressed

increased mutation rate

22
Q

Proto-oncogenes

A

activating, dominant,
gain of function mutations, increased
expression, affecting Bcl2 for example

23
Q

cell fate determination is regulated by…

A

chemical signalling (internally and externally)

24
Cell fates
1: survive 2: Grow and divide 3: differentiate 4: die
25
oncogenic mutations cause...
unregulated gene expression synthesis of unregulated and/or overactive proteins
26
phagocytes
immune system cells that can surround and kill microbes and remove dead cells
27
proteases
aka proteinases - destroy cell proteins - activated by CC release more specifically : caspases
28
tumour suppressor proteins
pro-apoptotic molecules (anti-mitogen) ex. BAX
29
all cell survival signals
are proto-oncoproteins
30
universal cell survival genes
proto-oncogenes (grow and divide) tumor-suppressor genes (pro-apoptosis) tumour-suppressor genes (differentiation)
31
successful cancer cell
like a stem cell unregulated ability to grow and divide no/partial differentiation no apoptosis!