Chapter 11: Cell Communication Flashcards

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1
Q

can signal to each other and interpret the signals they receive from other cells and the
environment

A

cells

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2
Q

are most often chemicals

A

signals

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3
Q

Any molecule that is binding superficially to the receptor.

A

ligand

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4
Q

what does communications among microorganism do

A

how cells
receive
send
respond to signals

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5
Q

has two
mating types, a and α

A

Saccharomyces cerevisiae

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6
Q

how do cells of different mating types locate each other

A

via
secreted factors specific to each type

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7
Q

initiates a series of steps called a signal transduction
pathway

A

binding of a mating factor at the cell surface

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8
Q

were
adopted for use in their multicellular descendants

A

signaling molecules

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9
Q

is critical among prokaryotes

A

cell signaling

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10
Q

allows
bacteria to sense local population density in a
process called quorum sensing

A

concentration of signaling molecules

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11
Q

the regulation of gene expression in response to fluctuations in cell-population density

A

quorum sensing

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12
Q

example of quorum sensing

A

formation of biofilm

or
secretion of toxins by infectious bacteria

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13
Q

is an aggregation of bacterial cells adhered to
a surface

A

biofilm

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14
Q

Interfering with the signaling pathways used in quorum
sensing may be a promising approach as an what

A

alternative to antibiotic treatment

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15
Q

Cells in a multicellular organism communicate via what

A

signaling molecules

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16
Q

animal cells may communicate by
direct contact

A

local signaling

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17
Q

directly connect the cytoplasm of adjacent cells

A

cell junctions

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18
Q

Signaling substances in the cytosol can pass freely
between what

A

adjacent cells

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19
Q

animal cells communicate using
secreted messenger molecules that travel only short
distances

A

paracrine signaling

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20
Q

which stimulate nearby target cells to grow and divide

A

growth factors

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21
Q

occurs in the animal nervous
system when a neurotransmitter is released in
response to an electric signal

A

Synaptic signaling

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22
Q

Local signaling in plants is not well understood
beyond communication between what

A

plasmodesmata

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23
Q

meaning
to stimulate, or set in motion

A

hormone

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24
Q

Compound produced in one part of the
body and then transported to other parts
of the body where it triggers responses in
target cells and tissues.

A

hormone

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25
Q

what do long distance signaling use

A

hormones

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26
Q

Hormonal signaling in animals is called

A

endocrine signaling

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27
Q

specialized cells release hormones, which
travel to target cells via the circulatory system

A

endocrine signaling

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28
Q

The ability of a cell to respond to a signal depends
on whether or not what

A

it has a receptor specific to that signal

29
Q

the target cell detects a signaling
molecule that binds to a receptor protein on the cell
surface

A

reception

30
Q

the binding of the signaling molecule
alters the receptor and initiates a signal
pathway;

A

transduction

31
Q

the transduced signal triggers a specific
response in the target cell

A

response

32
Q

a signal molecule

A

ligand

33
Q

the initial transduction of the signal

A

A shape change in a receptor

34
Q

Most signal receptors are what

A

plasma membrane proteins

35
Q

three types of signal processes

A

receptions
transduction
response

36
Q

three types of membrane receptors

A
  1. G-protein linked receptors
  2. Tyrosine-kinase receptors
  3. Ion-gated receptors (voltage gated)
37
Q

are the largest
family of cell-surface receptors

A

G protein-coupled receptors (GPCRs)

38
Q

G-protein signal transduction pathway steps

A
  1. Signal binds to G-protein receptor
  2. Converts GDP to GTP
    3.Active G-protein binds to another enzyme
  3. This triggers The next step in the pathway
  4. The G-protein acts as its own enzyme, GTPase, and
    Hydrolyzes the GTP to GDP and becomes inactive again
39
Q

many diseases such as
cholera, botulism and other vitamin deficiency
disorders are due to

A

malfunctioning G proteins

40
Q

G-proteins with a GDP (Guanosine Diphosphate) are considered what

A

inactive

41
Q

G-proteins with a GTP is considered what

A

active

42
Q

Changes in relay proteins are affected by
conformational changes involving what

A

phosphorylation

43
Q

an enzyme that transfers phosphate groups from the ATp tp protein

A

Involves protein kinase

44
Q

the signal is transmitted by a series or “cascade” of
protein phosphorylations, each resulting in a
conformational change of the protein
(enzyme).

A

Phosphorylation Cascade

45
Q

what changes a protein from an inactive to active form.

A

shape change in a Phosphorylation Cascade

46
Q

are involved in deactivating active proteins by removing a phosphate group

A

protein phosphates

47
Q

example of Second Messengers in Transduction Pathways

A

Cyclic Adenosine monophosphate (cAMP)
Inositol Triphosphate (IP3) AND Ca 2+

48
Q

can readily spread throughout the cell by
diffusion

A

Second Messengers in
Transduction Pathways

49
Q

cholera infections linked to what

A

g-protein recoetors

50
Q

what caused cholera

A

bacterium (Vibrio cholerae) it is from contaminated water.

51
Q

cholera bacteria modifies G-protein involved in what

A

regulating salt and water secretion

52
Q

what does cholera do the G-protein

A

it cant hydrolyze to GTP to GDP therefore it is always active

53
Q

is stimulated continuously to make cAMP

A

Adenylyl cyclase

54
Q

Trigger more than one signal transduction pathway
at once

A

Tyrosine-Kinase Receptors

55
Q

Often involve growth factor molecules (PDGF) as
chemical signals

A

Tyrosine-Kinase Receptors

56
Q

transfers phosphate group from ATP to Tyrosine

A

Kinase

57
Q

Before the signal molecule binds, the tyrosine-kinase receptors exist as individual what

A

polypeptides

58
Q

what do the receptor polypeptides consist of

A

– Extracellular signal binding site
– Intracellular tail containing several tyrosines
– A single helix spanning the membrane

59
Q

the steps of TYROSINE-KINASE ACTIVATION

A
  1. Signal binding to tyrosine-kinase receptor
    causes the T-K receptor to bind to another
    T-K receptor producing a dimer
  2. T-K enzyme phosphorylates the Tyrosine
    proteins on the opposite receptor
  3. Relay proteins attach at the
    phosphorylated tyrosines and become
    active
60
Q

Channels in these membrane proteins either open or close in response to a chemical signal (ligand) allowing or
blocking the flow of specific ions (such as Na+ or Ca2+)

A

Ion-Channel Receptors

61
Q

A specific ligand binds on the
extracellular side of the membrane

A

Ion-Chanel Receptors

62
Q

Not ALL Receptors are what

A

membrane proteins

63
Q

where are other places that receptor proteins are located?

A

cytoplasm or
nucleus of target cells.

64
Q

To reach non membrane protein receptor, a chemical messenger must be able to what

A

pass through the membrane (HYDROPHOBIC)

65
Q

examples of non membrane protein recepetors

A

Steroid hormones (testosterone)
• Thyroid hormones
• Nitric oxide (NO); small gaseous molecules

66
Q

Secreted by testis cells

A

testosterone

67
Q

steps of how testosterone works

A
  1. Secreted by testis cells
  2. The hormone travels through the blood
    and enters cells all over the body
  3. Target cells have testosterone receptor
    molecules in their cytosol; the hormone
    binds to the receptor, activating it.
  4. The active form of the receptive protein then
    binds to DNA directly and turns on genes in
    the nucleus that control male sex
    characteristics
  5. The receptor carries out the complete
    transduction of the signal.
68
Q

a molecule or molecular complex consisting of two identical molecules linked together.

A

dimer

69
Q

what binds on the extracellular side of a ion channel receptor

A

A specific ligand