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Biology > 7 - Cell Cell Interactions > Flashcards

7 - Cell Cell Interactions Flashcards

chapter 8

0
Q

What does ECM stand for?

A

extracellular matrix found in animals

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1
Q

What are integral proteins?

A

transmembrane proteins intracellular connection with actin - in they cytoskeleton binds with fironectins

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2
Q

Where would the ECM components be synthesized?

A

Rough ER

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3
Q

_______ bind with actin intracellurally and __________ fibers extracellularly

A

Integrins Fibronectin

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4
Q

ECM varies in the amount present based on what?

A

ECM varies upon which tissues - highly found in areas requiring structural support - skin & bones

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5
Q

Cartilage secretes what?

A

collagen

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6
Q

What is a tight junction?

A

The proteins that stitch cells together, like quilting

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7
Q

Which ECM does leaky gut syndrome affect?

A

it breaks tight junctions

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8
Q

What is the adhesion protein that rivets the cells together called?

A

desmosomes

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9
Q

What are the three characteristics of a desmosome?

A
  1. contains cadherin proteins - trans membrane protein that binds it
  2. only binds to the same kind of cadherin
  3. intracellularly binds to intermediate filaments
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10
Q

___________ channels are between animals cells and allow for communication and exchange of ions

A

Gap Junctions

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11
Q

What are the gaps between plant cells that allow for passage of ions and small molecules

A

plamodesmata

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12
Q

Where in the body do you find a prevalence of gap junctions?

A

in the heart tissue

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13
Q

Define gap junctions

A

they are the connection between adjacent calls specialized as protein channels, allow H20, a-a sugar and nucleotides to move

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14
Q

list the three main forms of communication between cells

A

1 - paracrine - localized chemical signals 2 - nerves - neurotransmitters 3- hormones & growth factors

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15
Q

Why do only some cells react to cellular communication?

A

signal receptors are specific and determine the response

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17
Q

briefly describe how lipid soluble signal transduction works this may be incorrect - standby

A

hormonal -> lipid soluble interacts directly inter-cellularly through direct signaling processing

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17
Q

The bacteria vibrio cholera permanently turns on a G protein resulting in the activation a pumps that secrete Na +, Cl-, K+ and other ions. What are the implications of this?

A

the cell is loosing hydrophilic ions which would draw out H20 from the body and encourage elimination

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18
Q

briefly describe how lipid insoluble signal processing works

A
  • cannot x mb Reception
  • Reception:
    • binds @ mb surface
    • changes shape reception site
  • Processing:
    • signal transduced from one form to another, eg G protein linked
    • Amplifies = 2nd messanger turns on pumps, genes
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19
Q

What is signal amplification?

name the major types

A

how a small message can turn on a huge response

intracellularly

2 types: enzyme linked & G Proteins

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20
Q

name the two general actions of signal transduction

A
  1. reception
  2. processing
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21
Q

Great question for the final: describe the process of either G protein related cell to cell interaction, or communication via enzyme linked receptors

A

know how to do this

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22
Q

Why would a G Protein be non-responsive?

A

hhmmmm - I can’t remember the answer to this, but I was sure that it would be a test Q possibly from cross talk

23
Q

What is cross talk?

A

the interaction of simultaneous communication between cells that can be excitatory, inhibitory or hold a response

24
Q

How are G Proteins and Enzyme linked receptors similar?

A

The both can cause both or either Phosphoralization cascades or 2nd messangers

25
Q

How is an enzyme linked receptor different than a G protein receptor?

A

the receptor acts as an enzyme (changes shape) & has a higher capacity to activate more transduction pathways

26
Q

How is the signal transduction phosphorylation cascade turned off?

A
  1. ligand moves away from the receptor
  2. enzymes deactivate in the cells eg in the G protein GTP -> GDP
  3. PHOSPHATASES protein - removes Pi from enzyme or dephosphoralates
  4. to stay operational - extracellular signal ahs to contine or it`s shut down
27
Q

Name the three 2nd messengers reviewed in class

A

Ca+ cyclic GMP cyclic AMP

28
Q

What do 2nd messangers do?

A
  1. turned on by an activated enzyme
  2. Change which genes are being expressed in a target cell
  3. Activate/deactivate target protein that already exists in a cell eg mb channel, activating gene
29
Q

What is protein kinase?

A

an enzyme that phosphorylates - that crops Pi’s off

30
Q

Signal transduction has 2 responses, what are they?

A
  1. converts extracellular messages to intracellular messages
  2. in many cases it causes the message to amplify
31
Q

T/F Are send messengers proteins?

A

no they are enzymes

32
Q

When a ligand binds to an enzyme linked receptor on two inactive monomer, what is formed?

A

a dimer

33
Q

What must be completed before a dimer can become an enzyme?

A

needs to be Phosphorylated

34
Q

list the sequence of events in the signal transduction pathway

A
  1. signal is received
  2. signal is transduced
  3. signal is amplified
  4. cellular response
35
Q

What is cross talk?

A
  • diverse signals can increase
  • decrease signal response
36
Q

Where can ECM be found in plants

A

they can`t, ECM is a fibre composite of protein found in animals

37
Q

In the animal world how are cells connected

A

desmosomes gap junctions tight junctions

38
Q

How are plant cells held together

A

tight junctions plasmodesmata held together by gelatenous proteins & sugars hydrophiliic keeps lamina wet

39
Q

List the steps of how a G Protein triggers the production of a 2nd messanger

A
  1. ligand binds to mb R = binding of inactive G protein (+GDP) - R
  2. GTP displaced GTP = activation station for the G protein
  3. Activates G Protein to bind to Enzyme => change of shape E
  4. Activated E => response -> amplification
  5. Ligand leaves -> G protein hydrolyses GTP ->GDP = inactive
40
Q

list the steps in signal transduction via enzyme-linked receptors

A
  1. 2 Ligands bind to 2 inactive monomers => dimer
  2. Dimerized + Pi = phosphorlated => enzyme
    • inactive protein => activation cellular responce => phosphorylation cascade
41
Q

some phosphorylation cascades cause what

A

production of 2nd messangers

42
Q

how does signal transduction help the system

A
  • increases the response time
  • can be shut down quickly
  • highly sensitive to small changes in hormones or signals
43
Q

What is the correct order for the following events in the interaction of a cell with a signal?

  1. Alteration of cell function
  2. signal binds to receptor
  3. signal released from source
  4. signal transduction

Select one:
A. 1234
B. 2314
C. 3214
D. 3241
E. 3421

A

which one is it

D

44
Q

Why do some signals (first messengers) trigger second messengers to activate target cells?

Select one:

  1. The first messenger requires activation by ATP
  2. The first messenger is not water soluble
  3. The first messenger binds to many types of cells
  4. The first messenger cannot cross the plasma membrane
  5. There are no receptors for the first messenger.
A
45
Q

The function of the extracellular matrix (ECM) in most multicellular organisms is
Select one:
1. To provide structural support
2. To provide strength
3. To organize cells
4. Cell signalling
5. All answers apply

A
46
Q

The activation of receptor tyrosine kinases is characterized by

Select one:

  1. Dimerization and phosphorylation
  2. Dimerization and calcium release
  3. A phosphorylation cascade
  4. GTP hydrolysis
  5. Channel protein shape change
A

1

47
Q

Plasmodesmata and gap junctions

Select one:

  1. Allow small molecules and ions to pass rapidly between cells
  2. Are both membrane-lined channels
  3. Are present only on either side of a cell
  4. Are involved in cell recognition
A

1

48
Q

Clostridium perfringens is a bacterium wich secretes several toxins, one which causes the break down of collagen and another which causes the breakdown of cell adhesion molecules. Explain the impact these toxins would have on cells

A
  • the matrix would start to disintigrate
  • the binding between gap junctions and desmosomes would break. terrible outcomes of bleeding, keeping things out that are supposed to stay out
  • intracellular communication difficult
49
Q

A cell receives a signal to manufacture integrins. Where in the cell would these proteins be produced

A

indomembrane system

50
Q

Compare and contrast gap junctions and plasmodesmata

A

They both are pores between cells for the passage of small molecules and ions

gap junctions = animal cells

plasmodesmata = plant cells

51
Q

Where would you expect to find te receptor for the teroid hormone aldosterone - inside the cell or in the mb. Why

A

intracellularly

lipid soluble = passes through mb and directly to receptors

52
Q

What is protein kinase, and what is its role in a signal transduction pathway

A

an enzyme that phosphorylates from ATM to another protein usually protein kinase = turns on the phosphorylated protein = series = cellular response therefore carrying the signal from outside the cell to the protein that brings about the cellular response

53
Q

Excessive levels of an enzyme-linked receptor called HER2 has been found in some breast cancers. When activated, this receptor stimulates cell proliferation. How could you develop a drug to thwart cancer cell growth in HER2 positive cancers

A

bind down the receptor sites where HER2 binds

54
Q
A

Biology (18 decks)

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