Exam 3: Cell-cell interactions (Class 2) Flashcards

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1
Q

What are the five categories of signaling?

A
  1. direct intercellular signaling
  2. contact-dependent signaling
  3. autocrine signaling
  4. paracrine signaling
  5. endocrine signaling
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2
Q

What is direct intercellular signaling?

A

Cell junctions allow signaling molecules to pass from one cell to another at rate of diffusion (via gap junction)

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3
Q

What type of junctions are used in direct intercellular signaling?

A

Gap junctions

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4
Q

How does contact dependent signaling work?

A

Receptors on adjacent cells bind to other cell surface molecules

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5
Q

What do the cell surface molecules in contact dependent signaling function as?

A

Signals

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6
Q

What is the difference between direct intercellular signaling and contact dependent signaling?

A

Direct intercellular: passed from cytoplasm to cytoplasm
Contact dependent: adjacent cell membranes

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7
Q

What is autocrine signaling?

A

Cells secrete signaling molecules that bind to its own surface or other neighboring cells

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8
Q

What is paracrine signaling?

A

Same as autocrine, but no receptors so a cell cannot receive its own signal

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9
Q

Endocrine signaling

A

Signals travel long distance through blood stream, take a long time to fade

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10
Q

What are the 4 stages of cell signaling?

A
  1. Signal reception
  2. Signal processing/transduction
  3. Signal response
  4. Signal deactivation
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11
Q

What occurs in signal reception (step 1)?

A

Signal receptors are bound

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12
Q

What are the two type of signals

A
  1. Hormones
  2. Other cell-cell signals
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13
Q

The presence of what dictates which cells will be able to respond to a particular hormone

A

appropriate receptor proteins

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14
Q

What does protein function depend on? (3 factors)

A
  1. Binding
  2. Shape
  3. Location
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15
Q

When the signal binds to the receptor, what happens to the receptor

A

It undergoes a conformational change

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16
Q

Signal receptors that bind to lipid-soluble hormones are located where

A

Inside the cell

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17
Q

Signal receptors that bind to non lipid-soluble hormones are located where

A

in the plasma membrane

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18
Q

Lipid-soluble steroid hormones are ___ soluble in water

A

less

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19
Q

Estrogen, progesterone, glucocorticoids, and ecdysone are examples of what

A

hormone response elements

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20
Q

The hormone receptor complex binds to…

A

the hormone response elements (HRE)

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21
Q

Where is the hormone-receptor complex transported to and for what

A

the nucleus, for altering gene expression

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22
Q

Are lipid-soluble hormones hydrophilic or hydrophobic

A

hydrophobic

23
Q

Are lipid-insoluble hormones hydrophilic or hydrophobic

A

hydrophilic

24
Q

When a signal binds at the cell surface, it triggers a complex series of events called a …

A

signal transduction pathway

25
Q

After the receptor undergoes a conformational change once a lipid-insoluble hormone binds to it, what happens

A

A secondary messenger is released

26
Q

What happens once the second messenger is released

A

It can be amplified

27
Q

Signal transduction moves information from where to where

A

From the cell surface to the nucleus/other targets

28
Q

What are the three kinds of cell surface receptors?

A
  1. G-protein coupled receptors (GPCR)
  2. Enzyme-linked receptors
  3. Ligand-gated ion channels
29
Q

All of the three kinds of cell surface receptors are what type of membrane protein

A

Integral

30
Q

How many transmembrane segments do GPCRs have?

A

7

31
Q

When G-proteins are bound to GTP, the G-protein is ___

A

on

32
Q

When G-proteins are not bound to GTP, the G-protein is ___

A

off

33
Q

What is the first step for GPCRs

A

Signal received

34
Q

What is the second step for GPCRs

A

G protein binds GTP and splits

35
Q

What is the third step for GPCRs

A

The activated G protein binds to an enzyme, which catalyzes the production of a secondary messenger

36
Q

GPCRs are found in all _____ and are common in _____

A

eukaryotes, animals

37
Q

What are the two parts of an enzyme-linked receptor?

A

Extracellular domain and intracellular domain

38
Q

Which domain of enzyme-linked receptors binds the signal?

A

Extracellular

39
Q

Which domain of enzyme-linked receptors becomes a functional catalyst?

A

Intracellular

40
Q

Most enzyme-linked receptors are ___

A

kinases

41
Q

What are the two types of receptor kinases?

A
  1. Receptor tyrosine kinase (RTK)
  2. Receptor serine/threonine kinase (RSTK)
42
Q

What is the first step of RTK catalyzing a reaction?

A

Hormone binds to an RTK, signal received

43
Q

What is the second step of RTK catalyzing a reaction?

A

RTK forms a dimer and is phosphorylated by ATP

44
Q

What is the third step of RTK catalyzing a reaction?

A

Ras protein exchanges its GDP for GTP, while it is bridged to RTK

45
Q

What is the fourth step of RTK catalyzing a reaction?

A

Ras protein triggers the phosphorylation and activation of another protein

46
Q

What is the fifth step of RTK catalyzing a reaction?

A

Phosphorylation cascade amplifies the signal many times

47
Q

What is phosphorylation cascade?

A

Sequence pathway where one enzyme phosphorylates another and so on

48
Q

Which type of cell surface receptor is found both in plant and animal cells?

A

Ligand-gated ion channels

49
Q

What is another name for a signal

A

ligand

50
Q

What happens when a ligand binds to a ligand-gated ion channel

A

The ion channel opens and ions flow in through the membrane

51
Q

In animals, synaptic signals are between ___ and _____ or between two _____

A

Neurons and muscles or between two neurons

52
Q

What are three examples of signal response (stage 3)?

A
  1. change enzyme activity
  2. change function of structural proteins
  3. change gene expression or regulation
53
Q

What are two factors that can alter signal deactivation

A
  1. concentration of hormones
  2. number and activity of signal receptors