Cell Communication Flashcards

1
Q

Quorum Sensing

A

Method of communication that allows bacteria to detect population density

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2
Q

Local Signalling

A
  • Signalling that occurs in near by cells
  • Includes direct contact via cell junctions and cell-to-cell recognition
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3
Q

Long-distance signalling

A

Signalling that occurs between different parts of the body

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4
Q

How does long-distance signalling work?

A

Based on the secretion of hormones produced by plants and animals

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5
Q

Endocrine Signalling

A

Long-distance signalling in animals

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6
Q

What are the 3 stages of cell signalling?

A
  1. Reception
  2. Transduction
  3. Response
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7
Q

What does reception require?

A

A protein with the correct binding site to recognize a signalling molecule

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8
Q

Ligand

A

Molecule that specifically binds to another often larger molecule

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9
Q

What happens when a signalling molecule binds to a receptor?

A
  • Its binding impacts the shape and function of the receptor
  • Activates it
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10
Q

2 different types of receptors

A
  1. Cell-surface receptors
  2. Intracellular proteins
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11
Q

What are cell-surface receptors?

A
  • Integral membrane proteins
  • 3 main types exist
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12
Q

G protein-coupled receptors (GPCRs)

A
  • First type of cell-surface receptor
  • Work with a G protein that binds to GDP/GTP
  • Activate or inhibit GDP/GTP
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13
Q

Receptor tyrosine kinases (RTKs)

A
  • Second type of cell-surface receptor
  • Self-phosphorylates, dimerizes and structurally modifies relay proteins
  • Can activate up to 10 signal transduction pathways
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14
Q

Dimerization

A

Process of joining molecular entities by bonding

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15
Q

Ligand-gated ion channel receptors

A
  • Third type of cell-surface receptor
  • Channel that opens in response to a signalling molecule
  • For signal molecules and transported metabolite
  • Can be voltage-gated
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16
Q

Histidine Kinases (HKs)

A
  • Cell-surface receptor in bacteria
  • Self-phosphorylates, then phosphorylates a response regulator protein
  • For signal molecule and response regulator
17
Q

Signalling Molecules

A

Molecules that are hydrophobic and small enough to pass through the plasma membrane

17
Q

Examples of signalling molecules

A

Steroids and NO gas

18
Q

Where are intracellular receptors found?

A

In the cytoplasm and nucleus

19
Q

Functions of intracellular receptors

A
  • Increase or decrease the rate of transcription
  • DNA binding protein that influences gene expression
20
Q

Signal Transduction

A
  • Conversion of a signal into a form that can cause a specific cellular response
  • Can be a single step but more often is a multistep process
21
Q

Multistep signal transduction pathway

A
  • Enable amplification of the signal and more opportunities for regulation
  • Involves relay molecules
22
Q

Protein Phosphorylation and dephosphorylation

A
  • Method of regulating protein function
  • Through addition or removal of phosphates
23
Q

Protein Kinase

A
  • Enzyme that adds a phosphate group to a protein from ATP
24
Protein phosphatase
Enzyme that removes a phosphate group from a protein
25
Phosphorylation cascade
Signalling pathway involving a series of phosphorylation events
26
What are second messengers?
- Small, nonprotein, water-soluble molecules - Can diffuse through cytoplasm
27
Second messenger functions
- Involved in signal transduction - Influence activity of relay proteins
28
What is cyclic AMP (cAMP)
- Second messenger - Activates other proteins, usually protein kinase A
29
How is cyclic AMP synthesized?
- Synthesized by adenylyl cyclase, which is activated and inhibited by G protein-coupled receptors
30
What are calcium ions?
- Second messenger - Act as allosteric regulators of proteins involving G protein-coupled receptors and receptor tyrosine kinases
31
Where are calcium ions found in the cell?
- Higher concentrations in extracellular fluid and ER lumen than in cytosol - Release of calcium ions from ER lumen are mediated by IP3
32
What is a response?
- Final stage of cell signalling - Involves changes in gene expression - Can also involve regulating the rate of a protein's activity
33
How does a response change gene expression?
Through the activation or repression of the transcription of specific genes
34
What is a proteome?
Complete set of proteins present in a cell
35
What is signal specificity?
Different cells have different responses to the same signal based on their collection of proteins
36
What is signal termination?
- Once the signal is removed everything inactivates - Based on reversibility of the changes produced by a signal