Cell Communation

Question 1

Three examples of how cells might change their behavior after receiving a signal:
a.
b.
c.

Answer 1

Express certain genes, carry out chemical reactions, change shape

Question 2

Types of molecules involved in cell communication:
a.
b.
c.

Answer 2

Signal molecule (ligand), Receptor protein, signal transduction proteins

Question 3

If the same signal causes a different response in two different cells, what proteins might be different between the two cells?

Answer 3

Signal transduction proteins

Question 3

Two features all receptors in cell communication have in common:
a.
b.

Answer 3

Bind specific ligands, change shape after binding to ligand (receptor activation)

Question 4

Type of interaction | Action that | Action that
or change | activates | terminates
——————————————————————————-
| Ligand is |Ligand unbinds|
| present and | from the |
__________ | binds to the | receptor and |
| receptor | diffuses away |

Answer 4

Ligand to receptor interactions

Question 5

Type of interaction | Action that | Action that
or change | activates | terminates
——————————————————————————-
| Exchange of | GTP hydrolysis|
__________ | bound GDP | to GDP |
| for GTP | |

Answer 5

G protein

Question 6

Type of interaction | Action that | Action that
or change | activates | terminates
——————————————————————————-
| The binding | The protein |
| of a protein | unbinds from |
__________ | to another | the other |
| protein | protein |

Answer 6

Protein to protein interactions

Question 7

Type of interaction | Action that | Action that
or change | activates | terminates
——————————————————————————-
| Intracellular | Intracellular |
| concentration | concentration |
__________ | of second | of second |
| messenger | messenger |
| increases | decreases |

Answer 7

Second messenger binding to a protein

Question 8

Type of interaction | Action that | Action that
or change | activates | terminates
——————————————————————————-
|Kinase adding| Phosphatase |
__________ | phosphate | removing |
| | phosphate |

Answer 8

Phosphorylation

Question 9

Type of interaction | Action that | Action that
or change | activates | terminates
——————————————————————————-
| Phosphatase | Kinase adding|
__________ | removing | phosphate |
| phosphate | |

Answer 9

Dephosphorylation

Question 10

Intracellular Steroid Hormone Receptor
Action that activates the receptor:

Answer 10

Ligand binding to the receptor

Question 11

Intracellular Steroid Hormone Receptor
Characteristics of ligand: polar / nonpolar

Answer 11

Nonpolar

Question 12

Intracellular Steroid Hormone Receptor
Location of receptor:

Answer 12

Cytosol or nucleus

Question 13

Intracellular Steroid Hormone Receptor
Cellular response:

Answer 13

Change in gene expression

Question 14

Intracellular Steroid Hormone Receptor
Example:

Answer 14

Estrogen binding to the estrogen receptor

Question 15

Ligand-Gated Ion Channels Action that activates the receptor:

Answer 15

Ligand binding to the receptor

Question 16

Ligand-Gated Ion Channels
Cellular response:

Answer 16

Passive transport of ions

Question 17

Ligand-Gated Ion Channels
Example:

Answer 17

Ion channel involved in muscle contraction

Question 18

G protein-coupled receptor
Action that activates the receptor:

Answer 18

Ligand binding to the receptor

Question 19

G protein-coupled receptor
Characteristics of ligand: polar / nonpolar

Answer 19

Polar

Question 20

G protein-coupled receptor
Location of receptor:

Answer 20

Cell surface

Question 21

G protein-coupled receptor
________________:
1. Receptor activates the exchange of GDP for GTP on the G protein
2. Active G protein binds to and activates adenylyl cyclase enzyme
3. Active adenylyl cyclase enzyme converts ATP to cAMP (second
messenger)
4. cAMP binds to and activates Protein Kinase A
5. Active protein kinase A phosphorylates target proteins

Answer 21

Signal transduction steps