Cell Signaling

Question 1

Communication between cells in a
multicellular organism is a critical function
of life

Answer 1

cell signaling

Question 2

Type of Signaling:
signaling between adjacent cells

Answer 2

juxtacrine signaling

Question 3

Type of Signaling:
signaling between nearby cells

Answer 3

paracrine signaling

Question 4

Type of Signaling:
signaling between distance cells

Answer 4

endocrine signaling

Question 5

who can respond to signals?

Answer 5

Only cells with a receptor tuned to the
specific signal can respond to the signal

Question 6

What is responding to signals?

Answer 6

changing some cellular signaling
-enzyme activity
-gene expression
-cell division

Question 7

Reception:
most chemical signals are ____

Answer 7

hydrophilic

Question 8

Hydrophilic signals can’t pass the membrane without help, which means…

Answer 8

most receptors are integral transmembrane proteins

Question 9

Transmembrane proteins function on ____ sides of the membrane

Answer 9

both

Question 10

Types of Chemical Signaling:
-Pass through the plasma membrane and bind a specific receptor in the cytoplasm or in the nucleus
-Activated Receptor–Ligand Complex
regulates genes by binding to DNA

Answer 10

Lipid-Soluble Signals (hydrophobic)

Question 11

• Receptors found in the cytoplasm or in the nucleus
• Signal must be primarily hydrophobic or very small to diffuse through the membrane.

Answer 11

intracellular signaling

Question 12

Types of Chemical Signaling:
-Cannot pass through the membrane
– Bind to specific plasma membrane receptors
– The Receptor–Ligand Complex activates a cascade of events in the cell

Answer 12

Water-Soluble Signals (Hydrophilic)

Question 13

Signal must be
hydrophilic and thus
unable to diffuse through
the membrane.

Answer 13

membrane-bound receptors

Question 14

-Ligand-Gated Ion Channel
-G Protein-Coupled Receptor
-Enzyme-Linked Receptor

Answer 14

Type of Membrane-Bound Receptors

Question 15

Type of Membrane-Bound Receptors:
a ligand (ex: ACh) binds to a receptor, which then opens to let ions through

Answer 15

Ligand-Gated Ion Channel

Question 16

Type of Membrane-Bound Receptors:
a receptor is coupled with a G-protein, which is activated and causes a cascade of signaling in the cell

Answer 16

G-protein Coupled Receptor

Question 17

Type of Membrane-Bound Receptors:
an enzyme (ex: insulin receptor) after signaling molecule binding can catalyze other molecules (substrates) which allows for cellular responses

Answer 17

Enzyme-linked receptor

Question 18

-Reception of a signal triggers a series of
steps that eventually leads to a
biochemical response
-pathway of changes

Answer 18

signal transduction pathway

Question 19

Signal Transduction:
The most common regulatory step is
the addition or removal of a
____

Answer 19

Phosphate Group

Question 20

Adding Phosphate

Answer 20

Phosphorylation

Question 21

Phosphorylation:
General name for an
enzyme that adds a phosphate group from ATP to a protein

Answer 21

protein kinase

Question 22

Removes phosphate

Answer 22

protein phosphatase

Question 23

Reverses the action of the kinase
- Returns protein to its original conformation
– Allows protein to be reused
- In cells, there is a balance between kinase activity
and phosphatase activity

Answer 23

protein phosphatase

Question 24

activated by the initial signal (First
Messenger) and carry instructions
through the cell

Answer 24

second messengers

Question 25

-A common and important second
messenger
-generated from ATP by adenylyl cyclase

Answer 25

cyclic AMP (cAMP)