Download Cell Communication Part II

Warm-Up (12/08)
On the piece of white paper from the back, answer
the following question.
Create a model showing a
generic cell signaling pathway
before and after a ligand binds
to a receptor. Show how
binding to a ligand regulates
gene expression.
Name
Date
Period
The Endocrine System
Glands release hormones (protein ligands) which
travel through the body through the bloodstream.
Signal-sending
cell
P
Signal-receiving
cell
The Endocrine System
Glands release hormones (protein ligands) which
travel through the body through the bloodstream.
Example: Insulin signaling
Signal-receiving
cell
insulin
P 2nd
messenger
Blood
glucose
stays low
Genes
encoding
proteins which
release glucose
Cell Communication
Cells can communicate…
Long distance: by, for example, hormones
released in the blood.
Short-range: by, for example,
neurotransmitters across a
synapse (Thursday).
Directly: by, for example, immune cells
recognizing antigens on pathogens
(Wednesday).
Critical Thinking Question #1
Discuss this question with your partner and write or
represent it. I will call on three people to share their
partners’ answers.
Explain why ligands can be secreted by
signal-sending cells or attached to the
surface of signal-sending cells. Which case
would be used to send a long-distance
signal?
Whole-Body Functions
Glycogen breaks
down to release
glucose.
Adrenaline
Hormones
regulate wholebody functions.
Liver
Whole-Body Functions
Signal transmission determines cell function.
amount of ligand
Gene
expressed
What if this was activated in
the head?
Whole-Body Functions
Signal transmission determines cell function.
Fly with this much
ligand
in the
head.
amount of ligand
Gene
expressed
Fly with this much
ligand
in the
head.
Unicellular Functions
Unicellular bacteria communicate with
each other through quorum sensing.
Bacterium
Ligand
Critical Thinking Question #2
Discuss this question with your partner and write or
represent it. I will call on three people to share their
partners’ answers.
Patients suffering from Type I diabetes are
required to take regular insulin injections to
maintain low blood sugar levels. Insulin is a
hormone ligand that has been proven to
reduce the release of glucose from liver
cells. Justify the claim that insulin causes
liver cells to stop secreting glucose.
Drugs work by
blocking receptors.
Example: blood-pressure drugs, birth-control drugs
ligand
Signal-receiving cell
(not activated!)
P
drug
2nd messenger
(not activated!)
receptor
(not activated!)
Target gene
(not activated!)
Closure
On the piece of white paper from the
back, answer the following question:
Explain how a drug could affect
signal reception between cells
and, consequently, the entire
signal transduction pathway.
Name
Date
Period
Scale
1 – 10