Cell SignalingGreg, Lauren, Nancy, Mark, Gene

Facilitator: Paula

LevelIntroductory biology

Knowledge of students prior to unitCell theory

Characteristics of life

Homeostasis

Chemistry of macromolecules

Cell Signaling

Learning Goals:• Understand why cells need to communicate.• Understand the cellular processes involved in

cell communication. • Examine the effects of cell signaling

malfunctions.

Cell Signaling

Learning Outcomes:• Describe the sequence of events that takes place in cell

signaling.• Discuss the relationship between the chemical nature of

ligands and the location of their cellular receptors.• Design and/or evaluate experiments to elucidate the

chemical nature of a ligand and the signaling pathway it induces.

• Explain why different types of cells may respond differently to the same chemical signal.

• Write a synopsis of a cell signaling pathway gone awry.

Learning Outcomes:• Describe the sequence of events that takes place in cell

signaling.• Discuss the relationship between the chemical nature of

ligands and the location of their cellular receptors.• Design and/or evaluate experiments to elucidate the

chemical nature of a ligand and the signaling pathway it induces.

• Explain why different types of cells may respond differently to the same chemical signal.

• Write a synopsis of a cell signaling pathway gone awry

How Would You Improve the USPS?

General Themes

Let’s complete this table

Signal Molecule (ligand)

Nature of Signal Molecule

Receptor Location Response Prior

Knowledge

S-Steroid Hormone P-Protein Hormone

M-Membrane I - Intracellular

E-alters enzymes activity first

G-alters gene expression directly

Write down anything you

may know about the

ligand.

Testosterone S I G

Glucagon P M E

Progesterone

Insulin

Growth Hormone

Let’s complete this table

Signal Molecule (ligand)

Nature of Signal Molecule

Receptor Location Response Prior

Knowledge

S-Steroid Hormone P-Protein Hormone

M-Membrane I - Intracellular

E-alters enzymes activity first

G-alters gene expression directly

Write down anything you

may know about the

ligand.

Testosterone S I G

Glucagon P M E

Progesterone S I G

Insulin P M E

Growth Hormone P M E

Clicker Question

Arrange the steps of cell signaling in the correct order:

a) Reception Response Transduction

b) Response Transduction Reception

c) Transduction Response Reception

d) Reception Transduction Response

e) Transduction Reception Response

Let’s dig a little deeper

1. Close your book and all notes.

2. Take about 2 minutes and draw a diagram of the generalized cell signaling pathway for a:

1. Protein Hormone

2. Steroid Hormone

3. Compare your diagrams with a partner. Make sure that together you have a complete story.

4. You may use your texts to verify your diagrams.

Watch this animation at home to review: http://youtu.be/FkkK5lTmBYQ

Clicker Question

BPA binds to an intracellular receptor. BPA is likely to be a:

a) Protein/Peptide

b) Carbohydrate

c) Steroid/Lipid

d) Nucleic acid

e) Not enough information

Clicker QuestionBL19 cells respond to both ligands X and Y as described in the table below:

If both X and Y are added to a culture of BL19 cells, the cells become yellow (a mixture of red and green). A protease that cannot enter the cells is added to a culture of BL19 cells and then washed off. If X and Y are both added to the protease treated cells, the cells would turn:

a) Red b) Green

c) Yellow d) Blue

Ligand Chemistry Response in BL19 Cells

X Steroid hormone Cells turn green

Y Protein hormone Cells turn red

Write, Pair, Share

1. Now, take a minute to write out a justification for your response.

2. Pair and Share your justifications.

Clicker QuestionBL19 cells respond to both ligands X and Y as described in the table below:

If both X and Y are added to a culture of BL19 cells, the cells become yellow (a mixture of red and green). A protease that cannot enter the cells is added to a culture of BL19 cells and then washed off. If X and Y are both added to the protease treated cells, the cells would turn:

a) Red b) Green

c) Yellow d) Blue

Ligand Chemistry Response in BL19 Cells

X Steroid hormone Cells turn green

Y Protein hormone Cells turn red

Group AssignmentThyroxin is a major hormone produced in the thyroid gland, affects virtually every cell in the body. An experiment to investigate the mechanism of thyroid hormone signaling was conducted in rats. Scientists first surgically removed the thyroid gland from the rats in the experimental group (THX). The rate of protein synthesis was then measured in experimental (THX) and control rats by measuring the rate of radioactive leucine (3H-leucine) uptake by liver cells. The rates of protein synthesis for both groups of rat are shown in the table below.

1. From this experiment, I would predict that thyroxin binds to a(n) ________ receptor.

a) cell surface receptor

b) intracellular receptor

2. The reason for my answer is:

Group Rate of protein synthesis

THX rats 150

Control rats 225