Homework #1 is posted and due 9/17 Bonus #1 is posted and due 10/24 Discussions started this week

Expressing genes under the appropriate conditions is critical for development and survival. Protein

Cells and organisms must monitor and respond to the environment. Is there anybody out there?

What is the most critical internal and external stimuli for a human cell to perceive and respond to?

Signal transduction step by step: Perception

Signal transduction step by step: Transduction

Signal transduction step by step: Response – such as changes in cellular components or production of new cellular components

Transduction can involve activation or inactivation of proteins.

Cellular responses may involve changes in the expression of genes.

Blood sugar levels as an example of cellular responses to the environment

Why so many steps?

Multiple steps allow for signal specificity. Different relay molecules lead to different responses

Multiple steps allow for signal amplification: Calcium is a simple method of amplifying signals