The extracellular matrix (ECM) is mostly made up of proteins with carbon chains attached (glycoprotein). These proteins (collagen, fibronectin, integrin, etc.) form chains that can communicate between the cytoskeleton and the ECM. Cell junctions (desmosomes, tight junctions, and gap junctions) connect cells through filaments and channels. In plants, plasmodesmata, channels between two cells, are an important means of communication. Cells can also communicate over distances through hormones. The three phases of signaling are reception, transduction, and response. Key receptor types include G-protein receptors, receptor tyrosine kinases (RTKs) (which can perform autophosphorylation), ligand-gated ion channels, and intracellular receptors. In the transduction phase, second messenger molecules like cGMP, inositol triphosphate, and diacylglycerol , calcium, IP3, and DAG carry the message to its destination. Responses can include the production of proteins, growth, and apoptosis.
plants, channels called plasmodesmata provide a means for
communication between cells by allowing the cytoplasm of adjacent
cells to be in contact with one another.
junctions are connections between cells which allow for
communication between cells and coordination of activities. Three
types of cell junctions are desmosomes, tight junctions and gap
first phase of cell signaling is the reception phase. This involves
the binding of a ligand to a receptor. This interaction induces a
conformational change in the receptor.
types of cell membrane receptors are G-protein coupled receptors,
ligand gated ion channels and receptors with intrinsic enzyme
activity, such as receptor tyrosine kinases.
transduction is the transmission of the message from the surface of
the cell to the inside of the cell via a cascade of steps, which
involve the activation of enzymes and proteins.
messengers such as cAMP, cGMP, IP3
and DAG often mediate the signal transduction pathway.
binding of a signal molecule to a receptor elicits a response by the
cell. Responses include increasing or decreasing the transcription
of a gene or increasing or decreasing the activity of a protein.
Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.
The book and CD package include two full length practice exams that are presented with all questions answered and explained. The author also presents detailed reviews of all test topics and includes multiple-choice and free-response questions with answers at the end of each topic's chapter.
This book includes a review of the AP Biology exam format and scoring, proven strategies for answering multiple-choice questions, and hints for tackling the essay questions. The practice tests include answers and explanations and there is also proven test-taking strategies for both the multiple choice and essay parts.