Section 5.5 & 5.6 (JP&MS) Flashcards
What is exocytosis?
The cell recreates certain biological molecules by the fusion of vesicles with the plasma membrane - how large molecules leave the membrane
What is endocytosis?
The cell takes in molecules and particulate matter by forming new vesicles from the plasma membrane - how the cell takes in large molecules
Three types of endocytosis
Phagocytosis - cell eating
Pinocytosis - cell drinking
Receptor mediated endocytosis - takes in cholesterol by human cells
How do neighboring cells signal each other
Local signaling by animal cells involves direct contact or the secretion of growth factors and other signaling molecules.
How do distant cells signal each other
For long-distance signaling, animals and plant cells use hormones; animals also signal electrically.
How do cells process signals
It is a three step process. (1 Reception) (2 Transduction) (3 Response)
What is the first step of cellular signaling
Reception. In Reception, a signaling molecule binds to a receptor protein causing the protein to change shape and send off a new signal. Two major types of membrane receptors are G protein-coupled receptors (GPCRs), which work with cytoplasmic G proteins, and ligand-gated ion channels, which open or close in response to binding by signaling molecules. Signaling molecules that are hydrophobic cross the plasma membrane and bind to receptors inside the cell.
What is the second step of cellular signaling
Transduction. At each step in a signal transduction pathway, the signal is transduced into a different form, which commonly involves a change in a protein’s shape. Many pathways include phosphorylation cascades, in which a series of protein kinases each add a phosphate group to the next one in line, phosphorylation (by protein phosphatase) regulates the activity of proteins in the pathway.
What is the role of Secondary messengers
Secondary messengers, such as the small molecules cyclic AMP (cAMP), diffuse readily through the cytosol and thus help broadcast signals quickly. Many G proteins activate the enzyme that makes cAMP and ATP.
Bulk transport
Across plasma membrane, used to transfer large molecules and macromolecules
