Chapter 2 - Guyton Flashcards
Water composes how much of the cell?
70-85%
What is the main structural difference between structural proteins and functional proteins?
structural - composed mainly of long filaments; functional - tubular-globular form
What is the significance of carbohydrate to the cell?
little function structurally except as part of glycoprotein but plays a major role in nutrition for the cell
Which type of proteins (integral or peripheral) are the majority of glycoproteins?
integral
The carbohydrates on the glycocalyx have what charge?
negative (repel other substances)
How does cholesterol contribute to the membranes structurally?
decreases fluidity and permeability while increasing flexibility and stability
Which organelle is similar to (and contiguous with) the plasma membrane?
ER
Pathway of newly formed substances to exit cell.
granular ER–>smooth ER–>transport vesicles–>Golgi apparatus–>secretory vesicles–>exit cell membrane
What happens to proteins when they are “processed”?
crosslinked, folded, glycosylated (N-linked), cleaved
What is synthesized in the smooth ER?
lipids (phospholipids and cholesterol)
General characteristics of Golgi apparatus.
membrane composition similar to that of the smooth ER and plasma membrane, composed of 4 or more stacked layers of flat vesicular structures
What occurs at the Golgi apparatus?
receives transport vesicles from the smooth ER, substances formed in the ER are phosporylated and glycosylated, substances are concentrated, sorted, and packaged for secretion
What occurs during exocytosis?
secretory vesicles diffuse through the cytosol and fuse to the plasma membrane, lysosomes fuse with internal endocytotic vesicles
What occurs during secretion?
secretory vesicles containing proteins synthesized in the RER bud from the Golgi apparatus, fuse with plasma membrane to release contents
What are the two types of secretion?
constitutive (random) and stimulated (trigger)