Cell model, Osmosis, Active Transport and Endo/Exocytosis

Question 1

Current cell model and what it means

Answer 1

Fluid mosaic model which is defined as the cell membrane being a tapestry of several types of molecules (phospholipids, cholesterols, and proteins) that are constantly moving. This movement helps the cell membrane maintain its role as a barrier

Question 2

What is the David-Danielli Model and why is it relevant to current models?

Answer 2

Danielli and Davson proposed that such a membrane would exhibit selective permeability, being capable of distinguishing between molecules of different size and solubility properties and also between ions of different charge.

Question 3

Who created the fluid mosaic model

Answer 3

Singer and Nicholson

Question 4

What is Osmosis

Answer 4

diffusion of solvent molecules through a selectively permeable membrane from a region of high water potential to a region of low water potential as to equalise.

Question 5

What is endo and exocytosis

Answer 5

Endocytosis is an invagination of the cell surface to form an intracellular membrane-bounded vesicle containing extracellular fluid67; exocytosis may be considered the opposite process—that is, fusion of a plasma membrane–bounded vesicle to the cell surface, followed by release of its contents.

Question 6

Explain the process of endo to exocytosis (dunno if this will be on test)

Answer 6

Material is brought from surface in coated vesicle which is fused with a primary lysosomes to become a secondary lysosome. Membrane with receptor detaches from secondary lysosomes which detaches material. Receptors and membrane are returned to surface.

Question 7

Difference between phagocytosis and pinocytosis

Answer 7

While phagocytosis involves the ingestion of solid material, pinocytosis is the ingestion of surrounding fluid(s)