Functional organization of the cell

Question 1

3. The student will be able to explain the differences between integral and peripheral membrane proteins

Answer 1

Peripheral protein
Adhere tightly to the surface of the plasma membrane
Integral protein
Spans the phospholipid bilayer one or more times OR
Are halfway through the membrane OR
On the outside but it’s attached to the cell membrane by a covalent bond

Question 2

The student will be able to explain the various roles of integral proteins

Answer 2

Receptors, adhesion molecules, transporters, enzymes, signal transduction components

Question 3

6. The student will be able to describe the junctional complexes: tight junctions, adhering junctions, gap junctions and desmosomes

Tight junction

Answer 3

(zonula occludens): impedes the passage of molecules and ions between the cells of the epithelial monolayer
Associated protein: claudins

Question 4

Adherens junctions

Answer 4

(zonula adherens): belt that encircles an entire epithelial cell just below the level of a tight junction. gives clues about nature / proximity of neighbors. Made of actin filaments
Associated protein: cadherins

Question 5

Gap junctions

Answer 5

channels that interconnect with the cytosols of neighboring cells. allow small molecule diffusion
Associated protein: connexons

Question 6

Desmosomes

Answer 6

(macula adherens): holds adjacent cells together tightly at a single, round spot. Have intermediate filaments
Associated protein: cadherins