Topic 6

Question 1

Most cells synthesize and secrete materials external to the

Answer 1

plasma membrane

Question 2

Extracellular structures include

Answer 2

Cell wall of plants
Extracellular matrix of animals
Intercellular junction

Question 3

Plant cell wall structure

Answer 3

Cellulose fibers embedded in other polysacs + proteins

Question 4

Primary cell wall

Answer 4

relatively thin and flexible

Question 5

Middle lamella

Answer 5

thin layer between primary walls of adjacent cells

Question 6

Secondary cell walls

Answer 6

(Insome cells): addded between the plasma membrane and the primary cell wall

Question 7

Plasmodesmata

Answer 7

Channels between plant cells

-Intercellular junctions of plant cenll

Question 8

Extracellular Matrix of Animal cells

Answer 8

Function of the ECM:
-maintains adhesion across tissue
-allows communication across tissue
and coordinates activities across tissue
-regulates gene expression
-support/protection ->tissue integrity

Question 9

More about ECM of Animal Cells

Answer 9

Made of glycoproteins such as collagen, proteoglycan and fibronectin
-Bind to receptor proteins in plasma membrane called Integrins

Question 10

Types of intercellular junctions:

Answer 10

• plasmodesmata (plants)
• tight junction (animal)
• desmosomes (animal)
• gap junctions (animal)

Question 11

Plasmodesmata

Answer 11

channels that perforate plant cells walls

-water and small solutes and sometimes proteins and RNA can pass from cell to cell

Question 12

Tight junction

Answer 12

membranes od neigboring cells are pressed together and bound together by proteins, preventing leakage of extracellular fluid

Question 13

Desmosomes

Answer 13

(anchoring junctions) function like rivets to hold cells together into strong sheets.

• distribute tension forces across tissues
• intercellular connection of cytoskeleton

Question 14

Gap junctions

Answer 14

(communicating junctions)
provide cytoplasmic channels between adjacent cells
-non-selective channel