Lecture 8

Question 1

Cell walls

Answer 1

extracellular structures that distinguish plant cells from animal cells
they protect, maintain shape and prevent excessive uptake of water

Question 2

Gram positive bacteria

Answer 2

• simpler structure
• single layer

Question 3

Prokaryotes

Answer 3

two types of cell wall, identified by different staining properties

Question 4

Gram negative bacteria

Answer 4

more complex structure, two layers, thin peptoglycan and exterior lipsaccharide

Question 5

Fungi

Answer 5

some are single cells like yeast
many fungi have hyphae

Question 6

Fungal cell walls

Answer 6

made of chitin
chitin is acetyl glucosamine

Question 7

Plant cell walls

Answer 7

cell wall called a frustule
made of silica
potential use for bio production

Question 8

Extracellular matrix

Answer 8

holding animal cells together
ECM consists of
glycoproteins such as:
-collagen
-proteoglycans
-fibronectin

Question 9

Integrins

Answer 9

ECM proteins bind to receptor proteins in the plasma membrane
- the skin ECM is primarily composed of collagen and proteases
- deterioration of eCM= loss in collagen production = wrinkles
- vitamin C increases collagen production
- UV damage kills fibroblasts cells

Question 10

Communication intercellular junctions

Answer 10

plasmodesmata (plants)
gap junctions (animals)

Question 11

Adhesion intercellular junctions

Answer 11

tight junctions (animals)
desmosomes (animals)

Question 12

Cellular connections

Answer 12

gap junctions
tight junctions
desmosomes

Question 13

Gap junctions

Answer 13

provide cytoplasmic channel between adjacent cells

Question 14

Tight junctions

Answer 14

membranes of neighbouring cells are pressed together, preventing leakage of extracellular fluid

Question 15

Desmosomes

Answer 15

anchoring junctions

fasten cells together into strong sheets