Exam 3: Cell-cell interactions (Class 1)

Question 1

What is an emergent property?

Answer 1

A property that a collection/complex system has, but the individual members do not have

Question 2

What is epithelial tissue?

Answer 2

A sheet of cells that covers a body surface or lines a body cavity

Question 3

In order for multicellularity to occur…

Answer 3

cells have to be bound together

Question 4

Sequence of connections in the epithelium

Answer 4

Epithelial tissue –> basal lamina –> connective tissue

Question 5

What bears the stresses of tension and compression

Answer 5

The extracellular matrix

Question 6

What transmits stresses from cell to cell

Answer 6

Cytoskeletal filaments anchored to cell-matrix and cell-cell adhesion sites

Question 7

What is the condition where mutations in proteins cause epithelia to not adhere to the basal lamina?

Answer 7

Epidermolysis Bullosa

Question 8

3 types of cell-cell attachments

Answer 8

1. tight junctions
2. desmosomes
3. gap junctions

Question 9

Function of tight junctions

Answer 9

seal cells together

Question 10

Function of desmosomes

Answer 10

connect the cytoskeletons of cells

Question 11

Function of gap junctions

Answer 11

act as channels between cells

Question 12

What are tight junctions composed of

Answer 12

Specialized proteins

Question 13

Where are tight junctions located

Answer 13

In the plasma membranes of adjacent animal cells

Question 14

How do the proteins in tight junctions orient themselves?

Answer 14

They line up and bind to each other

Question 15

Where do the proteins in tight junctions bind?

Answer 15

Between the two plasma membranes

Question 16

What does the stitching of the two cells in tight junctions form?

Answer 16

A watertight seal

Question 17

Which types of tissues are desmosomes common in?

Answer 17

Epithelial and muscle

Question 18

What do the proteins of desmosomes bind to? (2 answers)

Answer 18

1. to each other
2. to proteins that anchor intermediate filaments

Question 19

What are the adhesion proteins in desmosomes?

Answer 19

Cadherins

Question 20

What is selective adhesion in adult cells?

Answer 20

The way that adult cells attach to each other selectively, attach to the same kind of cell

Question 21

What are plant cells connected by?

Answer 21

Plasmodesmata

Question 22

In animal tissues, how do gap junctions connect adjacent cells?

Answer 22

Forming channels

Question 23

What five things bind adjacent cells to each other?

Answer 23

1. middle lamella
2. continuous ecm
3. tight junctions
4. desmosomes
5. cadherins

Question 24

What allows adjacent plant cells to communicate?

Answer 24

Plasmodesmata

Question 25

What allows adjacent animal cells to communicate?

Answer 25

Gap junctions

Question 26

What tissue in the human body needs gap junctions, desmosomes, and tight junctions?

Answer 26

Cardiac tissue

Question 27

What is decellularization?

Answer 27

Removal of cells to isolate the extracellular matrix scaffold

Question 28

What makes up the ECM? (3 things)

Answer 28

1. GAGs 2. Proteoglycans 3. Fibrous proteins

Question 29

What are the 4 types of fibrous proteins to know?

Answer 29

1. Laminin 2. Fibronectin 3. Collagens 4. Elastin

Question 30

What is the function of GAGs?

Answer 30

Gel-like squishiness and protection

Question 31

GAGs are highly ____ charged

Answer 31

negatively

Question 32

What are proteoglycans?

Answer 32

A polysaccharide (GAG) + a core protein

Question 33

What is the function of laminin and fibronectin

Answer 33

Connect cells to the ECM and organize components in the ECM

Question 34

What are the functions of collagens

Answer 34

Provides tensile strength

Question 35

What is the function of elastin

Answer 35

Stretch and recoil

Question 36

What is the sequence of how things are attached from cytoskeleton to ECM?

Answer 36

Actin --> integrin --> fibronectins --> collagen

Question 37

What is the cell wall made of?

Answer 37

Long strands of cellulose

Question 38

What are the long strands of cellulose in the cell wall bundled into?

Answer 38

Microfibrils

Question 39

What do the microfibrils in the cell wall form?

Answer 39

A crisscrossed network

Question 40

What are the two types of cell walls?

Answer 40

Primary and secondary

Question 41

Where is the primary cell wall?

Answer 41

Between newly made cells

Question 42

The primary cell wall is __ and __

Answer 42

Thin and flexible

Question 43

What is the primary cell wall mainly made of?

Answer 43

Cellulose

Question 44

What keeps the primary cell wall moist?

Answer 44

Pectins and glycans

Question 45

Which cell wall defines the shape of the cell?

Answer 45

Primary

Question 46

Where is the secondary cell wall?

Answer 46

Between the plasma membrane and the primary cell wall

Question 47

What are the three layers between adjacent plant cells?

Answer 47

1. primary cell wall of one plant cell 2. middle lamella 3. primary cell wall of the other plant cell