Cell Communication

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Slide 1

The Cellular Internet

Cell-to-cell communication is essential for multicellular organisms

Biologists have discovered some universal mechanisms of cellular regulation

The combined effects of multiple signals determine cell response

For example, the dilation of blood vessels is controlled by multiple molecules

Slide 2

Fig. 11-1

Slide 3

Concept 11.1: External signals are converted to responses within the cell

Microbes are a window on the role of cell signaling in the evolution of life

Slide 4

Evolution of Cell Signaling

A signal transduction pathway is a series of steps by which a signal on a cell’s surface is converted into a specific cellular response

Signal transduction pathways convert signals on a cell’s surface into cellular responses

Slide 5

Fig. 11-2

Receptor

 factor

a factor

a





a

Exchange

of mating

factors

Yeast cell,

mating type a

Yeast cell,

mating type 

Mating

New a/

cell

a/

1

2

3

Slide 6

Pathway similarities suggest that ancestral signaling molecules evolved in prokaryotes and were modified later in eukaryotes

The concentration of signaling molecules allows bacteria to detect population density

Slide 7

Fig. 11-3

Individual rod-

shaped cells

Spore-forming

structure

(fruiting body)

Aggregation in

process

Fruiting bodies

0.5 mm

1

3

2

Slide 8

Local and Long-Distance Signaling

Cells in a multicellular organism communicate by chemical messengers

Animal and plant cells have cell junctions that directly connect the cytoplasm of adjacent cells

In local signaling, animal cells may communicate by direct contact, or cell-cell recognition

Slide 9

Fig. 11-4

Plasma membranes

Gap junctions

between animal cells

(a) Cell junctions

Plasmodesmata

between plant cells

(b) Cell-cell recognition

Slide 10

In many other cases, animal cells communicate using local regulators, messenger molecules that travel only short distances