Communication

Question 1

Bacteria communicate with one another using

Answer 1

chemical signal molecules

Question 2

Bacteria examples of cell communication

Answer 2

Myxococcus xanthus fruiting body formation
Escherichia coli flagellar rotation
Biofilm formation
Sporulation in Bacillus

Question 3

Mating yeast cells

Answer 3

Use chemical signaling to identify cells of opposite mating type

Question 4

How many mating yeast types

Answer 4

Two mating types in sexual reproduction

a and a- are haploid

Question 5

Process of mating yeast cells

Answer 5

Exchange mating factors
Release specific mating factors
Only bind to receptors on other cell type
Change shape and grow toward each other

Question 6

End product of mating haploid yeast cells

Answer 6

New a/a cell (diploid)

Contains ALL genes of both original cells

Question 7

3 steps of the mating yeast cells

Answer 7

exchange mating factors
mating
new diploid cell a/a- cell

Question 8

what types of signaling are there

Answer 8

contact
local
long distance

Question 9

Communication requiring contact between cells

Answer 9

Cell junctions (gap junctions; plasmodesmata)
Cell-surface molecules

Question 10

Local signaling (few cells distance between)

Answer 10

Paracrine signaling

Synaptic signaling

Question 11

Local paracrine signaling

Answer 11

Secretion of local regulator (i.e., growth factor)

Question 12

Local synaptic signaling

Answer 12

Release neurotransmitter into synapse, stimulating target cell

Question 13

Long-distance signaling (up to body-length distance)

Answer 13

Endocrine (hormonal) signaling
Plant hormone (1 example)

Question 14

long distance endocrine signaling

Answer 14

Specialized endocrine cells secrete hormones into body fluids
(examples: insulin, epinepherine)
Hormones reach most body cells, but bind and affect only some cells

Question 15

long distance Plant hormone (1 example)

Answer 15

Ethylene (C2H4) promotes fruit ripening and regulates growth

Question 16

3 stages of cell signaling

Answer 16

Signal Reception

Signal Transduction

Cellular Response
Cell division

Question 17

1st stage of cell signaling– signal reception

Answer 17

-Signaling molecule (ligand) binds to receptor protein
Peptides, proteins, amino acids, lipids, gases, etc.
-Receptor protein changes shape

Question 18

2nd stage of cell signaling–Signal Transduction

Answer 18

• Relay signals from receptor(s) to target molecule(s)
• Protein phosphorylation and dephosphorylation
• Signal transduction pathway

Question 19

3 rd stage of cell signaling Cellular Response

Answer 19

• Cell division
• Regulation of transcription
• Enzyme activation and inactivation

Question 20

what happens in signal reception

Answer 20

Signaling molecule binds to a receptor, causing conformational change in receptor

Question 21

what are receptors for signal reception and where are most

Answer 21

G protein-coupled receptors (GPCRs)
Receptor tyrosine kinases
Ion channel receptors
in plasma membrane

Question 22

Intracellular receptors for reception

Answer 22

In cytoplasm, nucleus, organelle

Question 23

G protein-coupled receptors (GPCR)

Answer 23

Receptor works with G protein
Large family of eukaryotic receptor proteins
Single polypeptide has 7 transmembrane (TM) a helices

Question 24

GPCR binds with

Answer 24

Binds GTP (guanosine triphosphate)

Question 25

G-protein coupled receptors Diverse functions roles in:

Answer 25

Embryonic development Sensory reception Human vision, smell, taste

Question 26

Malfunctions of GPCRs lead to

Answer 26

many human diseases, including bacterial infections Cholera, pertussis (whooping cough), and botulism due to bacterial toxins that interfere with G protein function

Question 27

4 steps in g protein receptor | look at pp slide 8

Answer 27

-GDP bound to G protein = inactive -Activated receptor (signal molecule binds) causes GTP to displace GDP -Activated G protein diffuses along membrane, binds to an enzyme, activating it -G protein acts as GTPase GTP + H2O → GDP + Pi Shuts down pathway

Question 28

What happens if GDP is bound to g protein

Answer 28

in active

Question 29

What happens when G protein receptor is activated

Answer 29

GTP to displace GDP | GTP bound to GTP is active now

Question 30

What happens to the activated g protein

Answer 30

diffuses along membrane binds to enzyme activates enzyme

Question 31

When the G protein acts as GTPase what happens

Answer 31

shuts down pathway