Chapter 9

Question 1

what are the 2 types of signaling in muticellular organisms?

Answer 1

1. intercellular signaling

2. intracellular signaling

Question 2

what is intercellular signaling?

Answer 2

between cells (adjacent or far apart)

Question 3

what is intracellular signaling? give an example

Answer 3

within a cell

ex. turning an enzyme on or off

Question 4

what are chemical signals called and how do they work?

Answer 4

ligands; they bind to another molecule

Question 5

what two cells are involved in chemical signaling?

Answer 5

1. signaling cell

2. target cell

Question 6

what does the signaling cell do

Answer 6

produces ligand

Question 7

what does the target cell do?

Answer 7

binds to the receptor

Question 8

what are the four types of chemical signaling?

Answer 8

1. autocrine
2. singaling across gap junctions
3. paracrine
4. endocrine

Question 9

what is autocrine signaling?

Answer 9

a cell signaling itself

Question 10

what is signaling across gap junctions?

Answer 10

it allows passage of molecules between cells

Question 11

what is paracrine signaling?

Answer 11

when the target cell is near the signaling cell, but not connected to it, so ligands are released locally

Question 12

what is endocrine signaling?

Answer 12

long distance, endocrine glands in the body send ligands through the bloodstream to target cells with specific receptors for each hormone

Question 13

what type of signaling is neurotransmission?

Answer 13

paracrine

Question 14

what are the two cells associated with neurotransmission?

Answer 14

presynaptic cell and postsynaptic cell

Question 15

which is the signaling cell in neurotransmission?

Answer 15

presnyaptic cell

Question 16

what is the target cell in neurotransmission?

Answer 16

postsynaptic cell

Question 17

what is the synaptic gap, how big is it, and why?

Answer 17

the space between the pre and postsynaptic cells, has to be very small because neurons need to travel very quickly

Question 18

how does the endocrine system work?

Answer 18

communicating organs send ligands to target cells with receptors for certain hormones

Question 19

what are the 4 type of signal receptors?

Answer 19

1. internal receptor proteins
2. surface receptor proteins
3. ion channel receptor proteins
4. G-linked and enzyme-linked

Question 20

what do internal receptor proteins do?

Answer 20

respond to ligands to turn genes on or off

Question 21

what do surface receptor proteins do and what two types are there?

Answer 21

are integral and peripheral, receive and bind to ligands, change conformation, and trigger a reaction

Question 22

what do ion channel receptor proteins do?

Answer 22

regulate movement across membranes

Question 23

what do G-linked and enzyme-linked receptors do?

Answer 23

special functions

Question 24

what are the four responses to a chemical signal?

Answer 24

1. gene expression
2. regulation of cellular metabolism
3. regulation of cell growth
4. cell death (apoptosis)

Question 25

what is the region of DNA that houses the instructions to make proteins?

Answer 25

gene

Question 26

how do chemical signals regulate cellular metabolism?

Answer 26

metabolic pathways (like cellular respiration) can be regulated by turning enzymes on/off

Question 27

what is an example of a ligand in cellular respiration?

Answer 27

ATP, it bonds to phosphofructokinase and stops cellular respiration

Question 28

how do chemical signals regulate cell growth? give an example

Answer 28

cells don’t constantly grow, they have to stop once they are grown enough, so ligand signals stop growth
ex. brain cells stop dividing once you reach adulthood

Question 29

how do chemical signals regulate apoptosis?

Answer 29

cells have defined lifespans, and ligands send a signal telling them when it’s time to go, and the cell ceases function