Chapters 11,12,13,16, and 17

Question 1

What is quorum sensing?

Answer 1

organisms such as bacteria, can sense the density of their colony. This allows all of the cells in the colony to act the same, specific way.

Question 2

What is a biofilm?

Answer 2

a biofilm is the result of quorum sensing. When bacteria reach a certain density, the colony secretes molecules that attach the cells to a surface. It protects the bacteria and allows them to gain nutrients from the surface.

Question 3

examples of a biofilm

Answer 3

slippery log surface, bacterial infections, film on teeth, and bacteria producing toxins

Question 4

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

Answer 4

signal transduction pathway

Question 5

what allows bacteria to detect population density

Answer 5

the concentration of signaling molecules

Question 6

how do cells in a multicellular organism communicate

Answer 6

chemical messengers

Question 7

in local signaling, animal cells may communicate by ________ or _______

Answer 7

direct contact, or cell-cell recognition

Question 8

in cases where the cells are not directly beside one another, these messenger molecules travel short distances

Answer 8

local regulators

Question 9

what is used in long distance cell signaling

Answer 9

hormones

Question 10

who discovered how the hormone epinephrine acts on cells

Answer 10

Earl W. Sutherland

Question 11

what are the three steps of a cell receiving a signal

Answer 11

reception, transduction, and response

Question 12

this is another name for a signal molecule

Answer 12

ligand

Question 13

this is often the initial transduction of the signal

Answer 13

a shape change in the receptor

Question 14

most signal receptors are ______

Answer 14

plasma membrane proteins

Question 15

what are the three main types of membrane receptors

Answer 15

G protein-coupled receptors, receptor tyrosine kinases, and ion channel receptors

Question 16

What is the on/off switch in a G protein-coupled receptor and how does it work

Answer 16

the G protein is the on/off switch, if GDP is bound to the G protein, the protein is inactive

Question 17

what are G-Protein Coupled receptors used for

Answer 17

yeast mating factors, neurotransmitters, and epinephrine (adrenaline) plus other hormones

Question 18

What human diseases involve malfunctions of G-proteins

Answer 18

bacterial infections, cholera, pertussis, botulism

Question 19

how does a G-protein malfunction make someone ill

Answer 19

by producing toxins that interfere with G-protein function (up to 60% of today’s meds influence G-protein pathways)

Question 20

these are membrane receptors that attach phosphates to tyrosines usually causing enzymatic activity leading to a cellular response

Answer 20

receptor tyrosine kinases

Question 21

this receptor acts as a gate when the receptor changes shape

Answer 21

ligand-gated ion channel

Question 22

how do ligand-gated ion channel receptors work

Answer 22

when a signal molecule binds as a ligand to the receptor, the gate allows specific ions, such as Na+ or Ca2+, through a channel in the receptor

Question 23

where are intracellular receptor proteins found

Answer 23

in the cytosol or nucleus of target cells

Question 24

examples of hydrophobic messengers that activate intracellular receptors

Answer 24

steroid and thyroid hormones of animals

Question 25

what is the effect of many intracellular receptor transcriptions

Answer 25

turning on a specific gene, that is then coded into RNA and used to synthesize a protein

Question 26

what are the benefits of transduction being a multi-step pathway

Answer 26

the signal can be amplified (a few molecules can produce a large cellular response), and it provides more opportunities for coordination and regulation of the cellular response

Question 27

how does signal transduction work

Answer 27

a receptor activates the next protein and so on, until the protein producing the response is activated. Each step transduced the signal into a different form, usually a protein shape change

Question 28

these transfer phosphates from ATP to a protein, a process called phosphorylation

Answer 28

protein kinases

Question 29

these remove the phosphates from proteins, a process called dephosphorylation

Answer 29

protein phosphatases

Question 30

What is the "first messenger" in cellular communication?

Answer 30

the extracellular signal molecule that binds to the receptor

Question 31

what are second messengers

Answer 31

small, nonprotein, water-soluble molecules or ions that spread throughout the cell by diffusion

Question 32

what type of pathways do second messengers participate in and what is a common example

Answer 32

pathways initiated by G protein-coupled receptors and receptor tyrosine kinases, cyclic AMP and calcium ions are common second messengers

Question 33

what is the enzyme in the plasma membrane that converts ATP to cAMP in response to an extracellular signal

Answer 33

adenylyl cyclase