Chapter 9

Question 1

Ligand

Answer 1

Specific molecule that binds with receptor

Question 2

Receptor

Answer 2

membrane proteins, ligand binds to it

Question 3

Signal propogation

Answer 3

ligand ->
receptor ->
intracellular signal transduction ->
response

Question 4

Earl Sutherland Experiment

Answer 4

Vanderbilt 1951, studying epinephrine (adrenaline) stimulates glycogen breakdown, free up sugars in blood and meet immediate energy needs, fight or flight response
Nobel Prize 1971

Question 5

Epinephrine insights

Answer 5

linked to glucose production
glycogen phosphorylase activity increased
no direct connection
cells must be intact/functional

Question 6

Forms of cell signaling

Answer 6

Intra vs intercellular
autocrine
gap junctions
paracrine
endocrine

Question 7

Gap Junction and direct signaling

Answer 7

Cell to cell connection
gap junctions
plasmodesmata (in plants)
fluid filled
small signal molecules

Question 8

Channels with high specificity

Answer 8

cells are independent
respond quickly
coordinate response of cells
all plant cells are connected (plasmodesmata)

Question 9

Autocrine

Answer 9

Targets and effects self
signal = target cell
early development
ex: macrophage makes itself inflamed because of detected virus

Question 10

Endocrine

Answer 10

Distance signaling
slower response
longer lasting
endocrine glands (thyroid; adrenal)
ligand = hormones
travels in bloodstream

Question 11

Paracrine

Answer 11

Immediate/fast communication
short-lived response
ex chemical synapses
neurotransmitters

Question 12

Internal receptors

Answer 12

inside of the cell
cytoplasmic/intracellular
interact with hydrophobic ligands
pass through PM -> cytoplasm
bind w ligand -> nucleus
regulate gene expression

Question 13

Cell surface receptors

Answer 13

Outside of the cell
transmembrane receptors
anchored to plasma membrane
ligands interact/stay outside
signal transduction
external signal -> internal signal

Question 14

Ion channel linked receptors

Answer 14

ligand binds to channel, opens channel, specific ions pass through

Question 15

G protein receptors

Answer 15

specialized “G protein”, with channel or enzyme, important immune function

Question 16

Enzyme linked receptors

Answer 16

catalyze rxn. in PM
extra and intracellular domain
ex: HER2 receptor/breast cancer

Question 17

Small hydrophobic ligands

Answer 17

non-polar; diffuse directly across PM
interact with internal receptors
steroid hormones
thyroid hormone and vitamin D
carrier proteins deliver them ( cant dissolve in blood)

Question 18

Water soluble ligands

Answer 18

polar; will not readily diffuse
bind to extracellular domain
cell-surface receptors
diverse; peptides and proteins

Question 19

Nitrous Oxide

Answer 19

Gaseous; short-lived
interacts with smooth muscle
induce relaxation of tissue
Nitroglycerin helps release

Question 20

Stages of cell communication

Answer 20

signal reception -> membrane protein receives signal
signal transduction -> single/multistep signaling pathway
cellular response -> elicits specific cellular response

Question 21

Signaling pathways

Answer 21

binding of ligand (activates protein); signal initiation, pathway, integration
intracellular signaling (phosphorylation)
second messenger after ligand binds spreads signal through cytoplasm

Question 22

cell response to signals

Answer 22

regulate gene expression
increase cell metabolism
Cell growth and division
programmed cell death
signal termination

Question 23

Phosphatases

Answer 23

enzyme that stops signal

Question 24

Signaling in unicellular organisms

Answer 24

signaling occurs via specific molecules
detected by other bacteria
quorum sensing
monitor local density, coordinate behavior, biofilms

Question 25

Signaling Cascade

Answer 25

Series of chemical reactions that occur in a cell

Question 26

Secondary Messengers

Answer 26

Propagate signal through cytoplasm

Question 27

Caspases

Answer 27

enzymes involved in apoptosis

Question 28

Quorum sensing

Answer 28

Cell to cell communication process, allows bacteria to sense environment