Cellular communication

Question 1

Examples of positive feedback control in the human body include (select 3):
a. generation of an action potential
b. PaCO2 regulation
c. coagulation cascade
d. core temperature
e. serum glucose concentration
f. childbirth

Answer 1

a. generation of an action potential
c. coagulation cascade
f. childbirth

Question 2

________________ is a steady-state condition that comes with a price- it requires energy to maintain the system

Answer 2

Homeostasis

Question 3

A control system must be able to do 4 things:

Answer 3

sense the vital parameter
compare the input signal with the set point
multiply the error signal
adjust the vital parameter

Question 4

____________ reverse a disturbance in some factors and lead to stability

Answer 4

Negative feedback

Question 5

______________ enhance or accelerate a disturbance in some factor and usually lead to instability

Answer 5

Positive feedback systems

Question 6

Examples of beneficial positive feedback are

Answer 6

childbirth
the blood coagulation cascade
the generation and propagation of an action potential

Question 7

Which method of cell signaling occurs when a cell responds to a chemical signaling molecule that the cell itself produced and secreted?
a. endocrine signaling
b. paracrine signaling
c. neurotransmitter signaling
d. autocrine signaling

Answer 7

d. autocrine signaling

Question 8

The intracellular response to extracellular signals is called

Answer 8

cell signaling

Question 9

Cell signaling allows cells to

Answer 9

communicate with one another

Question 10

The conversion of information into a chemical change is called

Answer 10

signal transduction, a universal property of living cells

Question 11

Information arrives at cells in these four forms:

Answer 11

purely physical (energy)
chemical
cellular
extracellular matrix molecules

Question 12

Examples of purely physical forms include

Answer 12

light, sound, heat, pressure, electricity

Question 13

Examples of chemical forms include

Answer 13

neurotransmitters
hormones
eicosanoids
drugs
toxins

Question 14

Examples of cellular forms include:

Answer 14

gap junctions

Question 15

Examples of extracellular matrix molecules include

Answer 15

collage (think of platelet adhesion), integrins, laminin

Question 16

There are three main methods of intracellular communication:

Answer 16

endocrine
paracrine
autocrine

Question 17

Describe endocrine cell signaling.

Answer 17

A signaling molecule (i.e. a hormone) is secreted by an endocrine cell and transported through the circulation where it acts on a distant target cell

Question 18

________________ is a specific type of endocrine signaling where a neuron is the source of the hormone secreted into the blood

Answer 18

neuroendocrine cell signaling

Question 19

Describe paracrine signaling.

Answer 19

a chemical signaling molecule is released by one cell and acts locally to regulate the behavior of a neighboring cell

Question 20

Describe autocrine signaling.

Answer 20

A cell responds to a signaling molecule that is also produced

Question 21

Think of _____ as talking to your friends and family around the country on a mobile phone, ______________ as talking directly to your neighbors, and ________________ signaling as talking to yourself

Answer 21

endocrine, paracrine, autocrine

Question 22

Autocoid typically refers to

Answer 22

local hormones

Question 23

Neurotransmitter signaling is a specific form of which type of cell communication method?

Answer 23

paracrine

Question 24

A chemical molecule that binds to a receptors and initiates a cellular response is called a:
a. second messenger
b. transducer
c. ligand
d. kinase

Answer 24

c. ligand

Question 25

Signal transduction has the following 6 characteristics:

Answer 25

specificity and sensitivity amplification integration feedback compartmentalization desensitization

Question 26

The flow of information in a signal transduction sequence follows

Answer 26

orderly pathways

Question 27

There are six processes in signal transduction sequences (with occasional exceptions):

Answer 27

1. recognition 2. transduction 3. transmission 4. modulation 5. response 6. termination

Question 28

What are the four categories or types of receptor-based signal transducers:

Answer 28

1. transmembrane G protein coupled receptors 2. transmembrane gated ion channels 3. transmembrane enzyme linked receptors 4. soluble nuclear (intracellular) receptors

Question 29

Bonds ordered from weakest to strongest:

Answer 29

van der Waals< hydrophobic < hydrogen< ionic < covalent

Question 30

Amplification is when

Answer 30

a small signal produces a disproportionately larger effect

Question 31

The ability of a signal-transducing system to receive multiple signals and produce a unified response appropriate to the cell's needs is

Answer 31

integration

Question 32

___________ occurs when a signal is present continuously.

Answer 32

Desensitization

Question 33

A general term for any chemical that binds to a receptor is

Answer 33

"ligand" or first messenger

Question 34

Transduction is the generation of

Answer 34

a second messenger or the activation of a catalytic cascade

Question 35

What chemical messengers are derived from arachidonic acid? (select 3) a. prostaglandins b. thyroxine c. aldosterone d. leukotrienes e. dopamine f. anandamide

Answer 35

a. prostaglandins d. leukotrienes f. anandamide

Question 36

Most chemical signals fall into four categories of molecules:

Answer 36

1. small hydrophilic molecules 2. lipophilic molecules 3. peptides and proteins 4. others

Question 37

The following messengers are not stored in vesicles:

Answer 37

lipophilic purine gas endocannabinoid

Question 38

Chemical messenger molecules bind to either

Answer 38

cell-surface receptors or intracellular receptors

Question 39

Small hydrophilic chemical messengers can be broken up into 4 subclasses:

Answer 39

amino acids (glycine, glutamate, GABA, aspartate) biogenic amines (dopamine, norepinephrine, epinephrine, serotonin, histamine) choline esters (acetylcholine) iodothyronines (Thyroxine T4, Triiodothyronine T3)

Question 40

Characteristics of small, hydrophilic chemical messengers include:

Answer 40

polar molecules that are ionized don't cross plasma membranes stored in vesicles in the cells that synthesized them typically released by exocytosis (T4 & T3 are the exceptions)

Question 41

The following are derived from tyrosine:

Answer 41

dopamine NE epi iodothyronines

Question 42

_________ & __________________- can be interconverted

Answer 42

GABE & glutamate

Question 43

Subclasses of lipophilic chemical messengers include

Answer 43

steroids (aldosterone, cortisol, testosterone, progesterone, estrogens) eicosanoids (prostaglandins, leukotrienes, thromboxanes) miscellaneous (vitamin D3, retinoids)

Question 44

Steroids are derived from

Answer 44

cholesterol & maintain the cholesterol rings structure

Question 45

Steroids circulate in the

Answer 45

blood bound to a protein

Question 46

Steroids ______________ through the lipid bilayer of plasma membranes

Answer 46

diffuse

Question 47

Steroids are _____________ in the producing cells

Answer 47

not stored

Question 48

Steroids bind to receptors in the

Answer 48

cytoplasm or nucleus of the target cells