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Study guide chapter 11Cell Communication

Campbell et al. Biology. 8th ed., Chapter 11

Study hint: While working through this study guide, make a list of key terms inthe right margin. Usually, these terms are boldfaced in the study guides or theyappear in the referenced figures. Consult one of the glossaries if you are notsure of definitions.

0. Application

1. I cannot think of his name, but recently I saw an actor on TV who talkedabout the fact that as an adult dwarf he is mostly hired to play children.Explain how a mutation in a ene codin for receptor tyrosine kinasesleads to achondroplasia !dwarfism.

". Explain how the cholera toxin causes the symptoms of cholera bydisruptin #$protein$sinalin pathways !p. "11%.

&. 'nd finally, ha(e you heard of the drus )epcid 'C* +ow does it work*

I. The big picture

e all start out as a -yote. +ow do indi(idual cells know whether they aresupposed to become skin cells or li(er cells* Cells of different tissues perform a(ariety of tasks. )arietal cells, for example, produce +Cl to aid diestion. +owdoes a parietal cell know when to produce +Cl and how much* hat tells/ acell to beha(e this way or another* hat if a cell misbeha(es, if, for example, aparietal cell produced too much +Cl and cause heartburn*

0. hy do cells ha(e to communicate with each other* hat is thelanuae cells use*

. 2sin parietal cells as examples, explain why it is as important to stop asinal3response than it is to recei(e it.

4. 5e(iew fiure ".18 and explain how the dru morphine succeeds inrelie(in pain and causin euphoria. hat are the ears/ of cells* hatlanuae do drus use to communicate with cells*

II. Overview

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6. 7escribe the signal transduction pathway in matin yeast. Explain whywe belie(e these pathways e(ol(ed before the first multicellular oranismsappeared on Earth !i. 11." and 11.14%.

8. hat is the adapti(e ad(antae of quorum sensing in bacteria* 9otethat we will study an example of this in lab.

:. 7istinuish between direct, paracrine synaptic, and hormonal communication usin the table below !consult i. 11.0 and 11.%;

7irect <ynaptic )aracrine +ormonal

Example;rom === to!cell type%

9euron tomuscle

Via >unction orcell surfacemolecules

?ind of sinal@ocalreulator 

Example!messae%

)roduceinsulin

1A.@ist and briefly define the three staes of cell sinalin !i. 11.4%.

III. Signal !eception and the Initiation o" Transduction

11. +ow do cells know/ whether to respond to a particular sinal*1".7escribe the nature of a ligand#receptor interaction and state how such

interactions initiate a sinal$transduction system.

1&.Explain how testosterone turns on enes !iure 11.8%.10.Explain why receptors are widely used as dru tarets.

1.Compare and contrast membrane receptors usin the followin table !i.11.6%.

#$protein$linkedreceptors

Tyrosine$kinasereceptors

Ion channelreceptors

orm

unction!Importance%

hat happens

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when sinal binds

7isease example

I$. Transduction

14.7escribe two ad(antaes of usin a multistep pathway in the transductionstae of cell sinalin.

16.Explain how a sinal molecule can produce a cellular response withoutenterin the taret cell.

18.7escribe how phosphorylation propaates sinal information !i. 11.:%.

1:.+ow is the phosphorylation cascade stopped*

"A.Explain why a sinle cell may reBuire hundreds of different protein%inases.

"1.Explain why protein phosphatases are so important.

"".7efine the term second messenger . riefly describe the role of thesemolecules in sinalin pathways !i. 11.11%.

"&.7escribe how cyclic A&' is formed and how it propaates sinalinformation in taret cells !i. 11.1A%.

"0. Chanes in cytosolic CaDD concentration can stimulate life after afertili-ation e(ent, and they can trier death !apoptosis%. hy can slihtchanes of Ca"D le(els in the cytosol ha(e such hue effects !11.1" and11.1&%*

".+ow can such a widely used second messener as Ca "D trier (erydifferent reactions in different cells at different times !see fiure below%.

"4.+ow are sinals ampli"ied !iure 11.1&%*

$. Cellular !esponses to Signals

"6.#i(e examples for cellular responses to sinals from the outside."8.7escribe how sinal information is transduced into cellular responses in

the cytoplasm and in the nucleus !i. 11.10 and 11.1%.

":.Explain why different types of cells may respond differently !fi(e differentways% to the same sinal molecule !i. 11.16%.

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&A.Explain how scaffoldin proteins help to coordinate a cells response toincomin sinals !i. 11.18%.

$I. Apoptosis

&1.hat proram/ happens in apoptosis, and what is the ad(antae of thisproram*

&".7escribe three situations in which cells undero apoptosis.

&&.7escribe the molecular basis of apoptosis in C. elegans !iure 11."A%.

&0.In many cancers, cells with damaed 79' fail to undero apoptosis.hat kind of mutation would you expect in the enes homoloous to  Ced#( Ced#) and Ced#**

+ssay question

7escribe the protein kinase cascade stimulated by epinephrine !iure 11.1% or

the yeast matin factor !iure 11.14%. +ow can it o wron* hat happens ifit oes wron* Explain the usefulness of protein kinase cascades andmechanisms to shut them down. In order to et full credit you should i(eexplanations for e(ery step of this pathway. 7efine all technical terms you use.

Note: You should be prepared to describe either of the two pathways. You donot hae to know specific names such as !us" or glycogen phosphorylase.