L1 Cellular Transport 2010-2011

8/18/2019 L1 Cellular Transport 2010-2011

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Cellular Transport

How does a cell maintain

homeostasis?

Homeostasis = a constant internal state despite

changes in the environment



Outline

1. Cell membrane2. Selective permeability

3. Passive transport

a) i!!"sion

b) #smosis

c) $acilitated i!!"sion

%. &ctive transport

1. Cell membrane p"mps

2. 'ndocytosis

3. '(ocytosis



Outline



a) i!!"sion

b) #smosis


%. &ctive transport


2. 'ndocytosis

3. '(ocytosis



I. The Cell Membrane

Cell transport = movement o! materials

ino"t o! cell thro"gh cell membrane

Cell membranes are selectively

permeable * they control the !low o!

s"bstances intoo"t o! the cell




Cell +embrane made o!,

* phospholipid bilayer

* Proteins- carbohydrates- and cholesterol

are embedded in the bilayer.



Head

Symbol

Tails


Phospholipids are the

main str"ct"ral

components o!membranes

hey each have a

hydrophilic head andtwo hydrophobic tails




/n water- phospholipids !orm a stable

bilayer

he heads !ace o"tward and the tails!ace inward

Hydrophilic

heads

Hydrophobic

tails

Water

Water




ypes o! proteins

* /ntegral proteins * embedded in membrane

0 '(. eceptor transport proteins

* Peripheral proteins * lie on one side o!membrane

0 '(. 'nymes




$l"id4+osaic +odel

* Cell membrane can act li5e a !l"id

* Parts can move laterally in bilayer

* +osaic 4 many parts ma5ing a whole



Fibers of the

extracellular

matrix

GlycoproteinCarbohydrate

(of

glycoprotein)

Microfilaments of

the cytoseleton

!hospholipid

Cholesterol

!roteins

C"T#!$%SM

Glycolipid



II. Selective Permeability

Can pass

(permeable)&

* Small- "ncharged

molec"les

* Hydrophobic 6non4

polar) molec"les

Can't pass

(impermeable)&

* 7arge- water4sol"ble

6i.e. polar) molec"les

* /onscharged

molec"les

#nly some molec"les are allowed to passthro"gh the membrane while others are not.

8hy is this tr"e?



Outline



a) i!!"sion

b) #smosis


%. &ctive transport


2. 'ndocytosis

3. '(ocytosis



III. Passive Transport

+ovement o! molec"les across the

membrane 8/H#9 the "se o! cell"lar

energy 6&P)

& !ew de!initions,

1. i!!"sion = the :' movement o! molec"les,

greater concentration→ lower concentration

2. Concentration = the amo"nt o! s"bstance in a

given space 6in cells- amo"nt o! sol"te in water)



+olec"les spreading o"t to

reach a state o! e;"ilibri"m



*+$+,-+*M

Molecule of

dye Membrane

*+$+,-+*M

&t e;"ilibri"m- molec"les still contin"e to

move bac5 and !orth- b"t there is :# net

change in concentration on other side



Diffusion

+olec"les have net movement #8: aconcentration gradient 6HC → 7C)

+olec"les move in either direction *

+#' movement down the gradient.

Concentration gradient = a di!!erence in

concentration



http://www.northlan.cc.mn.us/biolo!y/"iolo!y####/animations/transport#.html

$choose simple from menu%



WORK ON TOP HALF OFDIFFUSION AND OSMOSIS

WORKSHEET



&actors that 'ffect the (ate of

Diffusion 'cross a Membrane1. emperat"re, molec"les move !aster with

higher temp

2. Concentration o! sol"te, a greater di!!erence inconcentration * more movement in one

direction

3. S"r!ace area o! membrane, increased

opport"nities !or moving to lower conc.

%. Charge, non4polar molec"les pass thro"gh

<. Sie, very small polar molec"les can slip

thro"gh pores in membrane



SURFACE AREA AND VOLUMEWORKSHEET



HTTP://HIGHERED.MCGRAW-

HILL.COM/SITES/007249555/STUDENT !VIEW0/CHAPTER2/ANIMATION!!HO

W!OSMOSIS!WORKS.HTML



WORK ON "OTTOM HALF OFDIFFUSION AND OSMOSIS

WORKSHEET



WORK ON DIFFUSIONWORKSHEET



HTTP://WWW.NORTHLAND.CC.MN.US

/"IOLOG#/"IOLOG#$$$$/ANIMATION

S/TRANSPORT$.HTML %CLICK

OSMOSIS&



CELL TRANSPORTWORKSHEET E'PERIMENT A



)ffects of Osmosis

he movement o! water into and o"t o!

cells will a!!ect the cell

ocab"lary, * Hypertonic = high concentration o! sol"te-

low concentration !ree water molec"les

* +sotonic = e;"al concentration o! sol"te * Hypotonic = low concentration o! sol"te-

high concentration !ree water molec"les



CELL TRANSPORTWORKSHEET E'PERIMENT "



)ffects of Osmosis* what happens

when you put cells in the followin!

solutions+

,-O moves out Cell shrins ,-O moves in Cell 0pops1



HTTP://WWW.NCLARK.NET/OSMOSISPOCUS.GIF



E'ERCISE (



)ffects of Osmosis in Plant Cells

Tur!or Plasmolysis




8atering a plant 6thin5 o! a water

balloon)

Hypotonic environment 6low sol"te

concentration)

* water moves in- swelling cell * "rgor press"re = press"re against cell wall

!rom incoming water




Hypertonic environment 6high sol"te)

* water leaves- shrin5ing cell

* Plasmolysis = cell shrin5 !rom cell wall-loss o! t"rgor press"re




Tur!or Pressure Plasmolysis




Small nonpolar molec"les di!!"se !reely

thro"gh the phospholipid bilayer

+any other 5inds o! molec"les @large-

polar 6H2#>)- or charged molec"lesA

pass thro"gh selective protein pores by!acilitated di!!"sion

i




C. $acilitated di!!"sion, movement o!speci!ic molec"les 6e(. Bl"cose- amino

acids) down a concentration gradient-

passing thro"gh the membrane Channel proteins *

ions 6open or

gated) Carrier proteins



HOMEOSTASIS AND CELL

TRANSPORT SECTION 5-$: PASSIVE

TRANSPORT WS



HTTP://GLENCOE.MCGRAW-HILL.COM/SITES/9(4092((9/STUDENT

!VIEW0/CHAPTER(/ANIMATION!-

!OSMOSIS.HTML



Outline

1. Cell membrane

2. Selective permeability


a) i!!"sion

b) #smosisc) $acilitated i!!"sion

%. &ctive transport


2. 'noocytosis

3. '(ocytosis



HTTP://PROGRAMS.NORTHLANDCOLLEGE.EDU/"IOLOG#/"IOLOG#$$$$/A

NIMATIONS/TRANSPORT$.HTML

/ntro to active transport and ion p"mps



Cell*membrane pumps 5 ion channels an carrier proteins 'TP is use to cause a chan!e in protein shape to help transport

I4. 'ctive Transport

I4 ' ti



I4. 'ctive

Transport

&ctive

transport intwo sol"tes

across a

membrane

Transport

protein

1

F$*+2

#*TS+2

C$$

First

solute

First solute3

inside cell3

binds to protein

!hosphorylated

transport protein

4 %T! transfers

phosphate to

protein

5 !rotein releases

solute outside

cell

6 Second solute

binds to protein

Second

solute

7 !hosphate

detaches fromprotein

8 !rotein releases

second soluteinto cell



HTTP://HIGHERED.MCGRAW-HILL.COM/OLC/DL/$200)/"IO0(.SWF

Sodi"m4potassi"m p"mp 6nerve cells- nephron)



'ctive Transport

o move large molec"les or particles

thro"gh a membrane- vesicles are "sed

* 'ndocytosis

* '(ocytosis



HTTP://HIGHERED.MCGRAW-HILL.COM/OLC/DL/$200)/"IO

02.SWF



'ctive Transport

'ndocytosis 6molec"les enter), Cell

membrane ingests e(ternal materials

and pinches o!! as a vesicle inside cell



'ctive Transport

hree types o! endocytosis

* Phagocytosis = cell"lar eating-D transport o! solid-

large particles or whole cells

0 '(. 9nicell"lar protists 6amoeba)0 '(. 8Cs 6bacteria)

* Pinocytosis = cell"lar drin5ing-D transport o!

sol"tes 6:&- protein) or !l"ids

* eceptor4mediated = highly speci!ic process- pitlined with receptor proteins that have pic5ed "p

partic"lar molec"les



'ctive Transport

hree types o! endocytosis

!seudopod of

amoeba

Food being

ingested

!lasma

membrane

Material bound to

receptor proteins

!+T

Cytoplasm



HTTP://PROGRAMS.NORTHLANDCOLLEGE.EDU/"IOLOG#/"IOLOG#$$$$/A

NIMATIONS/TRANSPORT$.HTML

'ndocytosis



HTTP://WWW.#OUTU"E.COM/WATCH*V+W)RNHIM'TKU

&moeba phagocytosis

L1 Cellular Transport 2010-2011

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Transcript of L1 Cellular Transport 2010-2011