7/18/2019 Biology I Lect 4 Cell Function.ppt http://slidepdf.com/reader/full/biology-i-lect-4-cell-functionppt 1/48 1 Biology I Lecture 4 Cell Structure and Function
7/18/2019 Biology I Lect 4 Cell Function.ppt
http://slidepdf.com/reader/full/biology-i-lect-4-cell-functionppt 1/48
1
Biology I Lecture 4
Cell Structure and Function
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Points to ponder
• What is a cell?• Why are most cells small?
• What do prokaryotic and eukaryotic cells have in
common?• How are cells organized?
• How do things move across the plasma
membrane?
• What is cellular respiration?
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What does the cell theory tell us?
• A cell is the basic unit of life.
• All living things are made up of cells.
• ew cells arise from pre!e"isting cells.
#.$ What is a %ell?
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Why are most cells small?
• %onsider the cell surface!area!to!volume
ratio.
& 'mall cells have a larger amount of surface
area compared to the volume.
& An increase in surface area allows for more
nutrients to pass into the cell and wastes to
e"it the cell more efficiently. & (here is a limit to how large a cell can be) and
be an efficient and metabolically active cell.
#.$ What is a %ell?
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(hinking about surface
area!to!volume in a cell
#.$ What is a %ell?
Figure 3.2 'urface area!to!volume ratio limits cell size.
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Total surface area
(height × width × nu!er of sides × nu!er of cu!es"
Total #olue
(height × width × length × nu!er of cu!es"
$urface area%
&olue 'er cu!e (surface area#olue"
)%13%11.5%1
)4 c3
3*4 c31+2 c3+) c3
)4 c3 )4 c3
,ne
4-c cu!e
ight
2-c cu!es
$i/ty-four
1-c cu!es
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)
What are some common
microscopes used to view cells?• %ompound light microscope
& /ower magnification
& 0ses light beams to view images
& %an view live specimens
#.$ What is a %ell?
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What are some common
microscopes used to view cells?• (ransmission electron microscope
& 1!2 image
& 0ses electrons to view internal structure
& High magnification) no live specimens
#.$ What is a %ell?
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What are some common
microscopes used to view cells?• 'canning electron microscope
& #!2 image
& 0ses electrons to view surface structures
& High magnification) no live specimens
#.$ What is a %ell?
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3lood cells viewed with different
microscopes
#.$ What is a %ell?
Figure 3.3 +icrographs of human red blood cells.
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a. Light icrogra'h !. Transission electron icrogra'h c. $canning electron icrogra'h
!lood #essel wall
red !lood cells
red !lood cell red !lood cell
!lood #essel wall !lood #essel wall
a4 * 2avid +. Phillips56isuals 0nlimited7 b 4 * Alfred Pasieka5 Photo 8esearchers7
c4 * 19$#5Warren 8osenberg5 3iological Photo 'ervice
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What are the 1 ma:or types of
cells in all living organisms?• Prokaryotic cells
& (hought to be the first cells to evolve
& /ack a nucleus
& 8epresented by bacteria and archaea
• ;ukaryotic cells & Have a nucleus that houses 2A
& +any membrane!bound organelles
#.1 How %ells are <rganized
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What do prokaryotic and
eukaryotic cells have in common?• A plasma membrane that surrounds and
delineates the cell
• A cytoplasm4 the semi!fluid substance inside the
cell that contains organelles
• 2A
#.1 How %ells are <rganized
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What do eukaryotic cells look like?#.1 How %ells are <rganized
Figure 3.4 (he
structure of a
typicaleukaryotic cell.
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a. 2.5
lasa e!rane%outer surface that
regulates entrance and
e/it of olecules
'rotein
'hos'holi'id
T,$6LT,7% aintainscell sha'e and assists o#eent
of cell 'arts%
8icrotu!ules% cylinders of 'rotein olecules 'resentin cyto'las9 centrioles9
cilia9 and flagella
Interediate filaents%'rotein fi!ers that
'ro#ide su''ortand strength
:ctin filaents% 'roteinfi!ers that 'lay a role in
o#eent of cell
and organelles
entioles% short9cylinders of icrotu!ules
&esicle% e!rane-!oundedsac that stores and trans'orts
su!stances
!.
yto'las% seifluidatri/ outside nucleus
that contains organelles
entrosoe% icrotu!ulesorgani;ing center thatcontains a 'air of centroles
Lysosoe% #esicle that
digests acroolecules
and e#en cell 'arts
<olgi a''aratus% 'rocesses9 'ac=ages9
and secretes odified cell 'roducts
olyri!osoe% string of ri!osoes siultaneouslysynthesi;ing sae 'rotein
8itochondrion% organellethat carries out cellular res'iration9 'roducing
:T olecules
>i!osoes%'articles that carry
out 'rotein synthesis
$ooth >% lac=sri!osoes9 synthesi;es
li'id olecules
>ough >% studded withri!osoes9 'rocesses 'roteins
7?,L:$8I >TI@L@8%
7ucleolus% region that 'roduces
su!units of ri!osoes
hroatin% diffuse threadscontaining ?7: and 'rotein
7uclear en#elo'e% dou!lee!rane with nuclear 'ores
that encloses nucleus
7@L@$%
itochondrion
chroatin
nucleolus
nuclear
en#elo'e
endo'lasicreticulu
* 2ennis =unkel56isuals 0nlimited
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Where did eukaryotic cells come from?#.1 How %ells are <rganized
Figure 3.5 (he evolution ofeukaryotic cells.
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?7:
1. ell gains a nucleus !y the
'lasa e!rane in#aginating and surrounding the ?7:
with a dou!le e!rane.
7ucleus allows s'ecific functionsto !e assigned9 freeing u' cellular
resources for other wor=.
2. ell gains an endoe!rane syste !y 'roliferation
of e!rane.
Increased surface area allows
higher rate of trans'ort of aterials within a cell.
3. ell gains itochondria.
:!ility to eta!oli;e sugars in
the 'resence of o/ygen ena!lesgreater function and success.
4. ell gains chloro'lasts.
:!ility to 'roduce
sugars fro sunlightena!les greater
function and success.
chloro'last
lant cell
has !oth itochondriacnd chloro'lasts.
:nial cellhas itochondria9!ut not chloro'lasts.
itochondrion
aero!ic!acteriu
'hotosynthetic!acteriu
,riginal'ro=aryotic cell
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What are some characteristics
of the plasma membrane?• -t is a phospholipid bilayer.
• -t is embedded with proteins that move in space.
• -t contains cholesterol for support.
• -t contains carbohydrates on proteins and lipids.
• -t is selectively permeable.
#.# (he Plasma +embrane and How 'ubstances %ross -t
7/18/2019 Biology I Lect 4 Cell Function.ppt
http://slidepdf.com/reader/full/biology-i-lect-4-cell-functionppt 15/4815Figure 3.) <rganization of the plasma membrane.
#.# (he Plasma +embrane and How 'ubstances %ross -t
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,utside
hydro'hilic
heads
car!ohydrate
chain
glyco'rotein
cholesterol
integral 'rotein
filaents of cytos=eleton
'hos'holi'id
!ilayer
hydro'ho!ic
tails
Inside
'eri'heral 'rotein
'lasa e!rane
e/tracellular
atri/ (8"
glycoli'id
# # (h Pl + b d H ' b % -
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What does selectively permeable
mean?• (he membrane
allows somethings in whilekeeping other
substances out.
#.# (he Plasma +embrane and How 'ubstances %ross -t
A
'hos'holi'id
olecule
'rotein
acroolecule
aCua'orin noncharged
olecules
D2,
charged olecules
and ions A
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Figure 3.0 'elective permeability of theplasma membrane.
# # (h Pl + b d H ' b t % -t
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How do things move across the
plasma membrane?
$. 2iffusion
1. <smosis#. >acilitated transport
. Active transport
@. ;ndocytosis and e"ocytosis
#.# (he Plasma +embrane and How 'ubstances %ross -t
# # (he Plasma +embrane and How 'ubstances %ross -t
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What are diffusion and osmosis?
$. 2iffusion is the random movement of molecules from
a higher concentration to a lower concentration.
1. <smosis is the diffusion of water molecules.
#.# (he Plasma +embrane and How 'ubstances %ross -t
# # (he Plasma +embrane and How 'ubstances %ross -t
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#.# (he Plasma +embrane and How 'ubstances %ross -t
Figure 3.* 2iffusion across the plasma membrane.
What are diffusion and osmosis?%opyright * (he +c,raw!Hill %ompanies) -nc. Permission reuired for reproduction or display.
'article
'lasa
e!rane water
cell cell
tie
a. Initial conditions !. Cuili!riu conditions
# # (h Pl + b d H ' b t % -t
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How does tonicity change a cell?
• -sotonic solutionshave eual amountsof solute inside andoutside the cell andthus do not affect thecell.
#.# (he Plasma +embrane and How 'ubstances %ross -t
Figure 3.+a ;ffects of changes in tonicity on red blood cells.
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a. Isotonic solution
(sae solute concen-
tration as in cell"* 2ennis =unkel5Phototake
# # (he Plasma +embrane and How 'ubstances %ross -t
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How does tonicity change a cell?
• Hypotonic solutionshave less solute thanthe inside of the celland lead to lysisburstingB.
#.# (he Plasma +embrane and How 'ubstances %ross -t
Figure 3.+! ;ffects of changes in tonicity on red blood cells.
!. Dy'otonic solution
(lower solute concen-
tration than in cell"
D2,
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* 2ennis =unkel5Phototake
# # (he Plasma +embrane and How 'ubstances %ross -t
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How does tonicity change a cell?
• Hypertonic solutionshave more solutethan the insideof the cell and lead tocrenation shrivelingB.
#.# (he Plasma +embrane and How 'ubstances %ross -t
Figure 3.+c ;ffects of changes in tonicity on red blood cells.
c. Dy'ertonic solution
(higher solute concen-
tration than in cell"
D2,
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* 2ennis =unkel5Phototake
# # (he Plasma +embrane and How 'ubstances %ross -t
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What are facilitated diffusion andactive transport?
#. >acilitated transport is the transport ofmolecules across theplasma membranefrom higherconcentration tolower concentrationvia a protein carrier.
#.# (he Plasma +embrane and How 'ubstances %ross -t
6A
7 a A
7 a A
Inside
,utside
glucose
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Figure 3.1 >acilitated transport across a cell membrane.
# # (he Plasma +embrane and How 'ubstances %ross -t
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What are facilitated diffusion and
active transport?. Active transport is the
movement of moleculesfrom a lower to higher
concentration using A(Pas energy7 it reuires aprotein carrier.
#.# (he Plasma +embrane and How 'ubstances %ross -t
7 a A
Inside
,utside
7 a A
6A
6A
6A
7 a A
6A6A
7 a A
7aA
7 a
A
7 a A
:T
:?
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Figure 3.11 Active transport and the sodium&potassium pump.
# # (he Plasma +embrane and How 'ubstances %ross -t
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What are endocytosis
and e"ocytosis?• @. ;ndocytosis transports
molecules or cells into the cell
via invagination of the plasma
membrane to form a vesicle.
• C. ;"ocytosis transports
molecules outside the cell viathe fusion of a vesicle with the
plasma membrane.
#.# (he Plasma +embrane and How 'ubstances %ross -t
'lasa e!rane
#acuole
a. hagocytosis
solute
#esicle
!. inocytosis
rece'tor 'rotein
coated #esiclecoated 'it
solute
c. >ece'tor-ediated endocytosis
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Figure 3.12 +ovement of large molecules across the membrane.
# (he ucleus and ;ndomembrane 'ystem
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2)
What structures are involved in
protein production?• ucleus
• 8ibosomes
• ;ndomembrane system
#. (he ucleus and ;ndomembrane 'ystem
# (he ucleus and ;ndomembrane 'ystem
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What is the structure and
function of the nucleus?
• 3ound by a porous nuclear envelope
•
• Houses chromatin4 2A with associatedproteins
• ucleolus contains ribosomal 8A r8AB
#. (he ucleus and ;ndomembrane 'ystem
# (he ucleus and ;ndomembrane 'ystem
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2*
What is the structure and
function of ribosomes?
• <rganelles made of r8A and protein
• >ound bound to the endoplasmic reticulumand free floating in the cytoplasm
• 'ites of protein synthesis
#. (he ucleus and ;ndomembrane 'ystem
# (he ucleus and ;ndomembrane 'ystem
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2+Figure 3.13 (he nucleus and endoplasmic reticulum.
#. (he ucleus and ;ndomembrane 'ystem
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nuclear
'ores
sooth >
nuclear
en#elo'e
chroatin
nucleolus
rough >
nuclear poresB4 %ourtesy ;.,. Pollock7 ;8B4 * 8. 3olender D 2. >awcett56isuals 0nlimited
# (he ucleus and ;ndomembrane 'ystem
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What is the endomembrane
system?• -t is a series of membranes in which molecules
are transported in the cell.
• -t consists of the nuclear envelope) endoplasmic
reticulum) ,olgi apparatus) lysosomes) and
vesicles.
#. (he ucleus and ;ndomembrane 'ystem
# (he ucleus and ;ndomembrane 'ystem
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How does the endomembrane system function?secretion
'lasa
e!rane
incoing #esicle
en;ye
lysosoe
contains digesti#e en;yes
that !rea= down cell 'arts or
su!stances entering !y #esicles
trans'ort #esicle
ta=es li'ids to
<olgi a''aratus
li'id
sooth endo'lasic
reticulu
synthesi;es li'ids and has
#arious other functions
rough endo'lasic
reticulu
synthesi;es 'roteins and
'ac=ages the in #esicles
trans'ort #esicle
ta=es 'roteins to
<olgi a''aratus
'rotein
<olgi a''aratus
odifies li'ids and 'roteins
fro the >E sorts and 'ac=ages
the in #esicles
secretory #esicle
7ucleus
ri!osoe
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Figure 3.14 (he endomembrane system.
#. (he ucleus and ;ndomembrane 'ystem
#. (he ucleus and ;ndomembrane 'ystem
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How can we summarize the parts
of the endomembrane system?• 8ough endoplasmic reticulum & studded with
ribosomes used to make proteins
• 'mooth endoplasmic reticulum & lacks ribosomesbut aids in making carbohydrates and lipids
• ,olgi apparatus & flattened stacks that process)package) and deliver proteins and lipids from the;8
#. (he ucleus and ;ndomembrane 'ystem
#. (he ucleus and ;ndomembrane 'ystem
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How can we summarize the parts
of the endomembrane system?• /ysosomes & membranous vesicles made by the
,olgi that contain digestive enzymes
• 6esicles & small membranous sacs used fortransport
#. (he ucleus and ;ndomembrane 'ystem
#.@ (he %ytoskeleton) %ell +ovement) and %ell Eunctions
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What is the cytoskeleton?
• A series of proteins that maintain cell shape) as
well as anchors and5or moves organelles in the
cell
• +ade of # types of fibers4 large microtubules)
thin actin filaments) and medium!sized
intermediate filaments
#.@ (he %ytoskeleton) %ell +ovement) and %ell Eunctions
#.@ (he %ytoskeleton) %ell +ovement) and %ell Eunctions
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Flagellu
icrotu!ules
'lasae!rane
cilia
s'er
flagellu
secretory cell
flagellu
!.
c.
a.
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bB4 * F. ikas5Photo 8esearchers) -nc.7 cB4 * 2avid +. Phillips5Photo 8esearchers) -nc.
• 3oth are made of
microtubules.
• 3oth are used inmovement.
• %ilia are about 19×
shorter than flagella.
What are cilia and flagella?
Figure 3.15 'tructure and function of the cilia
and flagella.
y ) )
#.@ (he %ytoskeleton) %ell +ovement) and %ell Eunctions
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3)
What are cell :unctions?
• Eunctions between thecells of human tissue
that allow them to
function in a
coordinated manner• # main types
& Adhesion :unctions
mechanically attach
ad:acent cellscommon in skin
cellsB.
y ) )
Figure 3.1)a Eunctions between cells.
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filaents of
cytos=eleton
'lasae!ranes
a. :dhesion unction
intercellular
s'ace
intercellular
filaents
#.@ (he %ytoskeleton) %ell +ovement) and %ell Eunctions
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What are cell :unctions?
& (ight :unctions are
connections between
the plasma membrane
proteins of
neighboring cells thatproduce a zipper!like
barrier common in
digestive system and
kidney where fluids
must be contained to
a specific areaB.
y ) )
Figure 3.1)! Eunctions between cells.
'lasa
e!ranes
tight unction
'roteins
intercellular
s'ace
!. Tight unction
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#.@ (he %ytoskeleton) %ell +ovement) and %ell Eunctions
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3*
What are cell :unctions?
& ,ap :unctions are
communication
portals between
cells7 channel
proteins of theplasma membrane
fuse) allowing easy
movement between
ad:acent cells.
y ) )
Figure 3.1)c Eunctions between cells.
'lasa
e!ranes
e!ranechannels
intercellular
s'ace
c. <a' unction
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#.C +itochondria and %ellular +etabolism
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3+
What do mitochondria do and what do
they look like?
• Highly folded
organelles in
eukaryotic cells
• Produce energy in the
form of A(P
• (hought to be derived
from an engulfed
prokaryotic cell
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2 natri/
intere!rane
s'ace
outer
e!raneinner
e!rane
cristae
topB 4 * 2r. 2on W. >awcett56isuals 0nlimitedFigure 3.10 (he structure of a mitochondrion.
#.C +itochondria and %ellular +etabolism
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4
;nzymes are important for cellular
respiration and many activities in the cell• +ost enzymes are proteins.• ;nzymes are often named for the molecules that
they work on) called substrates.• ;nzymes are specific to what substrate they workon.
• ;nzymes have active sites where a substrate binds.• ;nzymes are not used up in a reaction but instead
are recycled.• 'ome enzymes are aided by nonprotein molecules
called coenzymes.
#.C +itochondria and %ellular +etabolism
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How do enzymes work?
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acti#e site
en;ye
su!strate
'roducts
en;ye
en;yesu!strate
co'le/
$ynthesis
$u!strates are co!ined
to 'roduce a larger 'roduct.
?egradation
: su!strate is !ro=en
down to saller 'roducts.
'roduct
en;ye
en;yesu!strate
co'le/
en;ye
acti#e site
su!strates
Figure 3.1* Action of an enzyme.
#.C +itochondria and %ellular +etabolism
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42
What is cellular respiration?
• Production of A(P in a cell
• -ncludes
$. ,lycolysis
1. %itric acid cycle =rebs cycleB
#. ;lectron transport chain
#.C +itochondria and %ellular +etabolism
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43Figure 3.1+ Production of A(P.
%opyright * (he +c,raw!Hill %ompanies) -nc. Permission reuired for reproduction or display.
,utside cell
2 322
Inside cell
electrons
transferred
!y 7:?D
:T:T:T
itochondrion
lectron
trans'ortchain
itric
acidcycle
o/ygen
glucose
electrons
transferred!y 7:?D
glucose
<lycolysis
'yru#ate
#.C +itochondria and cellular metabolism
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44
,lycolysis
& <ccurs in the cytoplasm
& 3reaks glucose into 1 pyruvate
& A2H and 1 A(P molecules are made
& 2oes not reuire o"ygen
#.C +itochondria and %ellular +etabolism
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45
%itric acid cycle =rebs cycleB
& A cyclical pathway that occurs in the
mitochondria
& Produces A2H and 1 A(P
& 8eleases carbon dio"ide
#.C +itochondria and %ellular +etabolism
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4)
;lectron transport chain
• 'eries of molecules embedded in the
mitochondrial membrane
& A2H made in steps $ and 1 carry electrons
here & #1!# A(P are made depending on the cell
& 8euires o"ygen as the final electron
acceptor in the chain
#.C +itochondria and %ellular +etabolism
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40
What other molecules besides glucose
can be used in cellular respiration?• <ther carbohydrates
• Proteins
• /ipids
#.C +itochondria and %ellular +etabolism
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How can a cell make A(P without
o"ygen?
• >ermentation4
& occurs in the cytoplasm.
& does not reuire o"ygen. & involves glycolysis.
& makes 1 A(P and lactate in human cells.
& can give humans a burst of energy for a shorttime.