Cell Structure Cell Structure & Function& Function(What do cells look like?)(What do cells look like?)

(What do cells do?)(What do cells do?)

2 main types of cells2 main types of cells

ProkaryotesProkaryotes ( (ProkaryoticProkaryotic)) EukaryotesEukaryotes ( (EukaryoticEukaryotic))

ProkaryotesProkaryotes

SimpleSimple cells cells Unicellular onlyUnicellular only Typical size Typical size 1-2 μm1-2 μm in diameter in diameter NoNo nuclear membrane or other nuclear membrane or other membrane-membrane-

bound organellesbound organelles DNA is in a DNA is in a tangled looptangled loop Some prokaryotes have a second loop of DNA Some prokaryotes have a second loop of DNA

called a called a plasmidplasmid Cell wallsCell walls vary but can be very “tough” to help vary but can be very “tough” to help

the cell survive harsh environmentsthe cell survive harsh environments

Prokaryotic cell:Prokaryotic cell:

EukaryotesEukaryotes

ComplexComplex cells cells Both unicellular & multicellular organismsBoth unicellular & multicellular organisms. (All . (All

multicellular organisms are this type.)multicellular organisms are this type.) Typically about Typically about 10x larger10x larger than prokaryotic cells than prokaryotic cells Many Many organellesorganelles – some common, some only in plant – some common, some only in plant

cells, some only in animal cellscells, some only in animal cells DNA is extremely long so the cell condenses it to form DNA is extremely long so the cell condenses it to form

chromosomeschromosomes Some eukaryotic cells Some eukaryotic cells differentiatedifferentiate. This means they . This means they

can become different types of cells: skin cells, muscle can become different types of cells: skin cells, muscle cells, blood cells, fat cells, etc. Plants have different cells, blood cells, fat cells, etc. Plants have different types of cells too.types of cells too.

Eukaryotic cell:Eukaryotic cell:

Comparing prokaryotes Comparing prokaryotes to eukaryotesto eukaryotes

Prokaryotic cell Eukaryotic cell

Simple or Complex?

Size of Cell?

Unicellular, Multicellular, or Both

Any membrane-bound organelles?

What does the DNA look like?

Comparing prokaryotes Comparing prokaryotes to eukaryotesto eukaryotes

Prokaryotic cell Eukaryotic cell

Simple or Complex? SimpleSimple ComplexComplex

Size of Cell? 1 – 2 μm1 – 2 μm Typically 10x largerTypically 10x larger

Unicellular, Multicellular, or Both

UnicellularUnicellular BothBoth

Any membrane-bound organelles?

NoNo YesYes

What does the DNA look like?

Tangled loopTangled loop ChromosomesChromosomes

OrganellesOrganelles

Little “compartments” inside cellsLittle “compartments” inside cells.. Only found in Only found in eukaryoticeukaryotic cells. cells. Each type of organelle Each type of organelle has its own has its own

purpose/functionpurpose/function for the cell. for the cell. Organelles may have once been Organelles may have once been

prokaryotic cellsprokaryotic cells that were that were engulfedengulfed and and then incorporated into a larger cell then incorporated into a larger cell instead of being broken down as food.instead of being broken down as food.

NucleusNucleus

Holds genetic materialHolds genetic material

http://www2.plymouth.ac.uk/electronmicroscopy/TEM_BIOL/slides/Nucleus.jpg November 2007

Nuclear membraneNuclear membrane

Selects what can enter and leave the Selects what can enter and leave the nucleusnucleus

NucleolusNucleolus

An area in the nucleus that makes An area in the nucleus that makes ribosomesribosomes

Nuclear poreNuclear pore

Controls what molecules can enter/leave Controls what molecules can enter/leave the nucleusthe nucleus

http://www.abdn.ac.uk/emunit/emunit/temcells/images/nuclear%20pore%20%20.jpg

Cell wallCell wall

Supports and protects the cell.Supports and protects the cell.

Root cell: http://www.abdn.ac.uk/emunit/emunit/templant/images/root%20cell%20%20.jpg

Cell membraneCell membrane

Selects what can enter and leave the Selects what can enter and leave the cell.cell.

CytoplasmCytoplasm

Includes the internal part of the cell Includes the internal part of the cell except the nucleus.except the nucleus.

http://www.lifesci.sussex.ac.uk/home/Julian_Thorpe/tem22.jpg

http://www.lifesci.sussex.ac.uk/home/Julian_Thorpe/tem2.jpg

CytosolCytosol

The gel-like fluid that surrounds the The gel-like fluid that surrounds the organelles in the cytoplasm.organelles in the cytoplasm.

VacuolesVacuoles

StorageStorage

RibosomesRibosomes

Makes proteins (protein synthesis)Makes proteins (protein synthesis)

(Tiny dots!)

Endoplasmic reticulumEndoplasmic reticulum

Transports molecules around the cellTransports molecules around the cell Rough E.R. Rough E.R. has ribosomes on ithas ribosomes on it Smooth E.R. Smooth E.R. lacks ribosomeslacks ribosomes

http://219.221.200.61/ywwy/zbsw(E)/pic/ech7-5.jpg

Golgi apparatusGolgi apparatus

Packages molecules to be releasedPackages molecules to be released

http://www.lifesci.sussex.ac.uk/home/Julian_Thorpe/tem12.jpg

MitochondriaMitochondria

Makes ATP energy from the sugars that Makes ATP energy from the sugars that you ate earlieryou ate earlier

http://images.google.com/imgres?imgurl=http://ebiomedia.com/prod/LC/images/UnitofLife_img_10.jpg&imgrefurl=http://ebiomedia.com/prod/LC/LCcellunit.html&h=238&w=416&sz=19&hl=en&start=40&tbnid=oAv7kJ4T5Z0hFM:&tbnh=72&tbnw=125&prev=/images%3Fq%3Dmitochondria%2BTEM%26start%3D20%26gbv%3D2%26ndsp%3D20%26svnum%3D10%26hl%3Den%26sa%3DN

November 2007

ChloroplastsChloroplasts

Converts light to sugar molecules Converts light to sugar molecules (photosynthesis)(photosynthesis)

http://botit.botany.wisc.edu/images/130/Photosynthesis/Chloroplast_EN.gif

Where to find these Where to find these organelles:organelles:

Cell W

allC

ell Wall

Cell m

emb

rane

Cell m

emb

rane

Nu

cleus

Nu

cleus

Nu

clear mem

bran

eN

uclear m

emb

rane

Nu

cleolu

sN

ucleo

lus

Nu

clear po

reN

uclear p

ore

En

do

plas

mic

reticulu

mE

nd

op

lasm

ic reticu

lum

Go

lgi a

pp

aratus

Go

lgi a

pp

aratus

Rib

os

om

es

Rib

os

om

es

Vac

uo

les

Vac

uo

les

Mito

cho

nd

riaM

itoch

on

dria

Ch

loro

plasts

Ch

loro

plasts

Cyto

plasm

Cyto

plasm

Cyto

so

lC

ytos

ol

Plant cells Plant cells onlyonly

Animal Animal cells onlycells only

All All eukaryotic eukaryotic

cellscells

Where to find these Where to find these organelles:organelles:

Cell W

allC

ell Wall

Cell m

emb

rane

Cell m

emb

rane

Nu

cleus

Nu

cleus

Nu

clear mem

bran

eN

uclear m

emb

rane

Nu

cleolu

sN

ucleo

lus

Nu

clear po

reN

uclear p

ore

En

do

plas

mic

reticulu

mE

nd

op

lasm

ic reticu

lum

Go

lgi a

pp

aratus

Go

lgi a

pp

aratus

Rib

os

om

es

Rib

os

om

es

Vac

uo

les

Vac

uo

les

Mito

cho

nd

riaM

itoch

on

dria

Ch

loro

plasts

Ch

loro

plasts

Cyto

plasm

Cyto

plasm

Cyto

so

lC

ytos

ol

Plant cells Plant cells onlyonly XX XX

Animal Animal cells onlycells only

All All eukaryotic eukaryotic

cellscellsXX XX XX XX XX XX XX XX XX XX XX XX

Plant Cell & Animal CellPlant Cell & Animal Cell

Plant Cell Animal Cell

Cell VideoCell Video

http://aimediaserver4.com/studiodaily/videoplayer/?src=ai4/harvard/harvard.swf&width=640&height=520