AP Biology

Tour of the Cell 1

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Prokaryotebacteria cellsProkaryote

bacteria cellsTypes of cells

Eukaryoteanimal cellsEukaryote

animal cells

- no organelles

- organelles

Eukaryoteplant cellsEukaryoteplant cells

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

Comparing Prokaryotic and Eukaryotic Cells

Basic features of all cells:

– Plasma membrane

– Cytoplasm

– Chromosomes (carry genes)

– Ribosomes (make proteins)

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

Eukaryotic cells have internal membranes that compartmentalize their functions

Prokaryotes

• No membrane bound nucleus

• DNA located in an area called a nucleoid

• No membrane bound organelles

• Bacteria 1-10um

Eukaryotes

• Membrane bound nucleus

• DNA located inside a nuclear membrane

• Membrane bound organelles

• Eukaryotes 10-100um

LE 6-6

A typicalrod-shapedbacterium

A thin section through thebacterium Bacilluscoagulans (TEM)

0.5 µm

Pili

Nucleoid

Ribosomes

Plasmamembrane

Cell wall

Capsule

Flagella

Bacterialchromosome

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

Prokaryotic parts

• Pili- Attachment; conjugation

• Ribosomes – make proteins

• Plasma membrane – membrane around cytoplasm

• Cell wall – structure outside cell membrane; made of peptidoglycan for many bacteria

• Capsule – jelly-like outer coating

• Flagella – tail for movement

LE 6-7

Total surface area(height x width xnumber of sides xnumber of boxes)

6

125 125

150 750

1

11

5

1.2 66

Total volume(height x width x lengthX number of boxes)

Surface-to-volumeratio(surface area volume)

Surface area increases whileTotal volume remains constant

Why can’t cells grow indefinitely in size?

Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings

A Panoramic View of the Eukaryotic Cell

• A eukaryotic cell has internal membranes that partition the cell into organelles

• Plant and animal cells have most of the same organelles

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Why organelles? Specialized structures

specialized functions cilia or flagella for locomotion

Containers partition cell into compartments create different local environments

ie. separate pH

Membranes as sites for chemical reactions

embedded enzymes & reaction centers chloroplasts & mitochondria

mitochondria

chloroplast

Golgi

ER

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Cells gotta work to live! What jobs do cells have to do?

make proteins proteins control every

cell function make energy

for daily life for growth

make more cells growth repair renewal

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Building Proteins

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Proteins do all the work!

cellscells

DNADNA

proteinsproteins

organismorganismRepeat after me…

Proteins do all the work!

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Cells functions Building proteins overview

read DNA instructions build proteins process proteins

folding modifying

removing amino acids adding other molecules

e.g, making glycoproteinsfor cell membrane

address & transport proteins

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Building Proteins Organelles involved

nucleus ribosomes endoplasmic reticulum

(ER) Golgi apparatus vesicles

nucleus ribosome ERGolgi

apparatusvesicles

The Protein Assembly Line

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nuclearpores

nuclearpore

nuclear envelopenucleolus

histone protein

chromosome

DNA

Function protects DNA

Structure nuclear envelope

double membrane membrane fused in spots to create pores

allows large macromolecules to pass through

Nucleus

What kind of molecules need to

pass through?

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DNA

NucleusmRNA

nuclearmembrane

smallribosomal

subunit

largeribosomal

subunit

cytoplasm

mRNA

nuclear pore

production of mRNA from DNA in nucleusproduction of mRNA from DNA in nucleus

mRNA travels from nucleus to ribosome in cytoplasm through nuclear pore

mRNA travels from nucleus to ribosome in cytoplasm through nuclear pore

1

2

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Nucleolus Function

ribosome production build ribosome subunits from rRNA & proteins exit through nuclear pores to cytoplasm &

combine to form functional ribosomes

smallsubunit

large subunit

ribosome

rRNA &proteins

nucleolus

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smallsubunit

largesubunitRibosomes

Function protein production

Structure rRNA & protein 2 subunits combine 0.08m

RibosomesRough

ER

SmoothER

AP Biology membrane proteins

Types of Ribosomes Free ribosomes

suspended in cytosol synthesize proteins that

function in cytosol

Bound ribosomes attached to endoplasmic

reticulum synthesize proteins

for export or for membranes

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Endoplasmic Reticulum Function

processes proteins manufactures membranes synthesis & hydrolysis of many compounds

Structure membrane connected to nuclear envelope &

extends throughout cell

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Types of ER

rough smooth

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Smooth ER function Membrane production Many metabolic processes

synthesis synthesize lipids

oils, phospholipids, steroids & sex hormones

hydrolysis hydrolyze glycogen into glucose

in liver

detoxify drugs & poisons in liver ex. alcohol & barbiturates

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Membrane Factory Build new

membrane synthesize

phospholipids builds membranes

ER membrane expands bud off & transfer

to other parts of cell that need membranes

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Rough ER function Produce proteins for export out of cell

protein secreting cells packaged into transport vesicles for export

Which cellshave lot of rough ER?

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Synthesizing proteins

cytoplasm

cisternalspace

mRNA

ribosome

membrane ofendoplasmic reticulum

polypeptide

signalsequence

ribosome

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Golgi Apparatus

Which cellshave lots of Golgi?

transport vesicles

secretoryvesicles

Function finishes, sorts, tags & ships cell products

like “UPS shipping department” ships products in vesicles

membrane sacs “UPS trucks”

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Golgi Apparatus

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Vesicle transport

vesiclebuddingfrom roughER

fusionof vesiclewith Golgiapparatus

migratingtransportvesicle

protein

ribosome

Regents Biology

DNA

RNA

ribosomes

endoplasmicreticulum

vesicle

Golgi apparatus

vesicle

proteinon its way!

protein finishedprotein

Making Proteins

TO:

TO:

TO:

TO:

nucleus

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proteins

transportvesicle

Golgiapparatus

vesicle

smooth ER

rough ER

nuclear porenucleus

ribosome

cellmembrane protein secreted

cytoplasm

Making proteinsPutting it together…

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AP Biology 2007-2008

Any Questions!!