Cells & Cellular ProcessesCells & Cellular Processes

Where Life Begins…Where Life Begins…

Cells...

Are the simplest collection of matter that can live

Are the basic unit of structure & function for all living things

Communicate with one another Sense & respond to environmental changesAre descendents from earlier cells

AllAll Cells Have…

Plasma MembranePlasma Membrane – semipermeable layer that surrounds & protects every cell.

CytoskeletonCytoskeleton – semifluid substance within the membrane

DNADNA – in the form of chromosomes that contain specific genes coordinating cell functions

Ribosomes Ribosomes – tiny organelles that make proteins using instructions from genes

Types of CellsTypes of Cells1.1. ProkaryotesProkaryotes

– Pro – before; karyon – nucleus– No true nucleus– Nucleoid region

• Not a true membrane-bound nucleus but the area where DNA is concentrated

– Bacteria are

the only examples

E. coli

Salmonella

Lactobacilluslibrary.thinkquest.org

E.coli on the small intestine

2. Eukaryotes2. Eukaryotes– Contain a “true” nucleus enclosed by a

membrane– Also contain a variety of other membrane-

bound organelles

www.answers.com/topic/cytoskeletonhttp://nobelprize.org/nobel_prizes/medicine/laureates/1999/illpres/

(nucleus)

OrganellesOrganelles“tiny organs”

1.1. NucleusNucleus– Control center that directs cellular activity– Contains most of the genes in eukaryotic cells– Enclosed by a nuclear membrane, or envelope,

that contains pores– Contains DNA usually in the form of chromatin– Contains the nucleolus, nucleolus, the area where ribosomes are produced

http://www.public.iastate.edu/~ttt356/Nucleus.jpg

www.nsf.gov/news/overviews/biology/interact05.jsp

2. Mitochondria2. Mitochondria Powerhouse of the cell Produces the bulk of the ATP in the cell during

aerobic respiration Contains its

own DNA Thought be

free-living bacteria

at one time

http://kentsimmons.uwinnipeg.ca/cm1504/Image110.gif

3. Ribosomes3. Ribosomes The tiniest organelles; produce in nucleolus Assemble proteins through the process of

translation Some are “free” in cytoplasm; others are attached

to Rough ER

http://www.nsf.gov/news/overviews/biology/assets/interact05.jpghttp://genome.imim.es/courses/Madrid04/exercises/ensembl/images/ribosome.jpg

4. Rough Endoplasmic Reticulum4. Rough Endoplasmic Reticulum

“Rough” because of the ribosomes attached Continuous with

the nuclear membrane Produces internal

membranes Folds, proof-reads &

transports proteins made by ribosomeswww.biologycorner.com

http://www.biology.arizona.edu/CELL_BIO/tutorials/pev/graphics/smooth_er.gif

http://www.mhhe.com/biosci/genbio/enger/student/olc/art_quizzes/genbiomedia/0064.jpg

5. Smooth ER5. Smooth ER

Extension of RER without the ribosomes Makes lipids for the cell – fatty acids, steroids &

phospholipids Also functions in detoxification of poisons &

toxins within the cell

www.biologycorner.comhttp://www.biology.arizona.edu/CELL_BIO/tutorials/pev/graphics/smooth_er.gif

6. Golgi Apparatus6. Golgi Apparatus “Mailroom” of the cell Sorts, packages & exports proteins in vesicles

http://www.daviddarling.info/images/Golgi_apparatus.jpg

http://ghr.nlm.nih.gov/handbook/illustrations/cellgolgi.jpg

Golgi Implications in Disease

AlzheimersParkinson’sMad Cow Lesch-NyhanALS (Lou Gehrig’s)Pick’s Disease

7. Vacuole7. Vacuole Storage organelle for food, water & wastes Especially large in plant cells for the storage of

water

http://www4.alief.isd.tenet.edu/cahowe/PreAPBio/Projects/Cell_files/slide0013_image053.jpg

http://www.daviddarling.info/images/contractile_vacuole.gif

8. Lysosomes8. Lysosomes Enzyme-containing organelles that digest

(hydrolyze) cellular waste products, nonfunctional proteins & return usable components to cytoplasm

Enzymes are

made in SER

http://www.molecularexpressions.com/cells/lysosomes/images/lysosomesfigure1.jpg

Lysosomes in Tay SachsMutated genes produce enzymes that are less

effective than normal at breaking down fatty cell products known as gangliosides.

Gangliosides build up in the lysosomes and overload cells. http://www.sfn.org/index.cfm?pagename=brainBriefings_TreatingTaySachs

http://www.kellogg.umich.edu/theeyeshaveit/congenital/images/tay-sachs.jpg

9. Peroxisome9. Peroxisome

Enzyme-containing organelles that transfer H+ from various compounds to oxygen

Some break down fatty acids; others break down poisons such as alcohol

H2O2 is often a waste product of peroxisome reactions, and it is a toxin as well –

Our body breaks down H2O2 with an enzyme called _______. The products are ____ & _____.

Peroxisomes & Disease

ALD – featured in the movie “Lorenzo’s Oil”Zellweger Syndrome

http://www.neuro.jhmi.edu/BrainWaves/2004_Fall/photos/oil.jpg

A Tour of the Cell

The National Science Foundation Tour of the Cell -

http://www.nsf.gov/news/overviews/biology/interactive.jspAn amazing animation of the Inner Life of

the Cell - http://www.studiodaily.com/main/

searchlist/6850.html

The CytoskeletonThe Cytoskeleton Semifluid medium that supports organelles Consists of a network of fibers that support the

cell and allow for organized movement of material.

Fibers include:1. Microtubules

2. Actin microfilaments

3. Intermediate filaments

http://upload.wikimedia.org/wikipedia/commons/0/09/FluorescentCells.jpg

1. Microtubules1. Microtubules Hollow tubes that form the thickest of the fibers

in cytoskeletal frameworkMade in centrosome (MTOC) Shape & supports cellServe as tracks for movement of vesicles &

chromosomesOrganelle & vesicle movement along

microtubules is controlled by motor proteins called dynein & kinesin

Dynamic Instability of Microtubules

http://sparkleberrysprings.com/innerlifeofcell.html

AssemblyAssembly DisassemblyDisassembly

http://www.nsf.gov/news/mmg/media/images/microtubule_traffic_h3.jpg

http://www.hhmi.org/bulletin/may2007/chronicle/popups/molecules_1.html

http://www.dnatube.com/view_video.php?viewkey=a8ae0be8b5306971900a&viewtype=?

Microtubules in the cellMicrotubules in the cell Centrioles

– Found in animal cells only– Organize microtubules during cell division– Have a 9 + 3 arrangement

• 9 sets of 3 microtubules

http://micro.magnet.fsu.edu/cells/centrioles/centrioles.html

Microtubules as Chemo TargetMicrotubules as Chemo Target

Taxol, a chemo

drug, works by

stabilizing

microtubules (green)

used in cell division It halts cells in the

process of division

http://cose-stor.sfsu.edu/~huiyang/images/cell-fireworks.jpg

Cilia & Flagella– Core of microtubules covered by an extension of the

cell membrane– 9 + 2 pattern– Anchored by a basal body that has the same 9 + 3

microtubule arrangement as centrioles– Dynein arms are the “motors” responsible for the

bending movements of cilia & flagella

http://micro.magnet.fsu.edu/cells/centrioles/centrioles.html

2. Actin Microfilaments2. Actin Microfilaments Solid rods that are much smaller than

microtubules Two-stranded helical polymers of actin Found just beneath the plasma membrane

http://www.daviddarling.info/encyclopedia/A/actin.html

http://sparkleberrysprings.com/innerlifeofcell.html

Microtubules & Actin Microfilaments

http://publications.nigms.nih.gov/insidethecell/chapter1.html

3.3. Intermediate FilamentsIntermediate Filaments

Mid sized filaments

that provide framework

for organelle position The most stable &

durable fibers in the

Cytoskeleton Main component

in tough coverings

(skin, hair, nails)http://campus.queens.edu/faculty/jannr/cells/cell%20pics/cytoskeleton.jpg

http://www.studiodaily.com/main/searchlist/6850.html

Membranes & Transport

Gateways of

cells & organelles

http://www.biology.iupui.edu/biocourses/N100H/cells.html

Structure

http://www.bioteach.ubc.ca/Bio-industry/Inex/

http://images.google.com/imgres?imgurl=http://www.iupac.org/didac/Slide%2520Images/Didac%252005/Thumbs/D5%2520CG06.jpg&imgrefurl=http://www.iupac.org/didac/Didac%2520Eng/Didac05/Content/CG06.htm&h=254&w=378&sz=61&hl=en&start=24&tbnid=ukwDqpIAGNcyMM:&tbnh=82&tbnw=122&prev=/images%3Fq%3Dphospholipid%2Bbilayer%26start%3D20%26gbv%3D2%26ndsp%3D20%26svnum%3D10%26hl%3Den%26sa%3DN

http://commons.wikimedia.org/wiki/Image:Cell_membrane_detailed_diagram.svg

Passive Transport

Does not require energy [High] [Low]

1. Diffusion

2. Osmosis

3. Facilitated diffusion

1. Diffusion

Occurs across the phospholipids– CO2

– O2

– Urea

Lab Information on Diffusion

Dialysis tubing acts as a semipermeable membrane

Which materials can pass through the pores?

Which cannot permeate the bag?

Animation

2. Osmosis

Diffusion of waterWater moves from

– High [water] low [water]– Hypotonic [solute] hypertonic [solute]

Animation

http://www.ualr.edu/botany/osmosis.jpg

http://commons.wikimedia.org/wiki/Image:Turgor_pressure_on_plant_cells_diagram.svg

http://commons.wikimedia.org/wiki/Image:Osmotic_pressure_on_blood_cells_diagram.svg

3. Facilitated Diffusion

Molecules moving from [high] [low] but are too big to move between phospholipids

Requires a

membrane carrier

(facilitator)Glucose uses this

http://www.biology.arizona.edu/chh/problem_sets/kidneysmetals/07t.html

Active Transport

Requires ATP energy– ATP pumps– Cotransport– Endocytosis– Exocytosis

Often goes against concentration gradient

ATP Pumps

Na+/K+ pump

Cotransport

2 molecules transported on the same protein– 1 against the

gradient– 1 with the

gradient

Endocytosis

Engulfing large molecules by wrapping a piece of membrane around it to form a transport vesicle

3 Types of Endocytosis

Phagocytosis– Engulfing solids

Pinocytosis– Engulfing liquids

Receptor-mediated endocytosis– Engulfing with specific receptors

• LDL cholesterol

Exocytosis

Spitting out large molecules

Vesicles fuse with membrane

Endo & Exocytosis

http://en.wikipedia.org/wiki/Phagocytosis

http://www.dnatube.com/view_video.php?viewkey=6ebda4840e7360ce6e7e

Review

http://www.dwm.ks.edu.tw/bio/activelearner/05/ch5intro.html

Tutorial

http://www.dnatube.com/view_video.php?viewkey=4fdd9ee93bdf998c6ca0