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Cell BiologyCell Biology

Mark MayoMark MayoCypress CollegeCypress College

Last update 9/10/13

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Cell TheoryCell Theory All organisms are made All organisms are made

up of cellsup of cells All substances in All substances in

organisms are products organisms are products of cellsof cells

Cells come from other Cells come from other cells by reproductioncells by reproduction

Named by Robert HookeNamed by Robert Hooke while looking at slices of cork while looking at slices of cork **

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Types of CellsTypes of Cells

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Cell SizeCell Size

Cells are smallCells are small Seeing them requires the use of a Seeing them requires the use of a

microscope of some kindmicroscope of some kind

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Processes of Living CellsProcesses of Living Cells NutritionNutrition-food for energy and growth-food for energy and growth DigestionDigestion-breakdown of foodstuff-breakdown of foodstuff AbsorptionAbsorption-of nutrients after digestion-of nutrients after digestion BiosynthesisBiosynthesis-organization of absorbed nutrients into -organization of absorbed nutrients into

protoplasm for growth or repairprotoplasm for growth or repair RespirationRespiration-the chemical breakdown of molecules -the chemical breakdown of molecules

(glucose) to release energy(glucose) to release energy SecretionSecretion-expelling of products from inside the cell -expelling of products from inside the cell

(hormones, oil, etc.)(hormones, oil, etc.) ResponseResponse-to stimuli-to stimuli ExcretionExcretion-removal of waste products-removal of waste products ReproductionReproduction-splitting of cells to form two or more cells-splitting of cells to form two or more cells

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Prokaryote vs Eukaryote Cells Prokaryote vs Eukaryote Cells ** Prokaryotes Prokaryotes **

BacteriaBacteria No nucleusNo nucleus No internal No internal

membranesmembranes Fewer organellesFewer organelles

Eukaryotes Eukaryotes ** Yeast – plant - human cellsYeast – plant - human cells Numerous membrane-Numerous membrane-

bound organelles bound organelles ** Nucleus Nucleus ** Internal membranesInternal membranes

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OrganellesOrganelles An organelle is a small An organelle is a small

structure within the cell structure within the cell that performs a particular that performs a particular function function **

Many organelles within Many organelles within eukaryoticeukaryotic cells have a cells have a membrane that surrounds membrane that surrounds it and separates it from it and separates it from the rest of the cell the rest of the cell **

It separates chemical It separates chemical reactions in space reactions in space **

a. nucleus

b. chloroplast

c. Golgi complex

d. mitochondrion

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Cell membrane

Portions of the cell membrane is shown labeled with a fluorescent dye

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Cell membrane It is a bag that It is a bag that

surrounds the cellsurrounds the cell The cell membrane The cell membrane

is selective about is selective about what goes in or what goes in or comes outcomes out

They are found They are found around all animal around all animal and plant cellsand plant cells

It is composedIt is composedof a of a lipid bilayer lipid bilayer ** with numerous with numerous proteins proteins

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Cell membrane The cell membrane has The cell membrane has

many other names for itmany other names for it Plasma membranePlasma membrane PlasmalemmaPlasmalemma Neurilemma, sarcolemma Neurilemma, sarcolemma

etc.etc.

It is It is NOTNOT also called also called the cell wallthe cell wall

Plant cells and bacterial Plant cells and bacterial cells have cells have cell wallscell walls and and they also have cell they also have cell membranesmembranes

Plant cell Bacterial Cell

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Nucleus Nucleus (nuclei – plural form)(nuclei – plural form)

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NucleusNucleus control center of control center of

the cellthe cell all human cells all human cells

have a nucleus have a nucleus except the except the mammalian RBCmammalian RBC

without the without the nucleus the cell nucleus the cell will diewill die

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NucleusNucleus contains contains

DNADNA - the - the hereditary hereditary materialmaterial

DNA is DNA is bound to bound to proteins proteins called called histoneshistones

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NucleusNucleus surrounded by surrounded by

the nuclear the nuclear membrane membrane

has nuclear has nuclear porespores

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NucleusNucleus Cloning is Cloning is

the removal the removal of one of one nucleus from nucleus from an organism an organism and the and the insertion of it insertion of it into another into another cell (zygote)cell (zygote)

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Nucleolus Nucleolus (nucleoli - plural form)(nucleoli - plural form)

Nucleus

Nucleolus

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NucleolusNucleolus small dot(s) inside small dot(s) inside

of the nuclei of of the nuclei of most cellsmost cells

concentrated RNAconcentrated RNA site of RNA site of RNA

synthesis synthesis ** Three kinds of RNA Three kinds of RNA **

Ribosomal RNARibosomal RNA Transfer RNATransfer RNA Messenger RNAMessenger RNA

ribosomal ribosomal subunits are subunits are assembled here assembled here ** Nucleus Nucleolus

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Cytoplasm (cytosol)Cytoplasm (cytosol) Cytoplasm = cell fluidCytoplasm = cell fluid Fills the cellFills the cell Organelles "float" in the Organelles "float" in the

cytoplasmcytoplasm

Most chemical reactions Most chemical reactions occur here occur here

Not technically an Not technically an organelleorganelle

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CytoskeletonCytoskeleton

Keratins stain pink while laminins are green

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CytoskeletonCytoskeleton Definition of the Definition of the

cytoskeleton:cytoskeleton:

an interconnected an interconnected series of tubules and series of tubules and fibers that gives a fibers that gives a cell the ability to cell the ability to move, provides move, provides internal organization internal organization and causes cell and causes cell shape shape

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CytoskeletonCytoskeleton

The cytoskeleton is composed of three The cytoskeleton is composed of three main components main components ** : :

Microfilaments Microfilaments ** Intermediate filaments Intermediate filaments ** Microtubules Microtubules **

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CytoskeletonCytoskeleton microfilamentsmicrofilaments ** --

provide support and provide support and strengthstrength

myosin and actinmyosin and actin ** are contractile are contractile filamentous proteins filamentous proteins that are found in that are found in muscle tissuemuscle tissue

extremely conserved extremely conserved over evolutionary time over evolutionary time Actin filaments are green

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CytoskeletonCytoskeleton Actin and myosinActin and myosin are the basis for muscle are the basis for muscle

contractioncontraction

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CytoskeletonCytoskeleton Intermediate filaments Intermediate filaments

play important roles in play important roles in cellular activitiescellular activities

They strengthen cells They strengthen cells and organellesand organelles Desmin Desmin – attaches – attaches

muscle proteins muscle proteins together to allow together to allow contraction of contraction of myosin and actinmyosin and actin

KeratinKeratin – found in – found in skin, nails and hair skin, nails and hair – very tough – very tough

NeurofilamentsNeurofilaments – – exact function exact function unknown to me, but unknown to me, but useful to nerve useful to nerve impulse conduction impulse conduction

Intermediate filaments are colored red

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CytoskeletonCytoskeleton Microtubules are larger Microtubules are larger

than microfilaments than microfilaments and are hollowand are hollow

They are composed of They are composed of the protein tubulin the protein tubulin ** both alpha and beta both alpha and beta subunits subunits **

Microtubules are used Microtubules are used in cells division and in cells division and cell movementcell movement

Microtubules give Microtubules give shape to cells (allows shape to cells (allows shape changes)shape changes)

Microtubules are stained light blue

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CytoskeletonCytoskeleton Microtubules are found in cilia and flagellaMicrotubules are found in cilia and flagella

for motility or movement for motility or movement **

Cilia in the respiratory system Flagellum on a sperm cell

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CytoskeletonCytoskeleton The action of The action of

microtubules can microtubules can be inhibited by be inhibited by several drugsseveral drugs CholchicineCholchicine – –

stops cell division – stops cell division – used to make used to make mitosis slides for mitosis slides for biologybiology

TaxolTaxol – stops cell – stops cell division and is division and is used in cancer used in cancer treatment (rapidly treatment (rapidly dividing cells)dividing cells)It promotes the polymerization of tubulin, thereby causing It promotes the polymerization of tubulin, thereby causing cell death by disrupting the normal microtubule dynamics cell death by disrupting the normal microtubule dynamics required for cell division and vital interphase processes.required for cell division and vital interphase processes.

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Endoplasmic reticulum Endoplasmic reticulum

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Endoplasmic reticulumEndoplasmic reticulum means "inside fluid channel"means "inside fluid channel" the cell's pipeline the cell's pipeline **

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Endoplasmic reticulumEndoplasmic reticulum materials can be materials can be

transported transported throughout thethroughout thecell by thiscell by thisorganelleorganelle

connects with theconnects with thecell membranecell membraneand the nuclear and the nuclear membrane membrane

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Endoplasmic reticulumEndoplasmic reticulum

attachment site attachment site for ribosomes for ribosomes (granular E. R. ) (granular E. R. ) when they are when they are making making proteins for export proteins for export or membrane or membrane proteinsproteins

When the E.R. has attached ribosomes it is called ROUGH E.R. **

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Endoplasmic reticulumEndoplasmic reticulum Smooth E.R. Smooth E.R.

does not have does not have ribosomes and ribosomes and is involved with is involved with lipid synthesislipid synthesis

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RibosomeRibosome

The small, spherical objects attached to the E.R. are ribosomes

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RibosomeRibosome protein factoriesprotein factories they are involved with they are involved with

protein synthesis protein synthesis ** made of RNA, and made of RNA, and

proteinsproteins sometimes found sometimes found

connected to the connected to the endoplasmic reticulumendoplasmic reticulum

when ribosomes are when ribosomes are connected to the connected to the endoplasmic reticulum endoplasmic reticulum this is called rough E.R. this is called rough E.R. or granular E. R. or granular E. R. **

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RibosomeRibosome Ribosomes come in two Ribosomes come in two

states within the cellstates within the cell Attached ribosomesAttached ribosomes

– connected to the – connected to the endoplasmic reticulumendoplasmic reticulum

Free ribosomesFree ribosomes - float freely within the - float freely within the cytosolcytosol

Ribosomes move from Ribosomes move from one state to the other one state to the other freelyfreely

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RibosomeRibosome Polysomes Polysomes

form when form when several several ribosomes ribosomes attach to one attach to one piece of piece of mRNAmRNA

Each one Each one makes a makes a single strand single strand of new of new proteinprotein

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RibosomeRibosome The job ofThe job of

the the ribsomeribsomeis tois to““read”read”thethemessengermessengerRNA andRNA andmake a newmake a newproteinprotein

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RibosomeRibosome Translation is the final step Translation is the final step

on the way from DNA to on the way from DNA to protein. It is the synthesis protein. It is the synthesis of proteins directed by a of proteins directed by a mRNA template. The mRNA template. The information contained in information contained in the nucleotide sequence of the nucleotide sequence of the mRNA is read as three the mRNA is read as three letter words (triplets), letter words (triplets), called codons. Each word called codons. Each word stands for one amino acid.stands for one amino acid.

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RibosomeRibosome If a ribosome translates a signal sequence at the start of

protein synthesis, the ribosome attaches to the endoplasmic reticulum

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RibosomeRibosome After insertion of the signal peptide into the endoplasmic

reticulum the signal sequence is cut off. The rest of the protein in deposited within the E.R.

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Mitochondrion Mitochondrion (mitochondria - plural form)(mitochondria - plural form)

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MitochondrionMitochondrion powerhouse of the powerhouse of the

cellcell site of cellular site of cellular

respirationrespiration mitochondrion is the mitochondrion is the

location for the location for the conversion of energy conversion of energy stored in glucose into stored in glucose into ATP ATP **

ATPATP is produced in is produced in the mitochondrion the mitochondrion **

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MitochondrionMitochondrion inner folds of the inner folds of the

mitochondrial membrane mitochondrial membrane are called are called cristaecristae

Mitochondria are covered Mitochondria are covered by a membraneby a membrane

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MitochondrionMitochondrion many many

mitochondria are mitochondria are found wherever found wherever energy is energy is needed - such needed - such as in musclesas in muscles

Red structures are mitochondria

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MitochondrionMitochondrion Mitochondria are thought Mitochondria are thought

to have been separate to have been separate organisms at one timeorganisms at one time

They are self-replicatingThey are self-replicating

They have mDNA - sign They have mDNA - sign of of endosymbioticendosymbiotic origin origin

All your mitochondria All your mitochondria come from your mothercome from your mother

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CentrioleCentriole

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CentrioleCentriole Centrioles are Centrioles are

can-shaped can-shaped organelles that organelles that assist in cell assist in cell divisiondivision

They are found in They are found in an area close to an area close to the nucleus called the nucleus called the centrosome the centrosome

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CentrioleCentriole Centrioles Centrioles

are made of are made of nine fused nine fused triplets of triplets of microtubules microtubules

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CentrioleCentriole They serve as centers They serve as centers

for the attachment of for the attachment of the spindle apparatusthe spindle apparatus

Centrioles are self-Centrioles are self-replicating-have their replicating-have their own DNAown DNA (endosymbiotic)(endosymbiotic)

Each parent donates Each parent donates one centriole during one centriole during reproductionreproduction

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LysosomeLysosome

Lysosomes are shown in red

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LysosomeLysosome They are called They are called

suicide bags or suicide bags or sackssacks

They contain They contain digestive digestive enzymes enzymes **

Lysosomes are Lysosomes are used to digest used to digest ** bacteria and bacteria and "foreign" material "foreign" material

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LysosomeLysosome

Lysosomes are shown as black blobs in Lysosomes are shown as black blobs in this electron micrographthis electron micrograph

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LysosomeLysosome Incorrect lysosomal activity can lead to Incorrect lysosomal activity can lead to

defects like syndactyly where the digits of defects like syndactyly where the digits of the hand do not fully separate (vitamin A?)the hand do not fully separate (vitamin A?)

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LysosomeLysosome Incorrect lysosomal function can also lead to Tay Sachs Incorrect lysosomal function can also lead to Tay Sachs

diseasedisease Tay-Sachs disease is a disease that affects infants. Tay-Sachs disease is a disease that affects infants.

Symptoms generally appear by six months of age. While Symptoms generally appear by six months of age. While symptoms vary from one child to the next, there is always a symptoms vary from one child to the next, there is always a slowing down of development. Gradually, Tay-Sachs slowing down of development. Gradually, Tay-Sachs children lose motor skills and mental functions. Over time, children lose motor skills and mental functions. Over time, the child becomes blind, deaf, mentally retarded, paralyzed the child becomes blind, deaf, mentally retarded, paralyzed and non-responsive to the environment. and non-responsive to the environment.

Tay-Sachs children usually die by age five.Tay-Sachs children usually die by age five.

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GolgiGolgi

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GolgiGolgi The Golgi is known by The Golgi is known by

many namesmany names Golgi BodyGolgi Body Golgi ComplexGolgi Complex Golgi ApparatusGolgi Apparatus DictyosomeDictyosome

It was discovered by It was discovered by Camillo Golgi, an Camillo Golgi, an Italian scientistItalian scientist

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GolgiGolgi At first most in the scientific community did not embrace At first most in the scientific community did not embrace

Golgi’s new organelle; only when it was seen in the Golgi’s new organelle; only when it was seen in the electron microscope was his finding acceptedelectron microscope was his finding accepted

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GolgiGolgi There are three There are three

segments of the segments of the Golgi:Golgi: ciscis (vesicles join (vesicles join

here from E.R.)here from E.R.) medialmedial transtrans (vesicles bud (vesicles bud

off here toward off here toward lysosomes or lysosomes or plasma plasma membrane)membrane)

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GolgiGolgi Golgi cuts proteins and adds carbohydrates Golgi cuts proteins and adds carbohydrates

The Golgi apparatus is shown in green. Note there are numerous Golgi bodies within each cell.

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GolgiGolgi They are theThey are the packaging and shipping centers packaging and shipping centers of of

the cell the cell ** They are most numerous in cells actively They are most numerous in cells actively

secreting substances (glands)secreting substances (glands)

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Plant CellsPlant Cells

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Plant CellsPlant Cells External surfaces of Plant and animal cells comparedExternal surfaces of Plant and animal cells compared

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Plant CellsPlant Cells

Animal cells Animal cells ** Organelles evenly Organelles evenly

distributed throughout distributed throughout cytoplasmcytoplasm

Plant cells Plant cells ** Organelles compressed Organelles compressed

toward outer edges of the toward outer edges of the cellcell

Chloroplasts Chloroplasts ** Cell wall Cell wall **

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PlastidsPlastids

Unique spiral chloroplasts within the alga Spirogyra

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PlastidsPlastids Plastids are chemical Plastids are chemical

factories or storage factories or storage centers centers

They are usually They are usually highly colored, but highly colored, but also come in whitealso come in white

Chloroplasts

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PlastidsPlastids ChloroplastsChloroplasts

They are found in all green plant cellsThey are found in all green plant cells They are greenThey are green Chloroplasts Chloroplasts ** contains chlorophyll, the pigment contains chlorophyll, the pigment

needed for photosynthesis (the making of sugar from needed for photosynthesis (the making of sugar from sunlight, carbon dioxide, and water sunlight, carbon dioxide, and water **

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PlastidsPlastids LeucoplastsLeucoplasts

They are white in colorThey are white in color Leucoplasts are Leucoplasts are starch starch

storage bodies in plantsstorage bodies in plants Leucoplasts are Leucoplasts are

plentiful in the main plentiful in the main staples of food in the staples of food in the world:world: RiceRice PotatoesPotatoes WheatWheat PastaPasta BeansBeans

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PlastidsPlastids Chromoplasts are colored storage Chromoplasts are colored storage

containers within plant cellscontainers within plant cells They contain various plant pigmentsThey contain various plant pigments

Red chromoplasts in tomatoes

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PlastidsPlastids Plant PigmentsPlant Pigments

carotenecarotene-orange; -orange; found in carrots found in carrots and peppersand peppers

xanthophyllxanthophyll--yellow; found in yellow; found in bananas and bananas and pepperspeppers

chlorophyllchlorophyll-green; -green; the predominate the predominate color in plantscolor in plants