Chp. 7- Cell Theory & Chp. 7- Cell Theory & PartsParts

The Discovery of CellsThe Discovery of Cells

Robert Hooke (1665)Robert Hooke (1665) – Looked at Looked at corkcork under a microscope. under a microscope.– Saw many little boxes.Saw many little boxes.– Called them Called them cellscells..

Anton van Leeuwenhoek (1675)Anton van Leeuwenhoek (1675) – Looked at Looked at pond waterpond water under a microscope. under a microscope.– Saw living creatures.Saw living creatures.– Called them Called them animalculesanimalcules..

Cell TheoryCell Theory

1.1. All living things are All living things are made of made of one or moreone or more cells.cells.

2.2. Cells are the Cells are the basic basic unitsunits of structure and of structure and function in function in all livingall living things.things.

3.3. Cells are produced Cells are produced from from existing cellsexisting cells..

Prokaryote CellsProkaryote Cells

• Has Has no nucleusno nucleus. . – Just a mass of DNAJust a mass of DNA

• UnicellularUnicellular- - singlesingle celled organismcelled organism

• ExampleExample : bacteria : bacteria

Eukaryote CellsEukaryote Cells

• Contain a Contain a nucleusnucleus. .

• Unicellular or Multicellular-Unicellular or Multicellular-– Unicellular – Unicellular – Single celledSingle celled – Multi-Cellular- Multi-Cellular- Made of many cellsMade of many cells..

• Have Have organellesorganelles, which are surrounded by , which are surrounded by membranes. membranes.

• ExampleExample: plant cells, animal cells: plant cells, animal cells

Plant CellPlant Cell

Animal CellAnimal Cell

The (Plasma) Cell The (Plasma) Cell MembraneMembrane• A double-layered A double-layered

membrane of membrane of lipidslipids (fats)(fats)

• Contains different types Contains different types of proteins that help of proteins that help move thingsmove things in and out in and out of the cell. of the cell. – chemicals, food, and chemicals, food, and

wasteswastes

• The membrane The membrane keeps keeps the cell togetherthe cell together – if it – if it breaks, the contents of breaks, the contents of the cell will “spill” outthe cell will “spill” out

• Semi- Permeable-Semi- Permeable- Allows Allows some things some things inin but but not not others.others.

Cytoplasm (Cytosol)Cytoplasm (Cytosol)

• Mostly made of Mostly made of waterwater, but , but contains some contains some proteinsproteins

• The “The “soupsoup” of the ” of the cell, Jelly-Like cell, Jelly-Like substancesubstance

• ““Open spaceOpen space” of ” of the cellthe cell

• SupportsSupports all of the all of the cells cells organellesorganelles Cytoplasm

CytoskeletonCytoskeleton- - Microtubules/MicrofilamentsMicrotubules/Microfilaments

• Structure found within Structure found within the the cytoplasmcytoplasm

• A supporting network of A supporting network of proteinprotein fibers fibers

• Holds organelles in Holds organelles in placeplace

• Functions: Functions: support and support and cellular movementcellular movement

• Made of Made of substructuressubstructures called microtubules and called microtubules and microfilamentsmicrofilaments

The NucleusThe Nucleus • The The control centercontrol center of the cellof the cell

• Referred to as the Referred to as the ““brainbrain” of the cell” of the cell

• Contains the Contains the DNADNA, , ((genetic genetic material) material) and nucleolusand nucleolus

• NuclearNuclear MembraneMembrane--Surrounded by a Surrounded by a doubledouble-layered -layered membrane, lets membrane, lets ribosomes ribosomes in and in and out.out.

NucleolusNucleolus

• Dense Dense cluster cluster of DNA of DNA insideinside the nucleusthe nucleus

• Makes the Makes the RibosomesRibosomes & & RNARNA

Endoplasmic Reticulum Endoplasmic Reticulum (E.R.)(E.R.)

• System of internal membranes that moves proteins through the cell.

• Smooth versus Rough….what’s the difference???

Endoplasmic Reticulum Endoplasmic Reticulum (E.R.)(E.R.)

SMOOTH E.R.SMOOTH E.R.• SmoothSmooth outer surface outer surface• Not covered by Not covered by

ribosomesribosomes• Produces Produces lipidslipids like like

hormones, and hormones, and processesprocesses the proteins the proteins to send them to Golgi.to send them to Golgi.

• Breaks down Breaks down toxic toxic substances.substances.

ROUGH E.R.ROUGH E.R.• Rough Rough outer outer

surface due to surface due to attached attached ribosomesribosomes

• Produces Produces proteinsproteins that are used by that are used by the cellthe cell

RibosomesRibosomes• ““The Workers”The Workers”• Produce the Produce the

proteinsproteins for use for use inside and inside and outside the celloutside the cell

• Contain RNA Contain RNA ((messengermessenger of of the cell)the cell)

• Can be attached Can be attached to the to the RERRER or or free floatingfree floating in in the cytoplasmthe cytoplasm

MitochondriaMitochondria• The “The “powerhousepowerhouse” ”

of the cellof the cell• Location of Location of cellular cellular

respiration- respiration- converts our converts our food food into into fuelfuel..

• Makes Makes ATPATP- our - our energy.energy.

• Only other organelle Only other organelle that has its own that has its own DNADNA..

Centrioles- (Centrioles- (only in only in animal animal

cellscells))

• Help in Help in cell divisioncell division and replicationand replication

Vacuoles & VesiclesVacuoles & Vesicles

• Storage Storage compartments of compartments of the cellthe cell

• Holds Holds wasteswastes, , food, proteins, food, proteins, etc.etc.

• Very largeVery large in in Plant Cells- Holds Plant Cells- Holds waterwater in plant in plant cellscells

Golgi Apparatus Golgi Apparatus (or Golgi (or Golgi Bodies)Bodies)

• The “The “packaging packaging centercenter” or “” or “Postal Postal ServiceService” of the cell” of the cell

• ProcessesProcesses (modifies) proteins.(modifies) proteins.

• PackagesPackages proteins proteins in Vesiclesin Vesicles

• Ships Ships proteins out proteins out of cell.of cell.

Golgi BodiesGolgi Bodies

LysosomesLysosomes

• Most commonly found in Most commonly found in animal cellsanimal cells• Contain Contain digestivedigestive enzymes that enzymes that

break down the cells food.break down the cells food.• Digests Digests or or recyclesrecycles worn out cell worn out cell

parts, food, bacteria, etc.parts, food, bacteria, etc.• Also known as the suicide sacAlso known as the suicide sac

LysosomesLysosomes

Cilia/Flagella (found only in Animals)

• CiliaCilia- - Hair-likeHair-like projections for projections for locomotion.locomotion.

• FlagellaFlagella- long - long whiplikewhiplike tail, in tail, in sperm or euglena sperm or euglena for locomotion.for locomotion.

The Plant CellThe Plant Cell

ChloroplastsChloroplasts

• Found only in Found only in plant cellsplant cells

• Contain the green Contain the green pigment called pigment called chlorophyllchlorophyll

• Location of Location of photosynthesisphotosynthesis, , which produces which produces the energy for the energy for plant cellsplant cells

ChloroplastsChloroplasts

ChromoplastsChromoplasts

• Plastids that Plastids that contain contain other other colorscolors within a within a plant cell.plant cell.

• Gives the Gives the leaves/flowers leaves/flowers their their colorcolor..

Cell WallCell Wall• Found only in Found only in

plant cellsplant cells• A A rigid rigid outer layer outer layer

of a plant cellof a plant cell• Found outside the Found outside the

cell membranecell membrane• RemainsRemains even if even if

the cell the cell diesdies• Protects Protects and and givesgives

support to plantssupport to plants

Give your hand a rest…Give your hand a rest…

• But, don’t give your brain a rest.But, don’t give your brain a rest.• You will have a You will have a quizquiz soon! soon!• You will need to either identify the You will need to either identify the

function of each organelle, function of each organelle, identify the organelle in a identify the organelle in a diagram, or both…diagram, or both…

• BE PREPARED!!BE PREPARED!!