The Cell TheoryThe Cell Theory All living things are All living things are

made up of one or made up of one or more cellsmore cells

The cell is the The cell is the functional unit of lifefunctional unit of life

All living cells All living cells interact with the interact with the environment, use environment, use energy, grow and energy, grow and come from pre-come from pre-existing cellsexisting cells

The cell as a factory:The cell as a factory:

The parts of a cell can be compared to The parts of a cell can be compared to the workers and jobs in a factorythe workers and jobs in a factory Each department in a factory has specific Each department in a factory has specific

jobs that need to be done or else the jobs that need to be done or else the factory becomes less efficient and factory becomes less efficient and eventually shut down.eventually shut down.

The same idea is true for the cell, if one of The same idea is true for the cell, if one of its components stops working efficiently its components stops working efficiently then the cell or the organism could die. then the cell or the organism could die.

Cell Membrane:Cell Membrane:

The “gate keeper” or “bouncer” of the cellThe “gate keeper” or “bouncer” of the cell Decides which materials enter, which ones stay Decides which materials enter, which ones stay

and which ones leave a cell.and which ones leave a cell. Keeps the good ones in and bad ones out.Keeps the good ones in and bad ones out.

Every cell has a cellular membrane (including Every cell has a cellular membrane (including both animal and plant cells).both animal and plant cells).

It is a phospholipid bilayer with protein molecule It is a phospholipid bilayer with protein molecule inside it.inside it.

More about the cell membrane will be seen in More about the cell membrane will be seen in section D section D

CytoplasmCytoplasm The rest of the cell The rest of the cell

material that is inside material that is inside the cell membrane but the cell membrane but outside the nucleusoutside the nucleus

Organelles and Organelles and vacuoles are vacuoles are considered part of the considered part of the cytoplasmcytoplasm

Usually the cytoplasm Usually the cytoplasm is referred to as the is referred to as the semi-liquid material semi-liquid material that surrounds the that surrounds the organelles of a cellorganelles of a cell

NucleusNucleus The “control center” or the The “control center” or the

“Boss”“Boss” With few exceptions all plant With few exceptions all plant

and animal cells possess a and animal cells possess a nucleus (plural form is nucleus (plural form is nuclei).nuclei).

Dark mass usually seen in Dark mass usually seen in the middle of the cellthe middle of the cell

Contains the DNA or Contains the DNA or chromatin of the cell which chromatin of the cell which are the instructions for all are the instructions for all the activities of the cell.the activities of the cell.

It also contains nucleoplasm.It also contains nucleoplasm.

ChromatinChromatin

Floats in the Floats in the nucleoplasm nucleoplasm

Made of DNA and Made of DNA and ProteinProtein

Is known as Is known as chromosomes chromosomes when it is coiled up when it is coiled up for cell divisionfor cell division

Nuclear EnvelopeNuclear Envelope

The membrane The membrane that encloses the that encloses the contents of the contents of the nucleus.nucleus.

““the Boss’ office”the Boss’ office” Protects DNAProtects DNA It has pores in it for It has pores in it for

larger materials to larger materials to pass in and out.pass in and out.

Nuclear pore

NucleolusNucleolus

A visible darker A visible darker staining region staining region inside the nucleus.inside the nucleus.

It is where RNA and It is where RNA and the materials for the materials for ribosomes are ribosomes are made.made.

nucleolus

Cell OrganellesCell Organelles Like your body which has organs to Like your body which has organs to

perform the necessary functions for life, perform the necessary functions for life, similarly cells have organelles which similarly cells have organelles which perform the necessary function of perform the necessary function of particular cells.particular cells.

Many organelles are bound by their own Many organelles are bound by their own membrane(s)membrane(s)

The proportion of the different organelles The proportion of the different organelles inside a particular cell depends on the inside a particular cell depends on the function of the cell.function of the cell. For example a cell that produces a lot of For example a cell that produces a lot of

hormones will have a large amount of golgi hormones will have a large amount of golgi apparatus which is the organelle responsible apparatus which is the organelle responsible for packaging the products of a cell.for packaging the products of a cell.

VacuoleVacuole ““long term Storage long term Storage

Containers”Containers” Vacuoles serve a variety of Vacuoles serve a variety of

functions, including storing functions, including storing nutrients, wastes and water. nutrients, wastes and water.

Irregular shapeIrregular shape They are usually much larger They are usually much larger

in plant cells than in animal in plant cells than in animal cells.cells. Example: in the plant cell they Example: in the plant cell they

take up almost the entire cell.take up almost the entire cell. They help maintain the shape of They help maintain the shape of

the cellthe cell

RibosomesRibosomes The “workers” that put together the The “workers” that put together the

products of the cell.products of the cell. Non-membranous, and consists of Non-membranous, and consists of

two unequal sized subunits. two unequal sized subunits. The location of protein synthesisThe location of protein synthesis Made from RNA from the nucleolusMade from RNA from the nucleolus

RibosomesRibosomes Some are free in the cytoplasm or become Some are free in the cytoplasm or become

loosely clustered together to form loosely clustered together to form PolysomesPolysomes

A polysome is a cluster of ribosomes attached A polysome is a cluster of ribosomes attached to the same mRNA molecule; each ribosome to the same mRNA molecule; each ribosome is producing a copy of the same is producing a copy of the same enzyme/protein.enzyme/protein. The proteins produced by free ribosomes in The proteins produced by free ribosomes in

cytoplasm are generally used within the cellcytoplasm are generally used within the cell Other ribosomes are embedded in the rough Other ribosomes are embedded in the rough

endoplasmic reticulum (RER).endoplasmic reticulum (RER). The products of ribosomes in the RER are often The products of ribosomes in the RER are often

secreted from the cellsecreted from the cell

Endoplasmic Reticulum:Endoplasmic Reticulum: The “assembly line” The “assembly line”

for the products of for the products of the cellthe cell

Consists of Consists of membranous membranous channels that wind channels that wind through the through the cytoplasm usually cytoplasm usually close to the nucleusclose to the nucleus

1) Rough endoplasmic reticulum1) Rough endoplasmic reticulum

2) Smooth endoplasmic reticulum2) Smooth endoplasmic reticulum

There are two types of There are two types of endoplasmic reticulum:endoplasmic reticulum:

Rough Endoplasmic Rough Endoplasmic Reticulum:Reticulum:

AKA “rough ER” or AKA “rough ER” or “RER”“RER”

The ER that has The ER that has ribosomes embedded ribosomes embedded in it.in it.

Manufactures proteins Manufactures proteins for other cellsfor other cells

Assists in the Assists in the movement of movement of molecules from one molecules from one area of the cell to area of the cell to anotheranother

Smooth Endoplasmic Smooth Endoplasmic ReticulumReticulum

Aka : Smooth ER or “SER”Aka : Smooth ER or “SER” Lack ribosomesLack ribosomes Manufactures steroidsManufactures steroids Example: testicle cells which Example: testicle cells which

produce testosterone have produce testosterone have abundant amounts of smooth abundant amounts of smooth ER.ER.

Transporting productsTransporting products

When products of the RER and the When products of the RER and the SER accumulate, sections of the ER SER accumulate, sections of the ER filled with these products break free filled with these products break free in a process known as blebbing or in a process known as blebbing or buddingbudding

The result is a collection of small The result is a collection of small membrane bound sacs called membrane bound sacs called vesicles which contain the vesicles which contain the biochemicals.biochemicals.

VesicleVesicle ““transport containers”transport containers” Double membrane bound sacs Double membrane bound sacs

carrying different products and carrying different products and substances from one part of the substances from one part of the cell to another. cell to another.

Sometimes called transition Sometimes called transition or transport vesicles as they or transport vesicles as they are used to bring the are used to bring the products to the golgi products to the golgi apparatus for further apparatus for further processing or to the cell processing or to the cell membrane for secretion out membrane for secretion out of the cell.of the cell.

They can also carry food, waste They can also carry food, waste products, digestive enzymesproducts, digestive enzymes..

Golgi ApparatusGolgi Apparatus AKA “Golgi bodies”AKA “Golgi bodies” May looks similar to smooth ER, May looks similar to smooth ER,

but it is a set of about 7 or 8 but it is a set of about 7 or 8 flattened saccules between ER flattened saccules between ER and the cell membraneand the cell membrane

““Packages, processes and labels” Packages, processes and labels” the products from the ERthe products from the ER

Makes concentrated packages of Makes concentrated packages of proteins proteins

Put carbohydrate chains (labels) Put carbohydrate chains (labels) on the packages of proteins so on the packages of proteins so that specific cells recognize them that specific cells recognize them once they are released in the once they are released in the blood. blood.

Makes lysosomesMakes lysosomes

Golgi Apparatus:Golgi Apparatus:

New vesicles called secretory vesicles New vesicles called secretory vesicles with the newly modified products form by with the newly modified products form by blebbing from the golgi apparatus. blebbing from the golgi apparatus.

The vesicles move towards and join the The vesicles move towards and join the cell membrane so that their contents are cell membrane so that their contents are expelled from the cell.expelled from the cell.

This process is know as exocytosis which This process is know as exocytosis which will be taught later in this section. will be taught later in this section.

Secretory PathwaySecretory Pathway

Shows the Shows the interrelationships interrelationships between cell between cell organellesorganelles

LysosomesLysosomes

““Janitors or quality control”Janitors or quality control” Vesicle-like structures that Vesicle-like structures that

contain hydrolytic enzymes contain hydrolytic enzymes used for digestion of molecules used for digestion of molecules in the cells.in the cells.

Have a double membraneHave a double membrane Multicellular organisms use Multicellular organisms use

them to digest unwanted cells them to digest unwanted cells (dying cells) and cell parts that (dying cells) and cell parts that are defective (autodigestion)are defective (autodigestion) Think of them as the quality control Think of them as the quality control

or health board, that can shut or health board, that can shut down the cell at any time.down the cell at any time.

Mitochondrion:Mitochondrion: ““The GeneratorThe Generator” or “” or “power power

househouse” of the cell ” of the cell Plural form “mitochondria”Plural form “mitochondria” Performs Performs Cellular RespriationCellular Respriation Fluid filled, with a complex Fluid filled, with a complex

internal membraneinternal membrane The inner fluid is called the The inner fluid is called the matrixmatrix The inner membrane which folded The inner membrane which folded

in the matrix is called the in the matrix is called the cristaecristae..

Cellular RespirationCellular Respiration A series of chemical reactions that give the cell all A series of chemical reactions that give the cell all

the energy it needs the energy it needs The energy is saved in the high energy bonds of an The energy is saved in the high energy bonds of an

ATP (adenosine triphosphate) molecule.ATP (adenosine triphosphate) molecule.

Net Chemical Reaction: Net Chemical Reaction: Glucose + oxygen Glucose + oxygen →→ Carbon dioxide + water + energy Carbon dioxide + water + energy

Balanced Chemical Reaction:Balanced Chemical Reaction:

CC66HH1212OO66 + 6O + 6O22 →→ 6CO 6CO22 + 6H + 6H22O + 38 ATPO + 38 ATP

ChloroplastsChloroplasts

Chloroplasts are specialized Chloroplasts are specialized organelles found in all organelles found in all higher plant cells and some higher plant cells and some photosynthetic protists.photosynthetic protists.

The place where The place where photosynthesis takes place.photosynthesis takes place.

These organelles contain These organelles contain the plant cell's chlorophyll, the plant cell's chlorophyll, which enable them to which enable them to capture sunlight energycapture sunlight energy

ChloroplastsChloroplasts

They have a double outer membrane. They have a double outer membrane. Inside the inner membrane the fluid Inside the inner membrane the fluid

filled space is called the stromafilled space is called the stroma Within the stroma are other Within the stroma are other

membrane structures including the membrane structures including the thylakoids.thylakoids. Thylakoids are flattened sacs that Thylakoids are flattened sacs that

contain chlorophyll and are piled contain chlorophyll and are piled up like a stack of coins, each stack up like a stack of coins, each stack is called a granum (plural is grana)is called a granum (plural is grana)

There are membranous There are membranous connections between the grana connections between the grana called lamellae called lamellae

PhotosynthesisPhotosynthesis

Net Chemical Reaction: Net Chemical Reaction: Carbon dioxide + water + energy Carbon dioxide + water + energy →→ Glucose + oxygen Glucose + oxygen

Balanced Chemical Reaction:Balanced Chemical Reaction:

6CO6CO22 + 6H + 6H22O O →→ CC66HH1212OO66 + 6O + 6O22

SunlightSunlight

++

ChlorophyllChlorophyll

Cell WallCell Wall

The cell wall provides and The cell wall provides and maintains the shape of these maintains the shape of these cells and serves as a protective cells and serves as a protective barrier. barrier.

Made of celluloseMade of cellulose Has large pores that allow Has large pores that allow

many molecules to enter.many molecules to enter. Not found in animal cellsNot found in animal cells Restricts the size and shape of Restricts the size and shape of

a cell.a cell.

Cytoskeleton:Cytoskeleton:

Helps maintain the cell’s shapeHelps maintain the cell’s shape Anchors the organellesAnchors the organelles Allows the cell and its organelles to moveAllows the cell and its organelles to move Constist of two basic types of structures:Constist of two basic types of structures:

1.1. MicrotubulesMicrotubules: assembled by the Microtubule : assembled by the Microtubule organizing center (MTOC) which is found near organizing center (MTOC) which is found near the nucleus. Form spindle fibers during cell the nucleus. Form spindle fibers during cell division and make cillia and flagella.division and make cillia and flagella.

2.2. Actin filamentsActin filaments (AKA microfilaments): long (AKA microfilaments): long thin protein fibers, usually found in bundles. thin protein fibers, usually found in bundles. Capable of contracting. Found especially in Capable of contracting. Found especially in muscle cells and microvilli.muscle cells and microvilli.

Both canBoth can assemble and disassemble.assemble and disassemble.

Centriol:Centriol:

““Traffic Cop”Traffic Cop” Organizes organelles Organizes organelles

and chromosomes and chromosomes during cell during cell reproductionreproduction

Microtubules Microtubules arranged in a specific arranged in a specific pattern.pattern.

Found in the MTOC at Found in the MTOC at right angles to each right angles to each other.other.

Plant cells vs Animal cellsPlant cells vs Animal cells There are some There are some

structures that plant structures that plant cells possess that cells possess that animal cells do not. animal cells do not. Including:Including: Cell wallCell wall ChloroplastsChloroplasts

Also, plant cells have Also, plant cells have larger vacuoles (that larger vacuoles (that sometimes appear to sometimes appear to take up the entire cell).take up the entire cell).

Plant cell do not have a Plant cell do not have a centriole!centriole!

Cell membrane

Lysosome

Nucleus

Nucleolus

Nuclear Envelope

Vacuole

Mitochondrion

Centriol

Cytoplasm

Rough ER

Smooth ER

Ribosomes

Golgi Apparatus

Cell membrane

Golgi Apparatus

Ribosomes

Smooth ER

Rough ER

Lysosome

Cytoplasm

Mitochondrion

Chloroplast

Nuclear Envelope

Nucleolus

Nucleus

Vacuole

Cell Wall