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