The CellThe Cell

Chapter 15Chapter 15

The Cell TheoryThe Cell Theory

The theory has three The theory has three main parts summarized main parts summarized as:as: All living things are All living things are

made up of one or more made up of one or more cellscells

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

All living cells come All living cells come from pre-existing cellsfrom pre-existing cells

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

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

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

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

stay and which ones leave a cell.stay 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 Every cell has a cellular membrane (including both animal and plant cells).(including both animal and plant cells).

It is a thin flexible covering surrounding all It is a thin flexible covering surrounding all cells.cells.

Made up of primarily proteins and fats Made up of primarily proteins and fats

NucleusNucleus

The “Boss”The “Boss” With few exceptions all With few exceptions all

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

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

contain the DNA or genes contain the DNA or genes for the cell which are the for the cell which are the instructions for all the instructions for all the activities of the cellactivities of the cell

Nuclear EnvelopeNuclear Envelope

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

““the Boss’ office”the Boss’ office”

It has pores in it for It has pores in it for larger materials to pass larger materials to pass in and out.in and out.

NucleolusNucleolus

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

It is where RNA and It is where RNA and ribosomes are made.ribosomes are made.

nucleolus

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 vacuoles Organelles and vacuoles are considered part of are considered part of the cytoplasmthe cytoplasm

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 membranemembrane

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.

RibosomesRibosomes

The “workers” that put together the products The “workers” that put together the products of the cell.of the cell.

The location of protein synthesisThe location of protein synthesis Made from RNA from the nucleolusMade from RNA from the nucleolus Some are free in the cytoplasm and others are Some are free in the cytoplasm and others are

embedded in the endoplasmic reticulum (ER).embedded in the endoplasmic reticulum (ER). 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

Endoplasmic ReticulumEndoplasmic Reticulum

The “assembly line” for The “assembly line” for the products of the cellthe products of the cell

It consists of It consists of membranous channels membranous channels that wind through the that wind through the cytoplasmcytoplasm

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

1) Rough endoplasmic reticulum

2) Smooth endoplasmic reticulum

Rough Endoplasmic Reticulum:Rough Endoplasmic Reticulum:

AKA “rough ER”AKA “rough ER” The ER that has The ER that has

ribosomes embedded in ribosomes embedded in it.it.

Manufactures proteins Manufactures proteins for other cells and also for other cells and also phospholipids for the phospholipids for the cell membranecell membrane

Assists in the movement Assists in the movement of molecules towards of molecules towards the cell membranethe cell membrane

Smooth Endoplasmic ReticulumSmooth Endoplasmic Reticulum

Aka : Smooth ER Aka : Smooth ER Lack ribosomesLack ribosomes Manufactures steroidsManufactures steroids Example: testicle cells which produce Example: testicle cells which produce

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

Golgi ApparatusGolgi Apparatus

May looks similar to smooth ER, but May looks similar to smooth ER, but it is a set of about 7 or 8 flattened it is a set of about 7 or 8 flattened saccules between ER and the cell saccules between ER and the cell membranemembrane

““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

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

VesicleVesicle

““storage containers”storage containers” Double membrane Double membrane

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

Also carry food, waste Also carry food, waste products, digestive products, digestive enzymesenzymes..

LysosomesLysosomes

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

contain enzymes used for contain enzymes used for digestion of molecules in the digestion of molecules in the cells.cells. Example: to digest unwanted cells Example: to digest unwanted cells

(dying cells) and cell parts that are (dying cells) and cell parts that are defectivedefective

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.

MitochondrionMitochondrion

Plural form “mitochondria”Plural form “mitochondria” ““The GeneratorThe Generator” or “” or “power power

househouse” of the cell ” of the cell Give the cell the energy it needs Give the cell the energy it needs

by a series of chemical reactions by a series of chemical reactions called called cellular respirationcellular respiration

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..

VacuoleVacuole

““Storage Containers”Storage 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 They are usually much

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

they take up almost the entire they take up almost the entire cell.cell.

CentriolCentriol

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

and chromosomes and chromosomes during cell reproductionduring cell reproduction

Plant cells vs Animal cellsPlant cells vs Animal cells

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

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

Plant cell do not have a Plant cell do not have a centriol!centriol!

Cell WallCell Wall

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

Has large pores that Has large pores that allow many molecules allow many molecules to enter.to enter.

ChloroplastsChloroplasts Chloroplasts are specialized Chloroplasts are specialized

organelles found in all higher plant organelles found in all higher plant cells.cells.

These organelles contain the plant These organelles contain the plant cell's chlorophyll, hence provide the cell's chlorophyll, hence provide the green color. green color.

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

They have a double outer They have a double outer membrane. Within the stroma are membrane. Within the stroma are other membrane structures other membrane structures - including the thylakoids and grana - including the thylakoids and grana

where photosynthesis takes place.where photosynthesis takes place.

Vacuoles in Plant cellsVacuoles in Plant cells

Help the cell wall keep its shapeHelp the cell wall keep its shape Stand up, close eyesStand up, close eyes Pretend you are a plant that has not been Pretend you are a plant that has not been

watered for a week…what would you look likewatered for a week…what would you look like Now your mother waters the plant…what does Now your mother waters the plant…what does

it look like now.it look like now.

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