Cell Unit NotesCell Unit NotesLecture ILecture I

Cell Biology StandardsCell Biology Standardsin Lecture Iin Lecture I

1c ~ students know how 1c ~ students know how prokaryoticprokaryotic cells, cells, eukaryoticeukaryotic cells, and viruses differ in cells, and viruses differ in complexity and in general structurecomplexity and in general structure

1e ~ students know the role of the 1e ~ students know the role of the endoplasmic reticulumendoplasmic reticulum and the and the Golgi Golgi apparatusapparatus in the secretion of proteins in the secretion of proteins

*1j ~ students know how *1j ~ students know how eukaryoticeukaryotic cells are cells are given shape and internal organization by a given shape and internal organization by a cytoskeletoncytoskeleton, , cell wallcell wall, or both, or both

The Scientists involved in the The Scientists involved in the Cell TheoryCell Theory

In 1665 In 1665 Robert HookeRobert Hooke looked at a slice of cork looked at a slice of cork under a microscopeunder a microscope The tiny chambers reminded The tiny chambers reminded

him of the “cells” in a him of the “cells” in a monastery so he called them monastery so he called them cellscells

In 1674 In 1674 Anton von Anton von LeeuwenhoekLeeuwenhoek made better made better lenses for the microscope lenses for the microscope and was able to see cells in and was able to see cells in greater detailgreater detail

The Scientists involved in the The Scientists involved in the Cell TheoryCell Theory

In 1838 and 1839 Matthias Matthias SchleidenSchleiden and Theodore Theodore SchwannSchwann observed that all living things are made up of cells

SchleidenSchleiden noted that all plants are made up of cells

SchwannSchwann stated that all animals are made up of cells

In 1855 Rudolf VirchowRudolf Virchow states that all cells come from pre-existing cells

The Cell TheoryThe Cell Theory All living things are composed of cellsAll living things are composed of cells

Cells are the basic functional units of lifeCells are the basic functional units of life

New cells are produced from existing cellsNew cells are produced from existing cells

Prokaryotes vs. EukaryotesProkaryotes vs. Eukaryotes ProkaryotesProkaryotes smaller & simplersmaller & simpler Contain a cell Contain a cell

membrane & membrane & cytoplasm cytoplasm

Sometimes a cell wallSometimes a cell wall Also have ribosomesAlso have ribosomes No nucleusNo nucleus All bacteria are All bacteria are

prokaryotesprokaryotes DNA is “free – DNA is “free –

floating”floating”

EukaryotesEukaryotes Have a nucleus Have a nucleus

containing DNAcontaining DNA MostMost have specialized have specialized

structures called structures called organellesorganelles

All plants, animals, All plants, animals, protists, and fungi are protists, and fungi are eukaryoteseukaryotes

Larger and more Larger and more complexcomplex

Cell membrane

Cell membrane

Cytoplasm

Cytoplasm

Nucleus

Organelles

Eukaryotic Cell

Prokaryote vs. EukaryoteProkaryote vs. Eukaryote

Prokaryotic Cell

Prokaryotes & VirusesProkaryotes & Viruses

ProkaryotesProkaryotes are simple, living are simple, living organisms that can reproduce on organisms that can reproduce on their owntheir own

They have diverse ways of They have diverse ways of obtaining nutrients:obtaining nutrients: PhotosynthesisPhotosynthesis ChemosynthesisChemosynthesis Heterotrophic consumersHeterotrophic consumers

Bacteria (prokaryotes) Bacteria (prokaryotes) live in every habitat live in every habitat possible and are the possible and are the mostmost numerous of all numerous of all living things on our living things on our planetplanet

All living things depend All living things depend upon bacteria – upon bacteria – including, especially, including, especially, humans!humans!

Prokaryotes & VirusesProkaryotes & Viruses

3 Domains of Life on Earth3 Domains of Life on Earth

ArcheaArchea represent the “ancient bacteria” and represent the “ancient bacteria” and they live in they live in extremeextreme environments such as environments such as boiling water or extremely salty environmentsboiling water or extremely salty environments

They are the oldest living organisms on this They are the oldest living organisms on this planet. Evidence suggests that they were planet. Evidence suggests that they were present during the early stages of Earth over present during the early stages of Earth over 3.9 billion years ago3.9 billion years ago

Prokaryotes & VirusesProkaryotes & Viruses

Bacteria have Bacteria have cell cell membranesmembranes and and most have a most have a cell wallcell wall

Their Their DNADNA is is one one circular moleculecircular molecule

They often have They often have many many plasmidsplasmids Small circular rings of Small circular rings of

DNA usually DNA usually containing one genecontaining one gene

PiliPili help bacteria help bacteria “stick” to things“stick” to things

Prokaryotes & VirusesProkaryotes & Viruses

Many bacteria have a flagellum or many flagella to help them move

VirusesViruses are extremely are extremely small particles small particles notnot considered to be “alive”considered to be “alive”

They act like They act like parasitesparasites because they can because they can ONLYONLY reproduce in a reproduce in a hosthost

They consist of a protein They consist of a protein coat and contain either coat and contain either DNA or RNA insideDNA or RNA inside

Prokaryotes & VirusesProkaryotes & Viruses

Eukaryote Cell Structures Cell WallCell Wall

Found in many organisms including plants, algae, fungi, and nearly all prokaryotes

Not found in animal Not found in animal cellscells

Cell WallCell Wall

The The main functionmain function of the of the cell wall cell wall is is to provide to provide supportsupport andand protectionprotection for for the cellthe cell

Plant cell walls are Plant cell walls are made of made of cellulosecellulose

The NucleusThe Nucleus

The nucleus is the “control center” of the cellThe nucleus is the “control center” of the cell

The nucleus controls most cell processes The nucleus controls most cell processes and contains the hereditary information of and contains the hereditary information of DNADNA

Almost all eukaryotic cells, including plant Almost all eukaryotic cells, including plant and animal, contain a nucleus and animal, contain a nucleus

The NucleusThe Nucleus

Nucleolus – Nucleolus – small small dense region in dense region in nucleus where nucleus where ribosomesribosomes are are producedproduced

Nuclear envelope – double membrane layer surrounding the nucleus (aka. Nuclear membrane)

The CytoskeletonThe Cytoskeleton

A network of A network of protein protein filamentsfilaments that that help the help the cell maintain it’s cell maintain it’s shapeshape

It is also It is also involved in involved in many forms of many forms of movementmovement

Microfilament

Microtubule

The CytoskeletonThe Cytoskeleton

Made up of Made up of three typesthree types of structures of structures:: MicrotubulesMicrotubules – – hollow tubes of protein that help hollow tubes of protein that help

maintain cell shape and serve as “tracks” for maintain cell shape and serve as “tracks” for organelles to travel onorganelles to travel on

Intermediate FilamentsIntermediate Filaments – – smaller than smaller than microtubules – gives a cell its strengthmicrotubules – gives a cell its strength

MicrofilamentsMicrofilaments – – long thin fibers that support cell long thin fibers that support cell movement and supportmovement and support

Organelles in the CytoplasmOrganelles in the Cytoplasm RibosomesRibosomes

Organelle that Organelle that “assembles” proteins“assembles” proteins

A A ribosome is made up is made up of 2 parts:of 2 parts:• a protein a protein • rRNA (ribosomal rRNA (ribosomal

RNA)RNA) RibosomesRibosomes make make

proteins from the “coded” proteins from the “coded” instructions of the instructions of the DNA DNA inside the inside the nucleusnucleus

Ribosomes

Endoplasmic ReticulumEndoplasmic Reticulum

An internal membrane An internal membrane where parts of the cell where parts of the cell membrane are made and membrane are made and some proteins are some proteins are modifiedmodified

The The Rough Endoplasmic Reticulum is is where protein synthesis where protein synthesis occursoccurs Ribosomes are on it’s Ribosomes are on it’s

surface making it surface making it appear “rough”appear “rough”

Rough endoplasmic reticulum

Endoplasmic ReticulumEndoplasmic Reticulum

The The Smooth Endoplasmic Reticulum does does notnot have any have any ribosomes on it’s ribosomes on it’s surface surface It contains It contains

enzymes that enzymes that make lipidsmake lipids (fats) (fats)

Smooth endoplasmicreticulum

Golgi ApparatusGolgi Apparatus

After proteins are assembled and produced by the After proteins are assembled and produced by the Rough ER they move to the they move to the Golgi Complex where : where :

Carbohydrates (sugars) and lipids (fats) are attached to the Carbohydrates (sugars) and lipids (fats) are attached to the proteinprotein

They are then sent to their final destinationThey are then sent to their final destination

Golgi apparatus

LysosomesLysosomes Small organelles that are Small organelles that are

filled with digestive and filled with digestive and other enzymesother enzymes They break down lipids They break down lipids

(fats), carbohydrates (fats), carbohydrates (sugars), and proteins from (sugars), and proteins from food particles so it can be food particles so it can be used by the rest of the cellused by the rest of the cell

Lysosomes Lysosomes alsoalso break break down “old” organelles that down “old” organelles that have outlived their functionhave outlived their function

Basically, they “take out the Basically, they “take out the trash”trash”

VacuolesVacuoles

Serve as a storage for Serve as a storage for water, salts, proteins, water, salts, proteins, and “carbs” (plant and “carbs” (plant andand animal cells)animal cells)

In Plants : They usually have one

large vacuole filled with water to support structures like leaves and flowers

Vacuole

ChloroplastsChloroplasts

The The producer!producer! They use sunlight to They use sunlight to

power a familiar power a familiar process called process called PhotosynthesisPhotosynthesis

The green pigment The green pigment (color) (color) chlorophyllchlorophyll is is what gives leaves what gives leaves their color and is their color and is found inside found inside chloroplastschloroplasts

Chloroplast

MitochondriaMitochondria The “powerhouse” of The “powerhouse” of

the animal the animal andand plant plant cell!cell! Mitochondria use energy Mitochondria use energy

from food to make high-from food to make high-energy compoundsenergy compounds (ATP)(ATP)

The cell uses these high-The cell uses these high-energy compounds for energy compounds for growth, development, and growth, development, and movementmovement

In that way, the In that way, the mitochondria makes “fuel” mitochondria makes “fuel” for the cell for the cell

Typical Plant CellTypical Plant Cell

Typical Animal CellTypical Animal Cell