Cell Cell StructureStructure

I. Looking at CellsI. Looking at Cells A. Scientists only became aware of A. Scientists only became aware of cellscells

after the invention of the after the invention of the microscope.microscope. 1. 1. 16651665:Robert Hooke observed cork cells :Robert Hooke observed cork cells

and called them “little boxes”.and called them “little boxes”. 16751675:Anton van Leeuwoenhoek used a :Anton van Leeuwoenhoek used a microscope and observed pond water. He microscope and observed pond water. He discovered many living creatures.discovered many living creatures.

B. Measuring Cell StructuresB. Measuring Cell Structures

1. Measurement taken by scientists are 1. Measurement taken by scientists are expressed in Metric Units. The official expressed in Metric Units. The official name of the metric system is name of the metric system is International System of Measurements.International System of Measurements.

The metric system is based on powers The metric system is based on powers of 10.of 10.

fill in the metric chart.fill in the metric chart.

C. Types of MicroscopesC. Types of Microscopes

1. 1. Compound Light MicroscopeCompound Light MicroscopeThe most powerful Light microscopes can The most powerful Light microscopes can

magnify up to magnify up to 2000X2000X..

2. 2. Electron MicroscopeElectron MicroscopeElectron microscopes can magnify up to Electron microscopes can magnify up to

200,000X200,000X.. Transmission Electron Microscopes Transmission Electron Microscopes

(TEM)(TEM) reveal internal detailsreveal internal details..

Scanning Electron Microscopes (SEM)Scanning Electron Microscopes (SEM) shows 3-D images of surface.shows 3-D images of surface.

Eyepiece

Body Tube

Revolving Nosepiece

Arm

Stage Clip

Stage

Course Adjustment

Fine Adjustment

Base

Objectives

Light

Diaphragm

Eyepiece – lens closest to the viewers Eyepiece – lens closest to the viewers eyeeye

Body Tube – directs light from the Body Tube – directs light from the objective to the eye objective to the eye

Revolving nosepiece – hold the Revolving nosepiece – hold the objectives objectives

Arm – holds the base of the microscope Arm – holds the base of the microscope with the objectives and eyepiecewith the objectives and eyepiece

Stage Clips – hold the slide in place Stage Clips – hold the slide in place Stage – supports the slide Stage – supports the slide

Course Adjustment – used to bring an object Course Adjustment – used to bring an object into focus under LOW powerinto focus under LOW power

Fine Adjustment – used to fine tune the focus Fine Adjustment – used to fine tune the focus under LOW and HIGH power under LOW and HIGH power

Base – holds the light source, connects to the Base – holds the light source, connects to the arm to hold the other parts of the microscope arm to hold the other parts of the microscope together together

Objective – more magnification of the Objective – more magnification of the objective objective

Light source – light source Light source – light source Diaphragm – controls the amount of light that Diaphragm – controls the amount of light that

travels through the specimentravels through the specimen

*******TAKS QUESTION*************TAKS QUESTION******

The English scientist Robert Hooke used a The English scientist Robert Hooke used a crude microscope to examinecrude microscope to examine

A. individual atomsA. individual atoms C. single-celled organismsC. single-celled organisms B. electronsB. electrons D. cork cellsD. cork cells

II. Cell TheoryII. Cell Theory A. Whose observations helped form the A. Whose observations helped form the

CELL THEORY?CELL THEORY? 1838- 1838- Mattias SchleidenMattias Schleiden concluded that concluded that

cells make up every part of the cells make up every part of the Plant.Plant. 1839- 1839- Theodor SchwannTheodor Schwann concluded that concluded that

animalsanimals are made up of cells. are made up of cells. 1858- 1858- Rudolph VirchowRudolph Virchow determined that determined that

cells only come from other cells only come from other cellscells..

B. 3 parts of the Cell TheoryB. 3 parts of the Cell Theory

1. All living things are made up of one or 1. All living things are made up of one or more cells.more cells.

2. Cells are the basic units of structure and 2. Cells are the basic units of structure and function in organisms.function in organisms.

3. All cells arise from existing cells.3. All cells arise from existing cells.

CELL SIZECELL SIZE

Small Small cells function more efficiently cells function more efficiently than large cells.than large cells.

How many cells are our bodies made up of? How many cells are our bodies made up of?

100 trillion100 trillion The advantage of cells being smaller is thatThe advantage of cells being smaller is that substances that enter or leave a cell substances that enter or leave a cell

must cross that cell’s surface; if the cell must cross that cell’s surface; if the cell is small they can exchange substances is small they can exchange substances more readily than large ones. more readily than large ones.

Relationship between Surface area and Relationship between Surface area and

VolumeVolume

Common Features of CellsCommon Features of Cells Cell MembraneCell Membrane-- outer boundary of cellouter boundary of cell Function- Function- regulates what enters and leaves regulates what enters and leaves

the cellthe cell Made up of- Made up of- phosphoplipids and proteinsphosphoplipids and proteins

Cytoplasm- Cytoplasm- fills the cell;cellparts are fills the cell;cellparts are suspended in thissuspended in this

Function- same as aboveFunction- same as above Made up of-Made up of- water and salts water and salts

CytoskeletonCytoskeleton- - a system of microscopic a system of microscopic fibersfibers

Function- Function- provides framework, shape and provides framework, shape and supportsupport

Made up of- Made up of- protein fibersprotein fibers

RibosomesRibosomes-- proteins are made hereproteins are made here

DNADNA- found in the nucleus- found in the nucleus Function- Function- provides instructions for making provides instructions for making

proteins, regulates cell activitiesproteins, regulates cell activities Made up of- Made up of- nucleotidesnucleotides

5. 5. ProkaryotesProkaryotes Smallest and simplest cells.Smallest and simplest cells. Prokaryote- is a single-celled organism that Prokaryote- is a single-celled organism that

LACKS a nucleus and other compartmentsLACKS a nucleus and other compartments They were the only They were the only organismsorganisms on Earth for on Earth for 2 2

billion yearsbillion years. They are very . They are very simplesimple and and smallsmall. The familiar prokaryotes that cause . The familiar prokaryotes that cause infection and cause food to spoil are infection and cause food to spoil are commonly called commonly called BacteriaBacteria..

Characteristics of Characteristics of ProkaryotesProkaryotes They can live everywhere.They can live everywhere.

They can cause infection in humans and grow They can cause infection in humans and grow and divide very rapidly.and divide very rapidly.

Some do not need oxygen survive.Some do not need oxygen survive. Some can make their own food.Some can make their own food. Prokaryotic cells have cytoplasm,cell wall, Prokaryotic cells have cytoplasm,cell wall,

ribosomes, cell membrane & DNA (circular). ribosomes, cell membrane & DNA (circular). Some have flagella for movement.Some have flagella for movement.

Some prokaryotic cell walls are surrounded by a Some prokaryotic cell walls are surrounded by a capsule that enables the cell to cling to almost capsule that enables the cell to cling to almost anything.anything.

..

6. Eukaryotic 6. Eukaryotic CellsCells A eukaryote is an organism whose A eukaryote is an organism whose

cells have a nucleus.cells have a nucleus. OrganelleOrganelle-parts of the cell that -parts of the cell that

carry out specific activities carry out specific activities

NucleusNucleus-internal compartment that -internal compartment that holds DNA holds DNA

Function- controls cells activitiesFunction- controls cells activities

CiliaCilia-short hair-like structures-short hair-like structures Function-used for movementFunction-used for movement

CytoskeletonCytoskeleton- provides interior framework- provides interior framework Function- support and shape of the cellFunction- support and shape of the cell Made up of- protein fibers: microfilaments, Made up of- protein fibers: microfilaments,

microtubules, intermediate fibersmicrotubules, intermediate fibers

6. Cell6. Cell MembraneMembrane Cell Membrane- selective Cell Membrane- selective

permeability (barrier)permeability (barrier) Made up of- phospholipids and Made up of- phospholipids and

proteinsproteins Draw a picture below of the Cell Draw a picture below of the Cell

Membrane- Phospholipid and a Membrane- Phospholipid and a Lipid bilayer:Lipid bilayer:

7. Membrane Proteins7. Membrane Proteins Serve many roles including: as markers; as Serve many roles including: as markers; as

receptors to recognize and bind to substances; as receptors to recognize and bind to substances; as enzymes; as transport proteins to move enzymes; as transport proteins to move substances across the membranesubstances across the membrane

***************TAKS Question: *******************************TAKS Question: **************** A bacterium that lost its flagella would be unable A bacterium that lost its flagella would be unable

toto A. divideA. divide C. maintain its shapeC. maintain its shape B. moveB. move D. make proteinsD. make proteins

III. Cell OrganellesIII. Cell Organelles The NucleusThe Nucleus

– Contains Hereditary information- DNA & RNAContains Hereditary information- DNA & RNA– RNA- made in nucleus; used to make proteinsRNA- made in nucleus; used to make proteins– DNA- wound tightly into chromosomesDNA- wound tightly into chromosomes– Humans have 46 chromosomes. Garden peas Humans have 46 chromosomes. Garden peas

have 14 chromosomes.have 14 chromosomes.

B. Endoplasmic Reticulum-system of B. Endoplasmic Reticulum-system of internal membranesinternal membranes

Function- moves proteins and other Function- moves proteins and other substances through the cell substances through the cell

Made up of- lipid bilayer & embedded proteinsMade up of- lipid bilayer & embedded proteins

Rough ER- contains ribosomesRough ER- contains ribosomes

Smooth ER- (lacks ribosomes)-makes lipids Smooth ER- (lacks ribosomes)-makes lipids and breaks down toxinsand breaks down toxins

C. Golgi Apparatus- flattened membrane- C. Golgi Apparatus- flattened membrane- bound sacbound sac

Function- package and distribution center Function- package and distribution center (UPS)(UPS)

Made up of- proteinsMade up of- proteins

D. Lysosomes- vesicles that bud off of Golgi D. Lysosomes- vesicles that bud off of Golgi ApparatusApparatus

Function-contains cell digestive enzymesFunction-contains cell digestive enzymes

E. Mitochondria- “MIGHTY MITOCHONDRIA”-E. Mitochondria- “MIGHTY MITOCHONDRIA”-site of cell metabolism site of cell metabolism

(more mitochondria=more energy)(more mitochondria=more energy) Function-makes energy ATP for the cellFunction-makes energy ATP for the cell Made up of- 2 membranes-inner is folded out Made up of- 2 membranes-inner is folded out

and outside is smooth.and outside is smooth.

F. Structures of Plant Cells--------F. Structures of Plant Cells--------3 structures found only in PLANT 3 structures found only in PLANT

CELLS.CELLS. 1. 1. Cell Wall-Cell Wall- surrounds the cell membrane surrounds the cell membrane Function- support & maintains shape of the cell Function- support & maintains shape of the cell Made up of- proteins, carbohydrates->celluloseMade up of- proteins, carbohydrates->cellulose 2. 2. ChloroplastsChloroplasts-- found in plant cells as well as algae found in plant cells as well as algae

Function-use light energy to make Function-use light energy to make Carbohydrates ->glucose (sugar)Carbohydrates ->glucose (sugar) Made up of- 2 membranes; has own DNA Made up of- 2 membranes; has own DNA 3. 3. Central vacuole-Central vacuole- takes up most of a plant cell’s takes up most of a plant cell’s

volumevolume Function-stores water ,nutrients, wastes (when full cell Function-stores water ,nutrients, wastes (when full cell

wall is rigid)wall is rigid)

******** TAKS Question************** TAKS Question******

Which organelle serves as the packaging Which organelle serves as the packaging and distribution center of a eukaryotic and distribution center of a eukaryotic cell?cell?

A. NucleusA. Nucleus C. MitochondrionC. MitochondrionB. LysosomeB. Lysosome D. Golgi ApparatusD. Golgi Apparatus