Ch 2 Glencoe

Looking at Cells

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Daisy

•What does your skin do for you?

•What does your blood do for you?

•What do your bones do for you?

•What does your heart do for you?

•Each individual cell must also do these things to live and has structures that do them.

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Objectives:

• Objectives:- Relate cell structures to basic cell functions of typical plant and animal cells

• -Identify the structure and function of cell membrane, nucleus, cytoplasm, chloroplasts, mitochondria, nuclear membrane, chromosomes, vacuoles, endoplasmic reticulum, cell wall, and ribosomes

• -Compare and contrast the structures of a typical plant and animal cell

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Two types of cells:

• Eukaryotes and Prokaryotes

http://www.soe.uoguelph.ca/webfiles/mleuniss/Images/Logos_Clipart/celltypes4.gif

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Prokaryotes

• define cells without membrane-bound structures.

– No nucleus (pro rhymes with NO)

• genetic material (DNA) in the cytoplasm

• contain ribosomes, but not other organelles.

• all have cell membranes and cell walls, some flagellum

• all are unicellular bacteria

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A bacteria

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Two types of bacteria

• Eubacteria =true bacteria, live almost everywhere

• Archaebacteria = ancient bacteria

-live in extreme environments (extremophiles)

o Thermophiles live in hot environments

o Halophiles live in salty environments

o Methanogens are methane making

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Eukaryotes define (Eu = true, kary = nucleus)

• =A cell with a membrane bound nucleus and other organelles.

• all have a nucleus

• can be unicellular or multicellular

• all have cell membranes and ribosomes,

• some have cell walls, some have flagellum

• have many cell organelles

ex: plants, animals, fungi and protists

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Parts of Cells

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All cells have…..

• Genetic material (DNA)

• Cell membranes

• Ribosomes (may or may not have other organelles)

• Different types of cells have different organelles

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Ribosomes in all

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Cell Wall “fence “ • function-helps to protect and support the cell

• are found in plant cells, fungi cells, and a few other autotrophs, like bacteria

• in plants contains cellulose (a tough, yet flexible material)

• in fungi contains chitin

• materials can pass through pores in the cell wall.

• no cell walls in animal cells

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http://biology.unm.edu/ccouncil/Biology_124/Images/cellwall.jpeg

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Cell membrane “gatekeeper”

• just inside of cell wall (if it has a cell wall)

• function-controls which substances can enter or leave the cell and

• separates the cell’s contents from the cell’s environment

• All cells have cell membranes

• made up of phospholipids

• hydrophobic (define) and hydrophilic (define) ends

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http://library.thinkquest.org/C004535/media/cell_membrane.gif

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Cytoplasm “cell fluid“

• Define

• Cyto = cell plasm= fluid

• contains a gel-like material and dissolved nutrients

• Function: to hold the organelles in place.

– they are suspended in this fluid.

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Cytoskeleton “framework”

• = the fibers in the cell that hold the inside of the cell together.

• function= helps the cell retain its shape, move in its environment, and move its organelles.

http://publications.nigms.nih.gov/insidethecell/images/ch1_cytoskeleton.jpg

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Organelles in the Cytoplasm:

• Organelle (define)

-each organelle has a different function

(energy production, build and transport needed materials, store and recycle wastes).

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Nucleus “control center”

• -Function: contains the chemical instructions that direct all the cell’s activities and determines the cell’s characteristics.

http://www.agen.ufl.edu/~chyn/age2062/OnLineBiology/OLBB/www.emc.maricopa.edu/faculty/farabee/BIOBK/nucleus_1.gif

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Parts of the nucleus

• Nuclear membrane= protects the nucleus and controls what moves in and out of the nucleus. -outer membrane of the nucleus

Inside the nucleus we find:

• Nucleolus= a structure in the nucleus in which ribosomes are made.

• DNA (chromatin, chromosomes)

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Chloroplasts “solar panels”

• Function: captures energy from sunlight and uses it to produce food (sugars).

• photosynthesis occurs here

• found only in autotrophs.

• contain a green pigment called chlorophyll which traps the energy from sunlight

• Chloro=green

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http://micro.magnet.fsu.edu/cells/chloroplasts/images/chloroplastsfigure1.jpg

http://www.nature.com/nrm/journal/v5/n3/images/nrm1333-i1.jpg

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Mitochondria “powerhouse”

• function: to produce most of the energy for the cell

• ‘powerhouses’ of the cells

• where cellular respiration occurs (the breakdown of sugars to release energy as ATP)

• have their own DNA and can divide themselves

• a lot of mitochondria in animal cells, few in plant cells

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http://scienceblogs.com/worldsfair/Mitochondria.jpg

http://math.etsu.edu/symbiosis/mitochondria.jpg

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Ribosomes “factory”

function: to make proteins

• made in the nucleolus

• located floating in the cytoplasm and on the Endoplasmic Reticulum

• uses RNA as the directions to make proteins.

http://www.sciencegeek.net/Biology/review/graphics/Unit5/Protein.jpg

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Endoplasmic Reticulum “passageways”

• Function: helps make and carries proteins and other materials to other parts of the cell.

Two types:

• rough ER has ribosome on the surface (transports materials)

• smooth ER has no ribosomes( makes lipids and breaks down toxins)

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http://www.microscopy.fsu.edu/cells/endoplasmicreticulum/images/endoplasmicreticulumfigure1.jpg

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Golgi Complex “mailroom”

• function: receives proteins, packages them, and distributes them to other parts of the cell.

• -golgi bodies make up a larger structure called the golgi apparatus (or complex)

• -small bubbles break off to carry the proteins

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http://micro.magnet.fsu.edu/cells/golgi/images/golgifigure1.jpg

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Vesicle= “delivery truck”

• Function: transport materials around inside the cell and may release them outside the cell.

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Lysosomes “recycler” • Function: breaks down large food particles

into smaller ones and breaks down old cell parts.

• responsible for digestion in the cell

• rare in autotrophs, many in heterotrophs.

• Look similar to vacuoles in animal cells but will show large particles inside.

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http://www.biology4kids.com/files/art/cell_lysosome1.gif

http://www5.pbrc.hawaii.edu/allen/ch06/mimg/45-pmdv790419-1m.jpg

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Vacuoles “storage tanks”• Function: a storage area for food, water, and

wastes. • are small in animal cells, stores many substances

-Food and wastes will be dissolved in the water so it appears empty.

• but one large one in plants, primarily store water for photosynthesis-helps the plant cell keep its size and shape (will wilt with too little)

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ADD

• cells may have parts in common

• cells come in many shapes and sizes

• cells have many different functions

– Function determines the types of organelles and the shape of the cell

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Vacuole =storage tanks

Lysosome = recyclers

Chloroplasts=solar panels

Ribosomes = factory

Golgi bodies(vesicles) = delivery trucks

Cell Wall=

Cytoskeleton= buildings frame

Chromosomes= instruction manual

Mailroom

Passageway

Control center

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Copy Cell Structure

Animal Plant

Nucleus

Cell Wall

Chloroplasts

Lysosomes

Plant and Animal Cells

Yes Yes

No Yes

No Yes

Yes Many few if any

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Typical Plant cellDiagrams

3-D

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Typical Animal Cell diagrams

3-D

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Cell part Quiz: Identify each part

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Organization of Living things

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Eukaryotes can be unicellular or multicellular:

• * Complex Multicellular organisms have cells that can vary greatly in size, structure, and function.

-ex: skin, muscle, nerve, bone and blood cells.

-which means their cell parts may vary depending on function

• Simple multicellular organisms may have many cells but only a few different types of cells with different functions. Ex: sponge

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• Colonies are groups of unicellular organisms functioning together as a multicellularorganisms, but each cell could function by itself and reproduce.

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Benefits of being multicellular:

• larger size- the larger the organism the more cells it has

– smallest true animal has only about 1000 cells

• longer life-individual cells do not live very long but a multicellular organism can live longer because it can replace cells that get worn out

• specialization- makes the organism more efficient because each cell can focus on a specific job

• Larger organisms have fewer predators

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5 levels of cellular organization

Cell Tissue OrganOrgan system

Organism

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Tissue = define 4 types of tissue:

• muscle tissue = can contract or shorten, to make parts of your body move.

• nerve tissue = carries messages back and forth between the brain and body to direct and control body movements.

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• connective tissue = provides support for the body and connects all its parts.

ex: bone and cartilage

• epithelial tissue = covers the surfaces of your body, inside and out, for protection and can also absorb or release chemicals.

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• Organ = define

• Organ system = define

12 major organ systems (we will study these later).

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Section 2

• Viewing Cells

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What tool do we use to see cells?

Microscopes (pgs 22-23)

How a light microscope works:

• makes an object look larger

• uses lenses to bend the light that passes through them in order to focus the light rays.

• simple microscope has one lens

• compound microscope has two or more lenses

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Two important properties of Microscopes : • Magnification and Resolution

• 1) Magnification = the ability to make things appear larger

-multiple lenses create greater magnification (larger images).

• 2) Resolution= the ability to clearly distinguish the individual parts of an object. (sharpness or how sharp an image is).

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http://www.cis.rit.edu/class/simg553_03/images/Sun_comp.gif

For a telescope image of the sun

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Calculating Magnification on a compound Microscope:

• Multiply the magnification of the eyepiece by the magnification of the objective lens.

• These numbers will be written on the microscope.

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Electron Microscopes:

• use a beam of electrons instead of light to

examine a specimen.

• gives very high resolution

• Three types

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TEM • Transmission Electron

Microscope (TEM) magnifies thinly sliced specimens up to 500,000 times.

http://www.brookes.ac.uk/lifesci/research/images/GolgiTEM.jpg 56

SEM • Scanning Electron Microscope (SEM) magnifies the surface up to 150,000 times for a 3-D image.

http://www.andersonmaterials.com/images/sem_top.jpghttp://gsc.nrcan.gc.ca/labs/ebeam/i

mages/sem9.jpg 57

STM • Scanning Tunneling Microscope (STM) magnifies the surface of a cell up to 1,000,000 times to see individual molecules and atoms. Ex: graphite (carbon atoms)

http://www.wfu.edu/nanotech/Microscopy%20Facility/stm_view.jpg

http://www.physics.iisc.ernet.in/~arindam/images/hopg_STM_atomic.jpg

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First Sightings of cells:• Microscope define

• 1590: invention enabled people and to discover and learn about cells and other small organisms.

• Hans and Zacharias Janssen

-Dutch lens grinders, father and son

-produced first compound microscope (2 lenses)

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Discovery of cells:

• 1665 English scientist:

• -Robert Hooke observed 'tiny rectangular rooms' and named them cells

http://media-2.web.britannica.com/eb-media/68/99768-004-AF8F9553.jpg

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Other discoveries • 1673 Dutch

scientist • -Anton van Leeuwenhoek

observed one celled organisms now called bacteria (he called them animalcules)

http://www.euronet.nl/users/warnar/radardiertjeHBAKER.jpg

http://media-2.web.britannica.com/eb-media/15/3815-004-DCA02F83.jpg

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• 1838: German scientist

• Matthias Schleiden concluded all plants are made of cells. http://faculty.kutztown.edu/friehauf/science_

outreach/elodia_cells_001.jpg

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• 1839: German Theodore Schwann concluded all animals are made of cells, therefore all living things are made up of cells.

• Image: human cheek cells

http://www.uic.edu/classes/bios/bios100/labs/Cheek1.jpg

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• 1855: German

• Rudolf Virchow proposed that new cells are formed only from existing cells.

http://www.cbp.pitt.edu/faculty/yong_wan/images/main_cell_cycle.jpg

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*The Cell theory

• holds true for all living things regardless of size or complexity or cellular organization.

• Scientists write theories to explain natural phenomena.

• The cell theory puts together all of the ideas of Schleiden, Schwann, and Virchow.

• The modern theory adds a few ideas we have already discussed.

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The Modern Cell Theory States…

• All living things are made of one or more cells

• Cells are the basic unit of structure and function in living things

• All cells are produced from other cells.

• The cell contains hereditary information which is passed on from cell to cell during cell division.

• All cells are basically the same in chemical composition and metabolic activities

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