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Lecture 2Announcements

HW#1 Due Tuesday January 20, 2009 via email to jcarol@okstate.eduClass website: http://biosystems.okstate.edu/Home/jcarol/index.html and click on class link

Study Abroad Information Session Jan. 20th

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Quick ReviewWhy do we take this class?What is biomaterial?Should read the first chapter in your book (short chapter!)

Today: Cell StructureFriday: Physical Attributes Read pgs. 11 - 20

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•Cell HandoutForm and stability to cell, protective barrier

Selective permeable boundary between cell contents and wall,

Contains pectin, lignon. Provides support and flexibility between cells

Cytoplasm: contains organelles, transportation synthesis functions

NucleoplasmContains cell genetic code, cell “brain”, DNA

RNA

Plastid that contains chlorophyll, photosynthesis…sunlight to energy in the form of carbs.

Formation of chemical energy, aerobic respiration from ATP

Synthesis of proteinsProtein synthesis and transport, rough contains ribosomes, smooth transports

Synthesizes cell wall components

New cell wall production and motility

Assist in photosynthesis, respiration, breakdown of “trash” for recycling

“junkyard”, synthetic and degradativefunctions (low PH..acidic)

Graphic: www.eng.auburn.edu/.../plant_cell_structure.gif

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Tissues and Functions•Epidermis (Protective):

–clear covering–outermost part of plant–protects plant from loss of water to air–allows gas entry and exit–allows roots to absorb water

Graphic: http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/P/PlantTissues.html

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Tissues and Functions•Parenchyma:

–Found in leaves–Either contain chlorophyll for photosynthesis or store food

•Collenchyma:–Found in leaves–Support leaf or stem

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Tissues and Functions•Sclerenchyma

–Made of either fiber or sclerid–Fibrous: have a secondary cell wall and usually means the cells are dead…give flexibility and support–Sclerid: more pronounced secondary wall and provide hardness…coverings such as nut shells (coconuts, pecans..)

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Tissues and Functions•Endodermis:

–One layer thick–Found in root system–Direct water and minerals from soil to controlling plant tissue

Graphic: http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/R/Roots.html

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Tissues and Functions•Primary Xylem:

–Combination of 4 cell types•Vessel elements•Tracheids•Fibers•Parenchyma cells

–All die except parenchyma when they mature–Responsible for water transport in plant, vertical and horizontal movement

Graphic: http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/R/Roots.html

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Tissues and Functions•Primary Phloem

–Four cell types•Sieve tube•Companion cells•Fiber cells•Parenchyma cells

–Storage and lateral transport of food materials

Graphic: http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/R/Roots.html

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•Vascular Cambium:–Between xylem and phloem–Provides new cells to xylem and phloem–protects plant from loss of water to air

•Cork Cambium:–Outside of phloem–Prevents water loss from the interior of plant–Protects interior from environmental extremes–Example: tree bark

Graphic: www.eng.auburn.edu/~wfgale/usda_couse/section0_images_2/syle

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Cellular Respiration•Goal:

–Convert carbon-containing compounds into energy for life processes–Carried out in the mitochondria

•Two Types:–Aerobic: uses oxygen as electron acceptor–Anaerobic: uses other compounds for cellular respirtaion

•Both types start with glycolysis

6CO2 + 6H2O + Light Energy = C6H12O6 + 6O2

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Glycolysis•Occurs in the cytoplasm•Takes a molecule of glucose (6 carbon sugar molecule)•Converts it to pyruvic acid•Changes in molecules happen because of enzymatic activity•Enzymes: protein molecules that facilitate reactions

–Involves energy (use, production…)

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Anaerobic Respiration•Electron acceptor is NOT oxygen.•AKA…FERMENTATION•Two types of fermentation: lactic acid and alcoholic

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Aerobic Respiration•Majority of organisms respire aerobically•Terminal electron acceptor is oxygen•Consists of 2 processes:

–Kreb’s (aka Citric Acid) Cycle–Electron transport chain

•Kreb’s Cycle: produces CO2 and H2O•Electron Transport …transports electrons!!!

–From high energy compounds to lower energy compounds–Final receptor is oxygen molecules

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Respiration•Aerobic respiration is more efficient at producing energy for the plant•Some organisms (known as facultative anaerobes or aerobes) can do either kind of respiration•Example: yeast•With oxygen, use citric cycle and et to produce their energy•Without oxygen, use alcoholic fermentation…produce ethyl alcohol

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Photosynthesis•Heterotrophs: consume their energy•Autotrophs: produce their own food•Plants are autotrophs•Use sunlight, water, and carbon dioxide to form carbohydrates and oxygen

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Photosynthesis•Light Reactions

–Photosystem I: absorbs sunlight by chlorophyll molecule–Photosystem II: converts two water molecules into electrons, protons, one water molecule and ½oxygen molecule. –Electron transfer releases energy–Oxygen is either used in the cycle or given off through respiration

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Wavelength (nm)

Ref

lect

ance

(%

)R

efle

ctan

ce (

%)

0.25

0.5VisibleVisible Near InfraredNear Infrared

450 550 650 750 850 950 1050500 600 700 10009008000.00

Plant ReflectancePhotosyntheticPotential

Measure of living plant cell’s ability to reflect infrared light

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Photosynthesis•Dark Reactions

–Do not require light–AKA carbon fixation reactions–Carbon from CO2 is used to make sugars like glucose–Requires light reaction products (NADPH) and CO2

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Photosynthesis•Requries

–light for Light Reactions–Water for electron and proton source –Proper temperature for efficiency

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HW#2 Assignment: Due 1/23/09

•Explain the parts of an animal cell and the differences between plant and animal cells

–Include graphic(s) of animal cells–Include functions of the cell parts–Put your answer in the form of a Power Point –Email it to jcarol@okstate.edu by midnight on 1/23.

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Resources•http://sun.menloschool.org/~cweaver/cells/•http://cals.arizona.edu/pubs/garden/mg/botany/physiology.html#transpiration•http://www.eng.auburn.edu/~wfgale/usda_course/section0_2_page_3.htm