TA InfoTA Info

Francis (Frank) IosueFrancis (Frank) Iosue

Francis.iosue@villanova.eduFrancis.iosue@villanova.edu

Office = 192 Mendel Office = 192 Mendel Monday 9-10 AMMonday 9-10 AM Tuesday 9-10 AMTuesday 9-10 AM By AppointmentBy Appointment

AttendanceAttendance

260 points (37%) of your grade for the course 260 points (37%) of your grade for the course will be based on labwill be based on lab

Attendance is MANDATORY – NO Make-up Attendance is MANDATORY – NO Make-up labs labs

If you have a legitimate reason to miss lab, If you have a legitimate reason to miss lab, contact me or Ms. Jamison Immediatelycontact me or Ms. Jamison Immediately

2 Field Trips 2 Field Trips

Academic IntegrityAcademic Integrity

Policy set forth in the “Blue Book” will be strictly Policy set forth in the “Blue Book” will be strictly enforcedenforced

Unless specifically stated, all assignments are Unless specifically stated, all assignments are to be done alone!to be done alone!

If you are unsure, ASK ME!If you are unsure, ASK ME!

Safety Safety No food or drinkNo food or drink

Appropriate dress (no open-toe shoes, long Appropriate dress (no open-toe shoes, long pants, no halter tops)pants, no halter tops)

NO CELL PHONES!!!NO CELL PHONES!!!

Leave the lab cleanLeave the lab clean

Safety goggles and gloves when needed.Safety goggles and gloves when needed.

Plants & Plants & CivilizationCivilizationBIO 1785BIO 1785Lab #1: Lab #1:

The Microscope & Plant CellsThe Microscope & Plant Cells

The Microscope…The Microscope…A ReviewA Review

Compound Light Microscope – useful for viewing Compound Light Microscope – useful for viewing slidesslides

vs.vs.

Dissecting Microscope – useful for viewing 3-D Dissecting Microscope – useful for viewing 3-D images.images.

ALWAYS HANDLE THESE EXPENSIVE PIECES OF ALWAYS HANDLE THESE EXPENSIVE PIECES OF LAB EQUIPMENT WITH EXTREME CARE!LAB EQUIPMENT WITH EXTREME CARE!

Compound Light MicroscopeCompound Light MicroscopeIdentifying the parts of a microscopeIdentifying the parts of a microscope

Know where parts are located & what each is used for.

TA will demonstrate proper use if you don’t remember! Always ask if unsure so that you do not damage the scope!

Compound Light MicroscopeCompound Light Microscope

Recall…Recall…

1.1. Total MagnificationTotal Magnification = objective lens (listed on = objective lens (listed on objective) x ocular lens (10x).objective) x ocular lens (10x).

2.2. Field of View:Field of View: what you see when you look what you see when you look through the eyepiece. through the eyepiece.

How does this field change when switching to higher magnification? How does this field change when switching to higher magnification?

3.3. Depth of Field:Depth of Field: thickness of the object in thickness of the object in focus. focus.

Are all layers of your specimen in focus at the same time? If not, what Are all layers of your specimen in focus at the same time? If not, what does that indicate?does that indicate?

How to Make a Wet-How to Make a Wet-Mount PreparationMount Preparation

Solid SpecimenSolid Specimen(e.g. potato)(e.g. potato)

Drop of HDrop of H22O onto slideO onto slide

Very thin slice of potato Very thin slice of potato onto droponto drop

Liquid SpecimenLiquid Specimen

(e.g. (e.g. OscillatoriaOscillatoria))

Use pipet to “mix up” Use pipet to “mix up” specimen, then draw up specimen, then draw up

Place one drop of Place one drop of specimen onto slidespecimen onto slide

TA will DEMONSTRATE Onion wet-mount….

FOCUSINGFOCUSING on your wet-mount on your wet-mount

…“…“I can’t see anything on my slide!” I can’t see anything on my slide!” -first time scope user-first time scope user

1.1. First, fit slide securely into stage clip.First, fit slide securely into stage clip.

2.2. With scanning power objective lens (4x) in place, adjust the stage With scanning power objective lens (4x) in place, adjust the stage upwardupward using the coarse adjustment knob so that the lens is using the coarse adjustment knob so that the lens is almost almost touching the slide –DO NOT allow the lens to hit the slide touching the slide –DO NOT allow the lens to hit the slide & & DO DO NOTNOT LOOK THROUGH THE EYEPIECE YET! LOOK THROUGH THE EYEPIECE YET! (you (you should be looking from the side)should be looking from the side)

3. Now, while looking through the eyepiece, use coarse focus knob 3. Now, while looking through the eyepiece, use coarse focus knob to “focus downward” on your specimen.to “focus downward” on your specimen.[Focusing “upward”, that is moving the stage upward toward the objective lens, [Focusing “upward”, that is moving the stage upward toward the objective lens, may result in breaking your slide & damaging the objective lens – may result in breaking your slide & damaging the objective lens – never do thisnever do this].].

ALWAYS, ALWAYS, ALWAYS – FOCUS DOWNWARD!ALWAYS, ALWAYS, ALWAYS – FOCUS DOWNWARD!

Part II: PLANT CELLSPart II: PLANT CELLS

CELLS are the basic unit of life. All plants CELLS are the basic unit of life. All plants are comprised of cells.are comprised of cells.

Prokaryotes vs. EukaryotesProkaryotes vs. Eukaryotes

Prokaryotes: cells which do NOT contain a membrane-bound nucleus or other organelles. Instead, prokaryotes have a plasma membrane only.

Examples: bacteria & cyanobacteria.

PROKARYOTESPROKARYOTES[The Cyanobacteria][The Cyanobacteria]

Largest prokaryotes = CYANOBACTERIALargest prokaryotes = CYANOBACTERIA[a.k.a. “blue-green algae”][a.k.a. “blue-green algae”]

Cyanobacteria contain Cyanobacteria contain chlorophyll achlorophyll a & other pigments & other pigments (phycobilins) needed for photosynthesis.(phycobilins) needed for photosynthesis.

Pigments are Pigments are NOTNOT contained in chloroplasts, but in contained in chloroplasts, but in photosynthetic membranes called photosynthetic membranes called thylakoidsthylakoids..

Perform photosynthesis similar to eukaryotic plantsPerform photosynthesis similar to eukaryotic plants

Important 1Important 100 producers (both on land in aquatic producers (both on land in aquatic ecosystems).ecosystems).

Do they produce their own food???Do they produce their own food???

YES!!YES!!

Examine CyanobacteriaExamine Cyanobacteria

Prepare wet-mounts of & examine (sketch):Prepare wet-mounts of & examine (sketch):1.1. OscillatoriaOscillatoria – filamentous w/ rhythmic mov’t – filamentous w/ rhythmic mov’t2.2. NostocNostoc – filamentous w/ cell differentiation – filamentous w/ cell differentiation

((heterocystsheterocysts))3.3. AnabaenaAnabaena – filamentous w/ heterocysts – filamentous w/ heterocysts4.4. GloeocapsaGloeocapsa – heavy gelatinous sheath – heavy gelatinous sheath

holding holding uni-cellsuni-cells together together5.5. CylindrospermumCylindrospermum – filamentous with – filamentous with

heterocystsheterocysts & & akinetesakinetes

Cyanobacteria…Cyanobacteria… what can they do? what can they do?

Capable of photosyntheis - OCapable of photosyntheis - O22 evolving evolving

Heterocysts - NHeterocysts - N22 fixation (enriches fixation (enriches

aquatic environments)aquatic environments)

Akinetes – provide survival supportAkinetes – provide survival support

http://www.dr-ralf-wagner.de/Bilder/Cylindrospermum.jpg

Heterocyst

Akinete

Vegetative filament

BACTERIABACTERIA

Are prokaryotesAre prokaryotes

Not the same as cyanobacteria!Not the same as cyanobacteria!

How does the size of a bacterial cell How does the size of a bacterial cell compare to that of cyanobacteria?compare to that of cyanobacteria?

For answer: Compare your observations of For answer: Compare your observations of cyanobacteria to DEMOs of bacterial cells.cyanobacteria to DEMOs of bacterial cells.

EURKARYOTES – EURKARYOTES – Plant CellsPlant Cells

Eukaryotes: cells which do contain a membrane-bound nucleus & other organelles. The cytoplasm is contained within the plasma membrane.

Chloroplasts = green organelles which contain chlorophyll. This is the site of photosynthesis in plant cells.

Another organelle = mitochondria where cellular respiration occurs.

Eukaryotes-Eukaryotes-Plant Cells (con’d)Plant Cells (con’d)

Structure of Plant CellsStructure of Plant Cells

Note: cuboidal shape & numerous organelles

Specialized Plant Specialized Plant Cells & TissuesCells & Tissues

Types by Function:Types by Function:1.1. Support Support

Collenchyma, Sclerenchyma Collenchyma, Sclerenchyma (includ. Sclerids)(includ. Sclerids)

2.2. VascularVascular Xylem, PhloemXylem, Phloem

3.3. Storage, etc.Storage, etc. ParenchymaParenchyma

4.4. ProtectionProtection Epidermis, Cork, Cork CambiumEpidermis, Cork, Cork Cambium

Specialized Plant Specialized Plant Cells & TissuesCells & Tissues

SUPPORT:SUPPORT: Collenchyma cellsCollenchyma cells– provide mechanical support w/ – provide mechanical support w/

irregularly thickened cell walls esp. while cells are irregularly thickened cell walls esp. while cells are growing.growing.

Thickened at corners; Cells just beneath epidermis; reddish in Thickened at corners; Cells just beneath epidermis; reddish in color & appear ‘star or hexagon-shaped’ under scope.color & appear ‘star or hexagon-shaped’ under scope.

Sclerenchyma fibersSclerenchyma fibers– long & slender support occuring in – long & slender support occuring in bundlesbundles w/ heavy 2 w/ heavy 2oo cell walls made of cell walls made of ligninlignin..

Strong polymer; rigid support; If cell dies lignin can still provide Strong polymer; rigid support; If cell dies lignin can still provide support; also appears reddish in color.support; also appears reddish in color.

Sclerids:Sclerids: type of sclerenchyma cell variable in shape for type of sclerenchyma cell variable in shape for strength & rigidity, often branched & ‘gritty’ in appearance. strength & rigidity, often branched & ‘gritty’ in appearance.

Provides heavy 2Provides heavy 2oo cell wall support cell wall support Lignified (so it appears pink/reddish)Lignified (so it appears pink/reddish) Connects two air spaces Connects two air spaces Example: Stellate sclerid – named due to shape.Example: Stellate sclerid – named due to shape.

Examples of: Examples of: Support Cells & TissuesSupport Cells & Tissues

CollenchymaCollenchyma SclerenchymaSclerenchyma ScleridsSclerids

http://www.vet.purdue.edu/bms/intl/nourpix/an0020.jpg

http://www.sc.chula.ac.th/courseware/2303105/spec/03.JPG

http://www.rhodes.edu/biology/stinemetz/sclerid1.jpg

http://www.nsci.plu.edu/~jmain/b359web/images/sclerid(2TN).jpg

Specialized Plant Specialized Plant Cells & TissuesCells & Tissues

Vascular:Vascular: Xylem cells-Xylem cells- modified elongated cells that modified elongated cells that conduct conduct

HH22OO by capillary action. by capillary action. Xylem vessel elements (1 cell) align end-to-end forming Xylem vessel elements (1 cell) align end-to-end forming

xylem vessels.xylem vessels. Lignified 2Lignified 2oo walls, thickened in various patterns walls, thickened in various patterns (e.g. annular, (e.g. annular,

reticulate, sclariform).reticulate, sclariform). Xylem rings are deposited yearly – used to age a tree!Xylem rings are deposited yearly – used to age a tree!

Phloem cells-Phloem cells- modified cells for modified cells for transporttransport of of organic solutionsorganic solutions..

Consist of Consist of sieve tube memberssieve tube members & & companion cellscompanion cells.. At maturity, differentiated for conducting materials, loses At maturity, differentiated for conducting materials, loses

nucleus, but remains fully functional.nucleus, but remains fully functional.

Examples of: Examples of: Vascular Cells & TissuesVascular Cells & Tissues

Xylem & Phloem, c.s.Xylem & Phloem, c.s.

http://www.life.uiuc.edu/ib/202/labs/structure/plant_transpiration/buttercup400x.jpg

A = Phloem (green cells)

B= Xylem (red cells)

Xylem: A Closer LookXylem: A Closer Look

http://www.rothamsted.bbsrc.ac.uk/notebook/courses/guide/images/xilem.jpg

http://www.skidmore.edu/academics/biology/plant_bio/Anatomy-stems,seeds,embryos/Xylem%20fibers%20&%20vessels%20l.s..jpg

Longitudinal sections: note patterns of lignified cell walls

Phloem: A Closer LookPhloem: A Closer Look

http://www.bbc.co.uk/scotland/education/bitesize/standard/img/biology/structure_phloem.gif

Longitudinal section: showing sieve tube members with “sieve-like” end wall & associated companion cells.

http://botit.botany.wisc.edu/images/130/Stem/Zea_cross_section/Phloem.low.jpg

Cross section: showing green phloem cells in a vascular bundle w/ xylem.

Specialized Plant Specialized Plant Cells & TissuesCells & Tissues

Storage, etc.Storage, etc.

Parenchyma cellsParenchyma cells – thin-walled living cells that are – thin-walled living cells that are most abundant cell type in plants.most abundant cell type in plants.

Many kinds of parenchyma cells that perform diverse Many kinds of parenchyma cells that perform diverse functions including:functions including:

1.1. Photosynthesis (in leaves)Photosynthesis (in leaves)

2.2. Intercellular communicationIntercellular communication

3.3. **Food (starch) storage (in roots & stem of plant)Food (starch) storage (in roots & stem of plant)

Parenchyma CellsParenchyma Cells

http://members.tripod.com/ashley_tan/histology/images/plant_histology-basic_tissues_parenchyma_ts.jpg

Cross section: showing cellular inclusions. What are these inclusions & what do they tell you about the function of this type of parenchyma???

http://members.tripod.com/ashley_tan/histology/images/plant_histology-root_dicot_ts.jpg

Plant stem – parenchyma cells make up the cortex

Specialized Plant Specialized Plant Cells & TissuesCells & Tissues

Protection:Protection: Epidermis – outermost layer of cells of leaf, stem, &

roots exposed to environmental stresses. Covered by cuticle (waxy layer)

-prevents H2O loss

Where guard cells & subsidiary cells are found around stomata openings.

-regulate CO2 in & O2 out of plant cells

Periderm – consists of Cork & Cork Cambium which replaces epidermal tissue that is worn away by environmetal wear & developmental/mechanical stresses.

EpidermisEpidermis

http://www.emc.maricopa.edu/faculty/farabee/BIOBK/92462b.jpg

http://images.botany.org/set-13/13-021v.jpg

Outermost layer of cells = epidermis

Guard cells surrounding stomata opening (within epidermal layer)

http://bugs.bio.usyd.edu.au/2003A+Pmodules/graphics/A62a.jpeg

Trichomes = extensions of epidermis

Cork & Cork CambiumCork & Cork Cambium

http://www.botany.hawaii.edu/faculty/webb/BOT201/PrimSec/Peri-2240Lab.jpg

• Cork cambium cells undergo active mitotic division, then migrate to the outside to form cork.

• Cork cells form waxy material called suberin which provides protection, but seals cork off from other cells of the plant. Cork cells are still functional even when dead.

Found in roots & stems.

TODAY’S PLAN:TODAY’S PLAN:SummarySummary

Part IPart I - Microscope - Microscope Refresher CourseRefresher Course

Lab Manual pp. 1-20Lab Manual pp. 1-20

Label parts of microscope & recall proper usage (proper focusing technique, field of view, depth of view, magnification).

Making wet-mounts of potato, onion…for practice.

Study wet-mounts of cyanobacteria in part 2.

Part II – Specialized Plant Part II – Specialized Plant Cells & Tissues Cells & Tissues

Lab Manual pp. 21-42Lab Manual pp. 21-42

Prokaryotes Cyanobacteia wet-mounts &

sketches (label diagrams!) Bacteria types DEMO slide

vs. Eukaryotes

Plant cell general structure Elodea wet-mount

Specialized Cells & Tissues Support, Vascular, Storage &

Protective types View various slides of each,

sketch, & label.