Bio 1 Lab 2 review Hadley - Biology-Lab-1

Bio 1: Lab 2 Review
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PROKARYOTIC CELLS
! Single celled organisms (bacteria and blue-green algae)
! Lack nuclei and membrane bound organelles
! Fossilized cells 3.5 billion years old
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EUKARYOTIC CELLS
! Oldest fossils are 1.5 billion years
! Evolution & internal compartmentalization led to enormous bio diversity
! Evolution of loose cells to colonies led to specialization (locomotion,
reproduction)
! Specialization and diversification gave rise to fungi, plants and animals
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TYPES OF MICROSCOPES
! Light Microscopes
• Types vary by source and manner of light
o Phase contrast
o Darkfield
o Polarizing
o UV
• Compound Binocular Light Microscope used in lab
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COMPOUND = two+ magnifying lenses (ocular x objective)
OCULAR LENS is the lens in the eyepiece (10x)
INTERPUPILLARY DISTANCE is distance between eyepieces
FIELD OF VIEW is circle of light seen in microscope
OBJECTIVES are 3 lenses on the REVOLVING NOSEPIECE
! 4x = SCANNING LENS
! 10x = INTERMEDIATE LENS
! 40X = HIGH POWER LENS
! 100x = OIL IMMERSION
ARM supports the stage and CONDENSER LENS which is used
to focus the light from the lamp
IRIS DIAPHRAGM adjusts the amount of light
STAGE supports the specimen to be viewed
STAGE ADJUSTMENT KNOBS move stage on 2 axis
STAGE CLIPS secure the slide
COARSE and FINE ADJUSTMENT KNOBS adjust focus
LIGHT INTENSITY LEVER adjusts the intensity of the light
PARFOCAL means little refocusing necessary when changing
objectives lenses
WORKING DISTANCE = distance between the specimen and the
objective, and is greater with lower power lenses
Stereoscopic Microscope (Dissecting)
o Depth of field is much great to allow 3D images
o Light source can be directed down (REFLECTED or INCIDENT
LIGHT) as well as up (TRANSMITTED LIGHT)
2.1 BASIC MICROSCOPE TECHNIQUES
! Always start with 4x objective lens
! Use coarse adjustment to locate specimen and bring into focus
! Do not turn fine adjustment knob more than 2 turns in either direction
! Adjust CONTRAST via IRIS DIAPHRAGM opening (max light = little contrast)
! Image appears INVERTED relative to slide
! NEVER use coarse adjustment knob when using high power lens
! To measure FIELD OF VIEW
• Place mm ruler on stage, count # lines visible under each objective lens
• Convert to micrometers (1mm = 1000um)
• Field of view is smaller under higher magnification
! DEPTH OF FIELD is the thickness of specimen seen in focus at one time
• Higher magnification has SHORTER depth of field
• BOTTOM of specimen comes in focus first as stage moves down
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ORGANIZATION OF CELLS
! Unicellular (ex: Amoeba)
• All functions of life performed by the one cell
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Aggregate (ex: Protococcus or “moss on north side of trees”)
• Random and temporary aggregates or clusters
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Colonial (ex: Scenedesmus, Volvox)
• Clusters of consistent and predictable numbers of cells
• Simple Colonies have no physiological connection but maintain
predictable structure
• Complex Colonies have specialized groups of cells
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Multi-cellular (ex: Elodea, cheek cells)
• Large numbers of cells with specialized functions
• No one cell can exist by itself
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What cells are plant v animal v protist and what distinguishes each?
! Animal Kingdom
• Amoeba, Cheek Cells
• Unique structures: Centrioles, many vacuoles, lysosomes
! Plant Kingdom
• Elodea
• Unique structures: Cell wall, Central Vacuole, Chloroplasts,
! Protists
• Amoeba, Trichonympha, protococcus, scenedesmus, volvox
• Unique structures: Contractile Vacuole
• “Protists have relatively simple organization - unicellular, or they are
multicellular without specialized tissues.
• This simple organization distinguishes protists from other eukaryotes,
such as fungi, animals and plants.”
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ID cell wall, nucleus, plasma (or cell) membrane, chloroplasts, cytoplasm, central
vacuole
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What is the central vacuole, and how can you tell it is there (in Elodea?)
! The central vacuole is an organelle in plant cells that stores nutrients and
water for the cell.
! It gives the cell structure via TURGOR PRESSURE
! Animal cells do not have a central vacuole; they have many small vacuoles,
which contain proteins, carbohydrates, water, and nutrients
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Match type of specialized tissue w/ cell structures or organelles in abundance
! Enzyme secreting cells in pancreas = Ribosomes
! Insect flight muscles = Mitochondria
! Cells lining the respiratory passages = Cilia and Flagella
! White blood cells = Lysosomes
! Leafs of cacti = Chloroplasts
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Two types of organisms that make up Lichen = Algae and Fungi