1406 bio lab unit one

bacterial morphology color

Some bacteria produce pigments, giving the colony a distinct color. Pigments span the entire color spectrum. Recording the color is the first step. In addition to describing the color, this is also the time to identify the colony as opaque (you can't see through it), translucent (you can see through it), dull, or shiny.

differences between compound microscopes and steroscoic disecting microscope: steroscopic disecting

Steroscoic: one lense look at large objects 300x magnification light coming from above and allow zou to observe the surface texture of objects. 1. Focus wheel 2. Light source 3. Base 4. Ocular (eyepiece) lenses

light source of miscroscope

The light to illuminate the specimen comes from the light source. In many microscopes, this is a small bulb, but the ultimate light source may be from a lamp or even a candle - redirected by a mounted mirror.

Parcentral Definition

The property of a microscope which keeps the specimen relatively centralized in the field of view from one objective lens to the next lens

Step eighteen for handling the microscope

When observing a different slide, use coarse focus to lower stage to lowest setting. o Rotate 4X objective into light path o Remove slide, and replace with new slide, repeating above procedure described for focusing.

plasma membrane

a microscopic membrane of lipids and proteins that forms the external boundary of the cytoplasm of a cell or encloses a vacuole, and that regulates the passage of molecules in and out of the cytoplasm.

depth of focus

adjusted by low power objective on the microscope. best demonstrated with a slide containing overlapping threads how depth is percieved through the microscope

. Competition among genetically varied offspring for limited resources is one of the the cornerstones of

biological evolution

how can a compound microscope be used to complete a study

can be used to study small organisms such as bacteria

subcellular structures unique to prokaryotic cells.

capsule, pili, flagella, plasmids, nucleoid region

What are some key features to identifying a prokaryotic cell under the microscope

cell wall and are smaller than eukaryotic cells, no nuceus Are almost all unicellular Do not contain any membrane-enclosed organelles Replicate via process of binary fission Lack histones in their DNA

What effect (increase or decrease) does closing the diaphragm have on resolution?

decrease

3. Describe how the diaphragm affects contrast

decreases brightness and increases contrast

working distance

distance from the bottom of the objective lens to the specimen

yeast

easy to see at 400x magnification, larger than bacteria

cytoplasm

ell substance between the cell membrane and the nucleus, containing the cytosol, organelles, cytoskeleton, and various particles. Origin of cytoplasm Expand.

Organelles only found in Eukaryotic cells

endoplasmic reticulum, lysosomes, golgi apparatus, mitochandria, nucleus

parfocal

having corresponding focal points all in the same plane: have sets of objectives or eye pieces sumounted that they may be interchanged with out varying the focus of the instrument with which they are used.

Parfocal definition

having sets of objectives or eyepieces so mounted that they may be interchanged without varying the focus of the instrument (as a microscope) with which they are used.

rotating turret

holds the objective lenses

field of view

how much of the specimen or objective seen through the microscope

identifying bacteria under a microscope: gram reaction

if gram positive than purple if gram negative than red

Describe the characteristics used to identify eukaryotic cells when observed microscopically.

if they have a nucleus, or membrane enclosed orgaelles such as golgi aparatus, mitochandria, vacuoules, endoplasmic reticulum, cytoskeleton, choloroplast,

What effect (increase or decrease) does closing the diaphragm have on image contrast?

increase

resolution

is a measure of the clarity of an image; it is the minimum distance two points can be separated and still be distinguished points. For example what appears to the unaided eye as one star in the sky may be resolved as twin stars with a telescope which has a higher resolving ability.

Course focus adjustment

large, round knob on the side of the microscope used for focusing the specimen; it may move either the stage or the upper part of the microscope.

objective lens

magnifying lens attached to the miscroscope

cytoskeleton

provides shape to the cell through a "criss-cross" arrangement of protein-based filaments secured to the cell membrane; changes in filament tension lend to cell movement; certain cells move via the attachment of microtubules, cilia and flagella to the outer cytoskeleton; also plays a role in the separation of chromosomes during the process of mitosis

Exponential growth shows as a curved line on regular linear graph paper but will plot as a straight line on

semi log paper

lysosomes

single membrane bound organelle produced by the GOLGI APPARATUS that contain strong hydraulic enzymes which break down biological molecules -contains up to 40 different enzymes -breaks down worn out cell parts that are no longer functioning properly -involved in breaking down materials brought into a cell VIA phagocytosis

bacterial morphology size

size of the colony can be described in two ways. The more accurate technique would be to measure the diameter of the colony with a ruler and report the size in millimeters. The second technique would simply be to describe the colonies as punctiform (tiny pinpoints), small, medium, or la

Fine focus adjustment

small, round knob on the side of the microscope used to fine-tune the focus of your specimen after using the coarse adjustment knob.

brightness

the amount of light passing through it is not necessary to adjust the amount of light after changing objective lenses because higher magnification lenses require more light

contrast

the difference in brightness between light and dark areas of an image

ocular lens

the lens that you look through; magnifys the image produced by the objective

DNA

Deoxyribonucleic acid; a nucleic acid that consists of two long chains of nucleotides twisted together into a double helix and joined by hydrogen bonds between complementary bases adenine and thymine or cytosine and guanine; it carries the cell's genetic information and hereditary characteristics via its nucleotides

Step seven for handling a microscope

Do not allow the spring loaded clip to slip over or under the slide, make sure the clip is securely affixed to edge of slide

Step fourteen for handling the microscope

Do not change focus, rotate 10X objective in light path.

Step sixteen for handling the microscope

Do not turn the fine adjustment knob more than 2 revolutions in either direction when observing with 40X objective.

flagella

Flagella are long, whip-like protrusion that aids in cellular locomotion.

capsule

Found in some bacterial cells, this additional outer covering protects the cell when it is engulfed by other organisms, assists in retaining moisture, and helps the cell adhere to surfaces and nutrients

differences between compound microscope and stereoscoic disecting microscope; compound

Compound: two lenses look at small objects 1000x magnification Ocular (eyepiece) lens Objective turret or Revolver (to hold multiple objective lenses) Objective Focus wheel to move the stage Frame Light source, a light or mirror Diaphragm or condenser lens Stage (to hold the sample) Base Phototube (for attaching a camera)

What structure of bacteria determines the gram reaction?

Gram-positive bacteria have a thick mesh-like cell wall made of peptidoglycan (50-90% of cell envelope), and as a result are stained purple by crystal violet, whereas gram-negative bacteria have a thinner layer (10% of cell envelope), so do not retain the purple stain and are counter-stained pink by the Safranin.

pili

Hair-like structures on the surface of the cell that attach to other bacterial cells. Shorter pili called fimbriae help bacteria attach to surfaces.

Step seventeen for handling the microscope

If image does not focus, with 40X objective and fine focus knob, return to 10X and refocus with coarse focus knob, repeat as described above. o Use only coarse focus for 4X and 10X objectives. Use fine focus for 40X objective lens.

Step five for handling a microscope

If necessary clean the slide with moistened lens paper to remove dust and other debris.

Describe how to safely place and remove a slide from the mechanical stage.

If necessary clean the slide with moistened lens paper to remove dust and other debris. • Place slide securely within the spring loaded clip on the mechanical stage. • Do not allow the spring loaded clip to slip over or under the slide, make sure the clip is securely affixed to edge of slide. • Observing the slide directly with your eye, center the specimen over the condenser lens

Step fifteen for handling the microscope

If required, do not change focus, and rotate 40X objective in light path o Microscopes are both parfocal and parcentral

oil immersion

Image result for oil immersion objective definition In light microscopy, oil immersion is a technique used to increase the resolving power of a microscope. This is achieved by immersing both the objective lens and the specimen in a transparent oil of high refractive index, thereby increasing the numerical aperture of the objective lens.

Organelles

In cell biology, an organelle is one of several structures with specialized functions, suspended in the cytoplasm of a eukaryotic cell.

it is a basic tenet of biology that...

It is a basic tenet of biology that all successful species have the ability to grow their population size exponentially as long as the resources required for growth are not limiting that growth.

bacterical morphology shape

Shape refers to the overall appearance of the colonies. The descriptors here are punctiform, circular, irregular, filamentous (has individual thin projections), or rhizoid (has thin, branching projections).

what is wave lengths relationship with resolution

Shorter wavelengths are capable of resolving details to a greater degree than are the longer wavelengths.

Describe the characteristics used to identify bacteria when observed microscopically. morphology/ cell shape

Size Shape Color (also known as pigmentation) Texture Height (a.k.a. elevation) Edge (a.k.a. margin) Size Whole colony shape (circular, irregular, rhizoid) Colony edge (smooth, filamentous, undulating) Elevation (flat, raised, convex, crateriform) Surface (wrinkled, rough, waxy, glistening) Opacity (transparent, translucent, opaque) Pigmentation Color (red, yellow, white) Water solubility (water soluble - color tints surrounding media)

Step thirteen for handling the microscope

Slowly open the iris diaphgram until the entire field of view is evenly illuminated. o This is the correct position for both the condenser and iris diaphragm.

Functions of the nucleus

the major functions of nucleus are to maintain the integrity of DNA and to control cellular activities such as metabolism, growth, and reproduction by regulating gene expression. It has three main components: the nucleolus, the chromatin and the nuclear envelope. The nuclear envelope has nuclear pores to control the movement of molecules between the nucleoplasm and the cytoplasm.

parcentral

the property of a microscope which keeps the specimen relatively centered in the field of view from on objective

magnification

the ratio of an objects image size to its real size

how can a steromicroscope be used to complete a study

the steromiscroscope is good for looking at large objects or if you want to see somthing thats 3d

ocular lens; high power

40x magnification - highest magnification of microscope

Step one for handling a microscope

Place the stage to the lowest position using coarse focus knob.

By plotting bacterial population growth data on semi-log paper it is possible to visually determine

By plotting bacterial population growth data on semi-log paper it is possible to visually determine

nucleoid region

Area of the cytoplasm that contains the single bacterial DNA molecule.

Step two for handling a microscope

Rotate the 4X objective so it is in the light path over the condenser lens using the revolving nosepiece ring, not the objective lens itself.

endoplasmic reticulum

-an extensive network of channels that stretches from the nucleus to the plasma membrane -function is to transport materials through the cell -ROUGH ER - distinguished by the ribosomes attached to it -SMOOTH ER- many functions such as production of membrane phospholipids, production of sex hormones, breaks down harmful substances, stores calcium ions, transports liquid based compounds, and aids liver cells in releasing glucose into the blood when needed

golgi apparatus

-composed of many flattened sacs called cisternae, which are stacked on top of each other -normally located between the ER and plasma membrane -it collects, packages, modifies, and distributes materials throughout the cell -found in high numbers in cells that produce and secrete substances

mitochandria

-very large, double membrane bound rod-shaped organelles found scattered in the cytoplasm and contain their own DNA -other membrane is smooth -inner membrane is highly folded into cristane which increases the surgace area for cellular respiration, which is the main function of the mitochondria -found in high numbers in cells that have high energy needs (EX: muscle cells) -known as the "power house" of the cell

ocular lens; low power

10X magnification

ribosomes

A sphere-shaped structure within the cytoplasm of a cell that is composed of RNA and protein and is the site of protein synthesis. Ribosomes are free in the cytoplasm and often attached to the membrane of the endoplasmic reticulum. Ribosomes exist in both eukaryotic and prokaryotic cells.

Step ten for handling a microscope

Adjust interpupilary distance, and adjust right and left ocular lens focus.

Step four for handling a microscope

Adjust light intensity with iris diaphragm, set the rheostat to the brightest position that is comfortable

Step nine for handling a microscope

Bring the specimen into focus by looking through ocular lenses and at the same time slowly focusing upward with the course focusing knob

Step six for handling a microscope

Place slide securely within the spring loaded clip on the mechanical stage

Step twelve for handling the microscope

Looking through the ocular lenses, slowly lower the condenser until the graininess just disappears

Diaphragm of microscope

Many microscopes have a rotating disk under the stage. This diaphragm has different sized holes and is used to vary the intensity and size of the cone of light that is projected upward into the slide. There is no set rule regarding which setting to use for a particular power. Rather, the setting is a function of the transparency of the specimen, the degree of contrast you desire and the particular objective lens in use.

Describe how to properly adjust the interpupilary distance of the ocular lens and properly focus the ocular lens in relation to the objective lens.

Most ocular lenses can be moved back and forth to adjust to the interpupillary distance of the student. When first using the microscope, adjust the ocular lenses back and forth until a circular field is viewed with both eyes open. Additionally, many microscopes allow the ocular lenses to be adjusted up and down (mechanical tube length adjustment) and there is a scale alongside the tube.

What are some subcellular structures unique to eukaryotic cells?

Nucleus and organelles

What is the numerical aperture and what does it have to do with resolution

Numerical aperture determines the resolving power of an objective, but the total resolution of the entire microscope optical train is also dependent upon the numerical aperture of the substage condenser.

Step eight for handling a microscope

Observing the slide directly with your eye, center the specimen over the condenser lens

Describe how to properly use oil when using the oil immersion lens,

Placing a drop of oil with the same refractive index as glass between the cover slip and objective lens eliminates two refractive surfaces, so that magnifications of 1000x or greater can be achieved while still preserving good resolution. To use an oil immersion lens, first focus on the area of specimen to be observed with the high dry (400x) lens. Place a drop of immersion oil on the cover slip over that area, and very carefully swing the oil immersion lens into place. Focus carefully, preferably by observing the lens itself while bringing it as close to the cover slip as possible, then focusing by moving the lens away from the specimen. When in focus the lens nearly touches the cover slip. The focal plane is so narrow that it is very easy to focus right past it. If you are focusing toward the specimen, you can drive the lens right into it.

plasmids

Plasmids are gene carrying, circular DNA structures that are not involved in reproduction.

Step eleven for handling a microscope

Raise the condenser lens to its highest position, and fully close the diaphragm.

mechanical stage

The flat platform where you place your slides. Stage clips hold the slides in place. If your microscope has a mechanical stage, you will be able to move the slide around by turning two knobs. One moves it left and right, the other moves it up and down.

Nucleus

The large, membrane-bounded organelle that contains the genetic material, in the form of multiple linear DNA molecules organized into structures called chromosomes.

condenser lens of miscroscope

The purpose of the condenser lens is to focus the light onto the specimen. Condenser lenses are most useful at the highest powers (400X and above). Microscopes with in stage condenser lenses render a sharper image than those with no lens (at 400X). If your microscope has a maximum power of 400X, you will get the maximum benefit by using a condenser lenses rated at 0.65 NA or greater. 0.65 NA condenser lenses may be mounted in the stage and work quite well. A big advantage to a stage mounted lens is that there is one less focusing item to deal with. If you go to 1000X then you should have a focusable condenser lens with an N.A. of 1.25 or greater. Most 1000X microscopes use 1.25 Abbe condenser lens systems. The Abbe condenser lens can be moved up and down. It is set very close to the slide at 1000X and moved further away at the lower powers.

ocular lens; scanning

The scanning power objective lens magnifies the image by a factor of 4, for a total of 40X. (Total magnification is the product of the magnifications of each lens being used, that is, the ocular lens at 10X and, in this case, the scanning lens at 4X.)

Bacterial cells can often divide within minutes of being formed from the previous round of division.

This is their generation time, which is famously short in bacteria. If food, water, required gases and space are unlimited a single E. coli cell could found a population covering the entire planet to a great depth in a surprisingly short time.

Describe how to determine total magnification of an object viewed.

Total magnification of an object observed through the eyepieces (ocular lens) is calculated by multiplying the ocular lens magnification times the magnification of the objective lens being used (either: 4X, 10X, 20X, 40X, 100X, etc.). "X" is placed after obtaining the total magnification number. Example: Ocular lens magnification = 10X Objective lens magnification being used = 4X Total magnification? Calculation: (10X)(4X) = 40X

Step three for handling a microscope

Turn on the light

Describe how oil immersion increases resolution

When light passes from a material of one refractive index to material of another, as from glass to air or from air to glass, it bends. Light of different wavelengths bends at different angles, so that as objects are magnified the images become less and less distinct. With "dry" objective lenses this loss of resolution prevents using magnifications of above 400x or so. In fact, as you will see later, even at 400x the images of very small objects are badly distorted.

Nucleus

where DNA is housed -has a double membrane that allows the DNA to remain separate from the rest of the cell and can carry out its functions without interference from the other parts of the cell -nuclear membrane contains pores that allows for communication with the rest of the cell -DNA is contained here in the form of chromosomes -normally located in the center of the cell -most cells have only 1 nucleus, but some have multiple nuclei, while others have none (EX: Red Blood Cells) -if a nucleus is not present, that cell cannot reproduce -most nuclei have a nucleolus, a dark area inside the nucleus where ribosomes are made