Lab 4 - Microscopy

The field of view is the

Amount of the slide you are able to see through the eyepiece

Microscopes are often used to study

Bacteria, cells, and it uses

Stage adjustment knobs

Brings stage into center of view and focus -top brings forward and backward -bottom brings side to side

What is the most prominent organelle that you see in the Elodea images?

Chloroplasts

Which structure normally found in plant cells ( such as Elodea cells) is missing from the onion cells?

Chloroplasts -because it grows underground ( the onion bulb not photosynthetic) -the leaves are above ground and are green - has chorloplast so are is photosynthetic part of plant

What is the general shape of the cheek cell?

Circular and round shape ( fried egg)

iris diaphragm

Controls amount of light going to specimen

Glass that covers top of the pond water

Cover slide

The goal of microscopy is to

Create a magnified image of objects too small to be seen with the eye alone

Some chloroplasts appear to be moving ( crimculating). WHat is this activity called AND why are they moving?

Cytoplasmic Streaming -cytoplasm stream where organelles, this case chloroplasts, are transported via the cytoplasm stream to distribute nutrients and therefore food

As magnification of the image decreases the light intensity

Decreases and will have to be adjusted

How is the general shape of the cheek cell different from the plant cells you observed?

Different because plant cells are rectangular, while cheek cells ( animal) are round

3 factors that determine the quality of a microscopic image:

Magnification, resolution, and contrast

Objective lenses

Magnify the image from light at higher magnification up to 100x

Glass piece that forms base in wet mount is

Microscope slide

The sliding bar on the condenser lens is the aperture. -as you move the aperture to decrease the light to the slide, the contrast increases

Move the aperture to increase the light to the slide, the contrast decreases.

To calculate total magnification,

Multiply the magnification of ocular lens ( 10x) with the magnification of the objective lens

In what ways are plant and animal cells similar in structure?

Nucleus, arranged in tissues, mutipule organelles, and has endomemebrane system

Brightfield microscopes use a combination

Of glass lenses and light to view the specimen

The condenser lens focuses

The light on the slide

When focusing on a slide, start on the scanning or low power, objective lens

The lower the power objective, the greater the field of view.

Total magnification is

The overall enlargement of the image of a specimen

Light source

Use light to see the image

Oculars

eyepiece lenses of a microscope ( magnify the image at low magnification 10x)

In what ways are the cells and Elodea similar?

nucleus, cell walls, thin cells, rectangular like, and tightly arranged

what objective lens do you always start with then viewing a slide?

scanning objective, 4x

Cytocology

study of cells

Histology

study of tissues

how do the coarse and fine focus knobs work on a brightfield microscope?

the focus knob moves the stage up or down

most animal cells are colorless and appear transparent under the light microscope so it is helpful to stain them to impact color for viewing -true or false

true

To move the slide, you move the stage/ -the stage knob

-top moves the stage forward and back -bottom moves the stage side to side

Differences of cheek cells and the Euglena?

-Euglena has chloroplasts - photosynthetic -photoreceptor ( Euglena)

If you were given another unknown organism, how you would determine if the cells were prokaryotic or eukaryotic?

-Nucleus ( eukaryotic) or nucleotoid ( prokaryote) Prokaryotes do NOT have a nucleus that holds DNA. No endomembrane system -size: prokaryotes are very small. At 1000x magnification still cannot see the prokaryotes in detail. Also are single called

If you were given a slide of cells from an unknown organism, how you would determine if the cells were from a plant or an aminal?

-arrangement of cells in tissue ( tight - plant; loose-animal) -cell structures ( cell wall, chloroplasts , central vacuole - plants only) -cell shape/size ( rectangular -plants ; circular - animal)

Advantages of wet mount

-fast preparation -requires no special equipment other than a transfer puppeteer, slide, and cover slip -organisms may be viewed in their living state -movement of motile microorganisms can be observed

Similarities between plant cells ( onion and elodea) and the euglena?

-has chloroplast, photosynthetic -eukaryotic

Differences between the plant cell ( onion and Elodea) and the euglena?

-not same structure -not ridged like plants -able to move ( locomotive by flagella-unlike plants_ -does change shape ( unlike plant cells) -no cell wall ( unlike plant cells)

When adjusting focus always start with ____ ___ ____ then _____ _____ ____

-start with course focus knob, then fine focus

Only _____ lens are used with oil

100x

Total magnification = __________X__________

10x ( ocular) X 4x,10x, 40xor 100x, ( objective )

What is the total magnification of the observed objects in a microscope that is using the 40x objective lens?

400x ( 10x times 40x)

what is one objective view you do not use coarse focus knob as it would scratch glass

40x

The microscope you are using has 4 objective lenses to magnify the image:

4x, 10x, 40x, and 100x

Why are stain used when observed cells like onion?

Enhance contrast And details that we may not see as well without stain

Similarities of cheek cells and Euglena( protist)?

Eukaryotic In shape Capable of moving and surrounded by plasma membrane no Cell wall

Course focus

Finds focus

How does changing light intensity affect the contrast to an image in a microscope?

High light can blind the view where only you see is light. Dimming light allows you to see the contrast/increases contrast -increased light decreases contrast -decreased light increases contrast

Rotating nosepiece

Holds and rotates the objective lenses -changes magnification Ex/4x-100x

Mechanical stage

Holds and slightly moves the slide

When using the 100x objective lens, a drop of _____ is needed on the specimen slide.

Immersion oil

Resolution

Is the ability to distinguish fine detail

Magnification

Is the apparent increase in image size

Condenser

Lenses that collect light and directs it to specimen ( focuses it to specimen )

What is the stigma for the Euglena?

Photoreceptors which attracts/detects light to move by its flagella -is a eukaryotic , but not plant nor animal, but is a protist

What is the general shape of one Elodea cell?

Rectangular

Contrast

Refers to the ability to distinguish objects, such as cells, from the background

What is the difference between resolution and contrast?

Resolution is finding fine details while contrast is finding small details from the background

Course focus

Sharpens/enhances further focus (from course focus)

How do you bring a specimen into focus quickly?

Starting with larger field of view, ex/4x

Pathology

Study of disease

the Euglena were green in color because they contain

chloroplasts

what part of microscope is located below the stage and is used to focus the beam of light on the specimen ?

condenser

what is affected by the light source?

contrast