Cells and Structures
What are the two types of cells?
Prokaryotes and Eukaryotes
_____________ is how much larger an object appears compared to its real size
Magnification
Explain what the phrase "Technology begets discovery" means.
It means that improvements in technology can lead to new discoveries.
Look at the picture of the microscope. What is the name for the part labeled 8?
Ocular Lens
A microscope has a field of view (FOV) of 2.0 mm under the low-power lens (40x magnification). If the high-power lens provides 400x magnification, what is the FOV under high power?
.2 mm
Name the 4 cellular structures common to all cells.
Plasma membrane
Cytoplasm
DNA
Ribosomes
_____________ is the the smallest interval distinguishable by the microscope, which then corresponds to the degree of detail visible in an image created by the instrument.
Resolution
What do electron microscopes use to magnify the specimen?
electron beams focused by electromagnets
List the three steps involved with preparing a wet mount.
1. Place a small piece of your sample on a slide.
2. Using a pipette drop a few drops of water onto the specimen.
3. Place the edge of the cover slip over the sample at a 45 degree angle and carefully lower/drop the cover slip into place.
Look at the picture. Here is a drawing of a 150 μm cell viewed under the microscope at high power. Calculate the magnification of the drawing.
360x = 400x (sig figs)
What is the function of the plasma membrane?
Selective Barrier, Protection, Communication, Structural Support
What two things do compound light microscopes use to magnify an object?
light and lenses
A microscopy technique where a frozen biological sample is fractured along a plane, usually through the lipid bilayer of membranes. The fractured surfaces are then coated with a thin layer of metal, and the replica is viewed under an electron microscope.
Freeze-Fracture Microscopy
A __________ is a chemical that binds to structures within a sample and are used to make the structures show more clearly when being viewed.
Stain
Look at the picture. Here is an amoeba drawn at 300X life size. What is the actual size of the amoeba?
.57 = .6 (sig figs)
What is the function of cytoplasm?
Medium for Chemical Reactions
Suspension of Organelles
Nutrient Storage
Transport
What are the benefits and limitations of compound light microscopes?
Benefits:
Ease of use
Less expensive to buy
Can observe dead or living cells in color
Cell movement can be studied
Quick specimen preparation (minutes to hours)
No need for high voltage electricity
Limitations:
Maximum magnification of about 1500X
Low resolving power (0.25µm to 0.3µm)
A microscopy technique where samples are rapidly frozen (without forming ice crystals), and then imaged using electron microscopy at cryogenic temperatures.
Cryogenic Electron Microscopy
The __________ is the diameter of the area visible through the microscope.
Field of View (FOV)
When drawing a cell where should you place the drawing on the paper?
Center of the page
What is the function of ribosomes?
Protein Synthesis
What are the benefits and limitations of compound light microscopes?
Benefits:
Magnification of 100,000X to 300,000X
High resolving power (0.001µm)
Limitations:
Expensive to use
Requires cells to be killed and chemically
No movement can be seen
Without stain or dye, no color* can be seen
High voltage electric current is required
Specimen preparation usually takes few days
What type of microscopy uses antibodies tagged with fluorescent dyes to bind to specific proteins or molecules in a sample.
Immunofluorescence Microscopy
What method do we use to determine the FOV of a microscope on low power?
Place a transparent metric ruler under the low power objective lens of a microscope
What information should be included in the title of a cell drawing?
State what has been drawn and what lens power it was drawn under