Le Review Topic 9 Laboratory Skills

When preparing a wet mount slide of onion cells, a student put a drop of Lugol's iodine on the slide. This iodine was added to:

• prevent air bubbles
• make cell structures more visible
• increase the magnification
• increase the rate of photosynthesis in cells

A student views cheek cells under low power. Before switching to high power, the student should:

• adjust the ocular lens
• center the image being viewed
• adjust the course adjustment to move the stage away from the slide
• remove the slide from the stage

Paper chromatography is a laboratory technique that is used to 

• separate different molecules from one another
• stain cell organelles
• indicate the pH of a substance
• compare relative cell sizes

 A clear plastic ruler is placed across the middle of the field of view of a compound light microscope. A row of cells can be seen under low-power magnification (100×).
What is the average length of a single cell in micrometers (μm)?

•  10 μm
• 100 μm
• 200 μm
• 2000 μm

A student observes a red onion cell with a compound light microscope using low, then high power. The two views are represented in the picture.
The best explanation for the changes observed by the student is that, when switching from low to high power, the

• diameter of the field of view decreases
•  slide was accidentally moved
• diameter of the field of view increases
•  image is inverted and reversed

A student observes a red onion cell with a compound light microscope using low, then high power. The two views are represented in the picture.
Which diagram represents where the cell should be located in the low-power field of view to be sure the entire cell will be visible after switching to high power?

• 1
• 2
• 3
• 4

Bromthymol blue turns yellow in the presence of carbon dioxide. This characteristic makes it possible for bromthymol blue to function as:

• a measure of volume
• an energy source
• a catalyst
• an indicator

What is the volume of water represented in the graduated cylinder shown?

• 10.3 mL
• 13.0 mL
• 14.0 mL
• 15.0 mL

After switching from the high power to the low power objective lens of a compound microscope, the area of the low power field will appear: 

• Larger and brighter
• Smaller and brighter
• Larger and darker
• Smaller and darker

The diagram represents a technique used in some molecular biology laboratories
This technique is a type of

• chromatography
• gel electrophoresis
• direct harvesting
•  genetic engineering

Tags

NGSS.HS-LS3-2