Study Guide for Lab Exam II

A set of 20 question-and-answer flashcards based on the lab exam study guide covering microscopy, restriction enzyme mapping, and cell culture techniques.

What are the basic parts of the microscope?

A microscope consists of the eyepiece (ocular lens), objectives (typically 4x, 10x, 40x, and 100x), stage, stage clips, light source, and adjustment knobs.

How do you calculate total magnification?

Total magnification is calculated by multiplying the objective lens magnification by 10 (eyepiece magnification).

What are the steps to prepare a wet mount?

Start with a clean microscope slide, add a drop of water, place the specimen into the drop, and cover with a coverslip.

How did you determine cell density of the tetrahymena sample?

By placing a drop of culture on a clean slide, observing under phase contrast, and multiplying the average count per square by 10,000.

What matrix is used to separate DNA using gel electrophoresis?

Agarose gel is used to separate DNA fragments according to size.

What electrode do DNA fragments migrate towards during gel electrophoresis?

DNA migrates towards the positive electrode due to its negatively charged sugar-phosphate backbone.

How do you visualize DNA molecules after gel electrophoresis?

DNA fragments are visualized by staining the gel with a fluorescent dye like ethidium bromide and exposing it to UV light.

What are restriction enzymes and their scientific relevance?

Restriction enzymes are proteins produced by bacteria that can cut DNA at specific sequences, useful for genetic engineering and molecular cloning.

Where do scientists obtain restriction enzymes?

Scientists obtain restriction enzymes from bacteria.

What is the effect of restricting cleavage on a plasmid versus a linear piece of DNA?

Cleaving a plasmid will result in two linear fragments, while cleaving a linear piece of DNA will create two smaller linear fragments.

How can you determine the number of cleavage sites for a restriction enzyme on a DNA molecule?

You can determine the number of cleavage sites based on the number of recognition sequences in the DNA.

What are optimum conditions for cell growth?

Optimal cell growth conditions include a temperature range of 18 to 57°C, controlled CO2 levels, and proper humidity.

Describe the necessity of sterile technique in cell culture.

Sterile technique prevents contamination by microorganisms, ensuring reliable growth of the cells.

How do you practice sterile technique?

By washing hands, wearing gloves, and setting up a sterile environment.

What cell line was used in the cell culture lab?

mammalian cell

How did you determine the density of live versus dead cultured cells?

By using a hemocytometer and trypan blue dye indicator, which stains dead cells.

What did your research project entail?

My project focused on cyclin E

What database was used to find a gene sequence?

The specific database should be identified based on the research conducted.

What is the purpose of the BLAST computer program?

to compare biological sequences, such as DNA or protein sequences, against existing databases.

How did you evaluate evolutionary relationships between gene sequences?

By comparing DNA or protein sequences and constructing a phylogenetic tree.