BIOS 314 Lab Practical Exam 1 Review

Comprehensive question-and-answer study flashcards for BIOS 314 Lab Practical Exam 1 (Fall 2026), covering laboratory safety (30%) and laboratory content (70%) from Weeks 1 through 7.

What specific personal protective equipment (PPE) requirements are covered in the laboratory safety rules?

Appropriate laboratory clothing, closed-toe footwear, and eye protection.

When must laboratory workspaces be disinfected during lab sessions?

Workspaces must be disinfected both before and after all laboratory activities.

What specific fire response procedure is highlighted under laboratory safety topics?

Appropriate procedures for extinguishing ethanol fires.

Which specific contaminated items are identified for proper handling and disposal?

Pipette tips, culture tubes, Petri dishes, and other laboratory waste.

What is the distinction between resident and transient skin microbiota?

Resident skin microbiota are normally present and permanently colonize the skin, whereas transient skin microbiota are temporarily picked up from environmental surfaces and can be removed by proper handwashing.

What aspects of Bunsen burners must be understood for aseptic laboratory technique?

Identifying Bunsen burner components, adjusting for proper flame characteristics (such as the inner blue cone), using the flame to maintain sterility, and practicing fire prevention.

What three physical forms of culture media are studied in Week 3, along with their applications?

Liquid (broth) media, semi-solid media, and solid media (agar).

What are the primary transfer and plating procedures covered in Week 3?

Spread plating and plate-to-liquid transfers.

What is the primary purpose and procedural goal of quadrant streaking?

To systematically dilute a microbial culture across four quadrants on an agar plate to obtain isolated individual colonies.

How do isolated colonies differ from confluent growth, and why are isolated colonies important?

An isolated colony arises from a single cell or group of identical cells and represents a pure culture, whereas confluent growth is continuous and overlapping, preventing isolation of individual species or single clones.

How is total magnification calculated on a compound light microscope?

Total magnification is calculated as: $\text{Total Magnification} = \text{Ocular Lens Magnification} \times \text{Objective Lens Magnification}$

What is the difference between magnification and resolution in microscopy?

Magnification refers to the apparent enlargement of an object, whereas resolution is the minimum distance between two points at which they can still be distinguished as separate entities.

What are the three essential steps required in preparing a bacterial slide for staining?

Smear preparation, air drying, and heat fixation.

What four general categories of bacterial staining techniques are distinguished in Week 5?

Simple staining, positive staining, negative staining, and differential staining.

How do Gram-positive and Gram-negative cell walls differ structurally?

Gram-positive cell walls contain a thick peptidoglycan layer and teichoic acids, whereas Gram-negative cell walls contain a thin peptidoglycan layer surrounded by an outer membrane containing lipopolysaccharides (LPS).

What are the four reagents used in the Gram-staining procedure in sequential order?

1. Primary stain: Crystal Violet; 2. Mordant: Gram's Iodine; 3. Decolorizer: Ethanol or acetone-alcohol; 4. Counterstain: Safranin.

How is bacterial concentration calculated in viable cell counting following serial dilutions?

By counting colonies on a countable plate and dividing by the total dilution factor multiplied by the volume plated, expressed as: $\text{Concentration} = \frac{\text{Number of Colonies (CFU)}}{\text{Volume Plated (mL)} \times \text{Dilution Factor}}\,\text{CFU/mL}$

What three bacterial culture storage methods are compared in Week 6?

Agar slants, freezing, and lyophilization (freeze-drying).

Which specific biochemical tests are covered in Week 6 (Biochemical Testing I)?

Carbohydrate fermentation tests, MR/VP (Methyl Red / Voges-Proskauer) tests, citrate utilization test, SIM (Sulfide Indole Motility) test, nitrate reduction test, and urease test.

What key biochemical elements must be identified for each test in Biochemical Testing I?

Relevant substrates, enzymes, metabolic pathways, and chemical or pH indicators.

Which specific biochemical tests are evaluated in Week 7 (Biochemical Testing II)?

DNase test, casein hydrolysis test, catalase test, oxidase test, and indole spot test.

How are individual biochemical test results applied collectively in Week 7?

The collective pattern of positive and negative biochemical test results is used to characterize bacterial metabolism and differentiate unknown bacterial species.