Bio 211 Final Exam Study Guide

What is aseptic technique?

Methods used to prevent contamination by microbes

Example of aseptic technique #1

Flaming a loop before/after use

Example of aseptic technique #2

Wearing gloves and washing hands

Why is aseptic technique important?

Prevents infection and keeps experiments accurate

What is BSL-1?

Least dangerous microbes (basic PPE)

What is BSL-2?

Moderate risk microbes (gloves, goggles)

What is BSL-3?

Serious airborne diseases (respirators, airflow control)

What is BSL-4?

Deadly diseases (full hazmat suit)

Largest microbes?

Protozoa

Smallest microbes?

Viruses

Order (big → small)

Protozoa → algae → fungi → bacteria → viruses

How do bacteria look under microscope?

Tiny dots or rods

How do protozoa look?

Bigger and moving

How do fungi look?

Fuzzy, thread-like

How do algae look?

Green (photosynthetic)

Example of bacterial disease

Strep throat

Example of fungal disease

Athlete’s foot

Example of protozoan disease

Malaria

How is malaria spread?

Mosquito bites

What is the microbiome?

Good bacteria living in your body

One function of microbiome

Helps digestion

What disrupts microbiome?

Antibiotics

Purpose of streak plate

To isolate bacteria colonies

First step in streak plate

Sterilize loop

Common mistake

Not flaming loop

Gram positive color

Purple

Gram negative color

Pink

First step of Gram stain

Crystal violet

Why heat fix?

To stick bacteria to slide

What does MAC agar select for?

Gram-negative bacteria

What does MSA test?

Salt tolerance

Blood agar shows?

Hemolysis (blood breakdown)

What is pH?

Measure of acidity

What do pH indicators do?

Change color to show pH

Psychrophiles live in?

Cold environments

Mesophiles live in?

Moderate temps (body temp)

Thermophiles live in?

Hot environments

Isotonic solution effect

No change

Hypotonic solution effect

Cell swells

Hypertonic solution effect

Cell shrinks

How does salt preserve food?

Pulls water out of bacteria

What is fermentation?

Energy production without oxygen

Products of fermentation

Alcohol, acid, gas

What does plate count measure?

Number of living bacteria

What is Kirby-Bauer test?

Measures antibiotic effectiveness

Large zone means?

Antibiotic works well

Aerobic bacteria need?

Oxygen

Anaerobic bacteria need?

No oxygen

Facultative bacteria?

Can live with or without oxygen

How do bacteria gain resistance?

Mutation or gene transfer

Cause of resistance

Overusing antibiotics

What is fecal transplant?

Transfer of healthy gut bacteria

3 transmission methods

Contact, air, objects

Fomite

Contaminated object

Epidemic

Large outbreak

Endemic

Always present

Mortality

Death rate

Incidence

New cases

What do B cells do?

Make antibodies

What do T cells do?

Kill infected cells

Memory cells do what?

Remember infections

How do vaccines work?

Train immune system safely

3 major healthcare threats

Hospital infections, resistance, emerging diseases

Good antibiotic practice

Only use when needed and finish dose

Metric conversion (mm to µm)

1 mm = 1000 µm

Metric conversion (µm to nm)

1 µm = 1000 nm

Size comparison bacteria vs virus

Bacteria are larger than viruses

Size comparison human cell vs bacteria

Human cells are much larger than bacteria

Difference bacteria vs fungi

Bacteria are prokaryotic (no nucleus)

Difference fungi vs algae

Fungi do not photosynthesize

Difference protozoa vs bacteria

Protozoa are larger eukaryotes

What does Kligler’s iron agar test

Sugar fermentation and hydrogen sulfide production

Kligler’s iron agar color result

Yellow = fermentation

What does urea broth test

Urease enzyme activity

Urea broth positive result

Turns pink

What does SIM media test

Sulfur reduction

SIM indole positive result

Red layer after reagent

What does tryptone broth test

Indole production

Tryptone positive result

Red after Kovac’s reagent

What does PR lactose broth test

Lactose fermentation

PR lactose positive result

Yellow color (acid production)

What is a dichotomous key

A step-by-step tool to identify organisms using yes/no questions

How do bacteria change pH in media

They produce acids or bases during metabolism

Why pH indicators are useful

They show metabolic activity through color change

What is CFU/mL

Colony forming units per milliliter

How to calculate CFU/mL

Colonies × dilution factor ÷ volume plated

What is MIC

Minimum inhibitory concentration of an antibiotic

What does MIC measure

Lowest antibiotic amount that stops growth

Difference MIC vs Kirby-Bauer

MIC gives exact concentration

How to determine oxygen requirement in lab

Use thioglycollate broth and observe growth location

Where obligate aerobes grow

Top of tube

Where obligate anaerobes grow

Bottom of tube

How antibiotics work (cell wall)

They break or stop cell wall formation

How antibiotics work (protein synthesis)

They block ribosomes

How antibiotics work (DNA)

They stop DNA replication

Example of social inequity affecting health

Lack of healthcare access increases disease risk

Scientist contribution (Pasteur)

Disproved spontaneous generation

Scientist contribution (Koch)

Linked microbes to specific diseases

Scientist contribution (Fleming)

Discovered penicillin

What affects herd immunity

Vaccination rate and how contagious disease is (R0)