Biology Exam I Study Guide Chapter 1

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Questions and Answers

What are prokaryotes?

Simple cells without a nucleus.

Give an example of a bacterium and its characteristic.

E. coli - have a cell wall.

What is a eukaryote?

Complex cells with a nucleus.

What is a viroid?

Short pieces of RNA affecting plants. Signup and view all the answers

Define a prion.

Misfolded proteins causing brain diseases. Signup and view all the answers

How did ancient Egyptians use molds?

For making bread and beer, which involved yeast. Signup and view all the answers

Match the following microbiologists with their contributions:

Florence Nightingale = Helped show that germs spread disease. Louis Pasteur = Considered the father of microbiology. Ignaz Semmelweis = Tried to promote handwashing among doctors. Joseph Lister = Developed chemicals to clean surgical instruments. Edward Jenner = Created the smallpox vaccine. Robert Koch = Developed the process for identifying pathogens. Alexander Fleming = Discovered penicillin. Signup and view all the answers

What is Koch's first postulate?

Isolate infected host. Signup and view all the answers

Name one limitation of Koch's postulates.

Some microbes can't grow, like viruses needing a host cell. Signup and view all the answers

What is the difference between signs and symptoms?

Signs are observable by others; symptoms are felt by the patient. Signup and view all the answers

What are normal microbiota?

Good bacteria living on or in the body. Signup and view all the answers

What can normal microbiota do to prevent overgrowth of pathogens?

Compete for nutrients, produce antimicrobials, and maintain pH levels. Signup and view all the answers

How is the microbiome acquired?

From birth, environment, and diet. Signup and view all the answers

Define acute infection.

Short-term, quick onset, such as the flu. Signup and view all the answers

What is a chronic infection?

Long-lasting infection, such as tuberculosis. Signup and view all the answers

What is an opportunistic infection?

Infection that affects weakened immune systems, such as Candida. Signup and view all the answers

Study Notes

Differences Between Microorganisms

Prokaryotes: Simple cells lacking a nucleus.
- Bacteria: Example - E. coli, characterized by a cell wall.
- Archaea: Example - Methanogens, thrive in extreme environments with unique membranes.
Eukaryotes: Complex cells with a nucleus.
- Protists: Example - Paramecium, single-celled with organelles.
- Fungi: Example - Yeast, featuring a cell wall made of chitin.
Viruses: Consist of genetic material encased in a protein coat; not classified as living.
- Example: Influenza virus.
Viroids: Composed of short RNA strands affecting plants.
- Example: Potato spindle tuber viroid.
Prions: Abnormal proteins causing neurodegenerative diseases.
- Example: Creutzfeldt-Jakob disease.
Protozoa: Animal-like protists; be cautious about drinking water.

Ancient Use of Microbiology

Ancient Egyptians utilized molds in the brewing of beer and bread making, leveraging yeast.

Contributions to Microbiology

Florence Nightingale: Pioneered the understanding of how germs contribute to disease; documented soldiers' deaths.
Louis Pasteur: Renowned as the father of microbiology; disproved spontaneous generation.
Ignaz Semmelweis: Advocated for handwashing among doctors to reduce infections during childbirth; faced resistance.
Joseph Lister: Innovated disinfection techniques for surgical instruments.
Edward Jenner: Developed the first smallpox vaccine.
Robert Koch: Identified pathogens, establishing methods for isolating microorganisms, especially for cholera.
Alexander Fleming: Discovered penicillin, the first true antibiotic.

Koch’s Postulates

Postulate 1: Isolate the pathogen from an infected host.
Postulate 2: Grow the pathogen in pure culture.
Postulate 3: Introduce the cultured pathogen into a healthy host and observe results.
Postulate 4: Re-isolate the pathogen from the newly infected host.

Limitations of Koch's Postulates

Some microbes, like viruses, cannot be cultured outside a host.
Lack of suitable animal models for certain pathogens; for example, syphilis cannot infect many animal species.
Non-pathogenic strains can be present; many HIV carriers show no symptoms.
Asymptomatic carriers may harbor pathogens without showing signs of illness.
Chronic carriers may continuously infect others without exhibiting symptoms.

Signs vs. Symptoms

Signs: Observable indicators of disease (e.g., rash).
Symptoms: Subjective experiences reported by the patient (e.g., headache).

Normal Microbiota vs. Pathogens

Normal Microbiota: Beneficial microorganisms residing in the body (e.g., Lactobacillus).
Pathogens: Harmful microorganisms that lead to disease (e.g., Staphylococcus aureus).

Microbial Antagonism

Compete for nutrients to outcompete pathogenic bacteria.
Produce antimicrobial substances that inhibit or destroy pathogens.
Maintain pH levels by generating acids which deter pathogen growth.

Acquisition and Factors Influencing Microbiome

Acquired through mechanisms such as birth, environmental exposure, and dietary habits.
Factors influencing microbiome composition:
- Birth Method: Differences in microbiota of vaginal vs. cesarean deliveries.
- Diet: Dietary changes can significantly alter the microbiome's makeup.
- Antibiotics: Use can disrupt and diminish normal microbiota.

Types of Infections

Acute: Rapid onset and short duration (e.g., flu).
Chronic: Prolonged infection (e.g., tuberculosis).
Opportunistic: Infections arising in immunocompromised individuals (e.g., Candida).
Secondary: Subsequent infection following a primary one (e.g., bacterial pneumonia post-flu).
Localized: Confined to a specific body area (e.g., boil).
Focal: An infection that spreads from a local site to cause illness elsewhere.
Systemic: Widespread infection affecting various body parts.
Latent: Infections that are dormant and may reactivate (e.g., herpes simplex).

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Description

Prepare for your Biology Exam I with this comprehensive study guide focused on Chapter 1. Learn about the characteristics of prokaryotes, eukaryotes, viruses, viroids, and prions, along with specific examples for each. This guide covers essential differences and traits necessary for your success in the exam.