MICR 3050 Exam 1 : "Microbial World"

What is the cell size range for viruses?

0.01µm - 2.3µm

What is the cell size range for bacteria and archaea?

0.2µm - 10,000µm

What is the cell size range for eukaryotes?

0.8µm - millions of µm

List and describe Koch's postulates both theoretically and experimentally.

1. Suspected pathogen must be present in all cases of the disease and absent from healthy animals. (would not see pathogen in the blood stain of a healthy animal) 2. Suspected pathogen must be grown in pure culture. (streak agar plate with sample from either a diseased or healthy animal) 3. Cells from a pure culture of the suspected pathogen must cause disease in a healthy animal. (Inoculate healthy animal with cells of suspected pathogen) 4. Suspected pathogen must be reisolated and shown to be the same as the original. (pure culture matches suspected pathogen)

Eukarya appeared around __________ years ago.

2 billion

Bacteria & Archaea appeared approximately _______________ years ago.

4 billion

____ of Earth's history has been dominated by microbial lifeforms.

80%

What's the definition for a microbial species?

A collection of strains that share many stable properties (mainly DNA and house genes) and differ significantly from other groups of strains

What's the definition for a microbial strain?

A strain is a subset of a microbial species and consists of the descendants of a single, pure microbial culture.

The Universal Phylogenetic Tree proposes what?

A three domain system, based on comparison of the DNA encoding small subunit ribosomal RNA. Domains include: Archaea (Prokaryotes) Bacteria (Prokaryotes) Eukarya

Who is credited with discovering penicillin?

Alexander Flemming

Who is known for being the first to observe and accurately describe bacteria (but thought they were tiny animals)?

Antony van Leeuwenhoek

How is arrangement of cells determined?

By a plane of division and degree of separation after division

Who is attributed to naming microbes using binomial nomenclature?

Carl Linnaeus

What cell shapes are the most common?

Cocci (spheres) and bacilli (rods)

What are the different arrangement names for cocci?

Cocci - 1 sphere Diplococci - pair Streptococci - chains Tetrads - 4 cocci in a square Sarcinae - cubic configuration of cocci Staphylococci - grape-like clusters

______________ appeared around 2.3 billion years ago and is believed to be the first organisms to do oxygenic photosynthesis.

Cyanobacteria

What do all living cells have?

DNA, ribosomes, cytoplasm, and a cytoplasmic membrane

Who is attributed to using a vaccination procedure involving cattle to protect individuals from smallpox?

Edward Jenner

(T/F) Archaea is more closely related to domain Bacteria than Eukarya

False. Bacteria broke away first in phylogenetic history. Archaea and Eukarya are more closely related

Who is credited with discovering bacterial endospores and classifying bacteria based on shape?

Ferdinand Cohn

Who is known for discrediting spontaneous generation for large animals?

Francesco Redi

What are some cellular entities studied by microbiologists?

Fungi Protists Bacteria Archaea

Who is credited with postulating the "transforming principle" and finding DNA is the genetic code NOT proteins?

Griffith

Bacteria and archaea are (diploid/haploid)

Haploid

Who found that hand-washing prevented child bed fever?

Ignaz Semmelweis

Who developed a system of surgery designed to prevent microbes from entering wounds?

Joseph Lister

What is the name of the first microbe that is believed to have given rise to all other cells?

LUCA (last universal common ancestor)

Who is known for discrediting spontaneous generation as a whole?

Louis Pasteur

Who is credited with pioneering the use of enrichment cultures and selective media, as well as describing the first virus?

Martinus Beijerinck

What is the key distinction of microorganisms from other organisms not seen with the naked eye?

Microbes can not have highly differentiated tissues

Filamentous arrangement is characterized by what?

Mycelium, a network of long multicellular filaments

What are some of the ways you grow bacteria in pure cultures? (Koch's Methods and Materials)

Nutrient broth Nutrient agar Petri dish Streak plating technique to isolate bacterial colonies

What are microorganisms?

Organisms and acellular entities too small to be clearly seen by the unaided eye (<1mm in diameter), usually unicellular.

Louis Pasteur is also accredited with what other discoveries and developments?

Pasteurization Aseptic technique Discovering attenuation Discovering fermentation in bacteria

What's the difference between prokaryotic and eukaryotic cells?

Prokaryotic cells usually lack a true membrane bound nucleus whereas eukaryotic cells do, and also have membrane bound organelles. Eukaryotes are also more complex morphologically and larger usually.

What are the two main groups of microorganisms under Domain Eukarya

Protists (algae, protozoa, slime molds, water molds) Fungi (yeast, mold)

Who is known for describing the fruiting structure of molds during discovery of microorganisms?

Robert Hooke

Who is accredited with discovering and establishing the relationship between microorganisms and a particular disease?

Robert Koch

Who is credited with discovering numerous interesting metabolic processes such as anaerobic nitrogen fixation?

Sergei Winogradsky

How did microbes evolve?

Steps: 1. Mutation of genetic material 2. New genotypes form 3. Advantageous genotypes arise 4. Natural selection favors these genotypes

What properties do all cells have in common?

Structure Metabolism (analbolism - synthesizing macromolecules, catabolism - produce energy and building blocks) Growth (in number) Evolution

What's the benefit of a cell being smaller?

The smaller the cell, the large the SA:Volume ratio, meaning things are transported across the membrane faster as well as faster growth and adaptation.

(T/F) Animals, vascular plants and mammals have all existed for less than 1 billion years.

True. In fact, animals first appeared before vascular plants at around 0.6 billion years ago. Humans are most recent.

Most microorganisms are found where?

Underground

Coccobacilli are characterized as what shape?

Very short rods

What are each of the acellular entities made up of?

Virus - protein and nucleic acid Viroids - RNA Satellites - Nucleic acid and RNA Prions - protein

What are some acellular entities studied by microbiologists?

Viruses Viroids Satellites Prions

Vibrios are _______ shaped

comma

Spirochetes are _______ shaped

helical (flexible)

Spirilla are _______ shaped

helical (rigid)

Bacteria and archaea increase genetic diversity by _________________________ within the same generation.

horizontal gene transfer

pleomorphic bacteria are _______ shaped

variably