MICR 2420 Midterm

What microbes can degrade and/or utilize every molecule on earth?

bacteria and archaea

What is botulism used for?

medicine (is a very potent toxin; is a paralytic)

How do we identify new bacteria?

by sequence analysis of universal genes (i.e. with rRNA)

What is a process that is preserved between cells? Why?

translation of ribosomes; it is a complex process with lots of restraints on mutations (i.e. genes mutate very slowly)

What is good about rRNA?

these genes can be used to assess how related things are to each other (evolution; tree of life)

What is transduction by? And what are chromosomal insertions by?

bacteriophages; latent viruses/retroviruses

Why is bread non alcoholic?

the EtOH evaporates

What is yeast?

unicellular fungus

A sources of disease by the ancient Greeks and Romans?

unseen miasmas (bad air)

What is wrong with the statement: "Bacteria belong to the domain Prokarya."

this is not a domain; just needed a word to distinguish cell structures; no membrane bound organelles

Why does water not get vaporized in deep sea vents?

high P

Bacteria that can survive in high temperatures?

hyperthermophiles

What do bacteria do that the environment can't?

nitrogen fixing

Full word for lithotrophs?

chemolithoautotrophs

3 main greenhouse gases in order of potency and dominance?

Co2>CH4>NO2

What are methanes reserves?

a product of ancient archaea

3 important people for the birth of microbiology?

1. Louis Pasteur

2. Robert Koch

3. Antoine van Leeumenhoek

What did Antoine van Leeuwenhoek do?

created a powerful microscope to reveal "animal cules" (swimming in drop of water)

Important work by Louis Pasteur?

-pasteurization (doesn't sterilize, but removes micro from milk and apple juice)

-proved that microorganisms soil milk

-worked on disease and vaccines (like for rabies)

Important work by Robert Koch?

-solid media for isolation (agar)

-made a set of rules for causative agent of disease by cultures

What is bacterial fermentation?

a process that uses bacteria, mold, or yeast to convert sugars (carbohydrates) to alcohol, gases, and organic acids

Yeast fermentation yields....

CO2 and EtOH

Process for making bread with yeast?

Its cells metabolize the carbohydrates in flour (middle) and produce carbon dioxide, which causes the bread to rise (right).

Idea from Hippocrates?

(a) Hippocrates, the "father of Western medicine," believed that diseases had natural, not supernatural, causes.

Idea from Thucydides?

(b) The historian Thucydides observed that survivors of the Athenian plague were subsequently immune to the infection.

Idea from Marcus Terentius Varro?

(c) Marcus Terentius Varro proposed that disease could be caused by "certain minute creatures . . . which cannot be seen by the eye."

"Golden Age of Microbiology"?

-a host of new discoveries between 1857 and 1914

-Louis Pasteur and Robert Koch, were especially active in advancing our understanding of the unseen world of microbes

What are microscopes used for?

to produce magnified images of microorganisms, human cells and tissues, and many other types of specimens too small to be observed with the naked eye.

What are stains and dyes used for?

are used to add color to microbes so they can be better observed under a microscope.

What does growth media provide?

provides nutrients, including water, various salts, a source of carbon (like glucose), and a source of nitrogen and amino acids (like yeast extract) so microorganisms can grow and reproduce

What is a petri dish?

-a flat-lidded dish

-made out of either plastic or glass are used to hold growth media

What can test tubes be used for?

-cylindrical plastic or glass tubes with rounded bottoms and open tops

-used to grow microbes in broth, or semisolid or solid growth media.

What are Bunsen burners being phased out for?

Bunsen burners are being phased out in favor of infrared microincinerators, which serve a similar purpose without the safety risks of an open flame. [sterilize equipment]

What is taxonomy?

the classification, description, identification, and naming of living organisms

What is Linnaean taxonomy?

a system of categorizing and naming organisms using a standard format so scientists could discuss organisms using consistent terminology

In his taxonomy, how did Linnaeus divide the natural world?

three kingdoms: animal, plant, and mineral (the mineral kingdom was later abandoned)

The names of the levels in Linnaeus's original taxonomy?

kingdom, class, order, family, genus (plural: genera), and species

How did Linnaeus' system get modified?

taxonomies took into account the evolutionary relationships, or phylogenies, of all different species of organisms on earth

Linnaeus's tree of life contained what branches?

two main branches for all living things: the animal and plant kingdoms

Added branches to Linnaeus'?

Ernst Haeckel:

-Protista, for unicellular organisms -Monera, for unicellular organisms whose cells lack nuclei, like bacteria

Robert Whittaker:

-fungi

What else did Whittaker add to the tree?

a level of categorization above the kingdom level—the empire or superkingdom level—to distinguish between organisms that have membrane-bound nuclei in their cells (eukaryotes) and those that do not (prokaryotes)

What kingdoms did the Empire Prokaryota contain?

The Empire Eukaryota?

-just the Kingdom Monera

-the other four kingdoms: Fungi, Protista, Plantae, and Animalia

What do genetic methods allow for (regarding trees)?

a standardized way to compare all living organisms without relying on observable characteristics that can often be subjective

What does modern taxonomy rely on?

-comparing the nucleic acids (deoxyribonucleic acid [DNA] or ribonucleic acid [RNA]) or proteins from different organisms

-The more similar the nucleic acids and proteins are between two organisms, the more closely related they are considered to be.

How did Carl Woese and George Fox create a genetics-based tree of life?based on similarities and differences they observed in the gene sequences coding for small subunit ribosomal RNA (rRNA) of different organisms. I

based on similarities and differences they observed in the gene sequences coding for small subunit ribosomal RNA (rRNA) of different organisms

What did Carl Woese and George Fox discover from their tree? How did they accommodate this difference?

-a certain type of bacteria, called archaebacteria (now known simply as archaea), were significantly different from other bacteria and eukaryotes in terms of their small subunit rRNA gene sequences

-they created a tree with three Domains above the level of Kingdom: Archaea, Bacteria, and Eukarya

Analysis of small subunit rRNA gene sequences suggests that ...

archaea, bacteria, and eukaryotes all evolved from a common ancestral cell type

The evolutionary relationship between ____ and ____ is closer than to ____.

Archaea; Eukarya; Bacteria

What is horizontal gene transfer? Problem with it? Consequently, some scientists now think in terms of "____" rather than "trees of life."

-when a gene of one species is absorbed into another organism's genome

-can make it difficult to determine how organisms are evolutionarily related

-webs of life

What is binomial nomenclature?

-a two-word naming system for identifying organisms by genus and species

-the genus part of the name is always capitalized; it is followed by the species name, which is not capitalized.

-Both names are italicized.

What are the Bergey's Manual of Determinative Bacteriology and Bergey's Manual of Systematic Bacteriology?

the standard references for identifying and classifying different prokaryotes

_____ can be used to identify specific antibodies that will react against the proteins found in certain species.

serological tests

Most microbes are ____ and small enough that they require artificial magnification to be seen.

unicellular

Note that a typical virus measures about ____, ____ times smaller than a typical bacterium (~____), which is at least ____ times smaller than a typical plant or animal cell (~____-____).

100nm; 10; 1um; 10; 10-100um

An object must measure about _____ to be visible without a microscope.

100um

What is acellular?

not composed of cells (some viruses for ex)

What domains are microorganisms found in?

in each of the three domains of life: Archaea, Bacteria, and Eukarya

.......Some microorganisms, such as viruses, do not fall within any of the three domains of life.

What are microbes in the bacteria, archaea, and eukarya domains?

-Microbes within the domains Bacteria and Archaea are all prokaryotes (their cells lack a nucleus)

-whereas microbes in the domain Eukarya are eukaryotes (their cells have a nucleus)

Bacteria are prokaryotic because ....

their genetic material (DNA) is not housed within a true nucleus

Common bacteria shapes?

spherical (coccus), rod-shaped (bacillus), or curved (spirillum, spirochete, or vibrio)

Photosynthetic bacteria?

-oxygenic cyanobacteria

-anoxygenic green sulfur

-green nonsulfur bacteria

these bacteria use energy derived from sunlight, and fix carbon dioxide for growth

Non photosynthetic bacteria?

obtaining their energy from organic or inorganic compounds in their environment

Archaea are _______ _______ organisms.

unicellular prokaryotic

_______ and ______ have different evolutionary histories, as well as significant differences in genetics, metabolic pathways, and the composition of their cell walls and membranes.

Archaea and bacteria

Difference between bacteria and archaeal cell walls?

Unlike most bacteria, archaeal cell walls do not contain peptidoglycan, but their cell walls are often composed of a similar substance called pseudopeptidoglycan.

Some archaea live in the human body, but ....

none have been shown to be human pathogens

The domain Eukarya contains all eukaryotes, including ....

uni- or multicellular eukaryotes such as protists, fungi, plants, and animals

The major defining characteristic of eukaryotes is what?

that their cells contain a nucleus

What are protists?

an informal grouping of eukaryotes that are not plants, animals, or fungi.

---Algae and protozoa are examples of protists.

What are Algae (singular: alga)?

protists that can be either unicellular or multicellular

What are algae cells surrounded by?

cell walls made of cellulose, a type of carbohydrate.

An important property of algae?

they are photosynthetic organisms that extract energy from the sun and release oxygen and carbohydrates into their environment

What is agar?

-it is a gel derived from algae

-can be mixed with various nutrients and used to grow microorganisms in a Petri dish

What are algae being developed as a possible source for?

biofuels

What are protozoa (singular: protozoan)?

protists that make up the backbone of many food webs by providing nutrients for other organisms

How do protozoa move?

-some protozoa move with help from hair-like structures called cilia or whip-like structures called flagella

-others extend part of their cell membrane and cytoplasm to propel themselves forward. These cytoplasmic extensions are called pseudopods ("false feet")

What do protozoa feed on?

Some protozoa are photosynthetic; others feed on organic material.

Lifestyle of protozoa?

Some are free-living, whereas others are parasitic, only able to survive by extracting nutrients from a host organism.

How are fungi different from plants?

Fungi are not photosynthetic, and their cell walls are usually made out of chitin rather than cellulose.

What type of fungi resemble plants?

multicellular

What are molds?

-multicellular fungi organisms

-made up of long filaments that form visible colonies

Molds play a critical role in ...

the decomposition of dead plants and animals.

Holds can cause disease-causing metabolites (called ______).

mycotoxins

Examples of molds?

-penicillin

-cyclosporine, used to prevent organ rejection following a transplant.

What are helminths?

-Multicellular parasitic worms

-not technically microorganisms, as most are large enough to see without a microscope

Why do helminth worms fall within the field of microbiology?

because diseases caused by helminths involve microscopic eggs and larvae

What are viruses?

Viruses are acellular microorganisms, which means they are not composed of cells

What does a virus consist of/how does it work?

proteins and genetic material—either DNA or RNA, but never both—that are inert outside of a host organism

However, by incorporating themselves into a host cell, viruses are able to co-opt the host's cellular mechanisms to multiply and infect other hosts.

Do viruses cause disease?

usually no

_____ is the study of bacteria;

_____ is the study of fungi;

_____ is the study of protozoa;

_____ is the study of helminths and other parasites;

and ______ is the study of viruses

bacteriology; mycology; protozoology; parasitology; virology

During the Golden Age of Microbiology (1857-1914), microbiologists, including Louis Pasteur and Robert Koch, ...

discovered many new connections between the fields of microbiology and medicine.

Bacteria can be identified through ... (3)

1. biochemical tests

2. DNA/RNA analysis

3. serological testing methods.

Eukaryotes studied in microbiology include ... (4)

1. algae

2. protozoa

3. fungi

4. helminths.

What is a brightfieqld microscopy image?

renders a darker image on a lighter background

Visible light consists of ...

electromagnetic waves that behave like other waves.

Light waves interact with materials by ...

being reflected, absorbed, or transmitted.

Transmission occurs when ...

a wave travels through a material, like light through glass

Light waves can also interact with each other by ______, creating complex patterns of motion.

interference

What is diffraction?

when light waves interact with small objects or openings by bending or scattering

Refraction occurs when ...

light waves change direction as they enter a new medium