Microbio Quiz #1 - Chapters 1, 5, and 6

What is the importance of a DNA sequence of nucleotides?

To analyze an unknown DNA sample and match DNA

What is the cause of TB?

Mycobacterium tuberculosis

A single celled microorganism lacking a nucleus

Bacteria

Chemicals that fight disease and kill bacteria growth

Antibiotics

What is the ability of microorganisms to resist the effect of antimicrobial drugs designed to kill them?

Antimicrobial resistance

Why are microbes critical to maintain out environment?

Fix nitrogen into forms used by plants, produce vitamins, serve as primary producers in food webs

Microbes

Living organisms that are critical to human health (can not be seen by naked eye)

Pathogens

Agents that cause disease (germs)

Species

Shared set of genes and traits

Viruses

Noncellular, non-metabolic, unable to reproduce independently (must infect a host cell)

How are new viruses made?

Invade cells

Scientific name of a species is

Italicized and includes a capitalized genus name followed by a lowercase species name (ex: Staphylococcus aureus)

How are microbes classified?

By their genetic relatedness determined by comparing microbial genomes

Genome

Total DNA sequence of an organism

Can viral genomes be RNA or DNA?

Yes

Major trait of microbial cells

Poession or lack of a membrane enclosed nucleus

Prokaryotes*

No nucleus or nuclear membrane and are single celled (not bound by any membranes)

Examples of Prokaryotes

Bacteria and archaea

Eukaryotes*

Have a true nucleus and other organelles (DNA is stored and enclosed in a membrane)

Examples of Eukaryotes

Fungi (some types), protozoa, algae, animals, plants

What evolved by diverging from bacteria and eukaryotes?

Archaea

Do Archaea cause disease?

No due to absence of pathogensis

Who built the first compound microscope?

Robert Hooke

Who observed bacteria with a single-lens microscope?

Anton van Leeuwenhoek

How long did it take to discover the connection between microbes and human disease?

Nearly 200 years

Did microbial disease affected human demographics and cultural practices?

Yes

What is the theory that microbes arise spontaneously (without parental organisms) that was debated throughout the eighteenth century?

Spontaneous generation

Who proved that bacteria were living things capable of reproducing and potentially acting as a cause of disease?

Louis Pasteur

What theory stated that specific diseases are caused by specific microbes "germs"?

Germ Theory of Disease

Who demonstrated the statistical significance of mortality due to infectious disease by taking care of patients during war?

Florence Nightingale

Diagnosis requires direct evidence that a microbe caused the disease (chain of infection) - who worked on this problem in the 19th century?

Robert Koch (founder of scientific method for microbiology and won the nobel prize in 1905)

What were critical tools for Robert Koch?

Pure cultures grown from a single colony of bacteria

Can Koch's Postulates always be applied to identify that cause of a disease?

No

Who invented the practice of vaccination by infecting patients with cowpox to prevent smallpox?

Dr. Edward Jenner

What was called vaccination?

Cowpox inoculation

Who suggested the use of antiseptics (chemicals that kill microbes) by doctors to prevent patients?

Ignaz Semmelweis

Who used chemical treatment of surgical instruments to prevent transmission?

Joesph Lister

What discovery did Semmelweis and Lister find?

Aseptic operating rooms which are free of microbes

Who showed that exposure to attenuated (weakened) stains of bacteria conferred immunity to a disease without causing severe symptoms?

Louis Pasteur (cured rabies with a vaccines)

Who found that penicillin kills bacteria by noticing mold growing on one of his cultures?

Alexander Fleming

Who purified the first penicillin substance to save peoples lives

Florey and Chain

Who found that tobacco mosaic virus (TMV) was transmitted by a virus and causing a disease in tobacco plants

Dimitri Ivanosky and Martinus Bejerinick

Who was one of the first scientist to study microbes in their natural habitats by discovering microbes in wetlands?

Sergei Winogradsky

Winogradsky developed what methods and selective growth media to grow some bacteria while excluding others?

Enrichment culture

Who developed a method to sequence viruses in 1977 after understanding DNA structure led to the development of DNA sequencing techniques?

Frederick Sanger

What was the first genome sequence of a cellular microbe obtained in 1995?

Haemophilus influenza

Who first proposed a new form of prokaryotic life called archaea with characteristics distinct from other bacteria and eukaryotic life?

Carl Woese

What proposed in the 1950s that the structure of DNA was a double helix?

Rosalind Franklin

Who used Franklin's X-ray micrographs to propose that the four bases of the DNA alphabet pair in the interior of the helix

Watson and Crick

Who first proposed that the energy-converting organelles of eukaryotic cells (mitochondria and chlorplasts) evolved by endosymbiosis?

Lynn Margulis

What are microbes that live within a larger organziation?

Endosymbionts

Lyme disease causes what type of rash due to tick-borne bacterium

Bullseye

If Lyme Disease is undiagnosed and untreated

It can lead to more serious symptoms

This structure of the bacteria cell is a gel-like network of proteins and other macromolecules contained by a cell membrane

Cytoplasm

Outside of the membrane, the cell body is enclosed by a cell wall - the cell wall is made up of and acts like a filter for materials to pass through from the inside to the outside

Peptidoglycan (the composition and thickness can vary between Gram-positive and Gram-negative bacteria so this helps distinguish between the two)

What constiutes the cell envelope?

Cell membrane, cell wall and outer membrane (for Gram negative species)

The chromosome is organized within the cytoplasm as a system of looped coils containing DNA is called the

Nucleoid

What are the four main biochemical compositions of bacteria?

Water, macromolecules (proteins), small organic molecules (lipids), and inorganic ions

Four main biochemical compositions of bacteria % of total weight

70%, 16%, 3-5%, 1%

What defines a cell and separates the cytoplasm from the outside environment?

The cell/plasma membrane (inner membrane)

This is located within the cell membrane and has many floating proteins

Phospholipid bilayer (hydrophilic head and hydrophobic tail favored in aqueous enviorments)

Support, signaling, communication, export of toxins, transport and establishment of concentration gradients are functions of what?

Bacterial membrane proteins

T/F: Microbes must move nutrients across the membrane into the cytoplasm

True

This form of transport is driven with concentration gradients moving from high to low

Passive transport

This form of transport is driven against concentration gradients moving from low to high requiring the input of energy

Active transport

What refers to the use of energy from one gradient to drive transport up another graident?

Coupled transport

Symport vs antiport

Same direction, opposite direction

What transporters are powered by ATP to move solutes against a concentration and across the cell membrane

ABC (ATP-Binding Cassette superfamily)

What do you call proteins secreted by pathogens that bind iron more tightly than host cells

Siderophores

T/F Some bacteria lack cell walls

True

What single interlinked molecule encloses the entire cell (rigid and withstands pressure)

Cell wall

The cell wall is composed of peptidoglycan which consist of parallel polymers of disaccarides called

Glycan chains (cross linked with short peptides)

This is more often susceptible to antibiotics that target peptidoglycan synthesis (ex: penicillin)

Gram-positive bacteria

This is harder to treat because the outer membrane blocks many antibiotics and have efflux pumps and B-lactamases

Gram-negative bacteria

Gram-negative infections can trigger what due to LPS (endotoxin) in their outer membrane)

Septic shock

What are the 3 steps of bacterial cell division?

DNA replication, protein synthesis and formation of septum

This inhibits RNA synthesis by blocking RNA polymerase

Rifamycin

This inhibits DNA replication by targeting DNA gyrase and topoisomerase

Quinolone

What allows for movement (transport) and attachment of DNA

Pili

What term refers to membranous extensions of cytoplasm that secrete adhesion factors

Stalks

What involves the rotation of flagella that propels the cell in response to stimuli

Chemotaxis

4 main organelles of the endomembrane system of eukaryotic cells

Rough ER, Smooth ER, Lysosomes, Golgi

What structure maintains shape and provides structural support

Cytoskeleton

What have bacterial genomes, ribosomes that translate mRNA, and evolved through endosymbiosois by converting energy into ATP

Mitochondria and chloroplasts

These two structures are constructed of microtubules

Flagella and cilia

This structure remove water from cells

Contractile vacuoles

While microbes usually exist in complex multispecies communities, for laboratory studies, they must be grown separtely in what?

Pure culture (single species)

____ allows bacteria to move freely, while _____ is useful to seperate mixtures of different organisms

Liquid media, solid media

Bacterial cells form ___ on solid media with agar added to make a firm surface (cool-gel like structure becomes solid)

Colonies

This allows for separation of colonies into pure cultures

Isolation streaking

Pure colonies can be isolated using this technique in which you need to dilute multiple times

Spread plate techinque

Bacteria can be grown in a precisely defined ____ that contains only known components so bacteria share the same behavior

Synthetic medium

Bacteria can also be grown in a nutrient rich but less defined medium

Complex medium

Compounds in the media prevent some types of bacteria from growing, favoring the growth of one specific type

Selective media

Species grow equally well but compounds in the media are metabolized differently, often distinguished by a color indicator.

Differential media

Most bacteria reproduce by ___ (one parent cell divides and forms two offspring cells)

Binary fission

What are the four phases of bacterial growth (LLSD)

Lag phase, log phase, stationary phase and death phase

Growth in which population sizes doubles at a fixed rate is

Exponential growth

In an environment with few bacteria but plenty of resources, bacteria will divide at a constant interval called (𝑁₀×2ⁿ)

Generation time

A vessel in which a chemical process is carried out

Bioreactor