Microbiology Ch. 1

Which type of active transport protein uses one protein to pump two different molecules?

Antiport and Symport

interlocking molecules of protein or glycoprotein that prevents osmotic lysis and acts as a semipermeable barrier

S-layer

_________ ___, stains both Gram (+) and Gram (-), fluoresces green.

SYTO 13

Bacteria can have positive, neutral, or negative effects on humans and other macroorganisms. Which of the following would be a negative association?

Salmonella bacteria in the human gut

____ is the general magnification for compound microscopes.

10x

Characteristics of Escherichia coli:

- "standard" for micro-organisms - chemoorganotroph - rods: 2x10 micrometers - cell volume: 30 micrometers^3

Characteristics of Thiomargarita namibiensis:

- Sulfur chemolithotroph (litho - eating, troph - eating) - cocci: 750 micrometers (cocci - graph chain) - Cell volume: 200 million micrometers^3 (VERY LARGE)

Pasteur used a Pasteur flask to demonstrate that spontaneous generation was not the reason that microbes appeared in nutrient solutions. When he boiled the nutrient solution in this type of flask, no microbial growth appeared. Principles that Pasteur developed are now used to help keep food safe by reducing the microbes present through pasteurization. Traditionally, this involved heating liquid to 62.8°C for 30 minutes. However, it is now more common to use high temperature short time (HTST) pasteurization, which involves heating the liquid to 82°C for 15 minutes. If you had a sample of Lake Vida bacteria and needed to sterilize it (killing all of the microbes present), what types of approaches could you use?

- You could use a hypotonic solution to replace the salt solution in which the Lake Vida bacteria are normally found. - You could heat the sample, but probably would not need to raise the temperature as high as is needed for normal pasteurization. (In general, sterilization techniques are designed to be effective against human pathogens. The Lake Vida microbes could not be effective human pathogens because they would be unlikely to survive at human body temperature. In determining effective sterilization techniques, it is important to consider the microbes being targeted.)

What are two characteristics of a fatty acid structure?

- carboxyl group - hydrocarbon chain

Characteristics of Mycoplasma pneumoniae:

- pathogenic bacterium - pleomorphic: 0.2 micrometers - cell volume: 0.005 micrometers^3

CQ: The limits to resolution by electron microscopy are around ______.

0.2 nm

What are three characteristics of the SEM (scanning electron microscopy):

1. specimen coated w/ thin film of heavy metal (e.g., gold) 2. electron beam scans the object 3. images are called "micrographs"

What are the two ways to improve an image in a microscope?

1. Contrast 2. Dimensionality

What are three characteristics of the TEM (transmission electron microscopy):

1. electromagnets function as lenses 2. system operates in a vacuum 3. specimens must be very small to image

Bacteria was first observed in __________ by ________ _____ ___________________.

1676, Antoni van Leeuwenhoek

Most prokaryotes are the size of Escherichia coli which is:

1x2

___________ is about as high as magnification goes for light microscopy.

2000x

Life began ~__.__ __________ years ago.

3.9 billion

Earth is __.__ ___________ years old.

4.6 billion

Identify which situation would be harmful rather than beneficial. A. Escherichia coli in ground meat B. Escherichia coli as part of the microbial flora in the human colon C. nitrogen-fixing bacteria in root nodules D. microorganisms in the rumen of cattle

A. Escherichia coli in ground meat

Why is ATP necessary for active transport?

ATP provides energy to transfer material against its concentration gradient.

For each of the characteristics listed below, choose whether it is a characteristic of Archaea, a characteristic of bacteria, a characteristic of both, or a characteristic of neither. - Unique cell wall structure lacking peptidoglycan, cellulose, or chitin - Some are extremophiles - Most have single, circular main chromosomes - have peptidoglycan cell walls - Most hace single, circular main chromosomes

Archaea- Unique cell wall structure lacking peptidoglycan, cellulose, or chitin Bacteria- have peptidoglycan cell walls Both Archaea and Bacteria- Some are extremophiles. May have small, circular pieces of DNA called plasmids. Most have single, circular main chromosomes. (There are many shared characteristics between Bacteria and Archaea, including characteristics generally associated as major distinguishing features of prokaryotes [e.g., circular chromosomes, plasmids, and a lack of membrane bound organelles]. However, Bacteria and Archaea are very distinct groups with important differences, such as differences in cell wall structure.)

The step in Koch's postulates that most critically enabled him to determine that a particular microbe was the cause, and not an effect, of a particular disease was __________. A. the suspected pathogen must be reisolated from the experimentally infected animal and is shown to be the same as the original microbe isolated B. cells from a pure culture of the suspected pathogen must cause the disease in a healthy susceptible animal C. the suspected pathogen must be grown in pure culture D. the suspected pathogen must be present in all cases of the disease and absent from healthy animals

B. cells from a pure culture of the suspected pathogen must cause the disease in a healthy susceptible animal.

What are the three domains of life?

Bacteria, Archaea, Eukarya

The introduction describes research into unusual bacteria capable of living in an extremely harsh environment. The introduction mentions that the Lake Vida bacteria can contribute to both basic and applied science. However, is the work by Murray et al. referenced in the main body of the introductory passage best described as basic or applied research?

Basic research. The initial discovery and analysis of the bacteria allowed them to be classified and led to an understanding of their basic metabolic processes. This is basic research that gives us a greater understanding of the natural world. The introductory passage suggests several ways that this could lead to applied research, possibly by allowing the development of new products.

How does water enter and exit a cell?

By simple diffusion or by use of an integral transport protein

Hypothesize the most plausible reason why scientists accepted spontaneous generation for so many years. A. Spontaneous generation was based on many hundreds of different observations. Based on the wealth of data, it must be true. B. Biology was an experimental science from the beginning, and scientists could not falsify spontaneous generation. C. Biology was primarily an observational science for many hundreds of years until the acceptance of the scientific method. D. Many people believed in life forces that could create life from nonliving matter.

C. Biology was primarily an observational science for many hundreds of years until the acceptance of the scientific method.

tight, sticky matrix of either polysaccharide or protein that allows prokaryotes to attach to solid surfaces and protect from dessication

Capsule

Pioneered pure culture techniques. Discovered the cause of mycobacterium tuberculosis.

Robert Koch

_______________ emerged around 3 billion years ago and are responsible for putting more oxygen into the atmosphere.

Cyanobacteria

Which statement illustrates how the development of enrichment culture techniques by Beijerinck contributed to our knowledge of microbial diversity? A. Enrichment culture technique allows targeting of specific metabolic groups by using common nutrients but selective incubation conditions. B. Enrichment culture technique allows targeting of specific metabolic groups by using selective nutrients at atmospheric incubation conditions. C. Enrichment culture technique allows targeting of specific metabolic groups by using common nutrients at atmospheric incubation conditions. D. Enrichment culture technique allows targeting of specific metabolic groups by using selective nutrients and incubation conditions.

D. Enrichment culture technique allows targeting of specific metabolic groups by using selective nutrients and incubation conditions.

Differentiate between industrial microbiology and biotechnology. A. Industrial microbiology uses genetically engineered microbes to make low-value products, while biotechnology uses genetically engineered microbes to make high-value products. B. Industrial microbiology uses naturally occurring microbes to make low-value products, while biotechnology uses genetically engineered microbes to make low-value products. C. Industrial microbiology uses naturally occurring microbes to make high-value products, while biotechnology uses genetically engineered microbes to make low-value products. D. Industrial microbiology uses naturally occurring microbes to make low-value products, while biotechnology uses genetically engineered microbes to make high-value products.

D. Industrial microbiology uses naturally occurring microbes to make low-value products, while biotechnology uses genetically engineered microbes to make high-value products.

Although the existence of microorganisms was surmised long before, their discovery depended upon a technological development (the microscope) in order for scientists to __________. A. publish their results B. construct meaningful hypotheses concerning microbial activities C. synthesize meaningful theories about the roles of microbes in disease D. make direct observations of microbes

D. make direct observations of microbes.

Pasteur's experiments refuting the theory of spontaneous generation were crucial to the advancement of the field of microbiology because they led to the development of all EXCEPT which of the following? A. the germ theory of disease B. sterile technique C. food preservation D. optical isomers

D. optical isomers

~__ bya modern Eukaryotes emerged.

Eukaryotes

Scientific study as we know it first came into mainstream thanks to _____________ ________ in the ___________.

Ferdinand Cohn

numerous filamentous proteins extending from cell that aid in adhesion and pellicle or biofilm formation

Fimbriae

__________ _________ stains gram (+) bacteria and fluoresces orange.

Hexidium iodide

Which statement best illustrates the importance of a high surface-to-volume ratio that is found in microorganisms?

If a cell has a high surface-to-volume ratio, there will be enough surface area to get the needed nutrients in to support cellular metabolism and the accumulated waste out.

confers strength and protection and is toxic to many animals because of its lipid A component

Lipopolysaccharide layer

Used a swan neck flask to discredit spontaneous generation. Championed the Germ Theory of Disease. Developed the first rabies vaccine.

Louis Pasteur

Who are the Founding Fathers of Modern Microbiology?

Louis Pasteur, Robert Koch, Martinus Beijerinck, Sergei Winogradsky

Pioneered enrichment culture techniques. Discovered Nitrogen Fixation. Described the first virus.

Martinus Beijerinck

If an E. coli cell has a surface area-to-volume (S/V) ratio of 4.5, and a Pelagibacter ubique has an S/V ratio of 22, which cell will be able to exchange nutrients and wastes with the environment more efficiently?

Pelagibacter ubique, because its cells are smaller

gel-like space with hydrolytic enzymes for nutrient transport and chemoreceptors to direct movement

Periplasm

filamentous proteins extending from the cell with various functions such as conjugation, transformation, and twitching motility

Pili

Which of the following would not move freely across the cytoplasmic membrane?

Positively charged hydrogen ions

______________ is the shortest distance at which 2 points can still be distinguished from each other. Limited by wavelengths.

Resolution

Discovered chemolithotrophy ("earth eating bacteria"). Outlined importance of microbes for ecosystems (Nitrogen, Carbon cycling, etc.).

Sergei Winogradsky

loose, easily deformed, sticky matrix of either polysaccharide or protein that allows prokaryotes to form biofilms and avoid dehydration

Slime layer

Explain the germ theory of disease.

Some microorganisms can cause disease.

_______________ are fossils containing cyanobacteria that date back to ~3 bya.

Stromatolites

Which type of active transport protein moves two molecules into the cell at the same time?

Symport

The plaque (microbial biofilm) that forms between your teeth is a highly anaerobic (oxygen-free) environment, even though the mouth is one of the most aerobic habitats in the body and most of the bacteria living there can use oxygen if it is available. Why is there no oxygen in the plaque between your teeth?

The bacteria living between the teeth have used up the oxygen.

Why is no energy required in passive transport?

The concentration gradient drives the movement.

The bacteria living in Lake Vida have been using organic materials in their environment. Carefully read the introductory passage and consider how they are interacting with each other and with their environment. How are they changing their ecosystem as they metabolize and grow?

They are gradually consuming the organic carbon that is available and may eventually exhaust it. (Despite their small size, microbes can have a substantial effect on their environment and on each other. As they consume materials, they produce wastes. The earliest oxygenic cyanobacteria produced oxygen that was essential to the evolution of diverse aerobic microorganisms and large, multicellular organisms. In the Lake Vida ecosystem, microbes are consuming organic carbon that was trapped under the ice a very long time ago. Without the input of new energy from sunlight or chemosynthetic organisms, the organic carbon will gradually be consumed.)

Based on the material in the chapter, you know that organisms can be classified into two groups based on whether they obtain organic carbon by consuming preformed organic materials [heterotrophs] or by using inorganic carbon to make organic materials.Photoautotrophs use light energy to make organic compounds, while chemolithotrophs oxidize inorganic compounds to produce the energy needed to make organic compounds. Based on the information given in the introductory essay, what best describes the Lake Vida microbes?

They are heterotrophs. (The introductory essay states that, "...the Lake Vida bacteria are probably metabolizing and growing, albeit extremely slowly, on organic carbon that was trapped in the ice at the time the lake became ice-sealed, millennia ago." This suggests that they are consuming preformed carbon rather than using chemolithotrophy. In the full research article, however, chemolithotrophy is discussed as an additional possibility.)

What makes phospholipid membranes good at keeping some molecules out, and allowing others to freely pass?

They have both hydrophilic and hydrophobic regions.

made of peptidoglycan, enables prokaryotes to withstand high pressures without lysing

Thick cell wall

The largest known prokaryote is _________________ ________________.

Thiomargarita namibiensis

___________________ ___________________ is the name of one of the biggest prokaryotic organisms.

Thiomargarita namibiensis

How are organisms most effectively placed into a domain of life?

Through the sequencing of ribosomal RNA (rRNA). It works best because rRNA mutates at a much slower rate than other genes allowing an actual comparison to other genes of the same origin.

Which transport protein employs transporters that move molecules only in one direction?

Uniport and Symport

Based on your understanding of the chapter material and the information in the passage, the speed of Bacteria and Archaea is determined by:

a combination of structural, functional, and environmental factors.

The main functions of the bacterial cell wall include all EXCEPT the following __________. A. Actively transporting solutes against the concentration gradient B. Conferring a specific shape to the cell C. Limiting cell size D. Resisting cell lysis due to osmotic forces

actively transporting solutes against the concentration gradient

Arrange the types of microorganism in the order they evolved on Earth.

anaerobes, anoxygenic phototrophs, oxygenic phototrophs, aerobes, multicellular organisms

Explain how organisms are placed into the three major cell lineages or domains.

analysis of ribosomal RNA (rRNA)

Teichoic acid molecules in Gram-positive cell walls include phosphate groups. Therefore, they will __________.

bind positive ions like Mg2+ and Ca2+

The enzyme lysozyme kills bacterial cells by cleaving the β-1,4-glycosidic bonds in the peptidoglycan. This leads to which of the following?

breaches of the cell wall and cell lysis due to osmotic swelling

3 types of microscopy

bright field, phase contrast, dark field

CQ: Bacteria stains gram (-) or gram (+) because of difference in the _______ ________.

cell walls

Different species living in the same place at the same time are called ____________.

communities

Microbes evolve specific traits that increase their fitness in specific environments. Martinus Beijerinck developed the enrichment culture technique to isolate microbes from complex natural samples, like soil and water, by manipulating the __________.

culture conditions and nutrients.

Staining increases the visible contrast of cells compared with the background. Because the Gram stain results in some types of bacteria staining purple, and other types appearing pink, this is called a __________ stain.

differential

Uses electrons scattered by objects for visualization

electron microscope

In _____________ __________________ electrons travel in a vacuum, and there is no refraction to take images of specimens.

electron microscopes

Identify which of the following is a major function of the cytoplasmic membrane.

energy conservation

Transport proteins can become saturated with solute, have high specificity for certain substances, undergo conformational (shape) changes, and are highly regulated by the cell. What other type of cellular proteins have these four general characteristics?

enzymes

While many Archaea are extremophiles, the microbes at Lake Vida are classified as Bacteria. What is the most definitive way that researchers could have determined whether they had found Archaea or Bacteria?

genetic analyses

A ________________ is a type of peripheral protein above that can be used as a receptor or in enzymatic functions.

glycoprotein

Predict which type of organism would be more difficult to treat with antibiotics and why.

gram-negative organisms -- extra layer of LPS (Lipopolysaccharides)

CQ: Small prokaryotes tend to grow faster than larger ones because of what?

higher surface area to volume ratios

Given that the cytoplasmic membrane has a fluid dynamic nature, with phospholipids and proteins able to move about within the bilayer structure, what force or structure keeps the membrane from falling apart?

hydrophilic/hydrophobic forces

Small cells have ___________ surface area to volume ratios.

larger

A __________ is a curved transparent surface that bends light waves.

lense

Type of microscope that uses photons scattered by objects for visualization

light microscope

Like all forms of life on Earth, all microbial cells perform three major types of activities: __________.

metabolism, growth, and evolution

Microbes were discovered in _________ by __________ ___________.

microbes, Robert Hook

Once equilibrium is reached,

molecules move, but there is no net movement in a particular direction.

The cytoplasmic membrane is termed "semi-permeable" because some substances, like water and alcohols, can pass freely through while others, like sugars, amino acids, and ions, cannot. What molecular characteristics largely determine whether or not a substance can pass through the membrane?

size and hydrophobicity

Arrange Koch's postulates in the correct order.

pathogen present in all cases of disease; pathogen isolated in pure culture; pathogen able to infect healthy host; pathogen re-isolated.

Electron microscopes use electrons instead of __________ to image specimens.

photons

Specify which of the following is a major microbial ecosystem.

plants and animals

Distinguish which list of structural properties and activities are true for ALL cells.

plasma membrane, ribosomes, metabolism, evolution

A group of related species in the same area at approximately the same time is called a ____________.

population

All life on Earth can be divided into three main Domains, the Bacteria, the Archaea, and the Eukarya, based on the similarities of their __________.

ribosomal RNA

The presence of which of the components listed below would allow you to distinguish between a gram-positive or gram-negative cell wall?

teichoic acids -- gram-positive

Transport proteins (transporters) require energy expenditure for each molecule of substrate transported. The reason for this energy requirement is __________.

the solute must be transported against a concentration gradient

Some bacteria can carry out interesting and important metabolisms not found in any macroorganism. Many of these reactions are crucial to life on Earth because __________.

they recycle elements needed by living organisms.

Integral proteins are mostly involved in

transport function