Micro Exam 2

How do organisms use oxidation-reduction reactions?

All organisms use oxidation-reduction reactions to harness energy, and it is used to produce ATP

How is ATP an intermediate between catabolism and anabolism?

Anabolic reactions are coupled to ATP breakdown, and catabolic reactions are coupled to ATP synthesis

How do bacteriophages get nucleotides and amino acids if they don't have any metabolic enzymes?

Bacteriophages propagate themselves by hijacking the metabolic enzymes of bacteria they infect and using amino acids and nucleotides already present in the cytoplasm

Why doesn't the definition of viral species work for bacteria?

Because bacteria are not a virus

What does anoxygenic mean?

Being or carrying out photosynthesis in which oxygen is not produced as a by-product

Describe the formation of biofilms and their potential for causing infection.

Biofilms are a natural structure formed by microbes in the environment. They stick to healthy surfaces and will prevent nutrients from going through to keep it healthy. It will block any immune response and antibiotics because of the slime wall

What is on the chip, in DNA chips, to make it specific for a particular microorganism?

DNA probes

List the cell wall composition and disease they cause of the following algae: diatoms, dinoflagellates, oomycotes.

Diatoms - pectin and silica. Neurological disease, domoic acid --> domoic acid intoxication Dinoflagellates - cellulose. Neurotoxins "saxitoxins" --> paralytic shellfish poisoning (PSP), ciguatera fish deaths (red tide) Oomycotes - Cellulose. Cause crop diseases --> great potato famine in Ireland

How can one species have two different code numbers?

Each test can give a different number

What red alga is toxic for humans?

Gracilaria spp.

In what instances would the pour plate method be more appropriate than the spread plate method?

It shows the colonies on the surface AND in solidified medium. It sows aerobic and anaerobic bacteria

Could Louis Pasteur, in the 1800s, have grown rabies viruses in cell culture instead of in living animals?

No, viruses only reproduce in a living host cell.

Differentiate persistent viral infections from latent viral infections.

Persistent viral infections are disease processes that occurs gradually over a long period and are fatal, while latent viral infections can last for long periods of time without causing diseases

What is stained using the FISH technique?

RNA or DNA

In which process is the cell actively taking in the virus?

Receptor-mediated endocytosis

Discuss the advantages of the three-domain system

Ribosomes are present in all cells but, they are not the same in all cells. Comparing the sequences of nucleotides in ribosomal RNA shows that there are three distinctly different cell types which lead to the three-domain system. In this system, cells are classified by cell type, cell wall, rRNA, membrane lipid structure, tRNA, and sensitivity to antibiotics.

The axial filament distinguishes what genera of bacteria?

Spirochetes

How does the enzyme-substrate complex lower the activation energy of the reaction?

The enzyme-substrate complex can lower activation energy by bending substrate molecules in a way that facilitates bond-breaking, helping to reach the transition state

Why were microsporidia so difficult to classify?

The lack of microtubules and mitochondria and intracellular life

How does the sheath help the cell?

They aid in nutrients accumulation and protect the cell

How are rickettsias transmitted from one host to another?

They are transmitted by insects and tick bites

Why is Streptomyces and Actinomyces not classified with fungi?

They have prokaryotic cells

What is the primary use of lipids in cells?

They serve as structural components of biological membranes, and most membrane lipids are phospholipids

Why are microsporidia classified as fungi?

They used to be classified as fungi, then they were classified as protists because they lack mitochondria, but after genome sequencing, they were reclassified as fungi. they are obligated to intracellular parasites.

Are bacteria capable of growing at a high osmotic pressure likely to be capable of growing in the mucus found in nostrils?

Yes, because staphylococcus aureus found in the nasal passage have high tolerance to sodium chloride It prevents the growth of most bacteria but not Staphylococcus spp.

Members of which phylum can be identified by Gram staining?

bacteria

What are the end-products of lipid and protein catabolism?

glycerol, fatty acid, acetyl CoA, amino acids

How would one determine whether a microbe is a strict anaerobe?

if it is growing where there are no oxygen present

What group of bacteria makes most of the commercially important antibiotics?

streptomyces

taxa (taxon)

subdivisions used to classify organisms

Distinguish catabolism from anabolism

- Catabolism is all decomposition reactions in a living organism; the breakdown of complex organic compounds into simpler ones - Anabolism is all synthesis reactions in a living organism; the building of complex organic molecules from simpler ones

What is the difference between homolactic and heterolactic fermentation?

- In homolactic fermentation, one molecule of glucose is ultimately converted to two molecules of lactic acid. - Heterolactic fermentation, in contrast, yields carbon dioxide and ethanol in addition to lactic acid, in a process called the pentose phosphate pathway.

How are oxidative phosphorylation and photophosphorylation similar?

- a membrane associated electron transport chain - creation of a proton gradient - harvesting energy of the proton gradient by making ATP with the help of an ATP synthase

Outline the three ways that ATP is generated.

1)substrate-level phosphorlation-a high-energy P from an intermediate P in catabolism is added to ADP. 2)Oxidative phosphorlation: energy is released as electrons are passed to a series of electron acceptors (an electron transport chain) and finally to O2 or another inorganic compound. 3)photophosphorlylation:energy from light is trapped by chlorophyll, and electrons are passed through a series of electron acceptors. The electron transfer releases energy used for the synthesis of ATP.

If a single bacterium reproduced every 30 minutes, how many would there be in 2 hours?

16

How many membranes make up the nuclear envelope of a eukaryotic cell?

2 nuclear membranes

How many ATPs can be made from the oxidation of one NADH in the electron transport chain?

3 molecules

What is decarboxylation?

A chemical reaction that removes a carboxyl group and releases carbon dioxide

What is a coenzyme?

A coenzyme is a nonprotein substance that is associated with and that activates an enzyme

Explain the importance of osmotic pressure to microbial growth.

A hypertonic environment, or an increase in salt or sugar cause plasmolysis. Microbes need a certain osmotic pressure to maintain integrity and get nutrients.

Why is turbidity more useful in measuring contamination of liquids by large numbers, rather than small numbers, of bacteria?

A large number of bacteria is needed to make a suspension turbid enough to be read on a spectrophotometer

hypha

A long filament of cells in fungi or actinomycetes

What is the purpose of metabolic pathways?

A metabolic pathway is a series of steps found in biochemical reactions that help convert molecules or substrates into different, more readily materials.

Oxygen is so pervasive in the environment that it would be very difficult for a microbe to always avoid physical contact with it. What, therefore, is the most obvious way for a microbe to avoid damage?

A microbe that cannot encounter oxygen would live completely in water where oxygen cannot get to it

Which bacterium would theoretically be more likely to grow at refrigerator temperatures: a human intestinal pathogen or a soilborne plant pathogen?

A soilborne plant pathogen

What is the biological definition of family?

A taxon composed of genera, below order

Assume you have a gram-negative bacterium that produces acid from lactose and cannot use citric acid as its sole carbon source. What is the bacterium?

A type of Escherichia bacteria

How does a virus species differ from a bacterial species?

A viral species is a group of viruses sharing the same genetic information and ecological niche (host range) A bacterial species is genomically coherent group of organisms

Colony

A visible mass of microbial cells arising from one cell or from a group of the same microbes

What is made during light-dependent reactions?

ATP and NADPH

How does ATP provide the energy for synthesis?

ATP can power cellular processes by transferring a phosphate group to another molecule

Identify one advantage and one disadvantage of automated systems.

Advantage: it identifies bacteria at a rapid rate Disadvantage: the cost, displacement of human labor

How do aerobic and anaerobic respiration differ?

Aerobic means oxygen is used, anaerobic means oxygen is not used.

Explain how microbes are classified on the basis of oxygen requirements.

Aerobic use oxygen, anaerobic do not

How do algae differ from bacteria? From fungi?

Algae are eukaryotes while bacteria are prokaryotes Algae are photoautotrophs, while fungi are chemoheterotrophs. Algae are made of cellulose, while fungi are made of chitin. Algae are differentiated by pigment, while fungi are differentiated by sexual/asexual.

List the defining characteristics of algae.

Algae are photoautotrophs that produce oxygen Algae are mostly aquatic The body of the multicellular alga is called a thallus. The thallus consists of a stipe, a holdfast, and blades All algae can reproduce asexually via fragmenting a piece of itself and dividing the nucleus (by mitosis) Sexual reproduction can also occur in algae Algae are classified according to their structures and pigments

If bacterial cells were given a sulfur source containing radioactive sulfur (35S) in their culture media, what molecules would 35S be found in the cells?

Amino acids, proteins, DNA, and RNA

Describe the mechanism of enzymatic action.

An enzyme attracts substrates to its active site, catalyzes the chemical reaction by which products are formed, and then allows the products to dissociate (separate from the enzyme surface). The combination formed by an enzyme and its substrates is called the enzyme-substrate complex.

What is a ribozyme?

An enzyme consisting of RNA that specifically acts on stands of RNA to remove introns and splice together the remaining exons

Agglutination results when the bacteria are mixed with ______.

Antibodies

Compare archaea and bacteria; bacteria and eukarya; and archaea and eukarya.

Archaea and bacteria are both prokaryotes while eukarya is a eukaryote. The cell wall in archaea does not contain peptidoglycan while bacteria does contain peptidoglycan and the cell wall of Eukarya varies in composition but usually contains carbohydrates. Archaea and eukarya are not sensitive to antibiotics while bacteria are sensitive. Archaea live in extreme environments while most bacteria and eukarya live in more moderate environments.

Differentiate asexual from sexual reproduction, and describe each of these processes in fungi.

Asexual reproduction involves only one nuclei through mitosis, cell division, or binary fission. Two asexual spores, conidiospore and sporangiospores. Sexual reproduction involves the fusion of two nuclei in three phases.

Contrast the mechanism of sexual and asexual spore formation.

Asexual spore formation: produced by an individual fungus through mitosis and subsequent cell division Sexual spore formation: consist of 3 phases: Plasmogamy, karyogamy, and meiosis. Results from the fusion of nuclei from two opposite mating strains of the same species of fungus.

How do fungal colonies differ from bacterial colonies?

Bacterial colonies consist of a mass of bacterial cells arising from a single bacterium's fragmentation, while fungal colonies consist of fungal hyphae made up of a single spore. Bacterial colonies are tiny, whereas most hyphae-developing fungal colonies are huge.

What structure is made by both Clostridium and Bacillus?

Bacterial endospores

List two factors that contribute to the limits of our knowledge of microbial diversity.

Bacterial size and PCR (polymerase chain reaction)

What is the role of lichens in nature?

Because lichens enable algae to live all over the world in many different climates, they also provide a means to convert carbon dioxide in the atmosphere through photosynthesis into oxygen, which we all need to survive.

Explain how serological test and phage typing can be used to identify an unknown bacterium.

Because microorganisms are antigenic, they stimulate the body to form antibodies in the serum. In an antiserum, a solution of antibodies is tested against an unknown bacterium. Serological testing can differentiate between species, as well as strains within species. Examples of serological testing include slide agglutination test, ELISA, and western blotting.

Explain how microorganisms are preserved by deep-freezing and lyophilization (freeze-drying).

Because the conditions are extremely cold, the bacteria are quickly frozen and can be thawed and cultures many years later

Why are hyperthermophiles that grow at temperatures above 100 C seemingly limited to oceanic depths?

Because the immense pressure in the ocean depths prevents water from boiling even at temperatures well above 100 C, allowing these bacteria to grow and survive

If a technician were working with pathogenic prions, how would material leaving the lab be rendered noninfectious?

Because the pathogens they are dealing with cannot grow outside of their normal environment

Why is feedback inhibition noncompetitive inhibition?

Because the product binds to the enzyme at a site other than the active site

Why is it difficult to define psychrophile, mesophile, and thermophile?

Because their ranges & max. growth temps that define them "are not rigidly defined." And their temperature range overlap

Why are transformed cells referred to as "immortal"?

Because they can grow indefinitely in laboratory culture

Identify beneficial and harmful effects of fungi.

Beneficial: -citric acid in foods and beverages -Yeast: bread and wine -pest control -Hep B Vaccine Harmful -Mold, spoilage on fruits grains and vegetables -Chesnut trees almost extinct b/c of molds

Identify two beneficial and two harmful effects of algae.

Benefits: fix co2 into organic molecules, produce an estimated 80% of earths oxygen Harmful: red tides due to algal blooms, and diatoms, dinoflagellates and oomycotes cause disease

Most bacteria do not reproduce by budding; what method do they use?

Binary fission

Why is the prevention of biofilms important in a health care environment?

Biofilms form on almost all indwelling medical devices 70% of human bacterial infections involve biofilms

What is the role of lipases?

Break fats down into their fatty acid and glycerol components

In what way is budding different from binary fission?

Budding enlarges until its size approaches that of a parent's cell, then it separates, while binary fission creates 2 smaller cells

What is the function of amino acids in cells?

Building blocks for protein synthesis

Name one ascomycete that can infect humans.

Candida albicans

What is the technical name for bacteria that require a higher-than-atmospheric-concentration of CO2 for growth?

Capnophiles

What are the catabolic pathways through which high-energy electrons from all kinds of organic molecules flow on their energy-releasing pathways?

Carbohydrates Proteins Lipids

In the Calvin-Benson cycle, which molecule is used to synthesize sugars?

Carbon dioxide is used to synthesis sugars

What evidence is used to determine the phylogeny of prokaryotes?

Cell wall composition, living environment, membrane lipid composition, sensitivity to antibiotics

Transformed cells

Cells that acquire properties that are distant from the properties of unaffected cells or from infected cells that do not form tumors

Identify how and why the pH of culture media is controlled.

Chemical buffers are included in the growth medium You add acids or bases to control the pH

Almost all medically important microbes belong to which of the four aforementioned groups?

Chemoheterotrophs

Which gram-negative group has a life cycle that includes different stages?

Chlamydia and Chlamydophila

What human disease is caused by dinoflagellates?

Ciguatera

How do competitive inhibitors operate in comparison to noncompetitive inhibitors?

Competitive inhibitions involve molecules other than the substrate binding to the active site of an enzyme, whereas in noncompetitive inhibition molecules bind to any site other than the active site.

What is the chemical composition of a capsid?

Composed of protein called capsomeres

Why are continues cell lines of more practical use than primary cell lines for culturing viruses?

Continuous cell lines are generally more robust and easier to work with than primary cells. They have unlimited growth potential and are a quick, easy way to get basic information.

What is the nucleic acid in a virus?

DNA or RNA

Differentiate a dichotomous key from a cladogram.

Dichotomous keys are identification keys based on successive questions; each question has two possible answers. This method does not show phylogenetic relationships. A cladogram is a map that shows evolutionary relationships among organisms based on rRNA sequences. Each branch point is defined by a feature shared by various species on that branch. This method does show phylogenetic relationships.

What is being identified in phage typing?

Different strains within a given species

Describe how staining and biochemical tests are used to identify bacteria.

Differential staining is useful for identifying bacteria with cell walls. Two types are differential staining are gram-staining and acid-fast staining. Biochemical tests determine the presence of bacterial enzymes.

What can be found in the cell during biosynthesis and maturation?

During biosynthesis: replicated phage DNA and phage proteins During maturation: new viruses

How does lysogeny differ from the lytic cycle?

During the lysogeny cycle the host cell does not die when the virion invades it

How are polysaccharides used in cells?

Energy storage or structural support

Are energy-generating reactions oxidations or reductions?

Energy-generating reaction uses both oxidation and reduction

Describe the chemical and physical structure of both an enveloped and nonenveloped virus.

Enveloped: usually consists of some combination of lipids, proteins and carbohydrates. In many cases the envelope contains proteins determined by the viral nucleic acid and materials derived from normal host cell components. Some are covered in spikes-which project from the surface of the envelope and can be used to attach to host cells. Nonenveloped: capsid protects the nucleic acid from nuclease enzymes in biological fluids and promotes the virus's attachment to susceptible host cells.

Why does a chemical reaction require increased activation energy without an enzyme as a biological catalyst?

Enzymes are catalysts that speed up the rate at which a reaction occurs by lowering the activation energy of the substrate. In the absence of an enzyme, the substrate has a higher activation energy. The higher the activation energy, the longer it takes for the reaction to occur.

Identify the components of an enzyme.

Enzymes are proteins comprised of amino acids linked together in one or more polypeptide chains.

Why is enzyme specificity important?

Enzymes have this specificity because the 3-D shape of the specific amino acid of the active site fits the substrate almost perfectly.

Why is Epulopiscium not in the same domain as Paramecium?

Epulopiscium is placed with the prokaryotes

Using Escherichia coli and Entamoeba coli as examples, explain why the genus name must be written out on first use. Why is binomial nomenclature preferable to common names?

Escherichia coli and Entamoeba coli have the same specific epithet and the same first letter of its genus name, it is needed to write the full name to know which one is being talked about Binomial nomenclature is preferable to common names to help scientist chare knowledge efficiently and accurately

List the defining characteristics of fungi.

Eukaryotic Chemoheterotrophs Sterols in cell membrane Cell wall contains chitin Spores used for sexual and asexual reproduction hyphae

phylogeny

Evolutionary history of a species

Describe the chemical reactions of fermentation.

Fermentation is a metabolic process in which an organism converts a carbohydrate, such as starch or a sugar, into an alcohol or an acid.

Provide two examples of the use of biochemical tests to identify bacteria in the lab.

Fermentation test Oxidase text

Where do amino acids required for protein synthesis come from?

From intermediates of carbohydrate metabolism

Why is glucose such an important molecule for organisms?

Glucose has many hydrogen atoms that are highly reduced compounds, containing a large amount of potential energy

Describe how lipids and proteins undergo catabolism.

Glycerol enters the glycolysis pathway as an intermediate. Fatty acids are further broken down into 2 carbon molecules and ultimately forming acetyl CoA. microbes break down proteins into subunits - amino acids.

Name two diseases that may be diagnosed by Western blotting.

HIV and Lyme disease

Of what value are hemolysins to pathogens?

Hemolysins aid in the destruction of red blood cells. When the membrane of red blood cells is destroyed, hemoglobin is released and is used as a nutrient for bacteria.

Could humans exist on chemically defined media, at least under laboratory conditions?

Humans would probably not be able to exist on chemically defined media, unless other organisms lived in the same media with them.

What is in the Bergey's Manual?

Identification schemes based on cell wall composition, morphology, differential staining, oxygen requirements, and biochemical testing.

How is photosynthesis important to catabolism?

Important for obtaining and using energy in living organisms

How does a bud differ from a spore?

In budding the parent cell forms a bud on its outer surface that elongates and eventually breaks away after the parent cell's nucleus divides and is put into the new cell. During the spore formation, the parent produces and releases spores to produce new individual cells.

Where does chemiosmosis occur in eukaryotes? In prokaryotes?

In eukaryotes, it occurs in the mitochondria during cellular respiration and in the chloroplasts during photosynthesis. In prokaryotes, it occurs in the cell membrane

In what place in the human body do you often find Fusobacterium?

In the gingival crevice of the gums and in the intestines

How does a spirochete's motility differ from that of Spirillum?

It has an extra of two or more axial filaments enclosed in the space between an outer sheath and the body of the cell

What is the competitive advantage provided by attaching to a surface?

It increases their nutrient uptake

How can an RNA virus cause cancer if it doesn't have DNA to insert into a cell's genome?

It integrates it viral RNA into the host cell's DNA; new genetic material is thereby introduced into the host's genome

What is a latent viral infection and give an example.

It is a condition in which a pathogen remains in the host for long periods without producing disease. Simplexvirus

How do fimbriae contribute to pathogenicity?

It is used to attach to host cells

What is fungal dimorphism?

It is when the fungus can grow either as a mold or as a yeast depending on temperature

Why does PCR identify a microbe?

It produces a DNA barcode for each species

What is an environmental advantage of a pigment?

It protects from antimicrobial effects of sunlight

Identify a way in which pathogens find it advantageous to form biofilms.

It shelters them from harmful factors in the environment; the human immune system for example

Vibrio cholerae produces toxin and is capable of causing cholera only when it is lysogenic. What does this mean?

It's only capable of causing cholera when the viruses incorporate their DNA into the host cell's DNA and begin the lysogenic cycle.

List four compounds that can be made from pyruvic acid by an organism that uses fermentation.

Lactic acid, ethanol, propionic acid, and butyric acid

To which genus is Enterococcus more closely related: Staphylococcus or Lactobacillus?

Lactobacillus

In what ways are lichens unique?

Lichens are unique in that they are composed of two (or more) different species, or in fact, kingdoms.

Under what circumstances is the MPN method used to determine the number of bacteria in a sample?

MPN is most useful when the microbes being counted will not grow on solid media. It is also useful when the growth of bacteria in a liquid differential medium is used to identify the microbes.

Discuss the limitations of a two-kingdom classification system.

Many organisms such as fungi, bacteria, protozoa, and algae did not belong to either the plant or the animal kingdom but were placed in one or the other simply because no other kingdoms existed in this system to accommodate these organisms.

Why might primitive civilization have used food preservation techniques that rely on osmotic pressure?

Microorganisms obtain almost all their nutrients in solution form the surrounding water. Osmotic pressure can stop the growth of certain bacteria.

How can the cell structure of mycoplasmas account for their pleomorphism?

No rigid cell walls

Can a complex organism, such as a beetle, divide by binary fission?

No, because complex organisms reproduce sexual not asexual

If two mice started a family within a fixed enclosure, with a fixed food supply, would the population curve be the same as a bacterial growth curve?

No, this growth curve applies to bacteria and mammals function differently.

How do carrier molecules function in the electron transport chain?

Oxidation and reduction

How do oxidation and reduction differ?

Oxidation is the removal of electrons from an atom or molecule, a reaction the often produces energy. Reduction is the addition of electrons to a molecule

How can you detect the presence of a bacterium that cannot be cultured?

PCR

What is the basic difference between chemotrophs and phototrophs?

Phototrophs use light as their primary energy source, whereas chemotrophs depend on oxidation-reduction reactions of inorganic compounds for energy.

On what basis are fungi classified into phyla?

Phyla within the fungi are defined primarily based on life cycles, mode of reproduction, and cell wall and septum structure.

Differentiate virus, viroid, and prion.

Prions are infectious proteins that cause a number of neurological diseases and a virion is another name for a complete virus.

What is the principle involved in DNA probes?

Probes will hybridize with a complementary strand of DNA.

What is the value of a capsid to a virus?

Protect, transport, and deliver their genome

Classify microbes into five groups on the basis of preferred temperature range.

Psychrophiles, psychrotrophs, mesophiles, thermophiles, and hyperthermophiles

What happens to an enzyme below its optimal temperature? Above its optimal temperature?

Reaction rate is slower when the enzyme is below its optimal temperature. The reaction rate increases with temperature until the enzyme is denatured by heat and inactivated.

What is the result of the lytic cycle?

Release of multiple new virions and dead host cell

What evidence supports classifying organisms into 3 domains?

Ribosomes are present in all cells but, they are not the same in all cells. Comparing the sequences of nucleotides in ribosomal RNA shows that there are three distinctly different cell types which lead to the three-domain system. In this system, cells are classified by cell type, cell wall, rRNA, membrane lipid structure, tRNA, and sensitivity to antibiotics.

Which techniques involve nucleic acid hybridization?

Southern blotting, DNA chips, FISH

What is tested in Western blotting and Southern blotting?

Specific proteins separated by electrophoresis

What are the functions of nucleotides in a cell?

Stimulate and inhibit the rate of cellular metabolism

How does the arrangement of Streptococcus differ from Staphylococcus?

Streptococcus bacteria are usually in chains, and Staphylococcus bacteria usually form clusters.

List factors the influence enzymatic activity.

Temperature, pH, and concentration

Describe the roles of the fungus and the alga in a lichen.

The alga photosynthesizes, providing carbohydrates for the lichen; the fungus provides a holdfast Lichens colonize habitats that are unsuitable for either the alga or the fungus alone

What is a provirus?

The double-stranded DNA molecule synthesized from the viral RNA

What stage of the life cycle is infectious to humans?

The elementary bodies

What is the proton motive force?

The force that promotes movement of protons across membranes downhill the electrochemical potential

Why is sugar added to fruit to make jams and jellies?

The high sugar concentration draw water out of any microbial cells that are present and thus prevent the growth of bacteria

Describe how pure cultures can be isolated by using the streak plate method.

The last cells to be rubbed off the loop are far enough apart to grow into isolated colonies

Describe the chemiosmotic model for ATP generation.

The mechanism of ATP synthesis using the E.T.C. is called chemiosmosis. High Hydrogen Concentration on the outside of the Inner Mitochondrial Membrane undergoes active transport where it is pushed through ATP synthase (protein channel) -- the energy released from the proton pump/channel is used to synthesize ATP from ADP and Pi (Phosphate).

Describe the chemical reactions of glycolysis.

The most common pathway for the oxidation of glucose is glycolysis. Pyruvic acid is the end-product. Two ATP and two NADH molecules are produced from one glucose molecule

On what biochemical basis are Pseudomonas and Escherichia differentiated?

The oxidase test Pseudomonas is oxidase-positive, and Escherichia is oxidase-negative

What is glycolysis?

The oxidation of glucose to pyruvic acid with the production of some ATP and energy

How does specialized transduction differ from the lytic cycle?

The phage coat picks up the bacterial genes and transfer it to another bacterium

What physiological characteristic of Clostridium makes it a problem in contamination of deep wounds?

The rod-shaped cells contain endospores that usually distend the cell

taxonomy

The scientific study of how living things are classified

metabolism

The sum of all the chemical reactions that occur in a living cell

Assume you isolated a single-celled organism that has a cell wall. How would you determine that it is a fungus and not a bacterium?

There will be no peptidoglycan in fungal cell walls, instead there will be chitin

What is an opportunistic mycosis?

These are fungal infections of the body which occur almost exclusively in debilitated patients whose normal defense mechanisms are impaired. The organisms involved are cosmopolitan fungi which have a very low inherent virulence.

What are the similarities between the slide agglutination test and the ELISA test?

They both can identify bacteria quickly

What is the purpose of an amphibolic pathway?

They bridge the reactions that lead to the breakdown and synthesis of carbohydrates, lipids, proteins, and nucleotides.

How does the nutritional diversity of pseudomonas make them a problem in hospitals?

They can grow on minute traces of unusual carbon sources, such as soap residues or cap-liner adhesives found in a solution They also can grow in some antiseptics

How does the photosynthesis of cyanobacteria differ from that of the purple sulfur bacteria?

They do not use water as their reducing agent, and so do not produce oxygen. Instead, they use hydrogen sulfide, which is oxidized to produce granules of elemental sulfur

What is the value of the pentose phosphate and Entner-Doudoroff pathways if they produce only one ATP molecule?

They form 2 NADPH molecules

Other than controlling acidity, what is an advantage of using phosphate salts as buffers in growth media?

They have the advantage of exhibiting their buffering effect in the pH growth range of most bacteria

What features do chloroplasts, mitochondria, and bacteria have in common?

They have their own DNA, which is separate from the DNA found in the nucleus of the cell. And both organelles use their DNA to produce many proteins and enzymes required for their function

What is the primary role of algae in the ecosystem?

They play a vital role in aquatic ecosystems by forming the energy base of the food web for all aquatic organisms. As autotrophic organisms, algae convert water and carbon dioxide to sugar through the process of photosynthesis.

Of what value are taxonomy and systematics?

To facilitate research and communication we use taxonomy. To further study evolutionary relationships among organisms, we use systematics (or phylogeny).

What are the products of the Krebs cycle?

Two molecules of carbon, three molecules of NADH, one molecule of FADH2 and one molecule of ATP or GTP are produced

Differentiate a virus from a bacterium.

Viruses do not have plasma membrane They do not multiply by binary fission They do not have both DNA and RNA They do not have ribosomes There are not sensitive to antibiotics

Why are viruses grown in eggs and not in culture media?

Viruses need a living host to grow, they cannot grow in culture media

What is a plaque-forming unit?

Visible clearing in a bacterial culture caused by lysis of bacterial cells by bacteriophages

Differentiate Western blotting from Southern blotting.

Western blotting is a type of serological testing that identifies antibodies in a patients serum; used to confirm HIV infection. Proteins are separated. Southern blotting uses nucleic acid hybridization to identify unknown microorganisms using DNA probes. DNA is separated.

What chemical reaction causes the release of H2S?

When the bacteria remove sulfur from amino acids

When is denaturation irreversible?

When the denaturation continues until the enzyme has lost its solubility and coagulates, the enzyme cannot regain its original properties.

Are yeasts beneficial or harmful?

Yeasts are both beneficial and harmful. Some yeasts are used to make bread and wine while others cause infections

Is a colony formed as a result of streaking a plate always derived from a single bacterium?

Yes, each colony arises from a single bacterium that divides and redivides several times until the large colony of bacteria produces

List the asexual and sexual spores made by zygomycetes, ascomycetes, and basidiomycetes.

Zygomycetes - sexual spores are zygospores Ascomycetes - asexual spore are conidia Basidiomycota - sexual spores are basidiospores and asexual spores are conidiospores

List defining characteristics of the four phyla of fungi.

Zygomycota =conjugation fungi -Saprophytic molds (bread mold) Ascomycota = sac fungi -Includes molds and yeasts (like ones for brewing beer) Basiciomycota = club fungi -Fleshy fungi (mushrooms!) "Deuteromycota" = fungi imperfecti -Unknown sexual stages -Include most pathogenic fungi

mycelium

a mass of long filaments of cells that branch and intertwine, typically found in molds

Why shouldn't bacteria be placed in the plant kingdom?

bacteria have prokaryotic cells and rRNA loop (plants don't)

Distinguish chemically defined and complex media.

chemically defined medium: one whose exact chemical composition is known. Complex media: made up of nutrients including extracts from yeast, meat, or plants, or digest of proteins from these and other sources. the exact chemical composition varies slightly from batch to batch.

Is a cladogram used for identification or classification?

classification

Why do the DNA probe and cellular DNA hybridize?

complementary base pairing

What is the arrangement of Vibrio cholerae cells?

curved rod

Is oomycote more closely related to Penicillium or to diatoms?

diatoms

Whittaker

founded the five-kingdom system in which prokaryotes were placed in the kingdom Prokaryote, and eukaryotes comprised the other four kingdoms in 1969

Oncogenes

genes that cause cancer by blocking the normal controls on cell reproduction

Woese

in 1978 proposed elevating the three cell types (eukaryotes, bacteria, and archaea) to a level above kingdom, called domain. (Evolutionary Tree)

Linnaeus

introduced a formal system of classification with two kingdoms; Plantae and Animalia in 1735

Why is it difficult to measure realistically the growth of a filamentous mold isolated by the plate count method?

it is difficult to count with plate count method because in plate counts of actinomycetes and molds, it is mostly the number of asexual spores that are counted instead

Direct methods usually require an incubation time for a colony. Why is this not always feasible method for analyzing foods?

population numbers are usually recorded as the number of cells in a milliliter of liquid or in a gram of solid material. It is not practical to measure the small amount needed on food so instead a homogenate of 1 part food: 9 parts water is ground in a blender. Samples of this initial 1/10 dilution can then be transferred with a pipette for further dilutions or cell counts

Explain the differences between competitive inhibition and feedback inhibition

- Competitive inhibitors fill the active site of an enzyme and compete with the normal substrate for the active site. - Feedback inhibition is the inhibition of an enzyme in a particular pathway by the accumulation of the end-product of the pathway; also called end-product inhibition.

Compare the energy yield (ATP) of aerobic and anaerobic.

- The ATP yield is higher in aerobic respiration than anaerobic respiration. - Aerobic processes produce up to 38 ATP per glucose. Anaerobic processes yield only 2 ATP per glucose.

What happens during the preparatory and energy-conserving stages of glycolysis?

2 ATP used as 6 carbon glucose is broken down to form DHAP and GP which are readily converted to each other

During which phase of fermentation is ATP generated?

ATP is generated during glycolysis