BIOL 1011 - FINAL EXAM

A bacterial pathogen that has acquired resistance to multiple classes of antibiotics, often through plasmids, is commonly known as a:

Superbug

A color change from purple to yellow in a biological indicator using bromocresol purple signifies:

A drop in pH due to bacterial fermentation

A fundamental difference in genome organization is that eukaryotic main chromosomes are typically _____.

Linear and located in the nucleus

A macrolide antibiotic like erthromycin functions by inhibiting which cellular processes in bacteria?

Protein synthesis

A yellow turbid change that results in a spore test using bromocresol purple indicates that the spores of an indicator organism used were:

Viable and metabolically active

An antibiotic targeting the 70S ribosome is a good candidate for treating bacterial infections because this type of ribosome is absent from:

The human cytoplasm

An organism observed under a microscope measures approximately 3 µm in diameter and lacks a nucleus. It is most likely a(n):

Bacterium

Antibiotics like chloramphenicol and doxycycline can have side effects in humans because they can inhibit protein synthesis within:

Mitochondria

Besides prokaryotes, where does the process of binary fission also occur within eukaryotic cells?

In mitochondria and chloroplasts

Coupled transcription and translation allows for a rapid response to environmental stimuli and is a hallmark of which cell type?

Prokaryotes

Due to the presence of a nuclear envelope, what molecule must be transported to the cytoplasm to serve as the template for protein synthesis in eukaryotes?

Mature mRNA

Erythromycin is an effective and selective antibiotic because it specially binds to and inhbits:

Bacterial 70S ribosomes

Following the onset of an infection, which type of leukocyte is noted to peak in numbers approximately 24-48 hours later?

Neutrophil

Fungi, such as Aspergillus niger, are classified as what type of organism?

Eukaryotic

How do bacteria, such as Streptococcus pyogenes, primarily reproduce?

Binary fission

Human mitochondria are susceptible to certain antibacterial agents because they:

Contain 70S ribosomes, similar to bacteria

If an autoclave fails to sterilize its contents, what visual change indicating growth will be observed in the spore test vial after incubation?

The media will become turbid

In a failed autoclave run, the surviving spores are described as metabolically:

Active

In a PROSPORE biological indicator, what metabolic process is prevented if sterilization is successful?

Fermentation

In a spore test vial from a successful autoclave run, the spores do not germinate, meaning there is:

No growth

In addition to their main chromosome, bacteria can carry extrachromosomal DNA molecules that often contain antibiotic resistance genes. These molecules are called:

Plasmids

In the case of pulmonary aspergillosis, what type of microorganisms causes the infection?

A fungus

In the case study, a strain of Klebsiella pneumoniae that is resistant to almost all antibiotics is referred to as a:

Superbug

Meiosis is a specialized type of cell division in eukaryotes for the purpose of:

Producing gametic cells

Mitosis in a human is essential for processes like:

Growth and repair of skin tissue

Prokaryotic cells, such as bacteria, contain ribosomes with a sedimentation coefficient of _____ S:

70S

Ribosomes are complex structures composed of ribosomal RNA (rRNA) and what other macromolecules?

Protein

The antibiotic Gentamicin is listed as potentially affecting both cytoplasmic 80S and mitochondrial 70S ribosomes, which would explain its:

High potential for toxicity in humans

The DNA of a eukaryotic cell is primarily housed within which structure?

The true nucleus

The endosymbiotic theory explains why some antibiotics can inadvertently harm human cells by targeting the 70S ribosomes found in which organelle?

The mitochondrion

The evolutionary origin of mitochondria from an engulfed prokaryote is explained by the:

Endosymbiotic Theory

The filamentous structures that make up the body of a multicellular fungus like Aspergillus are known as:

Hyphae

The growth of surviving Geobacillus stearothermophilus spores leads to the fermentation of nutrient media, which causes the liquid to become more:

Acidic

The multiple, linear chromosomes characteristic of eukaryotic cells are found within which organelle?

The nucleus

The pH indicator bromocresol purple is purple in neutral/alkaline conditions and turns what color in acidic conditions produced by fermentation?

Yellow

The pilin subunits mentioned in the diagram of bacterial conjugation are the protein building blocks that form the:

Conjugation pilus

The primary function of a ribosome is to synthesize which type of molecule during translation?

Proteins

The primary genetic element transferred during bacterial conjugation that spreads traits like antibiotic resistance is the:

Plasmid

The process where a eukaryotic cell, such as a white blood cell, engulfs a bacterium is known as:

Phagocytosis

The ribosomes found in the cytoplasm of eukaryotic cells have a sedimentation coefficient of _____ S:

80S

The term “not turbid” in the context of a biological indicator test means the liquid is:

Clear

The turbidity observed in a failed spore test is caused by:

The massive growth of bacteria

What are the standard operating parameters for successful steam sterilization in an autoclave as listed on the slide?

121 degrees C

What is the typical size range for most eukaryotic cells like fungi and protozoa?

10 to 100 µm

What is the approximate generation time for Streptococcus pyogenes listed in the slide, highlighting its potential for rapid growth?

30 minutes

What structural feature of eukaryotic cells is the primary reason that transcription and translation are not coupled?

The nuclear membrane

Which of the following is an example of a unicellular eukaryote mentioned in the slides?

Yeasts

Which of the following organelles would NOT be found in a Streptococcus pyogenes cell?

Mitochondria

Which type of cell division is characteristic of eukaryotes for the growth and repair of multicellular tissues?

Mitosis

While some fungi form multicellular hyphae, others exist in a unicellular form known as:

Yeasts

Why is Geobacillus stearothermophilus chosen as the indicator organism for steam sterilization?

Its spores are highly resistant to heat and steam

A “saprobe” is a specific type of heterotroph that acquires its carbon and energy from what source?

Dead organic matter

A barophile is a microorganism specifically adapted to survive in what type of extreme physical enviornment?

Extreme pressure

A clinical isolate is identified as a unicellular microorganism whose cell wall is composed of chitin. Based on this information alone, which antimicrobial agent would be predicted to be completely ineffective?

Penicllin

A defining physiological characteristic of Acidthiobacillus ferroxidans is its ability to maintain a near-neutral internal pH of around 6.5 while thriving in an external environment with a pH of:

Less than 3

A fundamental structural distinction between the prokaryotic cells of Strep. pyogenes and the eukaryotic cells of its human host, which forms the basis for the efficacy of penicillin, is the:

Presence of a peptidoglycan-containing cell wall in the bacterium

A human pathogenic bacterium is most likely to be classified in which temp-dependent group due to its enviornment?

Mesophile

A microbe discovered thriving in a compost heap with a temp of 65 degrees C would be classified as a:

Thermophile

A microbiologist observes a eukaryotic microbe moving with numerous short, hair-like appendages that beat in a coordinated, wave-like fashion. These structures are identified as:

Cilia

A newly discovered motile bacterium thrives in a zero-sodium medium but stops moving when treated with a protonophore, a chemical that dissipates the proton gradient. What can be concluded?

It utilizes a proton motive force for motility

A specific vitamin that a bacterium cannot synthesize on it its own and must acquire from its environment is called a(n):

Growth factor

According to the diagram in the handout, the final step in the enzymatic breakdown of cellulose by Cellulomonas involves B-gluvosidase converting the disaccharide cellbiose into what final monomer product?

Glucose

According to the provided definitions in the handouts, a disease-causing parasite is referred to by what specific term in clinical microbiology?

Pathogen

According to the provided metabolic diagram, what does Acidthiobacillus ferroxidans use as its terminal electron acceptor during aerobic respiration?

Oxygen

Alkaliphiles are a class of extremophilic microbes defined by their ability to grow optimally at a pH:

Above 9

An organism that utilizes light for energy and inorganic CO2 as its carbon source is known as a:

Photoautotroph

Analogous to how penicillin targets peptidoglycan synthesis, a novel antimicrobial agent designed for selective toxicity against pathogenic fungi would most logically target the synthesis of which cellular component absent in human cells?

Chitin

During which phase of the microbial growth curve is the rate of cell division approximately equal to the rate of cell death, often due to nutrient limitation and waste accumulation?

Stationary Phase

Helicobacter pylori, a bacterium that colonizes the human stomach, is a classic example of a(n):

Acidophile

How does a chemoautotroph, such as lithotroph found in deep-sea vents, obtain its energy?

By oxidizing inorganic chemicals

In addition to surviving in highly alkaline conditions, many alkaphiles have a specific nutritional requirement for which ion for growth?

Sodium

Methanotrophic bacteria and archaea play a significant environmental role by using enzymes to perform what chemical conversion?

Oxidize methane into methanol

Penicillin is selectively toxic because it inhibits the synthesis of _____, a unique component of most bacterial cell walls; it is a consequently ineffective against eukaryotic fungi like yeast, whose cell walls are primarily composed of _____.

Peptidoglycan; chitin

The “danger zone” for food safety, which is between 30-40 degrees C, corresponds to the optimal growth range for which group of microorganisms?

Mesophiles

The bacterium Cellulomonas are notable for their ability to produce what?

Enzymes for cellulose decomposition

The clinical ineffectiveness of penicillin for treating a yeast infection stems from a fundamental difference in cell envelope biochemistry, specifically the yeast’s possession of a cell wall composed primarily of:

Chitin

The diagram on the “Misconception of Treating Yeast Infections” slide contrasts the penicillin target woth the structural polymer of the yeast cell wall, indicated by a green checkmark. This latter polymer is correctly identified as:

Chitin

The electrochemical gradient known as the proton motive force (PMF) is a versatile energy source used for flagellar motility and what other essential cellular process in bacteria?

ATP synthesis via ATP synthase

The image of Helicobacter pylori shows it possesses polar flagella. What does this term describe about the flagellar arrangement?

The flagella are located at one or both ends (poles) of the cell

The majority of microorganisms prefer an environmental pH that is best described as:

Neutral (pH 6-8)

The metabolic diagram of A. ferroxidans show it can use Fe3+ as a terminal electron acceptor instead of O2. This is an example of what type of metabolism?

Anaerobic respiration

The proton motive force is best descrived as an eleectrochemical gradient based on a differential concentration and separation of charge involving which particle?

Protons (H+)

The text and chemical equations indicate that some alkaiphiles, such as Strep. alkaliphilus, can actively adjust the pH of their local enviornment by utilizing which compound?

Sodium carbonate

To maintain a viable internal pH in a highly alkaline environment alkaliphiles rely on the crucial function of:

Specialized Na+/H+ anti porter systems

Under anaerobic conditions, the metabolic pathway of Acifithiobcvillus ferroxidans can involve the use fo ferric iron as an electron acceptor, reducing it to what compoynd?

Ferrous iron

What is the key characteristic that distinguishes active transport from passive transport?

Active transport requires a direct expenditure of energy, such as ATP

What term is used to describe a microbe adapted to thrive in environments with extremely high salt concentrations, such as the Great Salt Lake?

Halophile

Which nutritional category includes humans and most medically or environmentally relevant bacteria?

Hetetrophs

Which of the following correctly pairs a microorganism type with the primary structural biopolymer found in its cell wall?

Green Algae - Cellulose

Which process allows a microbe to scavenge scarce nutrients from a dilute environment by moving them against their concentration gradient?

Active transport

Which scientist famously ingested a culture of Helicobacter pylori to help prove the bacterium causes gastritis, fulfilling a key part of Koch’s postukates?

Barry Marshall

While most bacteria utilize a proton motive force, the genus Vibrio is a notable exception that powers its flagella using a gradient of which ion, reflecting its common habitat?

Sodium

Within the nutritional requirements of microbes, which of the following is classified as a micronutrient or trace element?

Zinc

A positive Catalase test is indicated by the production of:

Bubbles

Can Listeria monocytogenes cross the placenta?

Yes, causing harm to the fetus

Cholera Toxin (CT) is an A-B toxin. Which subunit binds to the GM1 ganglioside receptor on the host cell?

CtxB

High levels of cAMP cause the CFTR channel to pump which ion out of the cell and into the gut lumen?

Chloride

HpmA is a cytotoxin produced by:

Proteus mirabilis

If Proteus mirabilis ascends from the kidneys and crosses the tubular epithelial barrier, which serious condition can result?

Bactermia

In the aquatic enviornment, Vibrio cholerae can exit as free-swimming planktonic cells or in what other form?

Biofilms