Exam 1

Darkfield Microscopy

A filter is used to block visible light to create a highly contrasting background

Plasmid

Extrachromosomal DNA that can be shared between cells

Which structure is not found in all bacteria?

Flagella

Condenser lens

Focus light through the specimen

Antonie van Leeuwenhoek used his microscope to look at a drop of water from a rain puddle and saw little entities he called "animalcules." Which Figure (fig.) in his drawings likely made him think that these "animalcules" were alive?

(the one that looks like it's moving)

Bacterial cells use a form of asexual reproduction called:

Binary fission

What is the limit of resolution of the unaided human eye?

0.2 Millimeters

Which structure is found in all cells?

Cell membrane

For the most part, eukaryotic cells are more complex than prokaryotic cells. On the other hand, which of the following is more complex in prokaryotes than in eukaryotes?

Cell wall

Gram stain is used to differentiate bacteria based upon their:

Cell wall thickness

Which molecules are synthesized in the nucleus?

DNA, mRNA, and rRNA

Mannitol salt agar contains a sugar (mannitol) that some bacteria can ferment to produce acid. Phenol red is a dye that changes color (red to yellow) when acid is produced. Staphylococcus aureus ferments mannitol and turns yellow but Staphylocoocus epidermidis does not and there is no color change (see image). Scientists can use this medium to identify pathogenic S. aureus in clinical samples. Which term describes this pro

Differential

Endospore

Dormant bacterial structure for survival during unfavorable growth conditions

When a bacterium releases _____ from its outer membrane when it dies, this molecule is called endotoxin because it causes systemic problems in the host.

Lipopolysaccharide

Which molecule/structure is NOT found in every living cell?

Nucleus

When early prokaryotic cells began performing photosynthesis this led to the production of _______, which contributed to an increase in energy conversion by cellular respiration and the evolution of complex eukaryotic cells.

Oxygen gas

The bacterial cell wall is composed of ________ which is a complex polymer of alternating NAG and NAM sugar chains that are cross-linked with short amino-acid chains.

Peptidoglycan

Escherichia coli has multiple flagella that cover the surface of the bacterial cell (see image). This arrangement of flagella is called:

Peritrichous

Which part of the compound light microscope magnifies the specimen?

The objectives and the eyepiece

Which of the following is not typically a characteristic of bacterial pathogens?

They are not autotrophs

Why do some antibiotics that target bacterial 70S ribosomes show toxicity in humans?

They inhibit protein synthesis in the host cell mitochondria

In which location are the 70S ribosomes found?

the bacterial cell cytoplasm and the human mitochondria

Theory that explains the prokaryotic origins of energy-converting organelles of eukaryotes is called:

theory of endosymbiosis

Given the following cell diameters, all the following cells are microscopic except the one that is: 1.)0.08 millimeters 2.)66,000 nanometers 3.) 0.000047 meters 4.) 325 micrometers

325 micrometers

The ideal incubator temperature in the clinical microbiology lab is ​[ENTER NUMBER ONLY} degrees Celsius because that is equivalent to human body temperature.

37.0

Bacterial ribosomes are composed of a 30S small subunit and a 50S large subunit. Together these subunits make a ribosome that is how many "S" units?

70

Viruses have genes and they reproduce. They do not have ribosomes or metabolic activity and require a living host to reproduce. In which category are viruses classified?

Acellular

What is the key step of the Gram stain procedure, where thick and thin cell wall bacteria become differentiated?

Alcohol decolorize

According to the theory of endosymbiosis, phagocytosis of photosynthetic cyanobacteria by early eukaryotic cells led to the evolution of:

Algae and plants

Which microbes have 80S ribosomes?

Algae, fungi, and helminths

Which of the following has genes? a.) Helminths b.) bacteria c.) fungi d.) protists e.) viruses

All of them have genes

Sex pilus

Hollow protein tube used to transfer genetic material between cells

An incubator in a clinical microbiology lab is typically set to 37 degrees C for the growth of human pathogens. This temperature is used because it mimics:

Internal human body temperature

Which structure is involved in the spread of antibiotic-resistance genes amongst bacteria

Sex pilus

Confocal fluorescence microscopy

UV light is used to reveal fluorescent dyes that have been used to stain the specimen

Microbes are EVERYWHERE! Some of these microbes can cause infection in humans. What is the simplest and most effective method for limiting transmission of most microbes?

Wash your hands

Brightfield Microscopy

A colored stain is typically used to create contrast in the specimen against a light background

phase contrast microscopy

A filter is used to adjust the wavelength of visible light to create contrast in the specimen

What are the three domains of life, as described in the 1970's by Carl Woese, who designed a system of taxonomy by comparing sequences of ribosomal RNA from all living organisms?

Archaea, Eukarya, Bacteria

Robert Koch described the etiology of anthrax by isolating a rod-shaped bacterium from infected cattle and showed that it could cause similar infection in healthy test animals. Which of the following shows the correct usage of binomial nomenclature for this pathogen?

B. anthracis (italicized)

Pasteur's swan-necked flask experiments demonstrated that life can only be produced by preexisting life. This theory is known as

Biogenesis

How can porins be helpful to bacteria during infection of a human host?

Block the passage of antibiotics like penicillin through the membrane

C3b is a host protein that binds to the bacterial cell surface and aids in phagocytosis. Which bacterial structure helps with the evasion of host immune responses by preventing C3b from binding to its receptor on phagocytes?

Capsular polysaccharide

What process is being demonstrated in the picture of bacteria?

Conjugation

Escherichia coli is a bacterium that is part of the normal flora of the human intestines. Which of the following cell structures is likely critical to the ability of E. coli to colonize the intestinal lining?

Fimbriae

Which of the following statements about eukaryotic flagella is false? a.) flagella are composed of 9+2 arrangement of microtubules b.) cells can have more than one flagellum c.) flagella are found in some types of motile algae and protozoa d.) flagella are not found in most fungi e.) flagella can rotate in both clockwise and counterclockwise directions

Flagella can rotate in both clockwise and counterclockwise directions

What occurs during the most critical step of the Gram stain procedure, when bacterial cells on a slide are rinsed with alcohol?

Gram-negative cells lose their purple stain and become colorless

What is the simplest and most effective method for infection control?

Hand washing

Which of the following have ribosomes? a.) helminths b.) bacteria c.) fungi d.) protists e.) viruses

Helminths, bacteria, fungi, and protists

Molds are fungi that produce filaments called ________, which give the mycelium of mold colonies their characteristic "hair" appearance.

Hyphae

What do mold spores produce when they germinate that gives the mycelium its filamentous appearance?

Hyphae

On which item found in fast-food restaurants did a 7th grade student find more bacteria than in toilet water from the same restaurant (see Supplemental Reading on Bb)?

Ice

What are the five I's in the correct order?

Inoculation Incubation Isolation Inspection Identification

Cytoskeleton

Internal network of protein filaments that are involved in determining cell shape/growth/division

Streak plate is a dilution technique often used to study species in mixed specimens. Which term describes the goal of the streak plate?

Isolation

Which scientist introduced aseptic technique by using a carbolic acid (phenol) spray during surgeries to prevent infections?

Joseph Lister

Place the metric units in the correct order from largest to smallest: Micrometer, Kilometer, meter, millimeter, centimeter, nanometer

Kilometer Meter Centimeter Millimeter Micrometer Nanometer

Walking along the South Rim of Grand Canyon on summer vacation, I noticed small circular plaques in the walkway that marked the Trail of Time, where each unit of distance represented a number of millions of years. The Earth is old, so that was a long trail! What is the significance of the time marked on this plaque? (Hint: 3700 million years is 3.7 billion years)

Life appeared (first cells)

Which structure is unique to gram-negative bacteria?

Lipopolysaccharide

What is the flagellar arrangement seen in the picture?

Lophotrichous

Place the following microbes in the correct size order from largest to smallest -Candida albicans (yeast) -Staphylococcus aureus (bacteria cell) -Influenza virus (virus) Lymphocyte (human blood cell)

Lymphocyte Yeast Staph Flu

Ocular lens

Magnifies specimen; fixed magnification of 10x; also called eyepiece

When a microscopic fungal spore germinates, it produces filaments called hyphae. Overtime, the hyphae grow until a visible surface growth appears, which is called the:

Mycelium

Slime layer

Polysaccharide coating that is used for attachment to host surfaces

Flagellum

Protein appendage that rotates to produce motility

Fimbria

Protein fiber that is used for attachment to host surfaces

Round endoplasmic reticulum

Protein synthesis

Which pair of microbes is eukaryotic? a.) protists and viruses b.) archaea and fungi c.) bacteria and molds d.) bacteria and viruses e.) protozoa and fungi

Protozoa and fungi

An amoeba called entamoeba histolytica is a protozoan intestinal parasite that uses extensions of its cytoskeleton called ____ to help it "crawl" and "eat."

Pseudopods

Bacillus anthracis is a gram-positive streptobacillus. What do you expect to see under the microscope following a Gram stain?

Purple, rod-shaped cells in chains

In eukaryotes, proteins synthesized in the ____ will eventually be embedded in membranes or secreted outside of the cell

Rough endoplasmic reticulum

Which microbes have genes but are not composed of cells and require a living host for reproduction?

Viruses

What observation made by Semmelweis and others led to the understanding that hand hygiene was important for infection control?

When doctors delivered babies there was a higher incidence of childbed fever than when midwives delivered

Unicellular fungi called _____ reproduce by budding (see image), and some can form pseudohyphae

Yeast

Antibiotic usage in patients can cause a depletion of normal flora and lead to the development of diarrheal disease caused by "C. diff." One possible method to replace the good bacteria is:

a fecal transplant

Which pair of microbes is prokaryotic: a.) archaea and bacteria b.) protists and viruses c.) bacteria and molds d.) bacteria and viruses e.) protozoa and fungi

a.) archaea and bacteria

A polysaccharide called ____ which is derived from red algae, is used as a solidifying agent in microbiological culture media.

agar

What polysaccharide derived from red algae is used as a stable solidifying agent in microbial culture media?

agar

Algae and protozoa are both classified in the same kingdom. This classification is unusual because at the cellular level algae are more similar to plants and protozoa are more similar to:

animals

Helminths are classified as:

animals

An inoculating loop is sterilized in a flame before collecting a sample of a specimen. This ensures that contamination will not be introduced into a culture. This method is known as:

aseptic technique

Which statement about the current pandemic is FALSE? a.) individuals with asymptomatic covid can transmit the pathogen b.) COVID-19 behaves like the influenza in terms of contagiousness and incubation time c.) COVID-19 is caused by a novel coronavirus that emerged from animals d.) Case, hospitalization, and death rates for COVID-19 are higher in Black and Hispanic populations as compared to white e.) community spread of COVID-19 is increased in crowded, enclosed situations

b.) COVID-19 behaves like the influenza in terms of contagiousness and incubation time

Which statement about bacteria is false? a.) they do not have a nucleus b) they are classified as eukaryotic C.) they are generally smaller than human cells but larger than viruses d.) some causes diseases in humans E.) some are photosynthetic

b.) they are classified as eukaryotic

During the COVID-19 pandemic, young children have shown lower morbidity and mortality rates than adults, which is unusual fore most infectious diseases. Which of the following explanations does not fit this model? a.) young children have healthier blood vessels than adults b.) young children have stronger immune responses than adults c.) young children have lower expression of the cell receptor for the virus than adults d.) young children have recently acquired maternal immunity e.) young children have more recently been vaccinated against viral diseases

b.) young children have stronger immune responses than adults

Protozoan cysts are functionally similar to:

bacterial endospores

Slime layer is produced by Staphylococcus epidermidis to allow this otherwise harmless skin bacterium to attach to and form a ____ on indwelling catheters, which leads to serious bloodstream infections in hospital patients.

biofilm

All of the following are features of the bacterial cell wall except: a.) glycan chains comprised of alternating NAG and NAM sugars b.) peptide cross links for strength c.) selectively permeable barrier to the cell d.) provides structural support against osmotic pressure e.) weakened by the antibiotic penicilin

c.) selectively permeable barrier to the cell

To prevent meningicoccal meningitis, college students and other at-risk individuals can get a vaccine (e.g. Menactra) that stimulates the host immune system to produce antibodies that stick to the glycocalyx of Neisseria meningitidis and aid in the adherence to phagocytes. What bacterial molecule is contained in this vaccine? (if you are not sure, try to Google it)

capsule

Which part of a cell is composed of a selectively permeable, flexible, fluid, phospholipid bilayer that helps regulate the passage of molecules between the inside of the cell and the external environment?

cell membrane

Mitochondrion

cellular respiration and ATP synthesis

Fungal wall is comprised of

chitin

The theory of endosymbiosis describes the evolution of which two eukaryotic organelles?

chloroplasts and mitochondria

All of the following structures are associated with gram-negative bacteria except: a.) porins b.) lipopolysaccharides c.) cilia d.) cell wall e.) cell membrane

cilia

The picture shows "hairy" appearance on the protozoan. What do these "hairs" represent?

cilia

Glycocalyx

coating of polysaccharides that are used for attachment

Because all the daughter cells are derived from the original microscopic parent cell, an isolated _________ represents a macroscopic pure culture of identical cells from one species.

colony

All the following can be visualized with a typical light microscope except: -Human blood cell -Coronavirus particle -Staphylococcus aureus bacterial cell -Paramecium caudatum protozan cell

coronavirus particle

Cryptosporidium parvum is responsible for outbreaks of diarrheal illness at public swimming pools and water parks because this protozoan parasite produces chlorine-resistant _____ that are resistant to the antimicrobial chemicals added to the water

cysts

Which of the following terms is not associated with candida albicans (yeast): a.) budding b.) chitin c.) ergosterol d.) mycosis e.) endospores

e.) endospores

cell membranes are the same as cell walls

false

Which structure is found in both prokaryotes and eukaryotes

flagella

Smooth endoplasmic reticulum

lipid synthesis and vesicle production

Objective lens

magnifies specimen; usually 3-4 different powers

What does the prefix micro mean?

millionth

Mycobacterium tuberculosis is a bacterium that causes the lung infection tuberculosis (TB). It has a cell wall containing ________ acids, which are waxy substances that help the bacteria survive dehydration outside of the host and helps it survive host defenses and antibiotics in the host during infection.

mycolic

Nucleus

nucleic acid storage and synthesis

Chloroplast

photosynthesis

Axial filaments

protein fibers that are used for motility

Golgi apparatus

protein modification and sorting

An adult parasitic hookworm, Ancylostoma duodenale, can be classified using all of the following terms except: a.) animalia b) macroscopic c.) multicellular d.) eukarya e.) protista

protista

Which of the following classifications include microbes that use cilia for motility? 1.) Algae 2.) Helminths 3.) bacteria 4.) Protozoa 5.) fungi

protozoa

The site of the nucleolus is a site of abundant _____ synthesis

rRNA

What is the measurement of the clarity of image produced by a lens called

resolution

What males the RER "rough"

ribosomes

Flagellated bacteria respond to environmental signals by a process called chemotaxis. When a bacterium senses it is getting further away from a food source, it will rotate its flagellum in a clockwise direction that causes the cell to

tumble