Past Lab exams

The enzyme ATP synthase is used to produce ATP in the ________________ step of cellular respiration.

ETS

You inoculate a mixed culture of bacteria obtained from a patient's fecal sample onto EMB and MAC media. After allowing for bacterial growth overnight, the growth on the EMB plates has a green metallic-colored sheen, and there is dark pink, cotton candy-colored bacterial growth with a similar colored appearance of the media on the MAC plate. What organism are the results indicative of?

Escherichia coli

Why is the unknown in this example not Pseudomonas?

It ferments lactose.

Use the dichotomous key to determine the bacteria with the following characteristics: The organism is a gram-positive bacillus Doesn't form spores Catalase negative Glucose (A)- this means that acid was formed from the metabolism of glucose Mannitol negative

Lactobacillus delbrueckii

Which scientist proposed that streptococci be classified by variants within a species, called serovars?

Lancefield

Binomial nomenclature was established by

Linnaeus

Which scientist's finding proved that microbes cause surgical wound infections?

Lister

Why is microscopic visualization not sufficient to properly identify bacteria?

Many unrelated bacteria can share the same shape

Mike is one of your regular patients at the homeless clinic where you are a volunteer nurse. He has a severe cough and is quite thin. Last week you sent Mike's sputum sample to the laboratory and requested a Gram stain and acid-fast stain. The stain results are now posted in his chart: It says "acid-fast +." What infection does Mike likely have?

Mycobacterium tuberculosis

The cells that are solely involved in the first line of immune defense are __________, ___________, and ___________.

NOT : NK cells, T cells, eosinophils neutrophils, plasma cells, monocytes

Suzie's mother, Martha, took her to the family dentist for a dental examination. After Suzie's exam the dentist tells Martha that her daughter has 3 cavities and asks if she chews sugar-sweetened gum. Martha tells the dentist that Suzie does chew gum containing sugar. He suggests that Suzie switch to gum sweetened with xylitol to help reduce dental carries. Why may chewing gum sweetened with xylitol reduce the numbers of cavities, especially in children?

ONE OF: the fermentation of xylitol produces alcohol, so dental carries cannot form bacteria cannot ferment xylitol, so no lactic acid is produced

A number of different viruses can cause a condition in children call bronchiolitis. Which virus is the main etiological agent associated with bronchiolitis?

RSV

Which step of binary fission is the reason for genetically identical daughter cells?

Replication of the bacterial chromosome

What is the etiological agent of impetigo?

Staphylococcus aureus

Strep throat results in inflammation of the pharynx. What species of streptococci causes most cases of strep throat?

Streptococcus pyogenes

Two diseases that are associated with immune complex autoimmune disease are

Systemic lupus erythematosus and rheumatoid arthritis

Many possible explanations have been proposed as to why the numbers of pertussis infections have increased after the DTaP replaced the DTP vaccine. The DTP was made with heat-killed whole cells of the bacterium B. pertussis, while the DTaP is made with acellular pertussis components. The most likely explanation was that the DTaP vaccine was not as effective as the DTP at protecting children long-term. Which of the following best describes why this is the case?

The DTaP vaccine is not made with cellular components that would stimulate the immune system as effectively as the DTP vaccine

A certain species of bacteria grows the best on 5% peptone, 5% beef heart extract, and 8% sodium chloride. From this description, identify this general type of growth media.

complex

Dracunculiasis and Echinoccosis are neglected tropical diseases caused by infection with which type of pathogen

helminth

The "H" in the H1N1 virus stands for___________, and the "N" stands for ___________

hemagglutinin/neuramidase

Worldwide, the primary method of transmission of HIV is

heterosexual intercourse

In what type of conditions would you expect to find a halophilic acidophile?

high salt and low pH conditions

What is the result of histamine release from basophils?

inflammation

In the malaria parasite life cycle, humans are the ________ host, while mosquitoes are the ________ host as well as the vector.

intermediate; definitive

Microbes have utilized in certain manufacturing facilities resulting in environmentally friendly production methods. Certain bacteria can produce "bioplastic" molecules that can be harvested by inclusion bodies within the cells. What is the advantage of bioplastic as compared to plastics obtained from the refining of crude oil?

it is biodegradable

Species belonging to the phylum Euglenozoa have non-parasitic and parasitic members. Species in the genus Trypanosoma, such as T. brucei and T. cruzi, are blood parasites that are transmitted by blood-feeding insects. The two species displayed in the image possess a special type of organic molecule that is indicated by an arrow. What is the name of this special organic molecule?

kinetoplast DNA

Which of the following is caused by Chlamydia?

lymphogranuloma venereum

The image shows the results of a special staining method, called an endospore stain, that was performed on a patient sample who is suspected of having botulism caused by Clostridium botulinum. What is the primary stain used in the endospore staining technique?

malachite green

Haemophilus influenzae and Streptococcus pneumoniae cause which nervous system disease?

meningitis

What does it mean when scientists state that there is a "degeneracy in the genetic code"?

more than 1 codon can code for the same amino acid

A technician is staining organisms in a fecal sample collected from a boy complaining of abdominal cramping and diarrhea. The results show a protozoan that has eight flagella and structures that give the organism the appearance of having large "eyes". The technician identifies the organism as Giardia intestinalis. What are the structures that resemble eyes in this organism?

nuclei

When using a compound microscope, which of the following does the bulk of the magnification of the specimen?

objective lens

Neisseria gonorrhoeae causes the STI, gonorrhea. What other microbial disease of the reproductive system can it cause?

pelvic inflammatory disease (PID) NOT lymphogranuloma venereum (LGV)

What is the function of the structural elements of a virus?

To package and protect the viral genome

What is the end goal of PCR?

To quickly increase the number of copies of a specific DNA sequence

____________, the parasite that causes Chagas disease, can lay dormant for decades in the body before chronic, life-threatening symptoms such as swelling of the heart, appear.

Trypanosoma cruzi

The presence of nitrites and leukocytes in urine can indicate

UTI

Maryanne was prescribed the antibiotic clarithromycin to treat a bacterial infection. After finishing treatment, her symptoms persist. Upon performing a biopsy of the infected area, Maryanne still has the same bacterial infection. What is the most likely reason why the bacteria are still present?

the bacteria were resistant to clarithromycin

The results shown in this image were obtained from an antimicrobial sensitivity test assessing Escherichia coli. Using the Table of Interpretive Standards, determine the effect that antibiotic Ox [oxacillin] has on this strain of E. coli.

the bacterium is resistant to Oxicillin

The observations of Hooke and van Leeuwenhoek documenting the existence of microscopic cells formed the basis of what important theory?

the cell theory, stating that all living things are composed of cells

Use the information in the image to answer the following: Which of the following statements IS correct about the unknown bacterial sample?

the unknown is positive for acetoin

This image shows the results of a differential stain performed on a patient sample who is suspected to have an infection with Nocardia. The staining technique differentiates between bacteria who possess mycolic acid in their cell walls as opposed to not having this waxy substance in their cell walls. What can you conclude about the cells designated by the circles?

they are non-acid-fast

What is the rational of having a high salt content in the diagnostic media, MSA?

to select for halophiles

90% of healthcare-associated bacterial infections of the urinary systems are caused by which medical device?

urinary catheters

If you were setting up an experiment to disprove spontaneous generation in a liquid medium, which of the following would be essential to the experiment?

using a sterile liquid and eliminating exposure to microorganisms

Arthropods that transmit infectious diseases are called

vectors

Who developed the three-domain system of organism organization?

Woese

PCR uses oligonucleotide primers during DNA amplification. What is a primer?

a short sequence of DNA that binds to a complementary region of the denatured DNA

What type of greenish hemolysis pattern is observed in this image of a sheep's blood agar plate inoculated with Streptococcus pneumoniae?

alphamore than 1 codon can code for the same amino acid

Which of the following is NOT a domain in the three-domain system?

animalia

Clostridium difficile causes severe diarrhea that is associated with the altering of intestinal microbiota by ___________.

antibiotics

Products derived from extremophilic microbes that are part of the ecosystem of hydrothermal vents have the potential to improve many areas of our lives such as the treatment of certain diseases. For example, a peptide derived from Thermovibrio ammonificans has been shown to induce cell death (=apoptosis). Because of this property, it may have ____________ activity.

anticancer

What type of hemolysis pattern is observed in this image of a sheep's blood agar plate inoculated with Streptococcus pyogenes?

beta

When the antibiotics failed to work against a patient's eye infection contracted from extended-wear contacts, the doctor was concerned that it might be caused by a fungal pathogen. A lab technician collected a sample from the pair of contacts he was wearing, as well as the cleaning solution that he was using and plated the samples on Sabaroud-Dextrose agar. After growth appeared on the agar, a microscope slide was made, stained, and observed. Which of the following would the lab technician most likely see if the patient indeed has a fungal infection?

blue filaments and conidiospores

This image shows the results of a differential stain performed on a patient's sputum sample who is suspected of having tuberculosis, caused by the bacterium Mycobacterium tuberculosis. The staining technique differentiates between bacteria who possess mycolic acid in their cell walls as opposed to not having this waxy substance in their cell walls. What is the primary stain used in this technique?

carbolfuchsin

What is the carbon source that is "fixed" into glucose during the process of photosynthesis?

carbon dioxide

What molecule is used to capture light energy in the process of photosynthesis?

chlorophyll

Estimate the size of the DNA fragment labeled "B".

3500bp

What is the total magnification of a specimen viewed with a 10x ocular lens and a 45x objective lens?

450x

What results from the process of translation?

A polypeptide

What would happen if the mRNA codon that coded for Cys was mutated in the third position from a U to an A?

A stop codon would be introduced prematurely

Use the dichotomous key to determine the bacteria with the following characteristics: The organism is gram-positive; its cells are not spherical in shape; cells are not rod shaped; and cells are club shaped.

Corynebacteria

What species of bacteria causes Q fever?

Coxiella burnetii

Identify this parasitic species belonging to phylum Diplomonada that causes symptoms such as abdominal cramping and diarrhea.

Giardia intestinalis

Improved water sanitation and hygiene services are methods of prevention for neglected tropical diseases (NTDs). Why is water sanitation a possible method of prevention?

The ability to bathe in clean water can help in the reduction of disease transmission.

Why is reduction the term used to describe the gain of an electron?

The electron acceptor's net charge decreases

Fungal keratitis is a disease that causes inflammation of the _________.

cornea

The biochemical test shown in the image is used to identify bacteria that produce a certain enzyme of the bacterial electron transport chain that is present in aerobic bacteria. Name the enzyme and state which of the results observed in the image is a positive result.

cytochrome C oxidase; swab A NOT transferase; swab A

The most common reservoir for leptospirosis within the United States is

domestic dog

Agarose gel electrophoresis uses _________________ to separate fragments of DNA.

electrical charge

What occurs when a high-energy bond in ATP is broken resulting in ADP?

energy is released that will drive chemical reactions

The image shows the results of a differential stain performed on a patient sample. The staining technique differentiates between organisms that have a thick peptidoglycan layer in their cell wall as opposed to a thin layer of peptidoglycan in their cell wall. What differential stain was used on this sample?

gram stain

You are observing a Gram stain of spherical-shaped microorganisms that are linked in a chain and stain purple. How would you describe these bacteria using the correct terminology for the cell shape and arrangement?

gram-positive streptococci

A virus's ability to infect an animal cell depends primarily upon the

presence of receptor sites on the cell membrane.

The presence of specific ___________ on viruses determine whether it can infect a particular cell or not.

receptors

Shigella sp is the etiological agent of ___________, and Haemophilus influenzae is the etiological agent of ____________.

shigellosis/meningitis

Identify the phase of the bacteria growth curve labeled "C"

stationary

What phosphorylation mechanism is used to produce ATP in the Krebs cycle?

substrate-level phosphorylation

Glycolysis literally means

sugar splitting

What does the term phosphorylation mean?

the addition of a phosphate group onto a molecule