UF MCB3020 Exam 3

The primer used in Sanger sequencing _________.

has a nucleotide sequence complementary to the 3' end of the region to be copied

To carry out Sanger sequencing a mixture is needed containing _________.

single-stranded DNA, DNA polymerase, complementary DNA primer, and four deoxyribonucleotides A,T,C,G

In DNA sequencing. When a dideoxyribonucleotide is added to the daughter strand, replication of the strand ________.

stops

To sequence DNA by the Sanger method, the DNA must first be made in single-stranded form.

DNA sequencing is a technique for determining the complete sequence of bases (i.e., As, Ts, Gs, and Cs) for a particular piece of DNA. Sanger sequencing is the most popular method for DNA sequencing. T/F

True

In the Sanger method, examining the electrophoresis gel and reading from bottom to top, one base at a time, gives the sequence of DNA. T/F

True

Arrange the following events in the proper sequence for gene cloning.

1 = Incorporate gene into bacterial plasmid.

2 = Isolate DNA from organism containing desired gene.

3 = Incorporate cloned gene into bacterial cells.

4 = Fragment DNA with restriction enzyme.

2, 4, 1, 3

The function of the enzyme ligase is to ________.

form covalent bonds between cloned gene and plasmid

"Sticky ends" are ________.

single-stranded DNA sequences that are generated by staggered cuts

Restriction enzymes cut DNA at random sites. T/F

False

Which of the following is not a characteristic of lipid A?

Neurotoxicity

All of the following are components of the mammalian host immune system EXCEPT ________.

leukocytes

phagocytes

antigens

antibodies

antigens

Which is a primary reason that females are at greater risk of a urinary tract infection than are males?

The urethra is shorter in women; therefore, bacteria are closer in proximity to the bladder.

Which of the following is considered to be a biological defense mechanism?

Normal microbiota

Macrophages are phagocytic cells. T/F

True

The skin surface is a very favorable environment for colonization by most microorganisms. T/F

False

Which of the following features of a pathogen is not considered to be a virulence factor when establishing infection within a host?

Pigment production

Generally, exotoxins tend to be more heat stable than endotoxins. T/F

False

In which of the following areas of the human body do secretions play the greatest role in preventing microbial colonization?

Stomach

The lungs are protected from microorganisms by ________.

phagocytic action of alveolar macrophages

All of the choices are correct.

lysozyme in mucus

the mucociliary blanket

All of the choices are correct.

One example of infectious disease transmission by a fomite is _______.

a child developing a cold after playing with a toy that harbored rhinovirus

In a lichen, the fungal partner _________.

All of the choices are correct.

provides a substratum within which the alga grows

protects the alga from excess light intensities

provides water and minerals to the alga

All of the choices are correct.

Blood cell development occurs in the bone marrow of mammals during the process of ________.

hematopoesis

Which of the following must a pathogen possess in order for it to be successful at causing infectious disease?

Ability to damage the host

All of the choices are correct.

Ability to adhere to, colonize, or invade the host

Ability to be transported initially to the host

All of the choices are correct.

Bacteria within biofilms exchange _________.

nutrients

All of the choices are correct.

quorum-sensing molecules

plasmids

All of the choices are correct.

Methanogens are always engaged in relationships with other microbes because methane production requires _________.

interspecies hydrogen transfer

Cervical mucus has antibacterial activity. T/F

True

The endosymbionts of ruminant animals are useful to their hosts in which of the following ways?

They produce most of the vitamins needed by the ruminant.

They convert glucose to organic acids.

All of the choices are correct.

They digest the cellulose of plant cell walls.

All of the choices are correct.

Several cases of an emerging infectious disease are reported in workers at a research station that borders a tropical rainforest region. The pathogen is identified as a species of bacteria carried by nematodes that infect mosquitos, and disease transmission occurs in a human host following a mosquito bite. Which organisms should be targeted in the treatment of infected patients?

Nematode and bacteria

Why is innate host resistance a type of nonspecific immune response?

Innate resistance is nonspecific because any foreign material, microorganisms, or antigens encountered by the host are targeted.

Which of the following is a physical barrier in the nonspecific defense of a mammalian host?

Mucous membranes

Which of the following is NOT a virulence factor encoded by a pathogenicity island?

Lysozyme

________ is a predator that bores a hole through the outer membrane of its Gram-negative bacterial prey and then reproduces in the periplasm.

Bdellovibrio

When Nitrobacter utilizes nitrite produced from ammonia by Nitrosomonas to obtain energy by converting the nitrite to nitrate, the relationship between the two organisms is _________.

commensal

An inanimate object that may be contaminated with a pathogen is called a ________.

fomite

The lungs are protected from microorganisms by ________.

All of the choices are correct.

phagocytic action of alveolar macrophages

lysozyme in mucus

the mucociliary blanket

All of the choices are correct.

rRNA signature sequences can be used to place microorganisms in the correct domain. T/F

True

Which of the following is not part of the lichen association?

Brown algae

The toxic component of lipopolysaccharide is called ________.

lipid A

Lactobacillus contributes to the antimicrobial defenses for the adult female reproductive tract by making lactic acid to lower the pH. T/F

True

Movement of charged molecules in an electrical field, which is used to separate nucleic acid fragments for recombinant DNA work, is called _________.

electrophoresis

Which of the following types of immunity primarily relies on interactions between antigens and antibodies?

Adaptive immunity

The shorter urethra in females is one reason why urinary tract infections are more common in females than in males. T/F

True

In the rumen, food is quickly attacked by cellulase _________.

enzymes produced by microbes

Biofilm formation by Pseudomonas bacteria on the surface of a natural loofa sponge kept in the shower is an example of which type of relationship?

Commensalism

An inanimate object that may be contaminated with a pathogen is called a ________.

fomite

Colonization specifically refers to the multiplication of a pathogen on or within a host, and includes the resulting tissue invasion and damage. T/F

False

Fever response can be triggered by an endogenous pyrogen called interleukin-1. T/F

True

The mucociliary blanket is found in the digestive system of mammals. T/F

False

The rickettsial parasite Wolbachia pipientis can _________.

sometimes alter the sex of an infected wasp

Which is a primary reason that females are at greater risk of a urinary tract infection than are males?

The urethra is shorter in women; therefore, bacteria are closer in proximity to the bladder.

In which of the following situations did disease develop due to vertical transmission of the pathogen?

A fetus develops listeriosis after unpasteurized cheese infected with Listeria bacteria is consumed by the mother during pregnancy

Which of the following is used to help protect the lungs from infection?

The mucociliary escalator moves trapped organisms away from the lungs by ciliary action.

Turbulent airflow deposits airborne pathogens on sticky mucosal surfaces.

Coughing and sneezing forcefully expel organisms away from the lungs.

All of the choices are correct.

All of the choices are correct.

The reason coral reefs are among the most productive and successful ecosystems is due to _________.

the coral-dinoflagellate mutualistic relationship

When a pathogen is transferred from a water source to an animal before being transferred to a human, the animal is called a(n) ________ agent.

intermediate

Substances that are recognized as foreign and provoke immune responses are called ________.

antigens

The science dealing with classification is called _________.

taxonomy

The final outcome of most host-pathogen relationships depends on _________.

All of the choices are correct.

the virulence of the organism

the host's defenses

the number of organisms present in or on the host

All of the choices are correct.

The relationship between Trichonympha protozoa and its termite host, and Xenorhabdus bacteria and its nematode host, are both obligatory relationships. T/F

False

In mutualism _________.

the partners will not survive separately in many cases

the mutualist is dependent on the host

All of the choices are correct.

a reciprocal benefit accrues to both partners

All of the choices are correct.

The lower genitourinary tract is usually free of microorganisms. T/F

False

Before bacteria can establish an infection, they must be able to overcome resident microorganisms in direct competition for space and nutrients. T/F

True

A DNA molecule used to carry a foreign gene into a host organism is called a _________.

vector

The characteristics of a pathogen that determine its virulence include which of the following?

Pathogenicity

All of the choices are correct.

Invasiveness

Infectivity

All of the choices are correct.

PCR requires all of the following EXCEPT _________.

DNA of interest

DNA ligase

deoxyribonucleotides

primers

DNA polymerase

DNA ligase

If you start with one double-stranded DNA molecule and you perform SIX cycles of PCR, how many double-stranded copies of the DNA will you have?

64

The most likely source of the Taq polymerase used in PCR is a bacterium that lives in _________.

hot vents

PCR can be used to amplify DNA from any source. T/F

True

During the PCR, the hydrogen bonds of the double-stranded DNA molecules are broken by the enzyme helicase. T/F

False

On which of the following surfaces can biofilms form?

Biotic or abiotic surface

Initial attachment of microorganisms often involves ________.

flagella and is reversible

Which of the following gradients can form in a biofilm?

Oxygen, nutrient, and/or pH gradient

People with type AB blood have _________.

both type A and type B antigens on their red blood cells

When type B blood is given to a person with type A blood ________.

B antigen from the donor reacts with anti-B antibody in the recipient

A person with type AB blood may receive ________.

types A, B, AB, and O blood

People with type O blood can be universal donors because their red blood cells do not contain either A antigen or B antigen on their surface. T/F

True

A person with type O blood may receive blood from a person with type B blood. T/F

False