CH 8: Biology of Infectious Diseases

According to the graph showing stages of HIV infection, select all correct statements.

-during the acute phase, there is an initial burst of HIV replication -the amount of HIV in plasma rises dramatically in aids -CD4 T lymphocyte numbers never recover from their initial drop in the acute phase -during the chronic phase and aids, CD4 T lymphocytes decrease steadily

Select all of the proven practices that minimize the spread of HIV.

-sexual abstinence -sex with only a single uninfected partner -use of condoms with every sexual encounter

attachment

HIV gp120 binds to CD4 receptor

Malaria is caused by protists of the genus _____.

Plasmodium

The vector of malaria is__-

a mosquito

reverse transcriptase

converts viral RNA into viral DNA

XDR TB stands for extensively ___ resistant tuberculosis

drug

True or false: Malaria parasites are transmitted by male mosquitoes.

false

True or false: Under most circumstances, kissing can transmit HIV.

false

The immunodeficiency associated with HIV infection is mainly due to a decline in the number of _____.

helper t cells

Select two cell types infected by HIV.

helper t cells macrophages

A pathogen is a microbe that _____.

is a disease-causing agent

Tuberculosis is caused by a bacterial species of the genus _____.

mycobacterium

The enzyme inside the HIV matrix that catalyzes the conversion of viral RNA into viral DNA is ___ transcriptase

reverse

Acquired immunodeficiency syndrome is caused by _____.

the human immunodeficiency virus

How soon after HIV infection can an at-home test detect its presence?

within a matter of weeks

Approximately what proportion of the world's human population has been exposed to TB?

1/3

Although the virus probably existed much earlier, the first direct evidence of HIV infection in humans is from blood samples that were obtained from patients in the _____.

1950s

How many major types of HIV have been discovered?

2

As of 2019, about how many people were estimated to be living with HIV infection worldwide?

38 million

Approximately how many people died from HIV/AIDS in 2019?

690,000

An HIV-infected person who has a CD4 T-cell count less than 200 cells/mm3 and has developed at least one of the AIDS-defining opportunistic infections is classified in which CDC category of HIV infection?

C

The CDC's guidelines for the classification of HIV infection into categories A, B, and C are based on what two criteria?

CD4 T cell count history of AIDS-defining illnesses

pandemic

a global epidemic

epidemic

a higher than normal occurrence of disease in a certain area over a given period of time

What is a bacterial plasmid?

a small, circular piece of DNA separate from the bacterial chromosome

The human immunodeficiency virus causes AIDS, which stands for ____ immunodeficiency syndrome

acquired

Arrange these phases of infection with HIV-1B in chronological order, with the earliest step at the top.

acute phase -> chronic phase -> aids

The function of bacterial fimbriae relates to _____.

adhering to surfaces

HIV most likely originated on which continent?

africa

It is generally accepted that HIV originated in the continent of

africa

The bacterium that causes tuberculosis is mainly spread by _____.

airborne droplets

outbreak

an epidemic that is confined to a local area

Bacterial cell walls contain a unique amino disaccharide, the synthesis of which is inhibited by drugs like penicillin. What type of drug is penicillin?

antibiotic

There are generally two types of tests for HIV; those that detect the immune system's response are ______ tests.

antibody

Which of these are considered emerging or new diseases?

avian influenza swine flu middle east respiratory syndrome

mycobacterium tuberculosis

bacterial infection of lungs or lymph nodes

Tuberculosis is caused by what type of microbe?

bacterium

Which type of organism is a single-celled prokaryote?

bacterium

Select the factors that can affect the HIV prevention strategy, globally.

belief systems culture sexual practice

protease

breaks down viral polypeptides into functional proteins

kaposi sarcoma

cancer of the blood vessels

The cell wall of some bacteria is surrounded by a structure with a thick, gelatinous consistency, called a ___, that may help the bacteria to stick to surfaces

capsules

biosynthesis

cell produces viral rna, and viral proteins

Many bacteria can use hollow appendages called pili to transfer DNA between cells in a process called

conjugation

Which of these features is unique to the retroviruses?

convert viral RNA to DNA

HIV-2

corresponds more closely with a virus in green monkeys

Common signs or symptoms of influenza include which of these?

cough fever head and body aches

During category B HIV infection the CD4 T-cell count ________ while the viral load ________.

decreases;increases

Tuberculosis is likely to be transmitted to caregivers and on long plane flights because _____.

exhaled bacteria can be infectious in the air for hours

True or false: One benefit of highly active antiretroviral therapy (HAART) is that it can eliminate all HIV proviruses.

false

True or false: The first documented case of AIDS caused by HIV infection in the United States was in a homosexual man who died in the early 1980s.

false

Some bacteria have stiff fibers on their outer surface called ____ that help them adhere to host cells

fimbriae

Motile bacteria usually have one or more long, thin cellular appendages called

flagella

pneumocystis jiroveci

fungal infection of the lungs

During the first few weeks of an HIV-1B infection, the virus typically

generates high viral load

During a category A HIV infection, the number of helper T cells is ____ the minimum number needed for the immune system to function normally.

greater than

Select all functions of bacterial capsules.

help to avoid phagocytosis aid in sticking to surfaces

What type of disease does Ebola cause?

hemorrhagic fever

An opportunistic infection is one that takes advantage of a weakened _____ system

immune

Which body system fails as a result of the Ebola virus?

immune system

Select the two routes by which influenza virus is commonly contracted.

inhaling virus-laden droplets contact with contaminated objects

integrase

inserts viral DNA into host cell DNA

Select all of the following that are true about a retrovirus.

it has RNA a retrovirus uses reverse transcription

Which of the following are characteristic of category C HIV infection?

kaposi's sarcoma infection w mycobacterium tuberculosis

In the acute phase of HIV infection, the immune system combats the loss of CD4+ T cells by producing as many as two billion new T cells a day. This is what model for T cell loss?

kitchen sink

The number of HIV particles in a person's blood is called the viral

load

HIV-1

more virulent and widespread

MDR TB is (more/less) ____ common than XDR TB. Eastern Europe and Southeast Asia have the highest rates of (MDR/XDR) ____ TB

more;MDR

The function of bacterial flagella relates to _____.

motility

Select the three AIDS-defining opportunistic infections from the list.

mycobacterium tuberculosis toxoplasmic encephalitis pneumocystis jiroveci pneumonia

During the first three weeks of an HIV infection, the HIV antibody test is typically

negative

assembly

new viral particles are made

An infection that develops because an individual has a weakened immune system is called _____.

opportunistic

An epidemic that is confined to a local area is called a(n) ____, whereas a global epidemic is called a(n) _____

outbreak;pandemic

According to the graph showing stages of HIV infection, how much HIV is typically present in the plasma of a person who is sick/dying of AIDS?

over one million viruses per ml of plasma

Select all characteristics of viruses.

parasites of cells acellular

The general term for a bacterium, virus, or other microbe that causes disease is a(n) _____.

pathogen

Which of the following are signs or symptoms of a person with a category B HIV infection?

persistent or recurrent fever persistent fatigue, cough, and/or diarrhea

Bacterial pili can be related to the development of antibiotic resistance because _____.

pili can be used to transfer genes that code for resistance mechanisms

Genes coding for antibiotic resistance in bacteria are often located on small, circular pieces of DNA called

plasmids

The key factor that determines the distribution of malaria throughout the world is the _____.

presence of the mosquito vector

Infectious particles made of only proteins are called

prion

Which statement best summarizes the "kitchen sink" model of CD4 T cell loss during the acute phase of HIV infection?

production of T cells is the faucet; loss of t cells is the drain

All bacteria are ______ that ______ a nucleus.

prokaryotes;lack

Which of these enzymes are coded by the HIV genome?

protease reverse transcriptase integrase

Prions are infectious particles made of _____.

protein only

Malaria is caused by organisms of the genus Plasmodium, which are what type of microbe?

protists

toxoplasmic encephalitis

protozoan parasitic infection of the brain

A disease that comes back after a significant decline in incidence is considered to be _____.

reemerging

How is HIV classified?

retrovirus

HIV belongs to which group of viruses, all of which use reverse transcriptase to convert viral RNA into DNA?

retroviruses

Malaria is most common in which part of the world?

sub saharan africa

Select all the ways by which bacterial resistance to antibiotics can be minimized.

take antibiotics as prescribed until all medication is gone only prescribe antibiotics for confirmed bacterial infections

Antibiotics in the penicillin class kill bacteria by inhibiting production of _____.

the cell wall

Parasites of the genus Plasmodium, which cause malaria, are transmitted _____.

through the bite of a mosquito

True or false: A person with acute phase (category A) HIV infection typically is asymptomatic.

true

True or false: If an HIV antibody test is negative, there is a chance the person can still transmit HIV.

true

Which disease was once called "consumption"?

tuberculosis

Select the diseases and organisms that have been associated with a high degree of antibiotic resistance.

tuberculosis gonorrhea enterococci staphylococcus aureus

The nucleic acid packed inside an HIV particle consists of _____.

two molecules of single stranded RNA

Select ways in which HIV can be transmitted.

vaginal intercourse injection with contaminated needle rectal intercourse ingestion of breast milk

A living organism, such as a mosquito, that transfers a pathogen from one host to another is a(n)

vector

The HIV provirus is defined as _____.

viral dna inserted into the host genome

integration

viral dna inserts into host cell genome

fusion/entry

viral envelope fuses with host cell, hiv rna is released

reverse transcription

viral rna genome is converted into dna

The causative agent of influenza is a _____.

virus

Which type of microbe is a parasite of cells, is acellular, and bridges the gap between what is considered to be living and nonliving?

virus

budding

virus exists host cell