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
