A difference between an acute disease and chronic disease is that chronic diseases have an extended period of illness.
Missing Word
illness
Acute diseases are characterized by a rapid onset and short duration, whereas chronic diseases develop slowly and persist for a long time. The extended period of illness in chronic diseases can lead to long-term health complications.
Question 2
A person steps on a rusty nail and develops tetanus. In this case, the person has acquired a(n) noncommunicable disease.
Missing Word
noncommunicable
Tetanus is caused by Clostridium tetani spores entering the body through a wound and producing a neurotoxin. It is considered noncommunicable because it does not spread from person to person.
Question 3
A(n) opportunistic pathogen causes disease only when conditions are favorable for the microorganism because of transfer to an inappropriate body site or weakened immunity in an individual.
Missing Word
opportunistic
Opportunistic pathogens take advantage of compromised host defenses or unusual locations to cause infection. A healthy immune system or normal anatomical barriers typically prevent these organisms from causing disease.
Question 4
The concentration of pathogen needed to kill 50% of an infected group of test animals is the LD50.
Missing Word
LD50
LD50 (Lethal Dose 50) is a measure of virulence, representing the amount of a pathogen required to kill 50% of a group of infected animals. A lower LD50 indicates higher virulence.
Question 5
A(n) focal infection is a small region of infection from which a pathogen may move to another part of the body to establish a second infection.
Missing Word
focal
A focal infection is a localized site of infection from which pathogens or toxins can disseminate to other parts of the body. This secondary spread can lead to the establishment of a systemic infection or infections in other specific organs or tissues.
Question 6
Cilia, fimbriae, and pili are all examples of structures used by microbes for adhesion.
Missing Word
adhesion
Cilia, fimbriae, and pili are all external structures that enable microbes to attach to host cells or surfaces. This attachment, or adhesion, is a crucial first step in establishing an infection, allowing the microbe to colonize and potentially cause disease.
Question 7
The glycoprotein adhesion gp120 on HIV must interact with CD4 on some immune cells as the first step in the process of infecting the cell.
Missing Word
CD4
HIV's gp120 glycoprotein specifically binds to the CD4 receptor, primarily found on helper T cells. This interaction is essential for the virus to attach to and subsequently enter these immune cells, initiating the viral infection cycle.
Question 8
Adhesins are usually located on surface of the pathogen and are composed mainly of proteins and sugars.
Missing Word
surface
Adhesins, molecules that mediate microbial attachment, are typically located on the pathogen's outer surface to facilitate contact with host cells. They are often composed of proteins and carbohydrates, which provide the necessary structural diversity for specific binding to host receptors.
Question 9
The Shiga and diphtheria toxins target protein synthesis in host cells.
Missing Words
protein, synthesis
Shiga toxin and diphtheria toxin are potent inhibitors of protein synthesis in eukaryotic cells. By disrupting this fundamental cellular process, these toxins can cause cell death and contribute to the pathogenesis of bacterial infections.
Question 10
Antigenic shift is the result of reassortment of genes responsible for the production of influenza virus spike proteins between different virus particles while in the same host, whereas antigenic drift is the result of point mutations in the spike proteins.
Missing Word
shift
Antigenic shift involves major genetic reassortment, leading to new viral subtypes with significantly altered surface antigens, whereas antigenic drift involves minor mutations that gradually change the antigens. Shift can cause pandemics due to lack of pre-existing immunity, while drift contributes to seasonal epidemics.
Question 11
Candida can invade tissue by producing the exoenzymes protease and phospholipase.
Missing Word
protease
Candida species produce exoenzymes like protease and phospholipase that degrade host tissues. Proteases break down proteins, while phospholipases degrade phospholipids in cell membranes, both facilitating tissue invasion and nutrient acquisition.
Question 12
The larval form of Schistosoma mansoni uses a protease to help it gain entry through intact skin.
Missing Word
protease
Schistosoma mansoni larvae secrete proteases to digest proteins in the skin, allowing them to penetrate the host's integument. This enzymatic activity is crucial for the parasite's ability to initiate infection by directly entering the bloodstream.