There have been recurring cases of mad-cow disease in the United Kingdom since the mid-1990s. Mad-cow disease is caused by a prion, an infectious particle that consists only of protein. In 1986, the media began reporting that cows all over England were dying from a mysterious disease. Initially, there was little interest in determining whether humans could be affected. For 10 years, the British government maintained that this unusual disease could not be transmitted to humans. However, in March 1996, the government did an about-face and announced that bovine spongiform encephalopathy (BSE), commonly known as mad-cow disease, can be transmitted to humans, where it is known as variant Creutzfeldt-Jakob disease (VCJD). As in cows, this disease eats away at the nervous system, destroying the brain and essentially turning it into a spongelike structure filled with holes. Victims experience dementia; confusion; loss of speech, sight, and hearing; convulsions; coma; and finally death. Prion diseases are always fatal, and there is no treatment. Precautionary measures taken in Britain to prevent this disease in humans may have begun too late. Many of the victims contracted it over a decade earlier, when the BSE epidemic began, and the incubation period is long (VCJD has an incubation period of 10 to 40 years).
A recent study concluded that 1 in 2,000 people in Great Britain carry the abnormally folded protein that causes VCJD. In spite of these numbers, the death rate from VCJD remains low. It is not clear whether this means that the incubation period for the disease is much longer than previously thought, or whether they may never develop the disease.
How can a prion replicate itself without genetic material?
To determine: The way by which prions can replicate itself without genetic material.
Introduction: Viruses can have DNA or RNA as their genetic material. After entering the host body, these agents use host genetic material to synthesize their own genetic material. Prions are able to replicate itself without the aid of genetic material.
Explanation of Solution
Prions are infectious agents that do not contain any genetic material. As an infectious agent, prions contain misfolded proteins. Misfolded proteins act as an infectious agent in prions and cause several diseases in humans like mad cow disease and Creutzfeldt-Jacob disease. Prions use non-essential genes of the host to synthesize their misfolded proteins.
Therefore, prions replicate itself by using non-essential genes of the host.
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Chapter 9 Solutions
Human Heredity: Principles and Issues (MindTap Course List)
- There have been recurring cases of mad-cow disease in the United Kingdom since the mid-1990s. Mad-cow disease is caused by a prion, an infectious particle that consists only of protein. In 1986, the media began reporting that cows all over England were dying from a mysterious disease. Initially, there was little interest in determining whether humans could be affected. For 10 years, the British government maintained that this unusual disease could not be transmitted to humans. However, in March 1996, the government did an about-face and announced that bovine spongiform encephalopathy (BSE), commonly known as mad-cow disease, can be transmitted to humans, where it is known as variant Creutzfeldt-Jakob disease (vCJD). As in cows, this disease eats away at the nervous system, destroying the brain and essentially turning it into a spongelike structure filled with holes. Victims experience dementia; confusion; loss of speech, sight, and hearing; convulsions; coma; and finally death. Prion diseases are always fatal, and there is no treatment. Precautionary measures taken in Britain to prevent this disease in humans may have begun too late. Many of the victims contracted it over a decade earlier, when the BSE epidemic began, and the incubation period is long (vCJD has an incubation period of 10 to 40 years). A recent study concluded that 1 in 2,000 people in Great Britain carry the abnormally folded protein that causes vCJD. In spite of these numbers, the death rate from vCJD remains low. It is not clear whether this means that the incubation period for the disease is much longer than previously thought, or whether they may never develop the disease. What measures have been taken to stop BSE?arrow_forwardViruses are considered non-living microbes, and yet they are responsible for many major disease outbreaks in humans, animals, and even plants. Consider the following: How are these non-living microbes able to reproduce without metabolic functions? Can viruses be exploited to help humans fight bacterial pathogens? Which viruses are able to stay dormant in the human body and reactivate later in life or when immune defenses are compromised? What impact might travel outside of the United States have in blood, tissue, or organ donation?arrow_forwarde. coli is commonly found in the human Microbiome. while most strains are harmless some can cause various illnesses ranging from urinary track infections to severe gastroenteritis. which of the following is a primary mechanism by which e. coli obtains its pathogenicity? A. Vertical gene transfer from parent to offspring B. Endosymbiosis with other bacteria C. Mutation in the bacterial chromosome D. Horizontal gene transfer from other Bacteria or the environmentarrow_forward
- Why must primary cell cultures be restarted every so often when preparing primary cell cultures to observe morphological changes caused by cells infected by a virus? Why are tumor cells preferred? Why are non-enveloped viruses generally more resistant to disinfectants than are enveloped viruses? A public health physician isolated large number of phages from rivers used as a source of drinking water in western Africa. They physician is very concerned that humans might become ill from drinking this water, although she knows that the phages specifically attack bacteria. Why is she concerned?arrow_forwardWhich of the following highly contagious viruses is a single-stranded ribonucleic acid (RNA) virus with a helical capsid and envelope and is transmitted by coming in contact with respiratory secretions? "This is a highly contagious respiratory illness transmitted when an infected person coughs or sneezes virus particles into the air," the health department said in a written statement. "It's so contagious that if one person is sick and spreading measles, nine out of 10 people around them who aren't immune will get it, too." Group of answer choices a. Measles b. Parvovirus c. Coxsackie virus A d. Rhinovirusarrow_forwardWhich of the following statements concerning viruses and human health is false? a-in many diseases caused by viruses, the virus attacks cells as it reproduces b- many viral diseases can be controlled through vaccinations c- some viruses can remain dormant in the body for years before disease symptoms appear d-most viral infections are difficult to treat, but they can be finally destroyed by antibioticsarrow_forward
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- An experimental drug therapy to treat patients with antibiotic-resistant bacteria involves introduction of a highly specific bacteriophage to the infected patient's bloodstream. Which of the following bacteriophage types would be the LEAST useful for this therapy? a. a lytic bacteriophage b. An enveloped virus c. An RNA virus d. a lysogenic bacteriophagearrow_forwardIn terms of microbial pathogenicity, molecular Koch's postulates are a set of experimental criteria that show: A microbe is the aetiological agent of a disease A gene encodes a product that contributes to disease A gene encodes a product that contributes to immunity to a disease A mutation does not contribute to diseasearrow_forwardWhich of the following characteristics, structures,or processes is common to both bacteria andviruses?(A) metabolism(B) ribosomes(C) genetic material composed of nucleic acid(D) cell divisionarrow_forward
- Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning