Human Biology CH 13a Special Topic: Infectious Disease.

Virulence is the relative ability of a pathogen to cause disease. True False

true

When a person is infected with Plasmodium vivax, that person undergoes chills and fever about every ________ hours. This event corresponds with the ________. 48; release of the parasite from the red blood cells 24; release of parasites from the red blood cells 48; release of the parasite from the liver 48; entrance of the parasite into the red blood cells 24; release of the parasite from the liver

48; release of the parasite from the red blood cells

In the RNA virus (such as the one illustrated in the tutorial), what is the role of reverse transcriptase? Reverse transcriptase copies DNA to make RNA. Reverse transcriptase copies RNA to make DNA. Reverse transcriptase is the enzyme responsible for the assembly of the new viral particles. Reverse transcriptase signals the synthesis of new viral proteins

Reverse transcriptase copies RNA to make DNA.

In the example given in the tutorial, how did new viral particles exit the cell? The RNA and proteins are assembled inside the host cell. These new viruses then bud off. The RNA and proteins exit the cell by squeezing through the membrane channels; once outside the cell, the particles are assembled into new viruses. The proteins and the RNA are assembled inside the host cell. The viruses signal the membrane to produce protein pores, and the whole virus is then able to exit the cell. Viral particles do not exit the cell. Rather, the new viruses remain within the cell and gradually transform the cell into a large viral complex. Once a certain number of new viruses have been assembled inside the cell, the cell bursts.

The RNA and proteins are assembled inside the host cell. These new viruses then bud off.

Why do most attempts to develop antiviral drugs fail? The drugs are toxic to the host cell. The viruses mutate too quickly. The viruses combine with the host cell wall. The drugs lead to cancer.

The drugs are toxic to the host cell.

When discussing the sequence of events in the body of the mosquito, which of the following can we say? The gametocytes go to the salivary gland, where they unite to form a zygote. The zygote then travels to the intestine, where it is nourished. After maturation, it heads back to the salivary gland. The gametocytes head for the gut, unite to form a zygote, migrate to the outer wall of the intestine, and are released to the salivary gland. The gametocytes go to the gut, where they mature. From there, they go to the outer wall of the intestine, where they unite to form a zygote that is then released to the salivary gland. The zygote, which was formed in the human blood, goes to the mosquito gut, where it develops. Once mature, it goes to the outer intestinal wall and eventually to the salivary gland.

The gametocytes head for the gut, unite to form a zygote, migrate to the outer wall of the intestine, and are released to the salivary gland.

What happens when a mosquito infected with malaria bites a human? The gametocytes enter the human bloodstream, where they unite and begin infecting red blood cells. The larval parasites flow from the salivary gland of the mosquito and, in the human bloodstream, mature into gametocytes that then head for the liver. The larval parasites flow from the salivary gland of the mosquito into the blood of the human and head for the human liver. The mature malarial parasites flow from the salivary gland of the mosquito into the blood of the human and begin infecting mature red blood cells. The gametocytes flow from the salivary gland of the mosquito and head to the liver, where they unite and mature before attacking the red blood cells.

The larval parasites flow from the salivary gland of the mosquito into the blood of the human and head for the human liver.

Which statement about the genome of the virus is FALSE? The genome could be made of double-stranded RNA. The viral genome includes neither DNA nor RNA. The genome could be made of double-stranded DNA. The genome could be made of single-stranded DNA. The genome could be made of single-stranded RNA.

The viral genome includes neither DNA nor RNA.

Of the events listed below, which one occurs last? The genome enters the host cell. The host cell and the virus fuse. The capsid is removed. The virus replicates.

The virus replicates

What is an epidemic disease? a disease with clinically distinct symptoms whose incidence has increased, particularly over the last two decades a disease that occurs suddenly and spreads rapidly to many people a global outbreak of disease a disease that occurs only occasionally and at unpredictable intervals

a disease with clinically distinct symptoms whose incidence has increased, particularly over the last two decades

How do viruses gain entry to a host cell? by dissolving a piece of the host cell membrane by binding to an antibody site on the host cells by binding to a receptor site on the host cell by phagocytosis

by binding to a receptor site on the host cell

How do most disease-causing bacteria cause damage? by releasing toxins by reproducing asexually through high fevers through lesions

by releasing toxins

The mosquito is the vector for Lyme disease. True False

false

What causes antibiotic-resistant bacteria to develop? lack of sterile conditions homeopathic remedies new antibodies overuse of antibiotics

overuse of antibiotics

Malaria is caused by a ________ of the genus Plasmodium and requires two hosts, ________ and ________, to complete its life cycle. bacterium; mosquito; human virus; mosquito; human protozoan; mosquito; human protozoan; tsetse fly; human protozoan; mosquito; dog

protozoan; mosquito; human

When speaking of malarial gametocytes, we can say that ________. some of the parasites in the blood differentiate into male and female gametocytes. These then unite to form a zygote, which is then picked up by a mosquito so that the life cycle can be completed male and female gametocytes are formed in the human blood, but these are nonfunctional cells because no union is required for the life cycle to be complete some of the parasites in the blood differentiate into male and female gametocytes and are picked up by another mosquito to complete their life cycle the male and female gametocytes are formed in the human liver and unite to form a zygote in the human red blood cell. When the zygote is released, it can be picked up by a mosquito

some of the parasites in the blood differentiate into male and female gametocytes and are picked up by another mosquito to complete their life cycle

When speaking of the anatomy of a virus, we can say that ________. the capsid and genome are intertwined, and they may be surrounded by an envelope the core of the virus is the capsid. The genome surrounds the capsid, and the virus may or may not have an outer layer called an envelope the genome is surrounded by a protein coat called a capsid, which may or may not be surrounded by an envelope the genome is surrounded by an envelope, which may or may not be surrounded by a capsid the envelope is in the central portion of the virus. Around that is the genome, which may or may not be surrounded by a capsid

the genome is surrounded by a protein coat called a capsid, which may or may not be surrounded by an envelope

How do animals or humans become infected with prions? through tissue transplants through contaminated food through contaminated surgical instruments through contaminated food, contaminated surgical instruments, and tissue transplants

through contaminated food, contaminated surgical instruments, and tissue transplants

Fungi often cause disease by secreting enzymes that digest cells so that they can absorb the nutrients. True False

true

More than 40% of the antibiotics used in the United States are given to livestock. True False

true

The body contains some bacteria that are helpful in outcompeting bad bacteria. True False

true