What do host cells provide for viruses?

a. ATP

b. Nucleotides and amino acids

c. Ribosomes

d. All of the above

What does reverse transcriptase do?

In the viral replicative cycle, what reaction do viral proteases catalyze?

Select True or False for each statement.

T/F They catalyze polymerization of amino acids into peptides.

T/F They catalyze folding of long peptide chains into functional proteins.

T/F They catalyze cutting of polyprotein chains into functional proteins.

T/F They catalyze breaking of peptide bonds

What features distinguish the seven major categories of viruses?

The outer surface of a virion consists of either a membranous envelope or a protein capsid. How does the outer surface correlate with a virus's mode of exiting a host cell?

Compare and contrast the bacteriophage lytic cycle and lysogeny by addressing

(1) the rate of replication of the viral genome

(2) production of virions, and

(3) effect on the host cell.

If you come down with the flu, should your physician prescribe an antibiotic for you? Explain why or why not.

Of the viruses highlighted in Section 33.4, predict which of the following would be able to make viral proteins if nothing more than its genome were injected into a suitable host cell.

a. Pea mosaic (+ssRNA virus)

b. Bluetongue (dsRNA) virus

c. Measles (−ssRNA) virus

d. Human immunodeficiency (RNA reverse-transcribing) virus

If you were in charge of the government's budget devoted to stemming the AIDS epidemic, would you devote most of the resources to drug development or preventive medicine? Defend your answer.

Which of the following types of viruses would you expect to require periods of latency?

a. Viruses that have large genomes and require a long time for replication

b. Viruses that require a long time for transmission to new hosts

c. Viruses that require a long time for assembly into complex structures

d. Viruses that infect cells of the immune system

The mosquito-borne Zika virus (ZIKV) is one of the most feared viruses for pregnant women. Recent statistics justify this fear: Infants born to mothers infected with ZIKV during pregnancy face a risk of up to 42 percent of developing birth defects, including microcephaly (an abnormally small head and decreased brain volume).

What do we know about how ZIKV causes damage to the developing brain?

ZIKV is a Baltimore class IV virus. Based on this classification, what do you know about the structure of its genome?

The mosquito-borne Zika virus (ZIKV) is one of the most feared viruses for pregnant women. Recent statistics justify this fear: Infants born to mothers infected with ZIKV during pregnancy face a risk of up to 42 percent of developing birth defects, including microcephaly (an abnormally small head and decreased brain volume).

What do we know about how ZIKV causes damage to the developing brain?

Researchers have determined that host cells possess several different surface proteins that can serve as virus receptors for ZIKV. If you were to repeat the experiment described in Figure 33.8 using ZIKV instead of HIV, how would you expect the results to be different? Explain.

The mosquito-borne Zika virus (ZIKV) is one of the most feared viruses for pregnant women. Recent statistics justify this fear: Infants born to mothers infected with ZIKV during pregnancy face a risk of up to 42 percent of developing birth defects, including microcephaly (an abnormally small head and decreased brain volume). What do we know about how ZIKV causes damage to the developing brain? Several lines of evidence suggest that after ZIKV is transmitted to a pregnant woman via the bite of an infected mosquito, the virus then directly infects cells of the placenta, gaining access to the fetal brain.

Following attachment, the virion would most likely enter the placental cell by:

a. Insertion via the mosquito's mouthparts

b. Endocytosis

c. Degrading the cell wall with lysozyme

d. Injection through a hollow, needle-like protein structure

The mosquito-borne Zika virus (ZIKV) is one of the most feared viruses for pregnant women. Recent statistics justify this fear: Infants born to mothers infected with ZIKV during pregnancy face a risk of up to 42 percent of developing birth defects, including microcephaly (an abnormally small head and decreased brain volume). What do we know about how ZIKV causes damage to the developing brain? Researchers recently developed a mouse model for fetal brain defects associated with human ZIKV infection. To determine the effect of ZIKV on the number of neurons in the brain, ZIKV was injected into the brains of developing mouse embryos. Neurons were identified by staining sections of brain tissue with antibodies against NeuN, a neuron-specific protein, and the number of NeuN-positive cells per mm2 in specific regions was quantified. The results of three independent experiments are shown in the graph below. Use the P value provided to determine if the difference is significant or not (* means P< 0.05). Based on these results, what can you conclude?

The mosquito-borne Zika virus (ZIKV) is one of the most feared viruses for pregnant women. Recent statistics justify this fear: Infants born to mothers infected with ZIKV during pregnancy face a risk of up to 42 percent of developing birth defects, including microcephaly (an abnormally small head and decreased brain volume).

What do we know about how ZIKV causes damage to the developing brain?

Traveling and tourism have been badly affected in ZIKV-affected countries. What advice would you give a friend planning a trip to the Caribbean?

The mosquito-borne Zika virus (ZIKV) is one of the most feared viruses for pregnant women. Recent statistics justify this fear: Infants born to mothers infected with ZIKV during pregnancy face a risk of up to 42 percent of developing birth defects, including microcephaly (an abnormally small head and decreased brain volume).

What do we know about how ZIKV causes damage to the developing brain?

Draw a model to illustrate how the Zika virus genome is used to produce new virions. In your drawing, identify the steps required to replicate the genome and those used to produce mRNA.

Also note where mRNAs that are used to produce capsid and envelope proteins are translated.