Chapter 35

Question 1

virus

Answer 1

Any of various submicroscopic agents that infect living organisms, often causing disease, and that consist of a single or double strand of RNA or DNA surrounded by a protein coat. Unable to replicate without a host cell, viruses are typically not considered living organisms.

Question 2

Virion

Answer 2

the infectious particle that is designed for transmission of the nucleic acid genome among hosts or host cells.

Question 3

Bacteriophage

Answer 3

a type of virus that attacks only bacteria. It uses the bacteria to reproduce itself. Bacteriophages work by injecting their own DNA into bacterial cells. They use the biological machinery of the bacteria to reproduce, and many more viruses are created this way.

Question 4

Obligate

Answer 4

Capable of functioning or surviving only in a particular condition or by assuming a particular behavior.

Question 5

Intracellular parasite

Answer 5

cannot reproduce outside their host cell, meaning that the parasite’s reproduction is entirely reliant on intracellular resources.

Question 6

Host cell

Answer 6

an animal or plant on or in which a parasite or commensal organism lives.

Question 7

Epidemic

Answer 7

The occurrence of more cases of a disease than would be expected in a community or region during a given time period.

Question 8

Pandemic

Answer 8

an epidemic of infectious disease that has spread through human populations across a large region; for instance multiple continents, or even worldwide.

Question 9

Virulence

Answer 9

refers to the degree of damage caused by a microbe to its host. The pathogenicity of an organism - its ability to cause disease - is determined by its virulence factors.

Question 10

Transmission

Answer 10

the passing of a pathogen causing communicable disease from an infected host individual or group to a particular individual or group, regardless of whether the other individual was previously infected.

Question 11

Transmission Electron microscopy

Answer 11

Those forms of electron microscopy in which electrons are transmitted through the object to be imaged, suffering energy loss by diffraction and to a small extent by absorption.

Question 12

Capsid

Answer 12

the protein shell of a virus. It consists of several oligomeric structural subunits made of protein called protomers. The observable 3-dimensional morphological subunits, which may or may not correspond to individual proteins, are called capsomeres. The capsid encloses the genetic material of the virus.

Question 13

Envelope

Answer 13

lipoprotein outer layer of some viruses derived from plasma membrane of the host cell.

Question 14

Enveloped virus

Answer 14

A virus that has an outer wrapping or envelope. This envelope comes from the infected cell, or host, in a process called “budding off.” During the budding process, newly formed virus particles become “enveloped” or wrapped in an outer coat that is made from a small piece of the cell’s plasma membrane.

Question 15

acquired immune deficiency syndrome (AIDS)

Answer 15

a human disease characterized by death of immune system cells (helper T cells and macrophages) and subsequent vulnerability to other infections, caused by HIV

Question 16

Human immunodeficiency virus (HIV)

Answer 16

a retrovirus that causes AIDS in humans

Question 17

immune system

Answer 17

in vertebrates, the system whose primary function is to defend the body against pathogens. Include cells like helper T cells and macrophages as well as organs like the lymph nodes and thymus

Question 18

helper T cell lymphocyte/ macrophage

Answer 18

an effector t cell that secretes cytokines and in other ways promotes the activation of lymphocytes. Is descended from an activated CD4+ T cell that has interacted with antigen presented by dendritic cells, macrophages or B cells

Question 19

Koch’s Postulates

Answer 19

four criteria used used to determine whether a suspected infectious agent causes a particular disease

Question 20

lytic cycle

Answer 20

a type of viral replication in which a viral genome enters a host cell, new virus particles(virions) are made using host enzymes and eventually burst out of the cell, killing it.

Question 21

replicative growth

Answer 21

another name for the lytic cycle

Question 22

lysogenic cycle/ lysogeny

Answer 22

a type of viral replication in which a viral genome enters a host cell, is inserted into the hosts chromosome and is replicated whenever the host cell divides. When activated the viral DNA enters the lytic cycle, leading to the production of new virus particles

Question 23

nonenveloped virus

Answer 23

virus that consists of genetic material and possibly one or more enzymes inside a capsid (protein coat)