Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Microbiology > Acellular pathogens > Flashcards

Acellular pathogens Flashcards

(62 cards)

Start Studying
1
Q

Obligatory intracellular parasite

A

Require living host cells to multiply

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Describe the basic characteristics of viruses

A

Obligatory intracellular parasite, Contain DNA or RNA, contain protein coat, No ribosomes, no ATP generating mechanism

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is meant by host range?

A

Host range is the spectrum of host cells a virus can infect, most viruses infect only specific types of cells in one host (determined by specific host attachment sites and cellular factors)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is a bacteriophage?

A

Virus that infects bacteria, range from 20nm to 1000 nm in length

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Define and describe the components of a virion

A

A virion is a complete, fully developed viral particle, nucleic acid (DNA or RNA), can be single or double stranded; linear or circular, Capsid (protein coat made of capsomeres/subunits), Envelope (lipid, protein, and carbohydrate coating on some viruses), spikes (projections from outer surface for attachment or gaining entry into a host)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Helical viruses

A

Hollow, cyclindrical capsid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Polyhedral viruses

A

Many-sided, geometric in shape

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Enveloped viruses

A

Has outer coating lipid, protein, or carbohydrate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Complex viruses

A

Complicated structures (bacteriphages)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Nonenveloped viruses

A

naked viruses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Suffix -virus

A

Genus names end in -virus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Suffix -viridae

A

Family name ends in -viridae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Suffix -ales

A

Order name ends in -ales

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Viral species

A

A group of viruses sharing the same genetic information and ecological niche (host)

  • Descriptive common names are used for species
  • Subspecies are designated by a number
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What do viruses need to be grown in labs?

A

Viruses must be grown in living cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How are bacteriophages grown in a lab?

A

Bacteriophages are grown in bacteria, bacteriophages form plaques, which are clearings on a lawn of bacteria on the surface of agar-each plaque corresponds to a single virus; can be expressed as plaque-forming units (PFU)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Growing animal viruses in the lab

A
  • In living animals
  • In embryonated eggs (virus injected into the egg/ viral growth is signaled by changes or death of the embryo)
  • In cell cultures (Tissues derived from living organisms)- Tissues are treated with enzymes to separate cells, virally infected cells detected via their deterioration, known as cytopathic effect (CPE), continuous cell lines are used-Henrietta Lacks
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Describe the one-step growth curve for viral multiplication

A
  1. Inoculum
  2. Eclipse period- virus invaded host cell
  3. Burst- virions released from host cell *acute infection
  4. Viral titer-measure of how many viruses in filtrate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Describe the lytic cycle for phages

A
  1. Attachment – Phage attaches by the tail fibers to the host cell
  2. Penetration – the phage injects its DNA into the host cell by penetrating through the cell membrane
  3. Biosynthesis – the phage DNA replicates inside the cell, synthesizing new phage DNA and proteins
  4. Maturation – the replicated material assembles into fully formed viral phages (each made up of a head, a tail and tail fibers)
  5. Lysis – the newly formed phages are released from the infected cell
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Describe the lysogenic cycle for phages

A

In contrast to the lytic cycle, phages infecting bacteria via the lysogenic cycle do not immediately kill their host cell. Instead, they combine their genome with the host genome, allowing the bacteria to replicate the phage DNA along with the bacterial genome. The incorporated copy of the phage genome is called the prophage.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Generalized transduction

A

Random bacterial genes incorporated into capsid; can be transferred to another bacteria when infected; lytic or lysogenic phages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Specialized trasnduction

A

Specific bacterial genes transferred to another bacterium via a phage; When prophage excises, extra host DNA is taken; changes genetic properties of the bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Multiplication of animal viruses

A
  1. Attachment- viruses attach to cell membrane
  2. Entry- by receptor mediated endocytosis of fusion
  3. Uncoating- by viral or host enzymes
  4. Biosynthesis- production of nucleic acids and proteins
  5. Maturation- nucleic acid and capsid proteins assemble
  6. Release- by budding (enveloped viruses) or rupture
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

The biosynthesis of DNA viruses

A

DNA viruses replicate their DNA in the nucleus of the host using viral enzymes; Synthesize capsid in the cytoplasm using host cell enzymes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Adenoviridae (DNA virus)
Double stranded DNA, non enveloped; respiratory infections in humans, tumors in animals
26
Double stranded DNA, non enveloped; respiratory infections in humans, tumors in animals
Adenoviridae
27
Poxviridae (DNA virus)
Double stranded DNA, enveloped; cause skin lesions, vaccinia and smallpox viruses (orthopox virus)
28
Double stranded DNA, enveloped; cause skin lesions, vaccinia and smallpox viruses (orthopox virus)
Poxviridae
29
Herpesviridae (DNA virus)
Double stranded DNA, enveloped; HHV1-8 (simplex virus, cold sores, varicellovirus, chickenpox, lymphocryptovirus, mononucleosis, cytomegalovirus, roseolovirus, rhadinovirus, and kaposi's sarcoma)
30
Double stranded DNA, enveloped; HHV1-8 (simplex virus, cold sores, varicellovirus, chickenpox, lymphocryptovirus, mononucleosis, cytomegalovirus, roseolovirus, rhadinovirus, and kaposi's sarcoma)
Herpesviridae
31
Papoviridae (DNA virus)
Double stranded DNA, nonenveloped; papillomavirus (causes warts, can transform cells and cause cancer)
32
Double stranded DNA, nonenveloped; papillomavirus (causes warts, can transform cells and cause cancer)
Papoviridae
33
Hepadnaviridae (DNA virus)
Double stranded DNA, enveloped; Hepatitis B virus, use reverse transcriptase to make DNA from RNA
34
Double stranded DNA, enveloped; Hepatitis B virus, use reverse transcriptase to make DNA from RNA
Hepadnaviridae
35
Biosynthesis of RNA viruses
Virus multiplies in the host cell's cytoplasm using RNA-dependent RNA polymerase (replicase)
36
ssRNA + sense strand
Viral RNA serves as mRNA for protein synthesis
37
ssRNA - antisense strand
Viral RNA is transcribed to a + strand to serve as mRNA for protein synthesis
38
dsRNA
Double stranded RNA both + and -
39
+ Picornaviridae (RNA virus)
Single stranded RNA, + strand, non enveloped; enterovirus, rhinovirus, hepatitis A virus
40
Single stranded RNA, + strand, non enveloped; enterovirus, rhinovirus, hepatitis A virus
Picornaviridae
41
+ Togaviridae (RNA virus)
Single stranded RNA, + strand, enveloped; alphavirus (transmitted by arthropods), rubivirus (rubella)
42
Single stranded RNA, + strand, enveloped; alphavirus (transmitted by arthropods), rubivirus (rubella)
Togaviridae
43
- Rhabdoviridae (RNA virus)
Single stranded RNA, - strand, Lyssavirus (rabies), numerous animal diseases
44
Single stranded RNA, - strand, Lyssavirus (rabies), numerous animal diseases
Rhabdoviridae
45
Reoviridae (RNA virus)
Double stranded RNA, nonenveloped, reovirus, rotavirus (mild respiratory inf. and gastroenteritis)
46
Biosynthesis of RNA viruses that use DNA
Single stranded RNA produce DNA- use reverse transcriptase to produce DNA from the viral genome/ viral DNA integrates into the host chromosome as a provirus
47
Retroviridae (RNA virus that uses DNA)
Lentivirus (HIV), oncoviruses
48
Viruses and cancer
May develop long after viral infection; Cancers caused by viruses are not contagious
49
Sarcoma
Cancer of connective tissue
50
Adenocarcinomas
Cancers of glandular epithelial tissue
51
Oncogenes
Transform normal cells into cancerous cells
52
Oncogenic viruses
Become integrated into the host cell's DNA and induce tumors
53
Tumor specific transplant antigen and T antigen
A transformed cell harbors a tumor specific transplant antigen (TSTA) on the surface and a T antigen in the nucleus
54
DNA oncogenic viruses
``` Adenoviridae Herpesviridae Poxviridae Papoviridae Hepadnaviridae ```
55
RNA oncogenic viruses
Retroviridae- Viral RNA is transcribed to DNA (reverse transcriptase) which can integrate into host DNA; HTLV 1 and 2 cause adult T cell leukemia and lymphoma
56
Latent virus
Remains in asymptomatic host cell for a long period of time- may reactivate due to changes in immunity (cold sores/shingles)
57
Persistent viral infection
Occurs gradually over a long period; generally fatal, subacute sclerosing panencephalitis (measles virus)
58
What is a prion?
Proteinaceous infectious particles; inherited and transmissible by ingestion, transplant, and surgical instruments...spongiform encephalopathies (mad cow disease, crentzfeldt jakob disease, gertsmann-straussler-scheinker syndrome, fatal familial insomnia, sheep scrapie)
59
PrPc
Normal cellular prion protein, on cell surface
60
PrPsc
Scrapie protein; accumulates in brain cells, forming plaques
61
Plant viruses
Enter through wounds or via insects; plant cells are generally protected from disease by an impermeable cell wall
62
Viroids
Short pieces of naked RNA; cause potato spindle tuber disease

Microbiology (7 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions