Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Microbiology > Lecture #9 > Flashcards

Lecture #9 Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

Are viruses considered cells?

A

No because they have no internal cellular structures

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

What do viruses need in order to multiply?

A

Host cells as they are not free living

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

What do viruses do to a host cell?

A

Use host metabolic systems and usually disrupt normal host cell function

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

What does it mean for a virus to be an obligate intracellular parasite?

A

They do not reproduce outside, rather intracellular

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

What are viruses acellular?

A

They do not have a plasma membrane

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

What are viruses surrounded by?

A

A protein called a capsid

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

Do viruses contain DNA or RNA?

A

They contain a single type of nucleic acid. Can be RNA or DNA but never both

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

Do viruses have their own enzymes?

A

Very few, instead they take over the host enzymes

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

Do all viruses have a lipid envelope and or proteins?

A

No not all

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

What 5 things can viruses infect?

A

Animals, plants, fungi, bacteria and protozoa

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

Most viruses are specific for ______

A

A single host species

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

What must the virus recognize in order to infect a cell?

A

Particular features on the host cell surface

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

What does the HIV virus recognize in order to infect a human immune cell?

A

A specific receptors CO4

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

What microscope are you able to see viruses?

A

Electron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How long do viruses range in?

A

20-1000 nm

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

What type of genetic material is found in viruses?

A

Either RNA or DNA, not both

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

Can the genetic material in viruses be single or double stranded?

A

Both can be: dsDNA, ssDNA, dsRNA, or ssRNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What 3 shapes can the nucleic acids of viruses be?

A
  1. Linear
  2. Circular (two ends connect)
  3. Segmented
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What does it mean when a nucleic acid is segmented?

A

Arranged in many pieces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Why is segmented nucleic acids useful?

A

To make more of certain kinds of gene without having to make thousands of unnecessary genes ( don’t have to copy every single other gene not needed)

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

How many nucleic acids are there in a virus?

A

A few thousand- 250000 base pairs

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

How many base pairs does E.coli chromosome have?

A

4000000

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

What is the bare minimum thing you will find on a virus?

A

A capsid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is a capsid?

A

A protein coat surrounding the nucleic acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is a capsomere?

A

Individual proteins that make up a capsid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is a capsid made up of?

A

Capsomeres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What does a capsid do for a virus?

A

Provides the virus with its shape

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

How are capsomeres arranged on a virus?

A

As characteristic of a particular virus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is a nucleocapsid? What is it in regards to a virus?

A

A nucleic acid and a capsid together

This is the minimal required structure for a virus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Are envelopes found on all viruses?

A

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What is an envelope made up of? Where from?

A

A lipid bilayer (membrane) acquired from host cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Where is the envelope located on a virus when present?

A

External coating around the nucleocapsid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What are spikes? Do all viruses have them?

A

Additional viral protein inserted into envelope

No

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

When a virus is enveloped, where is the spikes attached to? What about when it is naked?

A

Enveloped- attached to envelope

Naked- attached directly to capsid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is the shape of a virus based on?

A

Capsid shape

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What are the 3 shapes of viruses?

A
  1. Helical
  2. Polyhedral
  3. Enveloped
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What does a helical virus look like? Describe

A

Long rod

Rigid and flexible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What does a icosahedral virus look like?

A

Icosahedral (20 triangular faces)

Other geometric shapes are possible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What shape are enveloped viruses? What dictates the shape?

A

Roughly spherical, dictated by lipid bilayer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What structure do complex viruses have?

A

Complicated structures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What may be attached to the capsid of a complex virus?

A

Additional protein structures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Complex viruses are most common in….?

A

Bacteriophages

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Classification of viruses are based one what 3 things?

A
  1. Nucleic acid type
  2. Capsid structure
  3. Envelope presence
44
Q

What 3 things are considered when classifying virus nucleic acid type?

A
  1. DNA or RNA
  2. Single or double stranded
  3. Segmented chromosome or single molecule
45
Q

What are two types of capsid structures that are considered when classifying a virus?

A
  1. Polyhedral

2. Helical

46
Q

If a virus ends with a viridae, what is it part of?

A

A family

47
Q

If a virus ends with the suffix virus, it is part of a…?

A

Genus

48
Q

If a virus is part of a species, how is the species specified?

A

The virus is given a descriptive name

49
Q

Give examples of a virus genus, family and species

A

Family: Retroviridae
Genus: Lentivirus
Species: Human Immunodeficiency Virus (HIV)

50
Q

What are the 6 steps of virus multiplication?

A
  1. Adsorption
  2. Penetration
  3. Uncoating
  4. Biosynthesis
  5. Maturation and Assembly
  6. Release
51
Q

What occurs during adsorption?

A

Virus attaches to host cell at protein or glycoprotein attachment sites within the host membrane that the virus recognizes

52
Q

What occurs during penetration?

A

Virus enters.
Naked viruses enter via endocytosis
Some enveloped enter via fusion of lipid bilayers

53
Q

What occurs during uncoating?

A

Separation of viral nucleic acid from the capsid (opening the lid)

54
Q

During biosynthesis, what occurs?

A

Viral nucleic acid is replicated

55
Q

Where does DNA vs RNA replication occur during biosynthesis?

A

RNA- host cytoplasm

DNA- nucleus of host cell

56
Q

Where are viral proteins synthesized during biosynthesis? What is constructed at the same time?

A

in the cytoplasm, capsomeres constructed

57
Q

If an RNA virus is taking over a host cell, what needs to happen in order to make RNA from RNA?

A

an RNA enzyme needs to be brought into the host cell

58
Q

What occurs during maturation and assembly of animal virus replication?

A

New virus particles are assembles from nucleic acids and capsomers forming nucleocapsids

59
Q

What is the difference in release between enveloped and non enveloped cells?

A

Naked- burst from cell destroying it
Enveloped- bud out of the host cell causing steady release of mature enveloped viruses over time and host cell remains alive longer

60
Q

What does the host defence do?

A

Protects against lethal infections

61
Q

Do healthy humans carry both viruses and antibodies for viruses?

A

Yes

62
Q

If a virus is transferred from the immune host to another individual, what can result?

A

In infection

63
Q

What are 5 types of infections?

A
  1. Acute infections
  2. Acute infections with late complication
  3. Persistant viral infections
  4. Latent Viral Infections
  5. Chronic Viral Infection
64
Q

How long do acute infections last?

A

Very short duration

65
Q

The symptoms from acute infections can cause?

A

Tissue Damage

66
Q

How does the host defence system eliminate the infection?

A

Gradually, from days to months

67
Q

Does the host always develop long lasting immunity after an acute virus?

A

It can or cannot e.g.. measles or polio

68
Q

How does a acute infection with late complications occur?

A

Following an acute infection, some particles still last which over time multiply and can cause a serious disease years later

69
Q

What is an example of an acute infection with late complications?

A

Measles can turn into subacute sclerosing panencephalitis

70
Q

What is a persistent viral infection?

A

An infection that is present at all times

71
Q

With a persistent viral infection, is the disease always present?

A

NO

72
Q

What is an example of a persistent viral infection?

A

Hepatitis B

73
Q

How is Hepatitis B transmitted? What are acute symptoms? What are long term symptoms?

A

Transmitted sexually or via blood
Acute: Fever, nausea and jaundice
Longterm: cirrhosis or cancer of the liver

74
Q

The infected host of a persistent viral infection serves as a…?

A

Reservoir

75
Q

What are latent viral infections?

A

An acute infection followed by an asymptomatic (different symptoms) period

76
Q

What does the virus do in a latent viral infection?

A

Virus inserts a copy of DNA into the host cell chromosome called a provirus (just sits there, doesn’t do anything)

77
Q

Can a latent virus infection be reactivated years later?

A

Yes

78
Q

What is an example of a latent virus infection? What family does it belong to?

A

Varicella Zoster Virus, belongs to herpes family

79
Q

What is the varicella zoster virus present early on as? Later on?

A

Early: chicken pox in children
Later: Shingles

80
Q

What is a chronic viral infection?

A

After an acute infection, infectious virus remains present at all times (may or may not have noticeable symptoms)

81
Q

What is an example of a chronic viral infection?

A

Hepatitis B (serum hepatitis virus)

82
Q

Viral DNA can transform normal animal cells into what?

A

malignant cancer cells

83
Q

Do all viruses have the capability to transform cells into cancer cells?

A

No only some

84
Q

What are photo-oncogenes?

A

Animal cells with normal genes

85
Q

What are photo-oncogenes required for?

A

to stimulate normal cell growth

86
Q

What do tutor suppressor cells do to cells?

A

Inhibit growth

87
Q

When mutations occur in photo-oncogenes, what does it result in?

A

Uncontrolled cell growth which then leads to tumor formation and cancer

88
Q

How can mutated genes form?

A

As a result of mutagens (carcinogens)

89
Q

What are oncogenic viruses?

A

Carry oncogenes which interfere with cell control mechanisms

90
Q

If oncogenes are present in viral DNA, what could be caused?

A

Proto-Oncogenes to be over expressed leading to increased transcription causing the proto-oncogne to become oncogene

91
Q

What are 3 possible oncogenic viruses?

A
  1. Human Papilloma Virus
  2. Epstein- Barr Virus
  3. Hepatitis B Virus
92
Q

How is the Human Papilloma Virus transmitted? What does it cause?

A

Sexually transmitted causing genital warts

93
Q

Which oncogenic virus is thought to cause cervical cancer?

A

Human Papilloma Virus

94
Q

How is the Epstein- Barr Virus transmitted?

A

Transmitted by sneezing

Can be caused by stress

95
Q

What does the epstein- Barr virus cause?

A

Mononucleosis which may cause lymphoma and cancers in the nose and throat

96
Q

Which virus is thought to cause almost all cases of liver cancer?

A

Hepatitis B and C

97
Q

What is a virod?

A

A single piece of naked RNA with no protein coat

98
Q

What does a virod result in?

A

Some plant diseases, not yet found in animals

99
Q

What are prions?

A

Infectious protein particles (turned from good to bad)

100
Q

Is there genetic material (DNA or RNA) present in prions?

A

No

101
Q

What are prions linked to cause?

A

Several fatal human and animals diseases

- ex. Transmissible Spongiform Ecephalophathy

102
Q

Why do prions cause FATAL human diseases? (what does it do)

A

Because it forms spongelike holes in brain tissue causing brain function to degenerate and neurons die

103
Q

How are prions transmitted?

A

Most frequently by food?

104
Q

How are prions transmitted to humans?

A
  1. Sheep is infected with prion (scrapie)
  2. Infected sheep eaten by cows and cow develops mad cow disease
  3. Cow is eaten by humans and develops Creutzfeldt- Jakob Disease
105
Q

What are 4 reasons prions are so resistant?

A
  1. Not usually destroyed by high temps (only by autoclaving but then food is inedible
  2. Onset of disease occurs several years after infection
106
Q

Does prions disease always kill you? Is there a cure?

A

Yes, no

107
Q

How does a single protein become infectious?

A

A known protein (with an unknown function), gets converted into a prion protein shape. Eventually all np’s become pp and this results in disease

Microbiology (16 decks)

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