Lecture 14 Flashcards Preview

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Flashcards in Lecture 14 Deck (60):
1

What is even the smallest bacteria capable of?

independent replication, synthesis of energy and proteins, cell enclosed with DNA and RNA

2

What do viruses not have?

cell wall, cytoplasm, ribosomes/mitochondria, nucleus, independent replication

3

Does nature have RNA carrying genetic information?

NO- not found in nature

4

Will viruses contain DNA and RNA?

Not both at the same time- one or the other

5

DO RNA viruses carry genetic information?

YES

6

Can virues synthetize their own energy or proteins?

NO

7

Can viruses be seen under a microscope?

NO- too small

8

How do antibiotics affect viruses?

THey are resistant to all antibiotics

9

What did Geirer and Schraman do?

extracted the infectious nucleic acid which produced disease in the host cells confirming it as living chemicals

10

Most viruses are what shape?

spherical

11

define virons

extracellular virus particles- vary in size from 20-300nm

12

What is the biggest virus equal to?

the size of the smallest bacteria (micro plasm)

13

List shapes of viruses

spherical, complex, bullet shaped/brick shaped

14

What can viral nucleic acids be extracted with?

phenol/detergents

15

What parts make up the viral structure?

central nucleic acid, protein coat (capsid), some may have an envelop

16

What part of the virus protects the nucleic acid and is the basic structure of a virus?

capsid- facilitates absorption

17

What is the envelop of the cell made up of?

envelop is a lipid layer derived from host cell during budding

18

Are viruses heat labile?

YES

19

At what temperature are viruses inactivated within a few seconds?

56 degrees celcius

20

What inactivates viruses?

sunlight, UV light

21

What are viruses resistant to?

chemical disinfectants- lysol for example

22

How doe viruses replicate?

disassemble into patricles inside the cell, multiply separately and then assemble- one virion giving rise to hundred of virion particles

23

Process of adsorption of a virus

virus adsorbed to host cell- there are specific receptors on host cell for viruses

24

Penetration of a virus

penetrate into the cell

25

Uncoating of a virus

stripping of virus from capsid by lysozyme of the cell

26

Process of virus attacking

absorption, penetration, uncoating, biosynthesis, maturation, release

27

Process of biosynthesis of virus

synthesis of enzymes for stages of viral replication, assembly and release. Followed by synthesis of nucleic acid and capsid protein takes place separately

28

Where does synthesis of nucleic acid take place?

nucleus

29

Where does synthesis of viral proteins occur?

cytoplasm

30

Where does RNA viruses synthesize nucleic acid and proteins?

cytoplasm

31

Process of maturation of virus

nucleic acid and viral proteins assembled together and form viral particle

32

Process of release of virus

done by cell lysis (non enveloped virus) or budding (enveloped virus)

33

Replication times for human virus

15-30 hours

34

Replication time for baceria

15-30 minutes

35

define Lysogenic cycle

alternate pathway of viruses in which viral genome (DNA) becomes integrated with host cell genome and multiply along with it

36

Name for the integrated viral DNA

prophage

37

What is the lysogenic cycle well studied for?

lambda bacteriophage

38

transduction

transferring of a gene

39

why would a virus infected cell undergo death of cell?

inhibition of protein, nucleic acid synthesis

40

list morphological changes of a viral infected cell

inclusion bodies, fusion of virus infected cells to form multinucleated giant cells, cytopathic effect, malignant transformation and cellular proliferation, no morphological/functional change

41

define cytopathic effect

darkening and rounding which may culminate in lysis/giant cell formation

42

forms of transmission of virus

through respiratory tract, skin, conjunctiva, genital tract

43

How are viruses spread person to person?

through respiratory tract, saliva, blood or semen, fecal contamination of water and food

44

How are viruses spread from mother to baby?

placenta or breast milk- vertical transmission

45

How are viruses spread animal to human?

by vectors (ex. yellow fever)

46

In what disease is virus spread systemically through body?

polio

47

What does cell killing result in?

loss of function and symptoms

48

non specific host defense against viral infections

interferon, NK cells, fever

49

Specific defense against viral infections

humoral Antibiotics & CMI

50

What is the main defense mechanism in viral infections?

specific immunity

51

define Natural Killer Cells

a type of T lymphocyte that recognize virus infected cells and kill them

52

Define Interferons

glycoproteins produced by leukocytes (neutrophils) during viral infection

53

What eliminates non specific visions?

fever- especially help enveloped virions

54

4 types of specific antibodies

IgA, IgM, IgG, and IgE

55

What does IgA protect?

respiratory and gastro infections

56

What does IgM and IgG protect?

against viruses entering blood

57

What do antibodies do?

neutralize viruses, facilitate phagocytosis, interferes with adherence and penetration, cause lysis of virus infected cells

58

What cell causes cell mediated immunity?

cytotoxic T cells- killing viral infected cells

59

What antibodies for passive immunity?

IgG and IgM

60

What are antibodies IgG and IgM used for?

rabies, Hep B, Varicella zoster