STRUCTURE, PROPERTIES AND CHARACTERISTICS OF VIRUSES

Question 1

________ introduced the term VIRUS in microbiology. In the year?

Answer 1

Edward Jenner
1798

Question 2

Virus in GREEK means _____

Answer 2

Poison

Question 3

Viruses lack cellular organelles such as _____ and ______ .

Answer 3

Mitochondria
Ribosomes

Question 4

Viruses multiply in chemically defined media. True/False

Answer 4

FALSE!
Viruses do not multiply in chemically defined media

Question 5

Viruses do not undergo binary fission. True/False.

Answer 5

True.

Question 6

Nanometer is also referred to as:

Answer 6

Milli-micron

Question 7

Capsule protects nucleus acid from ______

Answer 7

Inactivation by outer physical conditions .

Question 8

All ss- RNA viruses with negative polarity have the _______ aka______ inside virions.

Answer 8

Enzyme Transcriptase
RNA dependent RNA polymerase

Question 9

_______ and ______ contain the enzyme reverse transcriptase.

Answer 9

Retroviruses and hepatitis B virus

Question 10

Example of enveloped viruses:
(from slide)

Answer 10

Herpes Viruses
Rabies virus
Influenza viruses

Question 11

Example of unenveloped viruses:

Answer 11

Adenoviruses

Question 12

Viruses are divided into ____ (number) groups, based on the ______ and ______.
Namely:

Answer 12

Three(3)

Morphology of the nucleocapsid
Arrangement of capsomeres

• Cubic symmetry
Helical symmetry
Complex symmetry

Question 13

In cubic symmetry, the virus particle is ______ in shape( almost spherical particle) and the nucleic acid contained inside the capsid. The icosahedron particle is composed of ___ equilateral triangles, ____ vertices and has __,__,___ rotational symmetry.

Answer 13

Icosahedral
20, 12, 2,3,5

Question 14

In helical symmetry, the virus particle is ______ or ______ (not spherical), and the nucleic acid is _____. Capsomeres are arranged round the ____.

Answer 14

Elongated, pleomorphic
Spiral
Nucleic acid

NB: Pleomorphic means the ability of some microorganisms to alter their morphology, biological functions or reproductive modes in response to environmental conditions.

Question 15

Viruses that show cubic symmetry:

Answer 15

Adenovirus
Herpes virus

Question 16

Viruses show Helical Symmetry:

Answer 16

Influenza viruses
Rabies viruses

Question 17

Virus that exhibit complex symmetry:

Answer 17

Poxviruses

Question 18

Virion refers to :

Answer 18

Complete virus particle

Question 19

Smallest RNA virus:

Answer 19

Picornavirus

Question 20

Largest DNA virus:

Answer 20

Poxvirus

Question 21

Enzyme transcriptase aka RNA dependent RNA polymerase converts ____ sense strand to ____ sense strand.

Answer 21

Negative
Positive

Question 22

RNA virus replicates in _____

Answer 22

Cytoplasm

Question 23

2 RNA viruses replicates in the nucleus:

Answer 23

Orthomyxovirus
Retrovirus

Question 24

Double-stranded RNA virus:

Answer 24

Reovirus

Question 25

Single-stranded DNA virus:

Answer 25

PARVOVIRUS It is also the smallest DNA virus

Question 26

All segmented viruses are RNA viruses. True/False

Answer 26

True

Question 27

DNA viruses replicate in the ____

Answer 27

Nucleus

Question 28

Only _____ which is a DNA virus replicates in the cytoplasm.

Answer 28

Poxvirus. It therefore needs it down DNA dependent RNA polymerase.

Question 29

Cubic symmetry can be:

Answer 29

2-fold 3-fold 5-fold AS SEEN IN THE SLIDE