Viruses

Question 1

What is a virus?

Answer 1

A nucleoprotein complex which infects cells and uses their metabolic processes to replicate.

Question 2

What does Obligate Intercellular parasite mean?

Answer 2

It requires host to survive and lives inside of host’s body.

Question 3

What is a bacteriophage?

Answer 3

Virus that only affects bacteria.

Question 4

Are viruses capable of living independently?

Answer 4

No they are functionally dependent.

Question 5

When viruses are outside of cells what are they?

Answer 5

Outside of cells viruses are dormant.

Question 6

What organelles do viruses NOT have?

Answer 6

Cytoplasm, membrane bound organelles, or cell membranes.

Question 7

What type of genetic material can be found in a virus?

Answer 7

There is nucleic acid. This can either be RNA or DNA. It can be single or double stranded, linear or circular. However it can only have one.

Question 8

What structure does the virus HIV have?

Answer 8

It has a spherical shape.

Question 9

What structure does the tobacco mosaic virus have?

Answer 9

It has a cylindrical shape.

Question 10

What shape does the polio virus have?

Answer 10

It has small crystals that have about 20 sides.

Question 11

What is a prion?

Answer 11

Infectious particles that cause damage to nerve cells in the brain. They are proteins that lack DNA or RNA.

Question 12

Ignore this question couldn’t delete

Question 13

Name a prion causing brain disease found in humans?

Answer 13

Creutzfeldt - Jakob disease (CJD)

Question 14

What is the definition of lytic?

Answer 14

To cut or to break open something.

Question 15

What is the difference between the lytic and lysogenic cycle?

Answer 15

The lytic cycle breaks down the hosts chromosome, whereas in the lysogenic cycle the virus’s DNA integrates into the hosts chromosome.

Question 16

Shape is a way to classify viruses. Are viruses bigger, smaller, or the same size as a prokaryote? What about a eukaryote?

Answer 16

Viruses are smaller than both bacteria and eukaryotic cells.

Question 17

What is the capsid?

Answer 17

It is the protein coat encircling the viruses genetic material.

Question 18

What are the building blocks that capsids need to build it’s shape called?

Answer 18

They are called: Capsomeres

Question 19

What is the 6 sided diamond shape virus called?

Answer 19

Icosahedral configuration.

Question 20

What is the spiral virus shape called?

Answer 20

Helical

Question 21

What is the spherical shape that surrounds the virus’ called?

Answer 21

The envelope.

Question 22

What is a T4 virus?

Answer 22

It is a virus that only attacks bacteria. It is the short form for a bacteriophage.

Question 23

Bacteriophages have complex shapes. What is the head called?

Answer 23

The head of a bacteriophage is called a nucleocapside. These do not have envelopes.

Question 24

How does the T4 virus infects cells?

Answer 24

They inject the cell with its sheath containing the DNA or RNA.

Question 25

What is one way a T4 virus can infect a eukaryotic cell?

Answer 25

There are receptors on the outside of the cells. These receptors cannot distinguish between normal signals of cells or viral cells. So the virus sends a trick signal to the receptor where it will then form a pit. After going into the pit the virus will bud off into the cell.

Question 26

What is endocytosis?

Answer 26

It is when something enters the cell.

Question 27

If the nucleocapsid has an envelope it can also easily enter the cell. Explain how that will work.

Answer 27

The spherical envelope can fuse to the eukaryotic cell. Because it directly fuses with the membrane to let itself in it is called direct fusion.

*Note, this only works if the virus has the spherical envelope.

Question 28

What is Ebola?

Answer 28

It attacks the immune system and neutralizes its responses. It invades the lymph nodes, and vital organs which triggers a cytokine storm. That storm is an explosion of immune responses that will create damage to blood vessels and cause internal bleeding.

Question 29

How is Ebola contracted?

Answer 29

Through body fluids.

Question 30

How long does it take after contraction for Ebola to become fatal? How long does it take for symptoms to appear?

Answer 30

It takes 6-16 days after first symptoms occur. It can take 2-20 days after contraction for symptoms to appear though.

Question 31

Coronavirus structure, what does it look like?

Answer 31

A virus covered in spikes.

Question 32

How many of the hundreds of different corona strands infect humans?

Answer 32

7

Question 33

Out of the seven corona strands that can affect humans, how many cause colds?

Answer 33

4

Question 34

How many corona strands are susceptible for the lungs?

Answer 34

2

Question 35

What viruses can easily mutate, DNA viruses or RNA viruses? Why?

Answer 35

RNA can be smaller with fewer genes making it more likely to replicate and mutate faster than a DNA virus.

Question 36

Are viruses living organisms? Give examples for yes and no.

Answer 36

Yes, because they have genetic material that is needed in order to replicate in order to survive.
No, they are not capable of living or reproducing independently and have no membrane bound organelles.

Question 37

Explain the lytic cycle.

Answer 37

This cycle is fast. The virus attaches to the host and injects its chromosomal DNA into the cell. It destroys the host’s own chromosome using the protein and ribosomes in cell to replicate before leaving/ destroying cell.

Question 38

Explain the lysogenic cycle.

Answer 38

This cycle is slower. The virus attaches and injects its genetic material into the cell. It integrates into the host cells chromosome. From there the cell will duplicate, the virus remains dormant. With multiple cells now having the same genetic material integrated into the hosts dna the lysogenic cycle ends and the lytic cycle continues.