Microorganism And Disease Flashcards Preview

A-Level Biology (Edexcel) > Microorganism And Disease > Flashcards

Flashcards in Microorganism And Disease Deck (20)
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1
Q

What are pathogens?

A

Pathogens are invading microorganisms

2
Q

What are the 5 groups of pathogens

A
Viruses 
Bacteria
Fungi
Metazoa
Protoctista
3
Q

What are viruses?

A

Arrangements of genetic material and protein that invade other living cells and take over their biochemistry to make more viruses

4
Q

What is the capsid and what it is made out of?

A

It is the protein coat. It is made up of many repeating protein units known as capsomeres arranged in different ways

5
Q

Why is good having a capsid?

A

The repeating protein units minimize the amount of genetic material needed to code for the coat production

6
Q

Why are the good and bad points of a virus having a lipid envelope?

A

It makes it easier for it to pass from cell to cell

BUT

It makes them vulnerable to substances that can dissolve the lipid membrane. Eg. Ether

7
Q

What are the 5 structural things viruses have?

A
Capsid
Nucleic acids
VAPs (receptors)
Capsomere
Envelope
8
Q

What does the viral DNA do?

A

Acts as a template for both new viral DNA and mRNA needed to induce synthesis if viral proteins

9
Q

What are some examples of viruses with DNA?

A

Smallpox
Adenoviruses
Bacteriophages

10
Q

What does viral RNA do?

A

It directs the synthesis of reverse transcriptase which makes DNA molecules corresponding to the viral genome. This DNA is then used as a template.

11
Q

What are some examples of viruses with RNA?

A

Tobacco mosaic virus

HIV

12
Q

How do virus attach to their hosts?

A

Through antigens (VAPs) which target proteins in the host cell surface membrane.

13
Q

Where do viruses reproduce?

A

Within body cells

14
Q

What happens after bacteriophages insert their DNA in the host cell?

A

The viral DNA forms a circle (PLASMID) within the bacterium

15
Q

How can viruses infect cells?

A

By endocytosis: the host ingests the capsid releasing viral genetic material.

Or

By vectors like animals

16
Q

What are the 2 routes of infection?

A

Lysogenic and lytic pathway

17
Q

What is the lysogenic pathway?

A

When the virus inserts its provirus (DNA) in the host. It replicates every time the host cell divides.

The virus is dormant. mRNA is not produced because one viral gene causes the production of a repressor protein, so the rest of the viral genetic material isn’t translated

18
Q

What is the lytic pathway?

A

After viral DNA is replicated, mature viruses are made and eventually the host cells release viruses.

19
Q

How do retroviruses infect cells?

A

It attacks the cell
The viral RNA enters the host cell
The viral RNA is translated into viral DNA by reverse transcriptase in the cytoplasm because the RNA cant be used as mRNA
The viral DNA is incorporated into the host DNA in the nucleus and it directs the production of new viral RNA, mRNA and coat proteins
The new viral particles are assembled and leave the host cell by exocytosis. Viral DNA remains in the nucleus so this process is repeated

20
Q

How to viruses causes symptoms?

A

By the lysis of the host cells by making them release their own lysosomes and digest themselves from the inside.

Or by making toxins that inhibit cell metabolism