Topic 2.2 Prokaryotic cells Flashcards

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1
Q

Pilli

A

-Short hair-like structures on the cell surface
-They have a role in movement
-Are more often involved in adherence to surfaces, which facilitates infection and is a key virulence characteristic.

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2
Q

Flagella

A

-Primarily used for cell movement
-Spins creating forward movement
-Some prokaryote have more than one flagella, localised to one pole or spread out around the cell.

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3
Q

70S ribosomes

A

-These consist of a 30S subunit and a 50S subunit
-The smaller subunit is comprised of more than 20 proteins
-The larger subunit comprised of more than 30 proteins
-Their main role is in protein synthesis.

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4
Q

Nucleoid

A

-The space within prokaryotic cell where the genetic information (genophore) is found
-It doesn’t contain a membrane.

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5
Q

Plasmids

A

-Small loops of DNA that are separate from the main circular DNA molecule
-Plasmids contain genes that can be passed between prokaryotes.

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6
Q

Capsule

A

-A final outlier that surrounds some prokaryotes
-Sometimes called slime capsule
-Helps to protect bacteria from drying out.

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7
Q

Peptidoglycan

A

-Found in bacterial cell wall
-Made up of many parallel polysaccharide chains with cross links that form a net like structure.

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8
Q

How to distinguish between the two bacterial cell walls?

A

A technique called gram staining

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9
Q

Gram (+) cell wall

A

Have a thick peptidoglycan layer which means that stains get trapped in the cell wall leading to deeper colour when stained.

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10
Q

Gram (-) cell wall

A

Have a thin layer of peptidoglycan which means the stain doesn’t get trapped so much during the process and they have a lighter colour.

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11
Q

General viral structure

A

-Acellular: not living
-Has a protein coat or capsid
-Some have a lipid envelope which covers the protein coat which makes it easier for viruses to pass from cell to cell.

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12
Q

Virus shapes

A

-Helical
-Polyhedral
-Spherical
-Complex

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13
Q

Virus classification

A

-Mode of replication (lytic, lysogenic)
-Genetic material
-Capsule structure
-Host organism
-Size

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14
Q

Lambda phage (λ) virus

A

-Lambda phage is a virus particle consisting of a head containing 48514 base pairs of double stranded linear DNA
-It infect the bacterial species Escherichia coli (E coli)
-Usually goes through the lytic cycle and lambda DNA assembles in its host.

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15
Q

Tobacco mosaic virus

A

-Contains single stranded RNA as its genetic material
-It infects mostly tobacco plants and other membranes of the family Solanaceae
-Causes the mosaic/mottling discolouration on the leaves

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16
Q

Ebola virus

A

-Contains RNA which is the blueprint for assembling new virus
-A person infected with Ebola virus will typically develop a fever, headaches, joint and muscle pain, a sore throat and intense muscle weakness
-Symptoms start suddenly between 2 after becoming infected
-Ebola virus kills 90% of victims
-Breakout was in 2014

17
Q

Human immunodeficiency virus (HIV)

A

-HIV contains two copies of single-stranded RNA which are transcribed into double-stranded DNA (by reverse transcription)
-It damages cells in the immune system and weakens your ability to fight everyday infections and diseases
-Most people experience a short flu-like illness 2 to 6 weeks after HIV infection, which last a week or two
-After the symptoms disappear, HIV may not cause any symptoms for many years later although the virus continues to damage the immune system.

18
Q

Controlling disease

A

-Identifying contacts
-Rapid identification
-PPE
-Sterilising and disposing
-Avoiding contact
-Lockdowns
-Isolation
-Hygiene
-Social distancing
-Vaccines
-Vaccine passports

19
Q

Developments of medicine

A

-Takes up to 10 years
-Costs millions of pounds
-Involves many scientists and doctors

20
Q

Step 1 in developing medicines
(initial ideas)

A

Initial ideas come from:
-genome analysis
-computer modelling
-clinical compound banks
-medicinal plants

21
Q

Step 2 in developing medicines
(research)

A

Go through research and testing on:
-cell and tissue cultures
-safety analysis
-molecular modifications

22
Q

Step 3 in developing medicines

A

Animal testing is carried out to ensure it works in an organism and it is safe.

23
Q

Step 4 in developing medicines

A

Three phases of human testing to further ensure safety and that the drug works (lots of complex regulation and licensing procedures).

24
Q

Step 5 in developing medicines

A

Drug reaches the doctors surgery

25
Q

Duration of each step in developing medicines

A

-Early phase research (4-6 yrs)
-Preclinical testing (1 yr)
-Clinical trials (3 phases; 6-7 yrs)
-Regulatory review
-Scale up to manufacturing (0.5-2 yrs)
-post market surveillance (continuous).

26
Q

Vaccines and how they work

A

-Provides immunity
-Prevents disease outbreak
How antibiotics work:
-target the receptors by which the viruses recognise their host cells
-target the enzymes that help to translate or replicate the viral DNA or RNA
-inhibit the protease enzymes that enables new virus particles to bud from the host membranes

27
Q

Process of Gram staining

A

1) Stain culture with crystal violet. Remove and rinse with water
2) Add iodine solution and remove after 1 minute
3) Add alcohol
4) Counterstain with red safranin for 1 minute
5) Dry and examine sample under microscope