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Edexcel Biology B A-level > Prokaryotic cells 2.2 > Flashcards

Prokaryotic cells 2.2 Flashcards

1
Q

What type of ribosomes do prokaryotic cells have?

A

70S

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2
Q

What subunits do 70S consist of?

A

30S and 50S

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3
Q

What is the most common prokaryotic organism?

A

-Bacteria

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4
Q

What is a bacteria’s cell wall made out of?

A

Peptidoglycan

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5
Q

What is the function of the capsule/slime layer?

A

Protects the bacteria from phagocytosis by white blood cells

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6
Q

What are pili?

A

Thread-like protein projections from a bacteria’s surface

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7
Q

What is a disadvantage of a bacteria having pili?

A

Can make a bacteria more vulnerable to virus infections as a bacteriophage can use pili as an entry point to the cell

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8
Q

what does a prokaryotic cell not have that an eukaryotic cell does?

A

-Mitochondria
-Nucleus
-Golgi apparatus
-Endoplasmic reticulum
-Lysosomes

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9
Q

What are mesosomes?

A

Inner foldings of the bacteria’s membrane

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10
Q

What are plasmids?

A

Circles of DNA that code for specific aspects of the bacterial phenotype

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11
Q

What is a Nucleoid?

A

The area in a bacterial cell where DNA is folded and coiled to fit inside the cell

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12
Q

How do we distinguish what type of cell wall a bacteria has?

A

Gram staining

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13
Q

How does gram-positive bacteria differ to gram-negative bacteria?

A

-Gram-positive have a thick peptidoglycan wall containing teichoic acid.
-gram negative has no teichoic acid with thin layers of peptidoglycan

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14
Q

What stain is used in gram staining?

A

Crystal violet/ idoine complex

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15
Q

How is gram negative bacteria identified with gram staining?

A

Cells appear red

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16
Q

What are obligate aerobe bacteria?

A

Need oxygen for respiration

17
Q

What are facultative anaerobes?

A

Use oxygen if it is available but can manage without it

18
Q

What are obligate anaerobes?

A

Can only respire in the absence of oxygen, oxygen will kill them

19
Q

What is the capsid of a virus?

A

The protein coat, made up of repeating protein units or capsomeres

20
Q

How does the presence of an envelope make viruses vulnerable?

A

Makes them vulnerable to substances such as ether, which can dissolve the lipid membrane

21
Q

What do viruses use to attach to host cells?

A

using virus attachment particles

22
Q

What are the characteristics of DNA viruses?

A

-Genetic material is DNA
-viral DNA acts as a template for new viral DNA

23
Q

What are two examples of DNA viruses?

A

Lambda phage
Smallpox virus

24
Q

What is the characteristic of positive ssRNA viruses?

A

-RNA that acts as mRNA to be translated

25
Q

What are two examples of positive ssRNA viruses?

A

-Tobacco mosaic viruses
-Polio

26
Q

What happens in negative ssRNA viruses?

A

RNA strand must be transcribed before it is translated

27
Q

What are two examples of negative ssRNA viruses?

A

-Ebola
-Influenza

28
Q

What are the characteristics of RNA retroviruses?

A

-Have a protein capsid and lipid envelope
-Viral RNA directs the synthesis of reverse transcriptase

29
Q

What does reverse transcriptase do in viruses?

A

Makes DNA molecules corresponding to the viral genome.
This DNA is then incorporated into the host cell DNA

30
Q

What is one example of a retrovirus?

A

HIV

31
Q

What two pathways do DNA viruses use to replicate?

A

-Lysogenic pathway
-Lytic pathway

32
Q

How is ebola spread?

A

-From animals to humans through infected blood or meat

33
Q

What do antiviral treatments target?

A

Viral replication by targeting receptors and enzymes used in replication

34
Q

What are two ways to prevent viral disease?

A

-Vaccinations
-Disease control (isolation)

35
Q

What are three ways disease was controlled the ebola broke out?

A

-Rapid identification of disease
-Sterilising equipment after use
-Wearing protective clothing by health workers

36
Q

How was the process of development of vaccines sped up in the ebola breakout?

A

-Vaccines in trial that were being fast tracked
-Experimental drug being produced on higher scales to run bigger trials

37
Q

What are three factors to evaluate when considering whether a drug should be fast-tracked?

A

-Severity of the disease
-Availability of other treatments
-Effectiveness of disease control

38
Q

What are two ethical issues with using untested drugs?

A

-Some people feel it is unethical to use drugs that have not been tested on humans fully
-If an untested drug creates side effects than it can make the situation worse

Edexcel Biology B A-level (13 decks)

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