Prokaryotic cells 2.2

Question 1

What type of ribosomes do prokaryotic cells have?

Answer 1

70S

Question 2

What subunits do 70S consist of?

Answer 2

30S and 50S

Question 3

What is the most common prokaryotic organism?

Answer 3

-Bacteria

Question 4

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

Answer 4

Peptidoglycan

Question 5

What is the function of the capsule/slime layer?

Answer 5

Protects the bacteria from phagocytosis by white blood cells

Question 6

What are pili?

Answer 6

Thread-like protein projections from a bacteria’s surface

Question 7

What is a disadvantage of a bacteria having pili?

Answer 7

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

Question 8

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

Answer 8

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

Question 9

What are mesosomes?

Answer 9

Inner foldings of the bacteria’s membrane

Question 10

What are plasmids?

Answer 10

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

Question 11

What is a Nucleoid?

Answer 11

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

Question 12

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

Answer 12

Gram staining

Question 13

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

Answer 13

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

Question 14

What stain is used in gram staining?

Answer 14

Crystal violet/ idoine complex

Question 15

How is gram negative bacteria identified with gram staining?

Answer 15

Cells appear red

Question 16

What are obligate aerobe bacteria?

Answer 16

Need oxygen for respiration

Question 17

What are facultative anaerobes?

Answer 17

Use oxygen if it is available but can manage without it

Question 18

What are obligate anaerobes?

Answer 18

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

Question 19

What is the capsid of a virus?

Answer 19

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

Question 20

How does the presence of an envelope make viruses vulnerable?

Answer 20

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

Question 21

What do viruses use to attach to host cells?

Answer 21

using virus attachment particles

Question 22

What are the characteristics of DNA viruses?

Answer 22

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

Question 23

What are two examples of DNA viruses?

Answer 23

Lambda phage
Smallpox virus

Question 24

What is the characteristic of positive ssRNA viruses?

Answer 24

-RNA that acts as mRNA to be translated

Question 25

What are two examples of positive ssRNA viruses?

Answer 25

-Tobacco mosaic viruses -Polio

Question 26

What happens in negative ssRNA viruses?

Answer 26

RNA strand must be transcribed before it is translated

Question 27

What are two examples of negative ssRNA viruses?

Answer 27

-Ebola -Influenza

Question 28

What are the characteristics of RNA retroviruses?

Answer 28

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

Question 29

What does reverse transcriptase do in viruses?

Answer 29

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

Question 30

What is one example of a retrovirus?

Answer 30

HIV

Question 31

What two pathways do DNA viruses use to replicate?

Answer 31

-Lysogenic pathway -Lytic pathway

Question 32

How is ebola spread?

Answer 32

-From animals to humans through infected blood or meat

Question 33

What do antiviral treatments target?

Answer 33

Viral replication by targeting receptors and enzymes used in replication

Question 34

What are two ways to prevent viral disease?

Answer 34

-Vaccinations -Disease control (isolation)

Question 35

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

Answer 35

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

Question 36

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

Answer 36

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

Question 37

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

Answer 37

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

Question 38

What are two ethical issues with using untested drugs?

Answer 38

-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