Prokaryotic cells 2.2 Flashcards
What type of ribosomes do prokaryotic cells have?
70S
What subunits do 70S consist of?
30S and 50S
What is the most common prokaryotic organism?
-Bacteria
What is a bacteria’s cell wall made out of?
Peptidoglycan
What is the function of the capsule/slime layer?
Protects the bacteria from phagocytosis by white blood cells
What are pili?
Thread-like protein projections from a bacteria’s surface
What is a disadvantage of a bacteria having pili?
Can make a bacteria more vulnerable to virus infections as a bacteriophage can use pili as an entry point to the cell
what does a prokaryotic cell not have that an eukaryotic cell does?
-Mitochondria
-Nucleus
-Golgi apparatus
-Endoplasmic reticulum
-Lysosomes
What are mesosomes?
Inner foldings of the bacteria’s membrane
What are plasmids?
Circles of DNA that code for specific aspects of the bacterial phenotype
What is a Nucleoid?
The area in a bacterial cell where DNA is folded and coiled to fit inside the cell
How do we distinguish what type of cell wall a bacteria has?
Gram staining
How does gram-positive bacteria differ to gram-negative bacteria?
-Gram-positive have a thick peptidoglycan wall containing teichoic acid.
-gram negative has no teichoic acid with thin layers of peptidoglycan
What stain is used in gram staining?
Crystal violet/ idoine complex
How is gram negative bacteria identified with gram staining?
Cells appear red
What are obligate aerobe bacteria?
Need oxygen for respiration
What are facultative anaerobes?
Use oxygen if it is available but can manage without it
What are obligate anaerobes?
Can only respire in the absence of oxygen, oxygen will kill them
What is the capsid of a virus?
The protein coat, made up of repeating protein units or capsomeres
How does the presence of an envelope make viruses vulnerable?
Makes them vulnerable to substances such as ether, which can dissolve the lipid membrane
What do viruses use to attach to host cells?
using virus attachment particles
What are the characteristics of DNA viruses?
-Genetic material is DNA
-viral DNA acts as a template for new viral DNA
What are two examples of DNA viruses?
Lambda phage
Smallpox virus
What is the characteristic of positive ssRNA viruses?
-RNA that acts as mRNA to be translated
What are two examples of positive ssRNA viruses?
-Tobacco mosaic viruses
-Polio
What happens in negative ssRNA viruses?
RNA strand must be transcribed before it is translated
What are two examples of negative ssRNA viruses?
-Ebola
-Influenza
What are the characteristics of RNA retroviruses?
-Have a protein capsid and lipid envelope
-Viral RNA directs the synthesis of reverse transcriptase
What does reverse transcriptase do in viruses?
Makes DNA molecules corresponding to the viral genome.
This DNA is then incorporated into the host cell DNA
What is one example of a retrovirus?
HIV
What two pathways do DNA viruses use to replicate?
-Lysogenic pathway
-Lytic pathway
How is ebola spread?
-From animals to humans through infected blood or meat
What do antiviral treatments target?
Viral replication by targeting receptors and enzymes used in replication
What are two ways to prevent viral disease?
-Vaccinations
-Disease control (isolation)
What are three ways disease was controlled the ebola broke out?
-Rapid identification of disease
-Sterilising equipment after use
-Wearing protective clothing by health workers
How was the process of development of vaccines sped up in the ebola breakout?
-Vaccines in trial that were being fast tracked
-Experimental drug being produced on higher scales to run bigger trials
What are three factors to evaluate when considering whether a drug should be fast-tracked?
-Severity of the disease
-Availability of other treatments
-Effectiveness of disease control
What are two ethical issues with using untested drugs?
-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
