Lectures 7-15, Jasna's part Flashcards Preview

Microbiology > Lectures 7-15, Jasna's part > Flashcards

Flashcards in Lectures 7-15, Jasna's part Deck (19):

What are the components cytoplasmic membrane and cell wall of bacteria?

The bacteria cytoplasmic membrane is made up of phospholipid bilayers and can form bilayers.
The bacteria cell wall is made of murein and most bacteria contain a cell wall


What are the components cytoplasmic membrane and cell wall of archaea?

The archaea cytoplasmic membrane is made up of alkylglycerinethers and can form monolayers.
The archaea cell wall is made of pseudomurein, polysaccharides and proteins


Explain the simple transport system

The simple transport system is driven by the energy in the proton motive force, it is a symport transport as the transported substance enters the cell with the proton


Explain the group translocation system

Group translocation is the chemical modification of a substance because the transported substance becomes phosphorylated as it enters the cell. It is driven by phosphoenolpyruvate


Explain the ABC transporter

Transported substance binds to a periplasmic binding protein and enters the cell with the help of ATP


Explain the major differences between gram positive and gram negative bacteria

In gram positive bacteria there is no outer membrane, it has a thick peptidoglycan wall, technoic acid is present and it has a low lipid content. Gram staining binds and turns positive bacteria purple
In gram negative bacteria there is an outer membrane rich with lipids, there is a thin peptidoglycan wall and no technoic acid is present. Gram staining doesnt bind to negative bacteria and turns it pink


Name two surface appendages of bacterial cells and their functions

Flagella are surface appendages that assist in swimming motility of bacteria, allowing them to move
Pili are surface appendages that attach a bacterial cell to specific surfaces or to other cells. It can also attach two bacterial cells


Describe two different modes of bacteria motility

Swimming - Flagella (helical filaments) have a rotary motor which can turn clockwise and anti-clockwise. The motor is powered by the proton motive force
Gliding - Is a flagella independent motility, it is slower than swimming. It occurs along the long axis of cell and requires surface contact. Gliding specific proteins assist this movement.


What are the characteristics of endospores? Which bacteria can differentiate intoendospores?

Endospores are highly differentiated cells resistant to harsh environments like heat, chemicals and radiation. Endospores are in the dormant stage of the bacterial cycle and are present only in some gram positive bacteria


What is the difference between chemoorganotrophy and chemolithotrophy?

Chemoorganotrophy is when cells use organic chemicals in its metabolic pathway to make ATP. Fermetation only uses chemoorganotrophy to use organic electron donors.
Chemolithotrophy is when cells use inorganic chemicals in its metabolic pathway to make ATP


What is chemolithoautotrophy?

When an organism obtains energy from the oxidation of inorganic compounds (like ATP) and uses CO2 as its sole source of carbon for growth.


Explain the principle transcriptional regulation by attenuation

Attenuation is transcriptional regulation by premature termination of mRNA synthesis. Exerted after initiation of transcription but before its completion. A hairpin (mRNA stem-loop) is made which terminates transcription. The leader peptide is also a determining factor of attenuation


What is a silent, missense and nonsense mutation

Silent mutation is where the mutation does not affect the amino acid sequence and a normal protein is made.
Missense mutation is where the mutation changes the amino acid made, therefore the polypeptide is changed and the protein is faulty.
Nonsense mutation is where the codon becomes a stop codon and the polypeptide is incomplete.


Would you be able to identify a periplasmic protein based on its amino acid sequence?

Yes, perisplasmic proteins contain a signal sequence, which can be easily identified in the primary amino acid sequence. Perisplasmic proteins can differ from integral membrane proteins like lipoproteins because lipoproteins have membrane anchors and perisplasmic dont.


Explain the role of phosphorylation in the two-component signal transduction system in bacteria

The sensor kinase detects the environmental signal and autophosphorylates which activates the sensor kinase. The SK then phosphorylates the response regulator. The phosphorylated response regulater binds to the operator and blocks/stimulates transcription.


Explain the difference between fermentation, anaerobic and aerobic respiration

Aerobic respiration uses oxygen as its terminal electron acceptor. Anaerobic respiration uses H2, H2S, Fe2+ and organic electron donors (in chemoorganotrophy). Fermentation doesnt use the ETC like the other 2 and its product depends on the type of fermentation, where as the other two product is pyruvate. Fermentation products include lactic acid and VFAs. Fermentation only uses organic electron donors.


What is a bacteriorodopsin?

Bacteriorodopsin is a light powered protein pump that pumps protons to help make ATP. Used by archaea to generate a proton pump across membrane using light energy.


What is the role of fermentation from pyruvate to lactate in anaerobic bacteria?

Fermentation from pyruvate to lactate is stage III of the Embden-Meyerhof pathway. In the absence of respiration, NADH that came from stage II is oxidised in stage III to NAD+ to be used in stage II


Genome sequencing has revolutionized discovery of vaccine targets in bacteria. Explain this statement

Genome sequencing allows identification of surface proteins using computer analysis (bioinformatics) These proteins can be purified and can be analysed to identify which proteins reacted strongly and have a strong immune response. These proteins are conserved for clinical trials.