General Questions Flashcards
How is HIV replicated once inside the Th cell?
Reverse transcriptase used to make DNA from RNA.
HIV DNA is inserted into the Th cell DNA.
DNA is transcribed into HIV mRNA.
HIV mRNA is translated into new viral proteins for assembly into virus particles.
What type of behaviour moves whole organism towards light?
Positive phototaxis
Advantage of whole organism moving towards light?
- avoid predation - avoid competition
When do you know if a result is significant?
When a statistical test is carried out … do not presume before hand
In anaerobic conditions why is there high conc ammonia but low conc nitrite ions?
Less notification since nitrifying bacteria require oxygen to carry out the process.
Less oxidation of ammonium ions to nitrite and to nitrate
How do endo and exopeptidases increase rate of protein digestion?
More “ends” more “SA”.
Endopeptidases hydrolyse internal peptide bonds
Exopeptidases hydrolyse peptide bonds at the end of the poly peptide chain
Describe how stimulation of a Pacinian corpuscle produces a generator potential.
When pressure applied the membrane deforms.
And the stretch mediated sodium channels open.
Allowing sodium ions to flow into the pacinian corpuscle .
The influx of sodium ions triggers a generator potential due to te depolarisation.
Describe what is mean by the all or nothing principle.
An action potential is only generated when the threshold is reached.
when high pressure applied the threshold is reached.
Name of the period where no generator potential could be produced?
Refractory
How is something destroyed by lysosome?
Vesicle fuse with a lysosome.
Lysosome digests.
How can you have high species richness but low value of d (index of diversity)?
More species present in very small numbers.
Name two types of cells that stimulate an immune response.
Pathogens.
Antigen presenting cells.
