2017 unified Flashcards
state a material that can be used in thin layer chromatography
silica gel
describe 3 differences between the process of thin layer chromatography and the form of electrophoresis used to sequence DNA
-Separates by adsorption/ solubility with the stationary phase in TLC and separates size in electrophoresis and electrophoresis separates charged molecules
what are reasons why a test may be valid when looking at effect of temperatures
-suitable range/ intervals of temperatures have been chosen.
-volume controlled/ temperature controlled
-repeats to identify anomalies
-same yeast suspension used
explain the role of genes in creating a striping pattern in fur
-regulatory genes control the pattern where pigments are produced/ expression of genes
-genes switched on or off during development (e.g. epistatic changes in transcription factors)
-correct roles of epistasis- e.g. recessive epistasis preventing expression of pigment
where is rhizobium located and what do they convert
located in root nodules/ leguminous roots
-convert N2 and H+ to NH3
where are nitrosomonas located and what do they convert
-located in soil
-convert NH3 to NO2-
where are nitrobacter located and what do they convert
found in soil
convert NO2- to NO3-
where are denitrifying bacteria located and what do they convert
found in soil
convert NO3- to N2
Suggest how an immune response to the nervous system can cause damage to the nervous system
-antigens are present on nerve cells
-there are thus antibodies against nerve cells
-phagocytes/ neutrophils/ macrophages/ T killer cells attack/ break down nerve cells/ schwann cells
the schwann cells have become crumpled and fractured, how does this cause a reduction in speed of transmission
-damaged schwann cells
-fewer schwann cells
-damaged myelin sheath
-no saltatory conduction
an autoimmune response affects the central nervous system, explain what symptoms may be present
-greater loss of memory/ thinking/ cognition/ speech/ smell/ sight/ hearing AND damage to cerebrum/ cerebral cortex
-greater loss of balance/ coordination AND damage to the cerebellum
-greater loss of sleeping patterns/ temperature control/ water balance AND damage to the hypothalamus
-greater loss of heart rate/ breathing rate AND damage to medulla oblongata and brainstem
how does the insect tracheal system provide a large surface area for gas exchange
many/ branched trachea/ tracheoles
how does fish gills provide a large surface area for gas exchange
many filaments/ lamellae/ plates
what neurotransmitter does neurones secrete as part of the fight or flight response
noradrenaline
