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(3 * 10^-12 C/s) * (1 mole/ 96500 C) * (6 * 10^23 molecules/mole)
= 1.86 * 10^7 molecules of sodium per second 7.06 Spring 2004 PS 1 key 7 of 11 (iii) You find the transport of cations by the receptor to be independent of ATP. What
type of transport mechanism does the receptor use?
Facilitated diffusion. The capsaicin receptor is a channel protein that allows cations
to move down their concentration gradient. This process is thermodynamically
favored and thus ATP-independent.
(iv) How does the type of transport utilized by the capsaicin receptor differ from the
transport mechansim of the Na+/K+ ATPase?
The Na+/K+ ATPase uses active transport. It moved two potassium ions into the cell
as three sodium ions are moved out. Both ions are transported against their
concentration gradient, thus in order for the process to occur, the pump must
couple their transport to the hydrolysis of the high energy phosphodiester bond of
4. While studying families that have a severe skin blistering disease you find linkage to a
gene you name epidermo-1. The genomic structure is shown below, exons are depicted as
boxes, introns as straight lines: 1 2 3 4 Sequencing of affected individuals reveals a deletion of exon 3. You decide to try to
develop a mouse model of the disease.
(a) Using only a computer how would you determine whether mice have a homologous
gene? and whether it has been shown to be expressed in the skin of mice?
Since the evolutionary distance between mice and humans is only seventy five
million years you could do a blast search against the NCBI nr database or against
the Ensembl DNA database using the sequence of one of the human exons as a probe
– using intronic sequence is not recommended since there is less selective pressure
on intronic sequence than on exons and so it usually diverges at a faster rate.
To find out if epidermo-1 is expressed in the skin of mice you would take part of the
mRNA sequence (i.e. the exons) and bl...
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This note was uploaded on 01/23/2012 for the course LSM lsm1301 taught by Professor Seow during the Spring '11 term at National University of Singapore.
- Spring '11