Lab Report Tansport Across Membrane
The CFTR gene codes for an ABC transporter -class ion channel protein that conducts chloride [7] ions across epithelial cell membranes. Mutations of the CFTR gene affecting chloride ion channel function lead to dysregulation of epithelial fluid transport in the lung, pancreas Acriss Lab Report Tansport Across Membrane organs, resulting in cystic fibrosis.
Complications include thickened mucus in https://www.ilfiordicappero.com/custom/malaria-treatment-and-prevention/words-and-essay.php lungs with frequent respiratory infections, and pancreatic insufficiency giving rise to malnutrition and diabetes. These conditions lead to chronic disability and reduced life expectancy.
In male patients, the progressive obstruction and destruction of the developing vas deferens spermatic cord and epididymis appear to result from abnormal intraluminal secretions, [8] Mrmbrane congenital absence of the vas deferens and male infertility. The gene that encodes the human CFTR protein is found on chromosome 7on the long arm at position q CFTR orthologs [9] occur in the jawed vertebrates.
Nearly cystic fibrosis-causing mutations have been described.
The vast majority of mutations are infrequent. The distribution and frequency of mutations varies among different populations which has implications for genetic screening and counseling.
Mutations consist of replacements, duplications, deletions or shortenings in the CFTR gene. This may result in proteins that may not function, work less effectively, are more quickly degraded, or are present in inadequate numbers.
It has been Repkrt that mutations in the CFTR gene may confer a selective advantage to heterozygous individuals. Cells expressing a mutant form of the CFTR protein are resistant to invasion by the Salmonella typhi bacterium, the agent of typhoid feverand mice carrying a single copy of mutant CFTR are resistant to diarrhea caused by cholera toxin.
The most common mutations among caucasians are: [16].
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This protein does not escape the endoplasmic reticulum for further processing. Having two copies of this mutation one inherited from each parent is by far the most common cause of cystic fibrosis CFresponsible for nearly two-thirds of cases worldwide. The CFTR protein is largely expressed in cells of the pancreas, intestinal and respiratory epithelia, and all exocrine glands.
When properly folded, it is shuttled to the cell membrane, where it becomes a transmembrane protein responsible for opening channels which https://www.ilfiordicappero.com/custom/college-is-not-for-everyone/the-patient-with-diabetes-mellitus.php chloride Lab Report Tansport Across Membrane out of cells; it also simultaneously inhibits the uptake of sodium ions by another channel protein.
Both of these functions help to maintain an ion gradient that causes osmosis to draw water out of the cells. In organisms with two complements of the mutation, the protein is entirely absent from the cell membrane, and these critical ion transport functions are not performed. This causes increased water retention in cells, corresponding dehydration of the extracellular space, and an associated cascade of effects on various parts of the body.
These effects include: thicker mucous membranes in the epithelia of afflicted organs; obstruction of narrow respiratory airways as a result of thicker mucous and inhibition of the free movement of mucocilia; congenital absence of the vas deferens due to increased mucus thickness during fetal development; pancreatic insufficiency due to blockage of the pancreatic duct with mucus; and increased risk of respiratory infection due Mmebrane build-up of thick, nutrient-rich mucus where bacteria thrive.
Several studies indicate that heterozygous carriers are at increased risk for various symptoms. For example, it has been shown that heterozygosity for cystic fibrosis is associated with increased airway reactivity, and heterozygotes may be at risk for poor pulmonary function. Heterozygotes with wheeze have been shown to be at higher risk for poor pulmonary function or development and progression of chronic obstructive lung disease. One gene for cystic fibrosis is sufficient to produce eMmbrane Lab Report Tansport Across Membrane abnormalities even in the absence of infection. The CFTR gene is located on the long arm of chromosome 7, at position q Presence of the mutation on both copies causes the autosomal recessive disease cystic fibrosis.
Scientists have estimated that the original mutation occurred over 52, years ago in Northern Europe.
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The young allele age may be a consequence of past selection. One hypothesis as to why the otherwise detrimental mutation has been maintained by natural selection is that a single copy may present a positive effect by reducing water loss during choleraLab Report Tansport Across Membrane the introduction of pathogenic Vibrio cholerae into Europe did not occur until the late 18th century. The genotype is not strongly correlated with severity of the CF, though specific symptoms have been linked to certain Memgrane. The CFTR gene is approximately kb in length, with 27 exons and 26 introns. The protein consists of five domains. There are two transmembrane domains, each with six spans of alpha helices. These are each connected to a nucleotide binding domain NBD in the cytoplasm. ATP-driven conformational changes in CFTR open and close a gate to allow transmembrane flow of anions down their electrochemical gradient. CFTRs have two transmembrane domains, each linked to a Re;ort domain.]
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