Qualification > Sciences
Edexcel BIOLOGY Doubts!!!!
Amelia:
--- Quote from: moon on April 23, 2011, 05:06:08 pm ---Can u please help me in these questions
1) Explain what is meant by the term genetic carrier?
--- End quote ---
A genetic carrier (or just carrier), is a person or other organism that has inherited a genetic trait or mutation, but who does not display that trait or show symptoms of the disease. They are, however, able to pass the gene onto their offspring, who may then express the gene. This phenomenon is a direct result of the recessive nature of many genes.
For example, the daughters of Queen Victoria, the princesses Alice and Beatrix, were carriers of the X-linked hemophilia gene (more precisely, an abnormal allele of a gene necessary to produce one of the blood clotting factors). Both had children who continued to pass the gene to succeeding generations of the royal houses of Spain and Russia, into which they married. Males who carried the altered gene had hemophilia, while females simply passed it to about half of their children.
-Wikipedia. :P
--- Quote ---2) One of the polypeptide chains in the haemoglobin of a person with sickle cell anaemia has a change in one of its amino acids.Explain how change in
DNA can lead to a change in a single amino acid in polypeptide chain.
I appreciate ur help!!
--- End quote ---
Each base pairing in the DNA sequence codes for a different amino-acid. So, a change in these base-pairing will change the aminoacid it is supposed to code for. This will alter the polypeptide chain.
MKh:
Salaam all, I have a question:
what is the meaning of range bars and error bars? Are both the same thing? If yes, what are these actually? I think these are used in graphs but I am not sure how to draw or interpret a range bar or error bar??
Help if anybody knows anything about these...Thanks! :)
guMnam:
what is the role of elastic recoil in the arteries ??
Amelia:
--- Quote from: guMnam on April 27, 2011, 09:58:29 am ---what is the role of elastic recoil in the arteries ??
--- End quote ---
The vessels which receive blood from the heart, the elastic arteries, have thick, strong walls to cope with the sudden high pressure produced during diastole; they contain abundant elastic material to allow stretch so that the vessel lumen may accommodate the change of volume. They also have a thick, outer coat of collagenous connective tissue whose tensile strength prevents over-distension of the elastic tissue.
The elastic recoil of these elastic arteries is responsible for maintaining a continuous, though decreased, flow of blood to smaller vessels during systole.
mayisha:
Can sum1 plz explain the t-tests and confidence levels ? or suggest a book where its explained wel but not 2 detailed ... just wats needed for unit 6 bio ...
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