PATHOLOGY MCQ
GENETICS AND DISEASE
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
They will all carry the R allele.
|
|
|
They will all carry RR.
|
|
|
Some will carry R, some will carry r.
|
|
|
They will all carry the r allele.
|
Detailed explanation-1: -Q. If a person has a genotype of RR, what do you know about their gametes (sex cells)? They will all carry the R allele.
Detailed explanation-2: -Well, when an individual produces sperm or eggs, each gamete contains only one of the two alleles (i.e. either R or r). Each allele is equally likely to be included in a gamete, so half of the pollen grains from an Rr plant will be R and half will be r. Likewise, half of the ovules will be R and half will be r.
Detailed explanation-3: -Rr x Rr. You’ll note here that all offspring are not pink. Your genotypic ratio is 25% (RR), 50% (Rr), and 25% (rr). The phenotypic ratio is also the same in this case, with 25% red (RR), 50% pink (Rr), and 25% white (rr).
Detailed explanation-4: -To summarize, when you use the term gamete, it refers to a newly created organism from the union of a male sperm cell and a female egg. The term genotype, on the other hand, refers to the specific ‘genetic’ characteristics and heritable genetic identity that newly created ‘life’ would possess.