Answer:
A is the answer to the question
Photorespiration limits casualty products of light reactions
that build up in the absence of the Calvin cycle. In many plants,
photorespiration is a problem because on a hot, dry day it can drain as much as
50% of the carbon fixed by the Calvin cycle. The closing of stomata reduces access to CO2
and causes O2 to build up. These conditions favor a seemingly not useful process
called photorespiration. In most plants
(C3 plants), initial fixation of CO2, via rubisco, forms a three-carbon
compound. In photorespiration, rubisco
adds O2 instead of CO2 in the Calvin cycle. Photorespiration eats up O2 and
organic fuel and releases CO2 without producing ATP or sugar. Photorespiration
can evolve relic because rubisco first evolved at a time when the atmosphere
had far less O2 and more CO2.
(B it breaks down carbon- base sugar molecules to release energy and forms carbon dioxide
The BRCA 1 and BRCA 2 genes are two genes that are sought in the genetic study of an individual in order to seek a predisposition to breast cancer (in women and also in men).
The genes of Tay-sachs, are researched in order to diagnose or eliminate Tay-sachs disease.
The first difference lies in the goal of the research: for the BRCA (screening) genes, a predisposition is sought and for the Tay-sachs genes, it is sought to confirm the disease.
The second lies in the technique used:
The first step in the study of these genes is to isolate and replicate them. The best technique for this is the PCR (polymerase chain reaction). By using primers we can amplify the gene we want. So the primers used in BRCA and Tay-Sachs research are necessarily different.
