HD is called an autosomal dominant disorder because only one copy of the defective gene, inherited from one parent, is necessary to produce the disease. The genetic defect responsible for HD is a small sequence of DNA on chromosome 4 in which several base pairs are repeated many, many times.
Carbon dioxide cannot pass through the protective waxy layer covering the leaf (cuticle), but it can enter the leaf through an opening (the stoma; plural = stomata; Greek for hole) flanked by two guard cells. Likewise, oxygen produced during photosynthesis can only pass out of the leaf through the opened stomata.
carbon dioxide + water (+ light energy) Ã¢ glucose +  oxygen  Plants get CO2 and give out O2.  Although photosynthesis is performed differently by different  specâ¦ies, the process always begins when energy from light is  absorbed by proteins called reaction centers that contain green  chlorophyll pigments.