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.
A) ATP is not produced during photosynthesis, but only during respiration. B) Photosynthesis is ultimately powered by light energy and respiration by the chemical energy of fuel molecules. C) Photosynthesis consumes CO2; respiration consumes O2. D) Photosynthesis produces O2; respiration produces CO2.