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.
Photosynthesis is the process whereby plants using light energy from the sun convert carbon dioxide and water to glucose sugar and oxygen gas through a series of reactions. The overall equation for photosynthesis is. carbon dioxide + water =light energy=> glucose + oxygen. 6CO 2 + 6H 2 O =light energy=> C 6 H 12 O 6 + 6O 2 . Light energy from the sun is converted into chemical energy by the production of glucose molecules. Photosynthesis is carried out in the chloroplasts of plant cells using the green pigment chlorophyll.