Yeasts can grow in the presence or absence of air. Anaerobic growth, growth in the absence of oxygen, is quite slow and inefficient. For instance, in bread dough, yeast grow very little. Instead, the sugar that can sustain either fermentation or growth is used mainly to produce alcohol and carbon dioxide. Only a small portion of the sugar is used for cell maintenance and growth.
Best Answer: Dna is a double helical structure with two strands of nitrogenous bases being held together by hydrogen bonds. Phosphodiester bonds hold bases together on the same strand.Between deoxyribose and a phosphate group. Hydrogen bonds hold the two strands together. Adenine and Thymine have 2 H bonds always.Guanine and Cytosine have 3 H bonds always.hosphodiester bonds hold bases together on the same strand. Between deoxyribose and a phosphate group. Hydrogen bonds hold the two strands together. Adenine and Thymine have 2 H bonds always.
The chemical bond that holds the double helix together in DNA are  the hydrogen bonds. Hydrogen bonds are the weakest making them  perfect for DNA replication.