1. It would render a woman infertile because the conceptus could never implant on the uterine wall.

2. As explained in chapter 5, DNA polymerase leaves a small percentage of errors undetected and unrepaired. This creates a potential for a positive feedback cycle causing DNA polymerase to become less and less efficient with age. This could be summarized: unrepaired errors in the DNA polymerase gene -> structural defects in the DNA polymerase enzyme -> less efficient repair of DNA replication errors -> more errors in the DNA polymerase gene. After many cell generations, the DNA polymerase gene could accumulate so many mutations that the polymerase itself became too defective to repair DNA adequately.

3. As a protein, if superoxide dismutase (SOD) were taken orally, it would be digested like any other dietary protein. Therefore it would not have an enzymatic effect in the body.

4. Patent ductus arteriosus allows blood to flow from the aorta, where blood pressure is high, to the pulmonary trunk, where it is lower. Thus some of the systemic blood is misdirected into the pulmonary circuit, raising pulmonary blood pressure. By increasing the afterload in the pulmonary trunk, it puts a stress on the right ventricle and may lead to ventricular hypertrophy and right-sided congestive heart failure. Systemic diastolic pressure is low because so much of the systemic blood is diverted from that circuit into the pulmonary trunk.

5. Most spermatozoa never reach the immediate vicinity of the egg. They drain out of the vagina, die during migration, or do not migrate into the uterine tube with the egg in it. Of those that do reach the vicinity of the egg, hundreds may be needed to digest a path through the corona radiata and zona pellucida for the one sperm that follows them and fertilizes the egg. If 300 million spermatozoa are normally ejaculated and only 3,000 of them reach an egg, then the chance of reaching the egg is about 1 in 100,000. With these odds, if a man ejaculated only 10 million spermatozoa, approximately 100 sperm would reach the egg. Even in the unlikely event that they all attacked the same point on the egg surface, this might not be enough sperm to create a path to the egg membrane for one sperm to fertilize it.

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