Tuesday, May 13, 2008

Human Development Video Questions

1. Name the molecule that carries our genes. DNA.
2. Genes are located in the DNA.
3. What is the number of sperm the average man produces in a second? One thousand.
4. How can one person produce so many different combinations of genes? Through meiosis.
5. Most human cells have a total number of 46 chromosomes.
6. The gene shuffling that occurs from mitosis results in a great amount of this? Diversity!
7. Where in the female reproductive tract does the egg wait for fertilization? In the fallopian tube.
8. How does the egg move through the Fallopian tube? Muscular contractions of the tube and tiny hairlike structures called cilia.
9. Approximately how many sperm are contained within one teaspoon of seminal liquid? 300 million.
10. What are some of the challenges that sperm face once entering into the vagina? The acidity of the vagina, getting through the cervix, breaking through the shell surrounding the egg.
11. Describe the milestone event that takes place two weeks after conception? Gastrolation, when the blastocyst begins to turn into an embryo.
12. Describe the size and physical characteristics of the fetus at 4 and 1/2 weeks following conception. It is a 5th of an inch long, and resembles a dinosaur... The backbone is visible and very primitive looking, and the heart is present and beating. Also, groups of cells begin to bulge out to form legs and arms. The brain is also present and eyes are forming.
13. If the DNA in a single cell were stretched out, how long would it be? 6 feet.
14. After about how many weeks can doctors determine the sex of the baby from ultrasound? 18 weeks.
15. Aside from the ultrasound, how can a doctor determine the sex of a baby? By examining the chromosomes.
16. At what point does the embryo become a fetus? At about month 3.
17.When does the placenta begin to form? In the early weeks of pregnancy.
18. What is the fetus’s job in the last trimester? To grow!
19. Why are human births so much more dangerous than other mammals? Because our pelvis is narrower, to allow us to walk upright, so the baby has to go contort a certain way to get out, and may not always be able to fit out.