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Life greatest Miracle answer key

Name: _________________________________
Date: ______
Worksheet #_____: Life’s Greatest Miracle
1. How many human babies are born each day?
2. How many cells are there in the human body?
100 trillion cells
3. What does the video say is the “fundamental urge” for all life?
To reproduce
4. What is DNA “very good” at?
replicating itself
5. How does the DNA of a bacterium compare to its parent’s?
all ancestors have exact DNA
6. What risk is there for a species that only reproduces by cloning?
everyone would have the same immune system and one parasite could wipe us all out
7. How does the DNA of sexually produced offspring compare to the DNA of the
it is different from their parents and everyone else's which means that there is a variety
8. How many sperm are produced by the average human male each second?
9. What process is used to make sperm cells and egg cells?
10. How many chromosomes are there in a normal human body cell?
46 chromosomes
11. What happens to the genes when two chromosomes “embrace”?
genes get exchanged when they embrace
12. What is the advantage of diversity within a species?
the more diversity the more likely someone will survive long enough to create the next generation
13. When does a human female produce her eggs?
when the female is a fetus in her mother's womb
14. How many eggs does the average human female release per month?
15. What is an egg missing that it needs to survive?
DNA from sperm
16. About how many sperm are released into the vagina?
300 million
17. What danger confronts sperm in the vagina?
Acidity of the vagina
18. What does the sperm need in order to be allowed through the egg’s zona?
proteins from sperm must link up with proteins from zero
19. How much time passes between fertilization and the first division of the zygote?
24 hours
20. What happens if the dividing zygote accidentally separates into two?
Identical twins
21. After fertilization, how long does it take for the blastocyst to arrive in the uterus?
5 days
22. What risk does the blastocyst face after it attaches to the uterus?
the blastocyst would be attacked by the mother's immune system
23. What is gastrulation?
the cells organize themselves into an embryo
24. What will the lower layer of cells develop into?
lungs, liver, and the lining of digestive track
25. What will the middle layer of cells develop into?
heart, muscles, brain, and blood
26. What will the outer layer of cells develop into?
spinal cord, brain, skin, and hair
27. How long is the embryo after 4½ weeks?
1/5 of an inch
28. True or false: All cells have the same genes.
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29. What does a gene do when it has been turned on?
produce proteins
30. What do the following proteins do?
a. collagen: fiber that makes up much of your skin, tendons, and bones
b. crystallin: helps make the lens of your eye clear
c. actin and myosin: move muscle fiber
d. hemoglobin: carries oxygen from lungs to the rest of the body
31. How do cells communicate with each other?
Chemical messages
32. How is the Y chromosome different from the X chromosome?
The Y chromosome is one-third the size of the X chromosome and contains about 55 genes while the X
chromosome has about 900 genes.
33. Where specifically does the baby get its nutrients from?
the mother's blood
34. Do the baby’s and mother’s blood ever mix?
35. How old is the fetus when it gains the ability to hear sound?
5 months
36. What is the main job of the fetus during the last trimester?
To grow
37. What does myolin do?
wraps around the long connections of brain cells, helps nerves move faster, enhances brain power
38. Why is birth more dangerous for humans than for other animals?
the human brain is bigger than the human pelvis so sometimes there's not enough room
The birth of the baby will take place at 4:25. If you don’t wish to watch, now would be a good time
to look away.
Science Movie Worksheets – http://www.NewYorkScienceTeacher.com/movies