SNC 1D1
3.2 Pregnancy and Fetal Development (part 1)
In order to complete this homework, first read pages 91 through 94 in your textbook
1. Once fertilized, do sperm and egg cells reproduce by mitosis or by meiosis? Explain your reasoning.
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2. Define the following terms.
blastocyst _________________________________________________________________________________
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implantation _______________________________________________________________________________
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gastrulation ________________________________________________________________________________
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cleavage ___________________________________________________________________________________
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3. Twins can be ether identical, or non-identical. Using what you know about fertilization, meiosis and cell cleavage, explain how
each of these types of twins can form.
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4. Use a diagram to distinguish between the three distinct layers of a gastrula. Describe their make-up and their function
5. Fill in the chart below and then use a diagram to explain the four important tissues that surround and protect a developing
embryo.
tissue name
location
function
chorion
yolk sac
amnion
allantois
6. Describe the role of the placenta and the umbilical chord in pregnancy.
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From St.Andrews College web page