AP Biology Chapter 21 Study Guide
THE GENETIC BASIS FOR DEVELOPMENT
1. Model organism
2. Cell differentiation
3. Morphogenesis
4. Apical meristems
5. Blastula
6. Gastrula
7. Totipotent cells
8. Cloning
9. Clone
10. Stem cells
11. Embryonic stem cells
12. Pluripotent cells
13. Induction
14. Embryonic lethals
Name: _____________________Date______
15. Homeotic genes
16. Cell lineage
17. Apoptosis
18. Carpels
19. Stamens
20. Petals
21. Sepals
22. Chimeras
23. Homeobox**
24. Hox genes**
** Make sure you really understand these terms and relate to book “Your Inner Fish”
Questions:
1. A fertilzed egg divides by mitosis to produce an embryo, then a fetus, and eventually an adult.
What are 2 other important processes involved in embryonic development? Define each below:
a)
b)
2. Differential gene expression drives the 2 processes mentioned above. How are the following
terms related to differential gene expression?
a. genomic equivalence:
b. totipotency:
c. pluripotency:
3. As briefly as possible, explain reproductive cloning of a mammal by nuclear transplantation: (See
challenge sheet)
4. What are stem cells? How are these used in therapeutic cloning?
5. The following processes control differentiation and morphogenesis as mentioned in the first
question. Explain how each process works:
a. cytoplasmic determinant:
b. cell-cell signals:
c. determination:
d. pattern formation:
6. Use figure 21.11, page 11 in your text to explain how positional information controls pattern
formation in the embryo:
7. C. elegans is a model organisms for studying apoptosis in the development of animals. Explain the
importance of apoptosis in the development of of multicellular organisms. Note: programmed
cell death (“cell suicide”) is critical in the development of multicellular organisms..Why???
(give an example).
8. Refer to Figure 21.18, page 428. in your textbook. Ced-9, Ced-4 and Ced-3 are all caspase
enzymes involved in apoptosis. How does the result of a “death signal” binding a receptor affect
the transduction pathway or “cascade” of enzyme activity?
8. The DNA sequences called homeoboxes, which help homeotic genes in animals direct
development, are common to flies, mice and humans. Given this similarity, explain why these animals
are so different from each other?