Module 5 Cell Division

Lesson 3.5.6

3.5.6 page 3

Self-Check

Here is a chance to check your understanding. Complete the following questions on alternation of generations and then check your answers. If any give you trouble, ask your instructor for clarification about that concept.

Carefully study this illustration and then answer the question that follows.

Yeast life cycle.

1. What kind of cell division is involved in the budding process? Explain.

2. When a yeast cell undergoes meiosis how many ascospores are produced? Is this consistent with what you would expect for this kind of division? Explain.

3. The life cycle of yeast can be divided into two phases. Which one is the sexual phase and which one is the asexual phase?

4. What seems to trigger sexual reproduction in yeast cells?

Moss life cycle.

5. What kind of cell division is involved in the production of gametes in mosses? Explain why.

6. Identify the units produced by the reproductive process in mosses and the structure where meiotic divisions occur.

7. Why do mosses need moist conditions to reproduce?

8. With regards to dispersal, what is the advantage of producing spores?

9. Is the dominant stage in a moss’s life cycle haploid or diploid?

Fern life cycle showing alternation of generations.

10. Use the fern life cycle to answer the following questions:

a. Is the dominant stage of a fern a gametophyte or a sporophyte?

b. Are the cells of a fern diploid or haploid?

c. Do ferns produce gametes or spores for reproduction?

d. Are spores produced by meiosis or mitosis?

e. Are spores haploid or diploid?

f. Is a small prothallus a gametophyte or sporophyte?

g. Does the heart-shaped prothallus produce gametes or spores?

h. Does the zygote grow into a sporophyte or a gametophyte?

Check your work.

Self-Check Answers

1. Budding involves mitosis, because the bud is genetically identical to the original cell.

2. Four ascospores are produced. This is consistent with the results of meiosis because four cells are produced by this process.

3. Part A is the asexual phase and Part B is the sexual phase.

4. Unsuitable conditions appear to trigger sexual reproduction.

5. Mitosis is involved in production of gametes because the cells of the plant are already haploid, so meiosis cannot occur, nor does it need to.

6. Meiosis occurs in the capsule of the sporophyte, producing haploid spores.

7. The sperm must swim to the egg through a film of water.

8. Spores are resistant to dryness and can survive harsh conditions during dispersal.

9. The dominant stage is haploid.

10.

a. sporophyte

b. diploid

c. spores

d. meiosis

e. haploid

f. gametophyte

g. gametes

h. sporophyte