Question

1. which of the following best describes meiosis?

a) b. it occurs only in cells in the reproductive
structures of organisms.
b) c. it happens in all tissues except the brain and
spinal cord.
c) d. it is the first stage of mitosis.
d) a. it is carried out in all tissues that require cell
replacement.

1. which of the following phases of mitosis is represented by the diagram below?

a) b. metaphase
b) d. telophase
c) c. anaphase
d) a. prophase

1. a scientist wants to change the dna of a sexually reproducing organism and have the new dna present

in every cell of the organism. in order to do this after fertilization, she would change the dna in which of
the following?
a) c. testes of the father
b) b. placenta
c) a. zygote
d) d. ovaries of the mother

1. which row in the chart below indicates the correct process for each event indicated?

a) b. row 2
b) c. row 3
c) d. row 4
d) a. row 1

Explanation:

• Question 5: Meiosis occurs in reproductive cells (gametes) to produce haploid cells. Mitosis is for general cell - replacement and growth. So, meiosis occurs only in cells in the reproductive structures of organisms.
• Question 6: In metaphase, chromosomes align at the equatorial plate (metaphase plate). In prophase, chromosomes condense but are not aligned. In anaphase, sister chromatids separate. In telophase, nuclear envelopes reform.
• Question 7: A zygote is a single - celled fertilized egg. Changing its DNA will result in the new DNA being present in every cell of the organism as it undergoes mitosis to develop. The placenta is an organ for nutrient exchange, and the testes and ovaries are for gamete production.
• Question 8: Both egg and sperm (gametes) are formed by meiosis (to produce haploid cells). The growth of an embryo occurs by mitosis (to increase cell number while maintaining diploidy).

Answer:

1. a) B. It occurs only in cells in the reproductive structures of organisms.
2. a) B. metaphase
3. c) A. zygote
4. c) D. row 4