Question

1. analyze: answer the following questions:

a. what are the four phases of mitosis?

b. during which phase is the dna replicated?

c. what is the relationship between chromatin and chromosomes?

d. in which phase are chromatids pulled apart?

e. in which phase does a new nuclear membrane develop?

f. if you are shown a cell with a single line of chromosomes, what is the phase?

g. during which three phases are individual chromosomes indistinguishable from each other?

Explanation:

• A: Mitosis has four phases. Prophase is when chromatin condenses to chromosomes. Metaphase is when chromosomes align at the cell's equator. Anaphase is when sister chromatids separate. Telophase is when new nuclear envelopes form.
• B: DNA replication occurs in the S - phase of the cell cycle (not a mitosis phase, but a common confusion. Mitosis is about cell division of the nucleus after DNA has been replicated).
• C: Chromatin is the less - condensed form of DNA (with associated proteins) in the interphase nucleus. Chromosomes are the highly - condensed form of chromatin, visible during mitosis.
• D: Sister chromatids are pulled apart during anaphase. Spindle fibers attach to the centromeres and pull the chromatids to opposite poles of the cell.
• E: A new nuclear membrane develops during telophase. As the chromosomes de - condense, the nuclear envelope reforms around each set of chromosomes.
• F: When chromosomes are in a single line (aligned at the metaphase plate), the phase is metaphase.
• G: During interphase (not a mitosis phase, but before mitosis), prophase (chromosomes start to condense but may still be hard to distinguish as individual units in early prophase), and telophase (chromosomes de - condense), individual chromosomes may be indistinguishable from each other.

Answer:

A. Prophase, Metaphase, Anaphase, Telophase
B. S - phase (not a mitosis phase)
C. Chromatin is the less - condensed form; chromosomes are the condensed form of chromatin.
D. Anaphase
E. Telophase
F. Metaphase
G. Interphase, Prophase, Telophase