Question

label the phases of mitosis/cell cycle (they are not in order) below:
11.
12.
13.
14.
15.

1. helicase is an enzyme responsible for unwinding the double helix of the dna during dna replication. in which phase of the cell cycle is helicase performing this function?

a. s
b. m
c. g¹
d. g²

1. which phase occurred directly before the phase in the image?

a. interphase
b. prophase
c. cytokinesis
d. metaphase

1. which phase has not occurred?

a. metaphase
b. anaphase
c. telophase
d. cytokinesis

1. in which phase of meiosis does crossing over occur?

a. telophase ii
b. anaphase i
c. prophase i
d. metaphase i

Explanation:

1. The cell has visible chromosomes, a breaking nuclear envelope, and forming spindle fibers, matching Prophase.
2. Sister chromatids are pulled apart to opposite poles, matching Anaphase.
3. Chromosomes are aligned at the cell's equatorial plate, matching Metaphase.
4. The cell has a distinct nucleus, uncondensed DNA, and is growing/preparing, matching Interphase.
5. Two separate nuclei form, chromosomes decondense, and the cell begins to split, matching Telophase (with early cytokinesis).
6. DNA replication occurs during the S (Synthesis) phase, so helicase (for unwinding DNA) acts here.
7. The image shows Anaphase; the phase directly before it, where chromosomes align at the equator, is Metaphase.
8. The image shows Telophase (two nuclei forming); Cytokinesis (final cell splitting) has not yet occurred.
9. Crossing over, where homologous chromosomes exchange genetic material, happens during Prophase I of Meiosis.

Answer:

1. Prophase
2. Anaphase
3. Metaphase
4. Interphase
5. Telophase (with Cytokinesis initiation)
6. a. S
7. d. Metaphase
8. d. Cytokinesis
9. c. Prophase I