The Cell Cycle Worksheet featuring matching and fill-in-the-blank questions about mitosis phases and cellular structures.

Explanation:
Let’s go step by step through the matching and fill-in-the-blank sections using knowledge of the cell cycle and mitosis.

Matching Section (Terms: A. Prophase, B. Interphase, C. Telophase, D. Metaphase, E. Anaphase)

1. *The sister chromatids are moving apart.*
→ This happens in Anaphase (E). Spindle fibers pull sister chromatids to opposite poles.

2. *The nucleolus begins to fade from view.*
→ In Prophase (A), the nucleus starts breaking down; nucleolus disappears.

3. *A new nuclear membrane is forming around the chromosomes.*
→ This occurs in Telophase (C), when two new nuclei form.

4. *The cytoplasm of the cell is being divided.*
→ That’s Cytokinesis, but it’s not listed in the matching options — however, this question is only for matching with A–E, and cytokinesis usually follows telophase. But since only A–E are allowed here, and none directly say “cytokinesis”, we must check if any match loosely. Wait — the instruction says “match the term to the description” using only A–E. But #4 is about cytoplasm division → that’s cytokinesis, which isn’t among A–E. However, looking at the worksheet, #13 says “Cytokinesis is completed”, and #14 says “The cell plate is completed” (plant cells), so #4 likely expects C. Telophase? No — telophase is nuclear division, not cytoplasmic. Hmm — but in many simplified curricula, telophase and cytokinesis are taught together. However, strictly speaking, cytoplasm division = cytokinesis, not in A–E. Let’s hold and come back — maybe the worksheet intends #4 to be matched later? Wait — no, the matching section only uses A–E, and all 17 items must be matched to one of those five. So some terms repeat.

Let’s list key events per phase:

- Interphase (B): Cell grows, DNA replicates (S phase), chromosomes are invisible (chromatin), *not* dividing yet.
- Prophase (A): Chromosomes condense (become visible), nucleolus fades, nuclear envelope breaks down, spindle forms.
- Metaphase (D): Chromosomes line up at equator (metaphase plate).
- Anaphase (E): Sister chromatids separate and move to poles.
- Telophase (C): Nuclear membranes reform, chromosomes decondense, nucleoli reappear.

Now match each:

1. Sister chromatids moving apart → E. Anaphase
2. Nucleolus fades → A. Prophase
3. New nuclear membrane forms → C. Telophase
4. Cytoplasm divided → This is cytokinesis, but not in A–E. However, in many worksheets, they associate cytokinesis with C. Telophase (since it often overlaps). But let’s see #13: “Cytokinesis is completed” — that would also point to same idea. Since only A–E allowed, and telophase is when division finishes *nuclearly*, and cytokinesis usually follows, but the question says “the cytoplasm… is being divided” — best fit among given is still C. Telophase in simplified models. However, wait — look at #14: “The cell plate is completed” → that’s plant cytokinesis, and #13: “Cytokinesis is completed”. So #4 likely should be matched to something else? No — the matching only has A–E, so repeated use is allowed (“Some will be used more than once” is stated in fill-in, but not explicitly for matching — but typical worksheets allow repeats). Let’s assume repeats allowed.

But better: double-check standard matching:

Standard matching for these phrases:
- Sister chromatids move apart → Anaphase ✔ E
- Nucleolus fades → Prophase ✔ A
- Nuclear membrane reforms → Telophase ✔ C
- Cytoplasm divides → Cytokinesis (not listed), but since only A–E, and telophase often paired, many answer keys put C here. We’ll go with C for now, but verify later with other clues.

5. *Chromosomes become invisible.* → After telophase, chromosomes decondense into chromatin → C. Telophase (again)
6. *Chromosomes located at equator* → D. Metaphase
7. *Nuclear membrane begins to fade* → A. Prophase
8. *Division (cleavage) furrow appears* → animal cell cytokinesis, begins in late anaphase or telophase, but again, only A–E — cleavage furrow starts in telophase, so C
9. *Chromosomes moving toward poles* → E. Anaphase
10. *Chromatids line up along equator* → D. Metaphase
11. *Spindle is formed* → A. Prophase
12. *Chromosomes are not visible* → during Interphase (B) (they’re chromatin)
13. *Cytokinesis is completed* → not a mitotic phase, but often listed after telophase; still, only A–E — likely C. Telophase (as it wraps up)
14. *Cell plate is completed* → plant cytokinesis, end of telophase → C
15. *Chromosomes are replicated* → happens in Interphase (B), specifically S phase
16. *Reverse of prophase* → that’s Telophase (C) (nuclear envelope returns, etc.)
17. *The organization phase* → vague, but prophase is when structures organize (spindle, chromosomes condense) → A. Prophase

Now let’s assign uniquely where possible:

Let’s tabulate with most confident first:

- #1: E
- #2: A
- #3: C
- #4: ??? (cytoplasm division = cytokinesis → not in list, but worksheet likely expects C — telophase overlaps)
- #5: C (decondensing → telophase)
- #6: D
- #7: A
- #8: C (cleavage furrow begins in telophase for animal cells)
- #9: E
- #10: D
- #11: A
- #12: B (interphase — chromosomes as chromatin)
- #13: C (cytokinesis completes near end of telophase)
- #14: C
- #15: B (replication in interphase)
- #16: C (reverse of prophase = telophase)
- #17: A (prophase = organization)

So C is used many times — acceptable.

Now Fill in the blank section (options include: A. Prophase, B. Interphase, C. Telophase, D. Metaphase, E. Anaphase, F. Centromere, G. Chromatid, H. Cytokinesis, I. Mitosis, J. Spindle fiber, K. Cell plate)

18. *What phase are daughter cells in as a result of mitosis?*
→ After mitosis + cytokinesis, cells enter Interphase (B) — the next cycle starts with interphase.

19. *During what phase of mitosis do centromeres divide and chromosomes move toward poles?*
→ Centromeres split in Anaphase (E)

20. *What is the phase where chromatin condenses to form chromosomes?*
→ Prophase (A)

21. *What is the name of the structure that connects the two chromatids?*
→ Centromere (F)

22. *In a chromosome pair connected by a centromere, what is each individual chromosome called?*
→ Each is a chromatid (G) (after replication, two sister chromatids)

23. *What are the two parts of cell division?*
→ Mitosis and Cytokinesis → so answers: I. Mitosis and H. Cytokinesis

24. *What structure forms in prophase along which the chromosomes move?*
→ Spindle fiber (J) (or spindle apparatus — J is “Spindle fiber”)

25. *Which phase of mitosis is the last phase that chromatids are together?*
→ Up to end of metaphase, chromatids are together; in anaphase they separate. So last phase where they’re still together is Metaphase (D)

26. *Which phase of the cell cycle is characterized by a non-dividing cell?*
→ Interphase (B) — cells spend most time here, not dividing.

27. *What structure is produced when protein fibers radiate from...*
→ Incomplete sentence, but likely: “when protein fibers radiate from centrosomes” → forms the spindle → J. Spindle fiber (or possibly “spindle”, but J is closest)

Wait — #27 ends with “radiate from” — probably “centrosomes”, and the structure is the spindle, made of spindle fibers. So answer: J. Spindle fiber

Now compile final answers:

Matching:
1. E
2. A
3. C
4. C
5. C
6. D
7. A
8. C
9. E
10. D
11. A
12. B
13. C
14. C
15. B
16. C
17. A

Fill in the blank:
18. B
19. E
20. A
21. F
22. G
23. I and H (two parts)
24. J
25. D
26. B
27. J

But the worksheet likely expects single letters per blank, and #23 asks “What are the two parts”, so two answers: H and I (order? usually mitosis then cytokinesis → I, H)

Now verify consistency:

- #4: cytoplasm divided → technically cytokinesis, but since H is available in fill-in, and matching only A–E, and telophase is when it initiates, many textbooks match #4 to C. Acceptable.

All matches align with standard biology curriculum.

Final Answer:
1. E
2. A
3. C
4. C
5. C
6. D
7. A
8. C
9. E
10. D
11. A
12. B
13. C
14. C
15. B
16. C
17. A
18. B
19. E
20. A
21. F
22. G
23. I, H
24. J
25. D
26. B
27. J