Mitosis and Meiosis Worksheet
Define the following terms.
1. Binary fission – Asexual division where a parent cell splits into 2 (prokaryotes)
2. Sister chromatids – Identical Copies of DNA that together make up a chromosome
3. Centromere – Holds sister chromatids together (center of chromosome)
4. Cleavage furrow- “cleavage” in between the 2 new daughter cells that are being made during
mitosis (or meiosis)
5. Cell plate – new cell wall being made in dividing plants because there is no cleavage furrow
6. Somatic cell – Body cell; Diploid (46 chromosomes); every cell besides gametes (sex cells)
7. Homologous chromosomes – pairs of chromosomes that are from mom and dad; contains
same genes on them (gene for eye color, hair color, height, etc.); 23 pairs of homologous
chromosomes in diploid cells
8. Gametes – sex cells (sperm and egg); haploid (23 chromosomes) because homologous
chromosomes have been separated
9. Zygote – original diploid cell; 1 cell baby whenever sperm enter eggs
10. Autosomes – 22 pairs of normal homologous chromosomes; chromosomes that are the same
between boys and girls
11. Sex chromosomes – set of chromosomes that determines the gender of an individual (XX or
XY)
12. Crossing over – Trading of segments of the chromosomes during meiosis (after the 2
chromosomes have synapsed to form a tetrad)
13. Karyotype- A “picture” of your chromosomes
14. Name 3 reasons why a cell would undergo mitosis.
Grow, heal, normal cell repair
15. Name 1 reason why a cell would under meiosis.
Make sex cells (the only reason for meiosis)
16. Draw a diagram showing how much time a cell spends in each stage of the cell cycle (interphase,
mitosis, and cytokinesis).
17. Describe what occurs in each of the 3 phases of interphase. (Gap 1, Synthesis, and Gap 2)
G1 (Gap 1) – normal cell activities
S (Synthesis) – DNA synthesis (replication)
G2 (Gap 2) – prepares for cell division
18. We talked about 5 stages involved in the cell cycle (4 in mitosis and 1 that is not). List those 5
stages in order and describe what occurs during each of these stages.
1. Interphase
Events of Interphase:
The cell spends most of its life in interphase.
DNA is in chromatin form, spread throughout the nucleus.
DNA replicates, cell then contains two exact copies of each chromosome.
Centrioles found just outside the nuclear membrane of the cell.
2. Prophase
Chromosomes coil and become visible
Nuclear Membrane breaks down
Spindle Forms
3. Metaphase
Chromosomes go to the middle (equator); Moved by the spindle fibers
4. Anaphase
Chromosomes split apart and chromatids move away from each other
5. Telophase
Opposite of prophase; Cell is stopping dividing and going back to a “normal” cell
19. During what stage(s) of the cell cycle is DNA in chromatin form? When is it in chromosome
form? (Interphase, Mitosis, and Cytokinesis)
Interphase – Chromatin
Mitosis – Chromosome
Cytokinesis – Turning from chromosome back into chromatin (because going from being a dividing cell
to a non-dividing cell)
20. How are chromatin and chromosomes different?
Chromatin is DNA in a non-dividing cell (just a mass of loose fibers); chromosome is DNA in a dividing
cell (coiled up; visible)
21. We talked about the 4 stages of Meiosis 1. List those 4 stages in order and describe what
happens in each phase.
1. Prophase 1

Homologous Chromosomes synapse (pair
together)

This group of 2 chromosomes together is called a tetrad (because there are 4 chromatids)

Crossing – over occurs
When portions on one homologous chromosome are broken and exchanged with the corresponding
portion on one of the chromatids of the other homologous chromosome.
2. Metaphase 1
Paired Homologous Chromosomes line up in the middle of the cell.
3. Anaphase 1
Paired Homologus Chromosomes separate
Daughter cells are now HAPLOID
4. Telophase 1
Nuclear membrane forms around each set of chromosomes
Cytokinesis begins -division of cytoplasm
Left with two haploid daughter cells.
22. What is synapsis and during what phase of meiosis does this occur?
Joining of homologous chromosome pairs
Prophase I
23. What is a tetrad and during what stage of meiosis does this occur?
Joined homologous chromosomes after synapsis
Prophase I
24. When does the nuclear envelope disappear and when does it reappear? (Mitosis)
Disappears during prophase (so the cell can divide)
Reappears during telophase (because cell is done dividing)
25. Complete the following table to compare mitosis and meiosis.
Number of choromosomal duplications
Number of cell divisions
Number of daughter cells produced
Number of chromosomes in daughter cells
Genetic relationship of daughter cells to
parent cell (identical or different)
Functions performed in human body
Mitosis
1
1
2
46
identical
Meiosis
1
2
4
23
Different (half of the DNA)
Everything else
Make sex cells
26. If an intestinal cell in a grasshopper contains 24 chromosomes, a grasshopper sperm cell
contains how many chromosomes? 12
27. Which phase of mitosis is essentially the opposite of prophase in terms of nuclear changes?
telophase
28. (Multiple choice) A biochemist measured the amount of DNA in cells growing in the laboratory
and found that the quantity of DNA in a cell doubled
a. Between prophase and anaphase of mitosis
b. Between the G1 and G2 phases of the cell cycle.
c. During the M phase of the cell cycle.
d. Between prophase I and prophase II of meiosis
e. Between anaphase and telophase of mitosis.
29. Why is it important that EVERY SEXUALLY REPRODUCING ORGANISM (humans, plants,
everything) be capable of alternating between a haploid and diploid stage in their life cycles.
(For humans, we are diploid and our reproductive cells are haploid). So that we maintain 46
chromosomes. If we didn’t, babies would always have twice the chromosomes as their
parents because they would get 46 from dad’s sperm and 46 from mom’s egg (92 total).