Review Sheet – Haploid, Diploid, Meiosis, Mitosis, Life Cycles
1. For each of the cells below, write the correct term (HALOID, DIPLOID, TRIPLOID, or POLYPLOID) to
describe the cell on the blank provided. Then, fill in the blanks in the ____ n = ____ expression for each
cell. (1 point for each blank)
A._Diploid________
_2_ n = _2__
B.____Haploid______
__1__ n = _3__
C.____Diploid___
D.___Polyploid______
_2__ n = _8__
__4__ n = _4__
3. Name three ways in which meiosis and mitosis are similar.
 They both begin after the DNA has been copied in the S phase, so in both the chromosomes have 2 sister
chromatids
 By the end of each process, sister chromotids have separated so that each chromosome is a singe piece of
DNA
 A spindle forms in both processes
 The same phases (prophase, metaphase, anaphase, and telophase) occur in both
4. Name three ways in which meiosis and mitosis are different.
 Each phase occurs twice in meiosis vs once in mitosis
 In meiosis, resulting cells have half as many chromosomes as the original cell. In mitosis, resulting cells
have the same number of chromosomes as the original cell.
 In meiosis, cytokinesis occurs twice vs only once for mitosis.
 Meiosis produces 4 daughter cells vs 2 daughter cells in mitosis.
 Daughter cells produced in meiosis are not identical to the parent cell or to each other. Daughter cells
produced in mitosis are identical to each other and to the parent cell.
 Tetrads form in meiosis but not in mitosis.
 Crossing over may occur in meiosis but not in mitosis.
5. Explain how the process of meiosis provides the possibility for enormous variety in nature.
 Independent assortment of chromosomes when homologous chromosomes separate in anaphase 1 gives
many possible combinations (2n where n is the haploid number of chromosomes).
 Crossing over gives novel combinations of genes within a chromosome and produces sister chromatids
that are no longer identical.
 Random fertilization (which sperm fertilizes which egg) gives many possible combinations of genes from
a single set of parents
6. Explain the difference between somatic cells and gametes.
Somatic cells include all body cells except gametes. Gametes are sperm or eggs formed specifically for
the purpose of reproduction.
6. What are homologous chromosomes?
Homologous chromosomes are chromosomes that contain the same type of information but not
necessarily identical information. One of the homologous chromosomes in a diploid organism came from
its mother while the other came from its father.
7. When do homologous chromosomes come together?
Homologous chromosomes come together to form tetrads in Prophase 1 of meiosis.
8. Explain what crossing over is.
Crossing over occurs when homologous chromosomes exchange genes when they are in the tetrads. This
creates new combinations of genes, some from the maternal chromosome and others from the paternal
chromosome.
Life Cycle Practice Sheet
Fill in the blanks to indicate whether organisms are diploid (2n) or haploid (n) or to tell the name of a
process. Then circle sexual or asexual to tell what kind of reproduction is used in the cycle.
Life Cycle #1:
Adult (2n)
MITOSIS
Circle one:
MITOSIS
SEXUAL or ASEXUAL
Spore
2n
(because mitosis does not change the chromosome #) This is not a life cycle typically found in nature.
Fertilization
________________
(name of process)
Life Cycle #2:
Adult Male
(2n)
____________
Meiosis
(name of process)
Adult Female
(2n)
___________
Meiosis
(name of process)
Male gamete
(n)
2n
Zygote (___________)
Female gamete
(n)
____________
Mitosis
Circle one:
(name of process)
SEXUAL or ASEXUAL
Life Cycle #3:
MITOSIS
Spores
n
______
MITOSIS
Adult male
n
______
Adult female
MITOSIS
Mitosis
MITOSIS
n
______
Female
gamete
n
______
MEIOSIS
Spore case (2n)
MITOSIS
Zygote
2n
______
Male
gamete
n
______
Fertilization
___________________
(name of process)
Circle one: SEXUAL or ASEXUAL
Overall, this is a sexual life cycle, but it
also has a point where a single cell
becomes an entire organism. Note
however that the spore was formed by
meiosis so it is not genetically identical
to the cell that made it. This life cycle
shows alternation of generations.