Download Meiosis Reading - Helena High School

Cell Division – Meiosis
Name
Per
As learned, cell division involving mitosis divides somatic (body) cells, such as skin, bone, and blood.
Meiosis, on the other hand, divides germ cells into sex cells, such as sperm and eggs. Where mitosis
creates two genetically identical daughter cells with a full set, or diploid number of chromosomes,
meiosis produces sperm or eggs, also known as gametes. Unlike in mitosis, the resulting gametes are
not genetically identical to the parent cell. Gametes are haploid cells, with only half the DNA present in the diploid
parent cell (germ cell).
Cells contain sets of homologous chromosomes, one inherited from the mother and the other inherited from the father.
The maternal and paternal chromosomes in a homologous pair contain the same type of genes
at the same location. In other words, the alleles may differ, but they both code for the same
trait. In the box to the right, use two colored- pencils to draw the homologous pairs with one
color representing the chromosome from mom and the other representing the chromosome
from dad. Place a heterozygous genotype for eye color (one allele on each chromosome) at a
random location. What color eyes would this individual have?
During interphase, homologous chromosomes duplicate to make exact copies. One copy of the
maternal and one copy of the paternal chromosome is made during a process called DNA
replication. In the next box, draw a copy using the same color for mom and same color for dad.
Label each chromosome on the sister chromatid pair with the appropriate alleles. These four
chromosomes together (2 matching maternal and two matching paternal) form a tetrad. Circle
and label the tetrads. Since meiosis requires the genetic material be halved, meiosis must
occur twice. Human germ cells contain 46 chromosomes in the cells. In interphase, after the
duplication of the chromosomes, there are
chromosomes in the cell. At the end
of meiosis I each gamete contains 46 chromosomes. However, at the end of meiosis II each
gamete should contain
chromosomes.
Organize the above information into two column notes – main idea - left and supporting details & vocabulary - right
Main Idea
Supporting details- Use a dash – for supporting details and a dot for examples *
Draw meiosis and trace the homologous chromosomes of an organism with a diploid number of two.






The chromosomes need to be color coded to show homologous relationship (two separate colors),
Sister chromatids (same color after duplication).
Be detailed- nuclear envelop, spindle fibers, centrosomes, centrioles, etc.
Choose two gene locations (gene loci) to trace an individual heterozygous for brown eyes through each step.
Also, record the number of chromosomes at each stage and if it is diploid, haploid (or neither).
Summarize the events of each stage
Meiosis I or PMAT 1- Division of Drawing
Phase: Interphase
#
Event Name & Details
Phase:
Cells are Neither diploid or haploid
Phase: Prophase I
Phase:
Pro means=
Cells are:
Phase:
Phase:
M is for
Cells are
Phase:
Phase:
Phase:
Cells are
&
Phase:
telo for
Cells are
Ana for
&
Meiosis II OR PMAT II – Division of ----Drawing
# Event Name & Details
Phase: Prophase II
Phase:
Cells are
Phase:
Phase:
Cells are
Phase:
Phase:
Cells are
Phase:
&
Phase:
Cells are
&
Possible alleles in the gametes?
Number of cells:
Number of chromosomes in each?
Questions: RSQ
1. What is the goal and result of mitosis?
2. What types of cells undergo mitosis?
3. What is the goal and result of meiosis?
4. What type of cells go through meiosis?
5. What is a zygote and how is it created? Is the zygote diploid or haploid?
6. As the zygote begins to divide into a blastocyst, embryo and then fetus the type of cell division is
Practice –
Write the appropriate phase in the blank
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
Tetrads line up in the middle of the cell
Sister chromatids line up in the middle of the cell
Tetrads begin to separate to the opposite side of the cell
How many cells are created after meiosis 1?
Tetrads condense and are visible
`
Nuclear envelop has disappeared between interphase and
.
Nuclear envelop begins to reform around the sets of sister chromatids
.
Sister chromatids begin to pull apart toward opposite ends of the cell
.
The pinching off and creation of 4 haploid daughter cells
Individual chromosomes have separated and are at the far ends of the cell
.
Tetrads have separated into sister chromatids and are at the far end of the cell. The cell is just beginning to
move into cytokinesis
.
12. How many cells are created after meiosis II?
Are they haploid or diploid?
13. Are they identical?
Fill in the diploid and haploid number for the following organisms Diploid
14. A carrot has 18 chromosomes in all somatic cells
15. Humans have 46 chromosomes in all somatic cells
16. A fruit fly has 8 chromosomes in all somatic cells
17. A dolphin has 44 chromosomes in all somatic cells
Quiz your table buddy – Score
Haploid