Download Use pages 323 to 325 to Define, understand and model meiosis

Use pages 323 to 325 to Define, understand and model meiosis Name
Per
The last unit explored mitosis, the division of somatic (body) cells, such as skin, bone, blood, to create two identical
daughter cells allowing for growth, replacement, and repair in multicellular organisms. The next learning objective
includes understanding meiosis, a similar process necessary for the division of sex cells, such as sperm and eggs. Where
the goal of mitosis was to create two genetically identical daughter cells, the goal of meiosis is to produce sperm or eggs,
also known as gametes. 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)
Achieving the goal of meiosis requires a two-step process to separate homologous chromosomes in a diploid cell.
Homologous refers to corresponding chromosomes in a cell – one is maternal (from mom) and one is from paternal
(from dad). When these chromosomes are duplicated during the process of DNA replication in interphase they from
sister chromatids- matching pairs. If the germ cell begins with 46 chromosomes, how many chromosomes are present
after DNA replication in interphase?
The four chromosomes together (2 matching maternal and two matching
paternal) form a tetrad. The diploid cells of most adult organisms contain two
complete sets of inherited chromosomes (one from mom and one form dad)
and two complete sets of genes. For humans the diploid number is 46. The
goal is the make haploid, or sex cells with half the number or only one set of
chromosomes, or haploid. For humans the haploid number is 23.
Labeling: Based on the information provided label the homologous pair, sister
chromatids (use twice), centromere, the name of the process and fill in the
corresponding gene locations after DNA replication.
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 six.
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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 through the division.
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
Drawing
#
Phase: Interphase
Event Name & Details
Phase:
Cells are Neither diploid or haploid
Phase: Prophase I
Phase:
Cells are:
Phase:
Phase:
Cells are
Phase:
Phase:
Phase:
Cells are
&
Phase:
Cells are
&
Meiosis II
Drawing
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Event Name & Details
Phase: Prophase II
Phase:
Cells are
Phase:
Phase:
Cells are
Phase:
Phase:
Cells are
Phase:
&
Phase:
Cells are
&
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
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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