Sexual Reproduction Biology
INTRODUCTION
I. Have you ever wondered how the process of sexual reproduction begins in multi-cellular organisms such as ourselves?
II. It all begins through a cell division process known as meiosis.
III. I am currently a biology major at CSU-Pueblo looking to pursue a degree in wildlife biology.
IV. During the process of meiosis, diploid cells split in half, forming four haploid cells, which each have a single set of chromosomes. These cells are called either gametes or sex cells. Female gametes are egg and male gametes are sperm. Two meiotic divisions occur known as meiosis I and meiosis II, and each one of these divisions have four stages, which are; prophase, metaphase, anaphase, and telophase.
Now, I will discuss the definition and stages of meiosis.
BODY …show more content…
I. During a process known as meiosis, four haploid cells are created, in which each contain a single set of chromosomes, after diploid cells split in two.
A. The cells that are formed are known as gametes or sex cells.
1.
Female gametes are egg cells and male gametes are sperm cells.
2. When the sperm cell fuses with and fertilizes an egg cell, a zygote or fertilized egg forms.
B. There are two divisions of meiosis known as meiosis I and meiosis II that occur, and each division has four stages: prophase, metaphase, anaphase, and telophase.
II. I will now discuss the four stages of meiosis I.
A. During the first stage, which is prophase I, homologous chromosomes join together and cross over forming tetrads they condense.
B. In metaphase I, homologous chromosomes are moved to the metaphase plate, by microtubules. Independent assortment also occurs.
C. In anaphase I, homologous chromosomes are separated by microtubules, while sister chromatids stay together.
D. During telophase I, chromosomes are decondensed, travel to opposite poles, and cell membranes are closed off by cytokinesis, creating two daughter cells.
III. Now I will talk about the division of meiosis II.
A. In prophase II, the nucleoli and the nuclear envelope disappear and chromatids become shorter and thicker. Centrosomes travel to opposite poles and spindle fibers are arranged.
B. During metaphase II, sister chromatids join up together at the new metaphase
plate.
C. When anaphase II occurs, sister chromatids are separated from each other, attaching themselves to spindle fibers
D. Telophase II is similar to telophase I, but this time four haploid daughter cells are produced, instead of two.
E. The daughter cells are defined as either gametes or sex cells. The male gametes are sperm and the female ones are egg cells. When two gametes fuse together a fertilized egg also known as a zygote is formed.
Conclusion
I. In conclusion, four haploid daughter cells are created through meiosis, which are gametes, being either sperm or egg cells, and when sperm fertilizes the egg, a zygote is formed. But before this can happen, meiosis I and meiosis II must complete their four stages.
II. When meiosis occurs, diploid cells divide in two, four haploid cells are created, all containing a single set of chromosomes, known as either gametes or sex cells. Female gametes are egg and male gametes are sperm. Meiosis I and meiosis II are the two meiotic stages that occur, and each having four stages: prophase metaphase, anaphase, and telophase.
III. If you previously wondered how sexual reproduction starts, meiosis is the process where it all begins.
I. Have you ever wondered how the process of sexual reproduction begins in multi-cellular organisms such as ourselves?
II. It all begins through a cell division process known as meiosis.
III. I am currently a biology major at CSU-Pueblo looking to pursue a degree in wildlife biology.
IV. During the process of meiosis, diploid cells split in half, forming four haploid cells, which each have a single set of chromosomes. These cells are called either gametes or sex cells. Female gametes are egg and male gametes are sperm. Two meiotic divisions occur known as meiosis I and meiosis II, and each one of these divisions have four stages, which are; prophase, metaphase, anaphase, and telophase.
Now, I will discuss the definition and stages of meiosis.
BODY …show more content…
I. During a process known as meiosis, four haploid cells are created, in which each contain a single set of chromosomes, after diploid cells split in two.
A. The cells that are formed are known as gametes or sex cells.
1.
Female gametes are egg cells and male gametes are sperm cells.
2. When the sperm cell fuses with and fertilizes an egg cell, a zygote or fertilized egg forms.
B. There are two divisions of meiosis known as meiosis I and meiosis II that occur, and each division has four stages: prophase, metaphase, anaphase, and telophase.
II. I will now discuss the four stages of meiosis I.
A. During the first stage, which is prophase I, homologous chromosomes join together and cross over forming tetrads they condense.
B. In metaphase I, homologous chromosomes are moved to the metaphase plate, by microtubules. Independent assortment also occurs.
C. In anaphase I, homologous chromosomes are separated by microtubules, while sister chromatids stay together.
D. During telophase I, chromosomes are decondensed, travel to opposite poles, and cell membranes are closed off by cytokinesis, creating two daughter cells.
III. Now I will talk about the division of meiosis II.
A. In prophase II, the nucleoli and the nuclear envelope disappear and chromatids become shorter and thicker. Centrosomes travel to opposite poles and spindle fibers are arranged.
B. During metaphase II, sister chromatids join up together at the new metaphase
plate.
C. When anaphase II occurs, sister chromatids are separated from each other, attaching themselves to spindle fibers
D. Telophase II is similar to telophase I, but this time four haploid daughter cells are produced, instead of two.
E. The daughter cells are defined as either gametes or sex cells. The male gametes are sperm and the female ones are egg cells. When two gametes fuse together a fertilized egg also known as a zygote is formed.
Conclusion
I. In conclusion, four haploid daughter cells are created through meiosis, which are gametes, being either sperm or egg cells, and when sperm fertilizes the egg, a zygote is formed. But before this can happen, meiosis I and meiosis II must complete their four stages.
II. When meiosis occurs, diploid cells divide in two, four haploid cells are created, all containing a single set of chromosomes, known as either gametes or sex cells. Female gametes are egg and male gametes are sperm. Meiosis I and meiosis II are the two meiotic stages that occur, and each having four stages: prophase metaphase, anaphase, and telophase.
III. If you previously wondered how sexual reproduction starts, meiosis is the process where it all begins.