Cell Division Research Paper

2. a) How does meiosis introduce genetic variation into offspring? Think about how the chromosomes line up.(1 point)

Cells are the basic units of structure and function in an organism, and Cells come only from the reproduction of existing cells.

Biological sex is determined by chromosomes in your genes. At prenatal development, only a few weeks after conception, there is no notable difference between male and female structure until the Gonadal Ridges, the structure which develops either female or male sex organs, grows to determine the sex of the baby. All prenatal babies have genitalia that appears distinctly feminine until at three months, hormones- testosterone if the baby’s to be a boy, and oestrogen if the baby’s to be a girl- is released and the baby develops into the hormone determined gender. For these reasons it is believed that there is a direct link between chromosomes and sex, and therefore sex and

All living organisms have something called a ‘‘genome’. Genomes contain all of the DNA within that certain organism.The identity of an organism is defined by the DNA that is present in its genome. Humans are what is known as diploid organisms. The sperm from the dad have one set of chromosomes, and the egg in the mom has the

Meiosis consists of one DNA replication and two nuclear divisions resulting in 4 daughter cells. The process which provides for genetic variation is crossing over. Crossing over occurs in the early stages when homologous chromosomes move together so that their chromatids form a tetrad. This is called synapsis and allows for the exchange of chromosome sections.

The cell has the ability to reproduce, this ensure the continuation of the organism as cells regenerate and repair. There are two types of cell division:

In meiosis the pairs of chromosomes (that code for possible outcomes of characteristics) temporarily join and exchange information (crossing over) creating different combinations of gene types (alleles). For example; a pair of chromosomes could be a dominant allele (gene type) and a recessive allele which might code for brown hair. After crossing over it might be recessive which could be blond hair.

When a child is born you're either a boy or a girl . girls get a X chromosome from your mom and dad . a boy gets an X chromosome from mom and Y from your dad . if a girl gets that bad X chromosome from the mom and a good one from the dad it will be ok but if you get a bad one from mom then a Y-chromosome from

Usually women have two X chromosomes while men have one X chromosome and one Y chromosome. There are some cases where babies do not have any of these arrangements mentioned above (Through the Wormhole video). As people study these kind of cases, they have realized that there might be more than two sexes. For example, I learned that some women can be born with “Swyer syndrome”, which makes them anatomically and physiologically a female but they never achieve female sexual maturity (The Gene: An Intimate History). When their cells were examined, they discovered that they had XY chromosomes in their cells. Basically, they were chromosomally male but anatomically, physiologically, and psychologically female (The Gene: An Intimate History). Goodfellow discovered the SRY gene. This gene was the determinant of maleness but it was flicked off on women with Swyer

Diploid organisms have two copies of each chromosome, one of which they get from their father, the other which they get from their mother. These equivalent chromosomes are called homologous chromosomes.

As cells divide and reproduce in two ways, this is known as Mitosis and Meiosis. Mitosis is the process of asexual reproduction, which means the cell divides into two producing another, with an equal numbers of chromosomes resulting in a diploid cell. Meiosis is a type of cellular reproduction where the numbers of chromosomes are reduced by half, because of the separation of homologous chromosomes, which results in the production of two haploid cells.

D) Sexual reproduction is more likely to increase genetic variation than is asexual reproduction. E) Only asexual

Mitosis is the process in which the duplicated genome in a cell is separated into halves that are identical, which results in the growth and development of new cells. Mitosis can occur without cytokinesis, forming single cells with multiple nuclei (Ex: certain fungi and slime moulds). Mitosis occurs in four phases, one of which is Cytokinesis. Cytokinesis is the process where the cytoplasm of the cell divides to form two daughter cells and ensures that the chromosome numbers are maintained in the cell. During Cytokinesis, the cytoplasm of a cell is divided into two. The result is the formation of two daughter cells, each having a nucleus. Apart from the nuclei, Cytokinesis also results in the passing of cellular organelles equally between the two daughter cells. Since some of the molecules bind to the chromosomes, each daughter cell receives an equal share of the cytoplasmic components. Mitosis involves the division and duplication of the cell’s nucleus or separation of duplicated chromosomes whereas cytokinesis involves the division of the cytoplasm to form two distinct, new daughter cells. Mitosis also takes more time to complete than cytokinesis

Sometimes, genetic mutations can occur during meiosis. This is a permanent change in the sequence of base pairs in the strand of DNA; in other words, it is a “glitch” in the system. If there is a genetic mutation, it can possibly lead to an extra chromosome, or even the vacancy of one chromosome in the DNA strand. This will result in an organism having a completely extra set of chromosomes. This is the case of Down syndrome, a genetically mutated condition in which a person has 47 chromosomes instead of the usual 46.

Chromosomes are like computers, ‘carrying genetic information in the form of genes’. These chromosomes determine your hair color, eye color, skin color, etc. Every human contains 42 chromosomes, only two of them determine the gender of the person. During the reproductive system however, the mother gives 23 chromosomes and the father gives 23 chromosomes as well. Sometimes during the reproduction system, one parent gives 24 chromosomes which will affect the child later in his or her life after birth.