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Chromosome: Difference between revisions
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Chromosomes consist of two long strands of [[Deoxyribonucleic Acid]] (DNA) that are bound together, and twisted into the shape of a helix. Each chromosome contains a great many [[genes]]. | Chromosomes consist of two long strands of [[Deoxyribonucleic Acid]] (DNA) that are bound together, and twisted into the shape of a helix. Each chromosome contains a great many [[genes]]. | ||
This threadlike structure is found in the cells of every organism and is responsible for passing of characteristics to offspring is the process of heredity. They come in different shapes and sizes depending on what the organism is. In human body there are 46 chromosomes that inhibit the human body. The way that the chromosome is formed is that proteins, which are known as histones bend and coil the DNA strands, which then forms the chromosome. This is why DNA inhibits most of the space in the chromosome. In each organism there is a certain number of chromosomes. In cell division the chromosome takes on an important role. When the new cells are formed by division they produce daughter cells. When there was one cell there is now two cells. Each of these are duplicated chromosomes. During this process the chromosome are formed into rodlike structures but are paired. The new cell that is then formed will receive one of each pair of the rodlike structure. This way the cell then has a chromosome that is like the original chromosome cell. A process called rearrangement can cause the cells to break off one chromosome and join another chromosome. This can cause problems for the chromosome. This process may cause a disease to travel from the parent to the child because of the rearrangement of the chromosome. Cancer cells are an example of the chromosome number or the structure are changed. (World Book) | This threadlike structure is found in the cells of every organism and is responsible for passing of characteristics to offspring is the process of heredity. They come in different shapes and sizes depending on what the organism is. In human body there are 46 chromosomes that inhibit the human body. The way that the chromosome is formed is that proteins, which are known as histones bend and coil the DNA strands, which then forms the chromosome. This is why DNA inhibits most of the space in the chromosome. In each organism there is a certain number of chromosomes. In cell division the chromosome takes on an important role. When the new cells are formed by division they produce daughter cells. When there was one cell there is now two cells. Each of these are duplicated chromosomes. During this process the chromosome are formed into rodlike structures but are paired. The new cell that is then formed will receive one of each pair of the rodlike structure. This way the cell then has a chromosome that is like the original chromosome cell. A process called rearrangement can cause the cells to break off one chromosome and join another chromosome. This can cause problems for the chromosome. This process may cause a disease to travel from the parent to the child because of the rearrangement of the chromosome. Cancer cells are an example of the chromosome number or the structure are changed. (World Book)A chromosome is the DNA molecule that contains most or all of the genetic information of the cell or virus. In Eukayotes, a structure composed of DNA and proteins that bear part of the genetic information of the cell. (Purves, G-5) In a eukaryotic cell the chromosome is contained within the organelle known as the nucleus. Before the synthesis of DNA each of the chromosomes have only one double stranded DNA molecule : after the DNA has been replicated the new DNA molecule is called chromatids. These chromatids are then held together by cohesin. When the cell is in inter phase the chromosome has many DNA molecules roaming around the nucleosmoes(Purves, 196) | ||
== Variations Among Organisms == | == Variations Among Organisms == | ||
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The chromosome is made up of mostly deoxyribonucleic acid and proteins. Nucleotides are the bases for how the DNA structure is formed. A gene occupies much of the space within the chromosome. Because of the way that the chromosome is shaped even when the DNA is confined the chromosome can still go through with transcription. RNA is the molecule that tell the DNA what type of proteins will be produced in the different areas of the chromosome. Chromosomes are what make the DNA replicate and reproduce making each of its offspring have half of the parent cells genes. [http://encarta.msn.com/encyclopedia_761566230/Chromosome.html] | The chromosome is made up of mostly deoxyribonucleic acid and proteins. Nucleotides are the bases for how the DNA structure is formed. A gene occupies much of the space within the chromosome. Because of the way that the chromosome is shaped even when the DNA is confined the chromosome can still go through with transcription. RNA is the molecule that tell the DNA what type of proteins will be produced in the different areas of the chromosome. Chromosomes are what make the DNA replicate and reproduce making each of its offspring have half of the parent cells genes. [http://encarta.msn.com/encyclopedia_761566230/Chromosome.html] | ||
===Chromatin=== | |||
The chromatin is located within the nucleus. The nucleus is the place where DNA combines with proteins to form chromatin. The chromatin is made up of long thin threads. The chromatin is needed in order for a chromosome to emerge. Before the cell goes through cell division the chromatin aggregates, which makes the structure that is known as the chromosome. (Purves, 70) In a eukaryotic cell there is a dense material made up of DNA and proteins. This material is the chromatin. During mitosis the chromatin is more coiled because its nucleosomes begin to coil. The chromatin continues to fold until the chromosome begins to separate. (Purves, 169-171) In some eukaryoteschromatin is neede in order for transcription. This process is called chromatin remodeling. There are two types of chromatin: | |||
Euchromatin- conatins DNA that is to be transcribed to RNA. | |||
Heterochromatin- The genes are inactive and is not transcribed. (Purves, 294) | |||
===Histones=== | |||
His tones are located within the chromosome. The histons are used in order to from nucleosomes. Inside of the uncleosmes are eight histon molecules, 146 base pairs of DNA, and histone (H1) (Purves, 171) in a nucleosome a histone is positively charged and DNA is negatively charged. When the histones and the DNA combine and the shitone reduces its charge it will the give off the DNA. Acetylation is used to catalyze the histone to disaggregate the uncleosome (Purves, 294). A hisone is any one of a group of basic proteins forming the core of a nucleosome, the structural unit of a eukatryotic chromosome (Purves, G-12). | |||
==Sexual Reproduction== | |||
During sexual reproduction each offspring receives a gamete from their parent. A parent gives their offspring chromosomes, which are the gamete. Each of the gametes have a set of chromosome. During sexual reproduction the gametes or eff and sperm combine in order to make on cell. This one cell is known as a zygote. The zygote now contains two sets of chromosome. Somatic cells are those that inhibit multi cellular orgamisms that are not sued for reproduction these cells have two sets of chromosomes. One chromosome of these somatic cells are from their parent. These members appear to be the same size and appearance, which makes them homologous. Their genetic info are not identical to the two chromosomes, the number of chromosomes within the gamete is noted by n. the cell is called haploid. The fertilization is the fusion of two haploid gametes. The zygote is then the result. There is now 2 chromosomes and the zygote, which is call diploid. (Purves, 175) | |||
==Chromsomes in Eukaryotes== | ==Chromsomes in Eukaryotes== | ||
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* World Book | * World Book | ||
* | * Purves, William K. et al. Life: The Science of Biology. Gordensville, VA. 2004. | ||
* [[http://encarta.msn.com/encyclopedia_761566230/Chromosome.html Chromosome]] MSN Encarta | * [[http://encarta.msn.com/encyclopedia_761566230/Chromosome.html Chromosome]] MSN Encarta | ||
* [[http://en.wikipedia.org/wiki/Chromosome Chromosomes]] Wikipedia | * [[http://en.wikipedia.org/wiki/Chromosome Chromosomes]] Wikipedia | ||
