# data[].attributes.body
There are 46 chromosomes in the nucleus of body cells.

# data[].attributes.attachment_link.readable_text
Chromosomes are cell components that are composed of DNA and located within the nucleus of our cells. The DNA of a chromosome is so long, that it must be wrapped around proteins called histones and coiled into loops of chromatin in order for them to be able to fit within our cells. The DNA comprising chromosomes consists of thousands of genes that determined everything about an individual. This includes sex determination and inherited traits such as eye color, dimples, and freckles.

Discover ten interesting facts about chromosomes.

1: Bacteria Have Circular Chromosomes

Unlike the thread-like linear strands of chromosomes found in eukaryotic cells, chromosomes in prokaryotic cells, such as bacteria, typically consist of a single circular chromosome. Since prokaryotic cells do not have a nucleus, this circular chromosome is found in the cell cytoplasm.

2: Chromosome Numbers Vary Among Organisms

Organisms have a set number of chromosomes per cell. That number varies across different species and is on average between 10 to 50 total chromosomes per cell. Diploid human cells have a total of 46 chromosomes (44 autosomes, 2 sex chromosomes). A cat has 38, lily 24, gorilla 48, cheetah 38, starfish 36, king crab 208, shrimp 254, mosquito 6, turkey 82, frog 26, and E.coli bacterium 1. In orchids, chromosome numbers vary from 10 to 250 across species. The adder's-tongue fern ( Ophioglossum reticulatum) has the most number of total chromosomes with 1260.

3: Chromosomes Determine Whether You are Male or Female

Male gametes or sperm cells in humans and other mammals contain one of two types of sex chromosomes: X or Y. Female gametes or eggs, however, contain only the X sex chromosome. If a sperm cell containing an X chromosome fertilizes

4: X Chromosomes Are Bigger Than Y Chromosomes

Y chromosomes are about one-third the size of X chromosomes.

The X chromosome represents about 5 percent of the total DNA in cells, while the Y chromosome represents about 2 percent of a cell's total DNA.

5: Not All Organisms Have Sex Chromosomes

Did you know that not all organisms have sex chromosomes? Organisms such as wasps, bees, and ants do not have sex chromosomes. Sex is therefore determined by fertilization. If an egg becomes fertilized, it will develop into a male. Unfertilized eggs develop into females. This type of asexual reproduction is a form of parthenogenesis.

6: Human Chromosomes Contain Viral DNA

Did you know that about 8 percent of your DNA comes from a virus? According to researchers, this percentage of DNA is derived from viruses known as borna viruses. These viruses infect the neurons of humans, birds and other mammals, leading to infection of the brain. Borna virus reproduction occurs in the nucleus of infected cells.

Viral genes that are replicated in infected cells can become integrated into chromosomes of sex cells. When this occurs, the viral DNA is passed from parent to offspring. It is thought that borna virus could be responsible for certain psychiatric and neurological illness in humans.

7: Chromosome Telomeres are Linked to Aging and Cancer

Telomeres are areas of DNA located at the ends of chromosomes.

They are protective caps that stabilize DNA during cell replication. Over time, telomeres wear down and become shortened. When they become too short, the cell can no longer divide. Telomere shortening is linked to the aging process as it can trigger apoptosis or programmed cell death. Telomere shortening is also associated with cancer cell development.

8: Cells Don't Repair Chromosome Damage During Mitosis

Cells shut off DNA repair processes during cell division. This is because a dividing cell does not recognize the difference between damaged DNA stands and telomeres. Repairing DNA during mitosis could cause telomere fusion, which may result in cell death or chromosome abnormalities.

9: Males Have Increased X Chromosome Activity

Because males have a single X chromosome, it is necessary for cells at times to increase gene activity on the X chromosome.

The protein complex MSL helps to up-regulate or increase gene expression on the X chromosome by helping the enzyme RNA polymerase II to transcribe DNA and express more of the X chromosome genes. With the help of the MSL complex, RNA polymerase II is able to travel further along the DNA strand during transcription, thereby causing more genes to be expressed.

10: There Are Two Main Types of Chromosome Mutations

Chromosome mutations sometimes occur and can be categorized into two main types: mutations that cause structural changes and mutations that cause changes in chromosome numbers. Chromosome breakage and duplications can cause several types of chromosome structural changes including gene deletions (loss of genes), gene duplications (extra genes), and gene inversions (broken chromosome segment is reversed and inserted back into the chromosome). Mutations can also cause an individual to have an abnormal number of chromosomes. This type of mutation occurs during meiosis and causes cells to have either too many or not enough chromosomes. Down syndrome or Trisomy 21 results from the presence of an additional chromosome on autosomal chromosome 21.

"Chromosome." UXL Encyclopedia of Science. 2002. Encyclopedia.com. 16 Dec. 2015 (http://www.encyclopedia.com).

"Chromosome Numbers For Living Organisms." Alchemipedia. Accessed 16 Dec. 2015 (http://alchemipedia.blogspot.com/2009/10/chromosome-numbers-for-living-organisms.html).

"X chromosome." Genetics Home Reference. Reviewed January 2012. (http://ghr.nlm.nih.gov/chromosome/X).

"Y chromosome." Genetics Home Reference. Reviewed January 2010. (http://ghr.nlm.nih.gov/chromosome/Y).

# data[].attributes.attachment_link.description
Chromosomes are cell components that are composed of DNA and located within the nucleus of our cells. The DNA of a chromosome is so long, that it must be wrapped around proteins called histones and coiled into loops of chromatin in order for them to be able to fit within our cells.

# data[].attributes.body
There are over 20,000 genes in our DNA.

# data[].attributes.attachment_link.readable_text
Genes are segments of DNA located on chromosomes that contain the instructions for protein production. Scientists estimate that humans have as many as 25,000 genes. Genes exist in more than one form. These alternative forms are called alleles and there are typically two alleles for a given trait. Alleles determine distinct traits that can be passed on from parents to offspring. The process by which genes are transmitted was discovered by Gregor Mendel and formulated in what is known as Mendel's law of segregation.

Gene Transcription

Genes contain the genetic codes, or sequences of nucleotide bases in nucleic acids, for the production of specific proteins. The information contained within DNA is not directly converted to proteins, but must first be transcribed in a process called DNA transcription. This process takes place within the nucleus of our cells. Actual protein production takes place in the cytoplasm of our cells through a process called translation.

Transcription factors are special proteins that determined whether or not a gene gets turned on or off. These proteins bind to DNA and either aid in the transcription process or inhibit the process. Transcription factors are important for cell differentiation as they determine which genes in a cell are expressed. The genes expressed in a red blood cell, for example, differ from those expressed in a sex cell.

An Individual's Genotype

In diploid organisms, alleles come in pairs. One allele is inherited from the father and the other from the mother. Alleles determine an individual's genotype or gene composition. The allele combination of the genotype determines the traits that are expressed or the phenotype. A genotype producing the phenotype of a straight hairline, for example, differs from the genotype resulting in a V-shaped hairline.

Inherited Through Both Asexual and Sexual Reproduction.

Genes are inherited through both asexual reproduction and sexual reproduction. In asexual reproduction, resulting organisms are genetically identical to a single parent. Examples of this type of reproduction include budding, regeneration, and parthenogenesis.

Gametes Fuse to Form a Distinct Individual

Sexual reproduction involves the contribution of genes from both male and female gametes that fuse to form a distinct individual. The traits exhibited in these offspring are transmitted independently of one another and may result from several types of inheritance.

In complete dominance inheritance, one allele for a particular gene is dominant and completely masks the other allele for the gene.

In incomplete dominance, neither allele is completely dominant over the other resulting in a phenotype that is a mixture of both parent phenotypes.

In co-dominance, both alleles for a trait are fully expressed.

Some Traits Determined by More Than One Gene

Not all traits are determined by a single gene. Some traits are determined by more than one gene and are therefore known as polygenic traits. Some genes are located on sex chromosomes and are called sex-linked genes. There are a number of disorders that are caused by abnormal sex-linked genes including hemophilia and color blindness.

Variation Helps Adapting to Changing Situations

Genetic variation is a change in the genes that occur in organisms in a population. This variation typically occurs through DNA mutation, gene flow (movement of genes from one population to another) and sexual reproduction. In unstable environments, populations with genetic variation are typically able to adapt to changing situations better than those that do not contain genetic variation.

Mutations Are From Errors and the Environment

A gene mutation is an alteration in the sequence of nucleotides in DNA. This change can affect a single nucleotide pair or larger segments of a chromosome. Changing gene segment sequences most often results in non-functioning proteins.

Some mutations can result in negative impacts, while others may have no negative impact on or may even benefit an individual. Still, other mutations may result in unique traits such as dimples, freckles, and multicolored eyes. Gene mutations are most commonly the result of environmental factors (chemicals, radiation, ultraviolet light) or errors that occur during cell division ( mitosis and meiosis).

# data[].attributes.attachment_link.title
Genes, Mutations, and Genetic Inheritance

# data[].attributes.attachment_link.description
Genes are segments of DNA located on chromosomes. Genes are inherited from our parents and contain the codes for the production of specific proteins.

# data[].attributes.body
It's made up of 4 different kind of nucleotides. (AGTC)

# data[].attributes.attachment_link.readable_text
Nucleotides
A nucleotide is the basic structural unit and building block for DNA. These building blocks are hooked together to form a chain of DNA. A nucleotide is composed of 3 parts:

* five-sided sugar
* phosphate group
* nitrogenous base (nitrogen containing)

The sugar and phosphate group make up the backbone of the DNA double helix, while the bases are located in the middle. A chemical bond between the phosphate group of one nucleotide and the sugar of a neighboring nucleotide holds the backbone together. Chemical bonds (hydrogen bonds) between the bases that are across from one another hold the two strands of the double helix together.
Bases
There are four types of bases in DNA. They are called:

* Adenine (A)
* Cytosine (C)
* Guanine (G)
* Thymine (T)

Bases are the part of DNA that stores information and gives DNA the ability to encode phenotype, a person's visible traits. Adenine and guanine are purine bases. These are structures composed of a 5-sided and 6-sided ring. Cytosine and thymine are pyrimidines which are structures composed of a single six-sided ring. Adenine always binds to thymine, while cytosine and guanine always bind to one another. This relationship is called complementary base paring. These complementary bases are bonded together via hydrogen bonds, which can be easily broken apart when the DNA needs to unzip and duplicate itself.

to learn about DNA to learn about single nucleotide polymorphisms
CLICK HERE to learn about DNA mutations

# data[].attributes.attachment_link.title
Nucleotides and Bases - Genetics Generation

# data[].attributes.attachment_link.description
Nucleotides and Bases Nucleotides A nucleotide is the basic structural unit and building block for DNA. These building blocks are hooked together to form a chain of DNA. A nucleotide is composed of 3 parts: * five-sided sugar * phosphate group * nitrogenous base (nitrogen containing) The sugar and phosphate group make ...

# data[].attributes.body
DNA is made of up chain chemical "letters" means Adenine ,Guanine, , Thymine, & Cytosine

# data[].attributes.body
In the 1940s, DNA they didn't want to  say that it was a genetic material because of the chemistry that it had.

# data[].attributes.attachment_link.title
Lowestoft 1940s Festival Weekend | Discover Lowestoft

# data[].attributes.attachment_link.description
Step back in time for Lowestoft's 1940s weekend with FREE ENTRY! With something for everyone there's no better way to spend the weekend!

# data[].attributes.body
There are 2 copies of genes ,since chromosomes come in pairs.

# data[].attributes.body
Proteins does work within our body and cells.

# data[].attributes.body
DNA stands for Deoxyribo Nuclei Acid

# data[].attributes.attachment_link.readable_text
DNA is the acronym of deoxyribonucleic acid, is an organic compound that contains the genetic information of a living being and some viruses, in prokaryotic cells and in the nucleus of eukaryotic cells, inside chromosomes.

The main function of DNA is to store genetic information for the construction of proteins and RNA, which is essential for any vital function of an organism. The DNA stores and transmits from generation to generation all the information essential for the development of the biological functions of an organism.

Source

The DNA segments that carry the genetic information are known as genes, but the other DNA sequences are for structural purposes or take part in the regulation of the use of genetic information.

Referring to what has been said above, the coding DNA and the non-coding DNA can be observed. Also, in a gene the sequence of nucleotides established in a strand of DNA is transcribed to a messenger RNA and, in turn, it is translated into a protein that an organism synthesizes in one or some moments of its life and, finally, the replication of DNA consists in obtaining identical copies of a fundamental DNA molecule for the transfer from one generation to another, the basis of the inheritance.

DNA is made up of bands formed by chemical compounds called nucleotides. In turn, each nucleotide is made up of 3 units: a sugar molecule, that is, deoxyribose, a phosphate group and a 4-base group: adenine, guanine, thymine and cytosine. In the center of the nucleotide is the deoxyribose molecule and is surrounded by one side of a phosphate group and the other a base, the linked deoxyribose-phosphate form what is known as the sides of the ladder.

Source

The DNA of each human being is exclusive, each human being has 2 forms of each gene, that is, one that receives from the father and the other from the mother, but in spite of being the same genes among people, some DNA sequences vary from person to person. DNA is characterized by the position and quantity of these nucleotides along the chains, this sequence is known as genetic or genetic code.

Source

MItochondrial DNA

Mitochondrial DNA is a fragment of nucleic acid in mitochondria. The mitochondrial genetic material is inherited exclusively by the maternal part. Mitochondrial DNA was discovered by Margit M. K. Nass and Sylvan Nass using electron microscopy and a marker sensitive to mitochondrial DNA.

Mitochondria are small organelles within eukaryotic cells, in order to produce energy for the cell to perform its functions. However, each mitochondrion has its own genome and its cellular DNA molecule.

Source

Thank you for reading my post, for more information visit this page.
https://www.significados.com/adn/

# data[].attributes.attachment_link.description
DNA is the acronym of deoxyribonucleic acid, is an organic compound that contains the genetic information of a living being and some viruses, in prokaryotic cells and in the nucleus of eukaryotic cells, inside chromosomes. The main function of DNA is to store genetic information for the construction of proteins and RNA, which is essential for any vital function of an organism.

# data[].attributes.body
DNA can be found in your very own fingerprints.

# data[].attributes.attachment_link.description
Your DNA makes you, you -- but how does it work? These talks explore what we know about the genome, the unique genetic sequence that makes up life as we know it.