DNA is the carrier of the legacy.
Mother cell is called the "first" cell before divided to different daughter cells. To the daughter cells will be as just as her mother cell needed molecules that gives them characteristics similar to the mother. DNA molecule found in the cell nucleus.
Bacteria have a long circle formed DNA molecule kalals the chromosome and is free (nucleus is missing).
Eukaryotes have their DNA as extremely thin kromatintrådar a cell nucleus.
The DNA molecule is constructed in the same manner to any organism.
DNA looks like a wound rope ladder (spiral). In the spiral, there are four nitrogen bases:
A (adenine) - T (thymine)
C (cytosine) - G (guanine)
The order of nitrogenous bases is called the sequence of bases. It is that which makes each DNA molecule is unique. The base sequence is the same in all cells of the individual.
Man is 98.6% relative of the chimpanzee.
From DNA to protein
In the beginning the earth arose many different cells, some developed further, as the important building material protein. The protein functions as an enzyme (wings chemical reaktiner in cells and organisms). Protein is made up of 20 different amino acids, 8 of which are essential (vital). The base sequences determine how to arrange the amino acids in a protein. Protein formation takes place in the ribosomes.
The mitochondria (mtDNA) act as cellular power plants and supplies energy to protein formation to work. They may also form self-protein.
Heredity = Genes.
Genes comprise DNA. They are genes that tell how we will look and be. The word genetics does heredity. It defines a gene that is a base sequence. The genes determines which protein is formed. Varke chromosome contains thousands of genes. Humans have 46 chromosomes and has about 3 billion nitrogenous bases, which shows that humans have approximately 35,000 genes.
Each individual has received half of its chromosomes from the mother and father.
Homologous chromosomes meant by equal. They sit in pairs and codes for the same property. Allelic genes mean alternative forms of a particular gene. A chromosome can be dominant (AA) or recessive (aa). A property built on equally strong alleles (AA) or (aa) called homozygous. Property that includes both (Aa) is called heterozygous.
Women denoted XX and men designated XY. X is dominant while the Y recessive because it contains less genes.
Each chromosome consists of two chromatids. Chromatids held together by a point called the centromere. It can sit imitten or at its end. It helps chromosomes will be separated from each other.
Normal cell division or mitosis
Cell division or mitosis is part of the cell cycle.
During mitosis assigned a cell and the resulting 2 daughter cells that are genetically identical to the parent cell. At the beginning is the daughter cells are smaller than the mother cell, but they are growing.
The mother cell has et double stranded DNA which differ from each other, after which a new string immediately grow. The part is called replication (duplication) and results in 2 identical DNA molecules. The result is two chromatids. Then repair it before it will introduce the next mitosis.
Mitosis is divided into:
Prophase, metaphase, anaphase and telophase.
Centriolerna are located at each end of the cell (such as north and south pole)
Reduction Sharing or meiosis
In the gonads, ovaries and testes occur both mitosis and meiosis. Meiosis is a form of cell division. It halves the number of chromosomes in the future gametes. Meiosis occurs in the same four phases of mitosis, but consists of two divisions, meiosis I and meiosis II. In meiosis I is an exchange (crossing-over) between the father and the moderkromatiderna and become a mixture. Meiosis I give to results cells with a halved number of chromosomes. The cells have become haploid (N). Other cells are diploid (2n).
Then follows meiosis II, which is the same as mitosis.
The two haploid cells go through a cell division and get together four haploid cells.
Thanks to the crossovers, they are genetically slightly different from each other.
This applies only to males, with females constituting each mother cell only one egg.
The eggs are always the X chromosome.
Half of the sperm may be X and the other half Y. The fertilized egg become diploid.
Mutations of good and evil
Mutations = changes in the genome
They occur in both könceller (can form cancer) and body cells.
It distinguishes between spontaneous and causing mutations. Spontaneous mutations have been around for ages, it is one of the causes of evolution. Contact with chemical substances and viruses are involved in both spontaneous and causing mutations.
Usually, mutations are negative and lead to disease, birth defects and other impairments. This is because a dominant allele (A) has been mutated to a recessive (a).
Cells have repair enzymes, which in most cases corrects errors occurred in the genome. Greater risk of mutation when you get older and repair enzymes is becoming weaker.
Mutations are the 3 huvuslag:
Gene mutations, chromosome mutations and chromosomal mutations century.