Unraveling DNA http://www. youtube. com/watch EQ: How do genes and chromosomes work together to determine an organism’s traits?

Unraveling Almost every cell in your body contains about 2 meters of DNA. If you unraveled all your chromosomes from all the cells of your body, then laid out the DNA end to end, the strands would stretch from the Earth to the Sun about 600 times. - How does all that DNA fit in your body? How does the DNA hold a code that affects your traits?

Unraveling DNA is found in the cells of all organisms, including plants, bacteria, mosquitoes and humans. Each organism has a unique set of DNA, but DNA functions the same way in all organisms

Unraveling DNA is often wound around proteins, coiled into strands, and then bundled even more. In the nucleus of a cell, the strands of DNA are bundled into chromosomes.

Unraveling The structure of DNA allows it hold information. The order of the bases (A, T, G, C) on one side of the molecule is a code that carries information.

Unraveling A gene consists of a long strand of nucleotides, the subunits that make up DNA, that give the cell information about how to make a specific trait.

Genes and Proteins DNA contains the information that is needed by your body to make proteins. The different proteins have specific functions, such as making our hearts, hair, eyes and ears. The smallest part of proteins are amino acids. There are 20 amino acids. One or more can make up a protein, depending on the specific protein.

Genes and Proteins The bases adenine, thymine, guanine and cytosine are grouped in bundles of three and are the codes for specific amino acids For example, the three bases CCA form the code for the amino acid proline, and the bases AGC form the code for the amino acid serine. These groups of three bases are called codons

Genes and Proteins A long string of amino acids forms a protein. Therefore, each gene is usually a set of instructions for making a protein.

Proteins and Traits Proteins, which are long strings of amino acids that consist of groups of three bases, are found throughout our cells and cause most of the differences you can see among organisms.

Proteins and Traits Proteins act as chemical triggers and messengers for many of the processes within cells. Proteins help determine how tall you will grow, what colors you can see, and your hair texture. Proteins exist in almost a limitless variety and a single organism may have thousands of genes that code for thousands of proteins.

Help from RNA Another type of molecule that helps make proteins is called RNA Ribo Nucleic Acid. The job of the RNA is to help the DNA make proteins

RNA RNA is made in the nucleus on a DNA pattern. But it’s different from DNA --- it’s a half ladder with its rungs sawed in half. RNA has the bases A, C, G like DNA, but instead of thymine, it has a base called uracil (U)

The Making of Protein http://www. youtube. com/watch

How DNA Works: Mutations EQ: How do genes and chromosomes work together to determine an organism’s traits? https://www.youtube.com/watch?v=C8OL1MTbGpU&feature=share

Mutations Substitutions can sometimes happen in DNA Changes in the number, type or order of the bases on a piece of DNA is called a mutation

Types of Mutations Deletions : when a base is left out of a base sequence Insertions: when an extra base is added to a base sequence Substitutions: when the wrong base used in a sequence. Most common type

Consequences There are three possible consequences to changes in DNA: An improved trait No change harmful trait Fortunately, cells make some proteins that can detect errors in DNA and when an error is found, it is usually fixed. But occasionally the error is not detected or the repair does not work. If the mutation occurs in the sex cells, the gene can be passed through generations

How do mutations happen? Mutations happen regularly because of random errors when DNA is copied. In addition, mutations can happen when abnormal things happen to cells. Radiation from X-rays Ultraviolet radiation Cigarette smoke Asbestos exposure These agents of exposure are called mutagens.

Common Mutations in Humans Heterochromia-- eyes that have multiple colors in them. Distichiasis – double eyelashes Red Hair Blue eyes Freckles

Genetic Engineering Scientists can manipulate individual genes within organisms. This manipulation is called genetic engineering Genes are transferred from on type of organism to another. Used to create new products such as medicines, foods and fabrics

Genetic Information Your DNA is unique, so it can be used like a finger print to identify you. DNA can be used as evidence when solving a crime, to identify family relations or hereditary diseases. Identical twins have identical DNA.