DNA and Modern Genetics Chapter 5C

D eoxyribo N ucleic A cid DNA is a molecule that stores information that a cell needs to function, grow, & divide. Proteins are large molecules that are made up of chains of amino acids.  Do most of the work of the cell and make up much of the structure of a cell  20 different amino acids combine to make up thousands of different proteins. DNA provides the code, or set of rules, for making proteins. **How do DNA and proteins work together??

Nucleotide Bases DNA is a double-stranded spiral, much like a twisted ladder. It is made up of four nucleotides:  adenine (A),  thymine (T),  cytosine (C), and  guanine (G).  Adenine pairs with thymine & cytosine pairs with guanine Genes are made up of a sequence of bases at a particular location on the DNA All Tigers Can Growl

D eoxyribo N ucleic A cid Before a cell divides, its entire DNA is copied in a process call replication. DNA separates into 2 strands.  Each strand is used as a template to produce a copy of the other strand Nucleotides in the area match up with the bases left & form 2 new strands

R ibo N ucleic A cid RNA, ribonucleic acid, is involved in making proteins. 3 types of RNA  Messenger RNA (mRNA): carries the information from DNA to a ribosome.  Ribosomal RNA (rRNA): forms the ribosome with other proteins.  Transfer RNA (tRNA): carries an amino acid and matches up to a complementary mRNA at the ribosome.

Transcription and Translation Transcription: the process of transferring information from DNA to RNA.  RNA base pairs: cytosine pairs with guanine & adenine pairs with uracil. Transcription VS. Replication  Only 1 strand of DNA is transcribed, producing a single strand of RNA  After transcription, RNA is released  Many copies of RNA can be made from the same gene Translation: the assembly of amino acids in their proper sequence according to the mRNA template.

D eoxyribo N ucleic A cid 46 chromosomes contain 6 billion base pairs of DNA. 99.9% of DNA in the cells of two different humans is the same. 0.1% variation in DNA makes a unique person. Errors can occur when DNA is copied.  Any change in DNA is called a mutation. This mutation can have no effect: each cell has 2 sets of DNA, even if one is mutated, the other may work fine minor effect: could affect physical appearance major effect: can cause genetic disorder  A genetic disorder is a disease or condition that results from mutations that affect the normal functioning of a cell.

Pedigree: a diagram of family relationships that shows two or more generations

What can we use DNA for? Selective breeding: process of selecting and breeding parent organisms to pass on particular traits to the offspring  People are not changing DNA, but causing certain alleles to become more common in a particular breed.  **How does selective breeding affect the DNA of a species? Genetic Engineering: process in which a sequence of DNA of another organism is first isolated, then inserted into the DNA of another organism, changing that organisms DNA  Example: plants, organic foods **What is one major difference between changing offspring through selective breeding and genetic engineering?

DNA Technology: DNA identification helps police establish if a criminal is guilty. Specialists can compare DNA evidence from a crime scene with DNA from a suspect to determine if the person was at the scene. Cloning is a technique that uses technology to make copies of DNA. Cloning has been used in bacteria to make proteins and drugs to fight disease.  In 1996, scientists successfully cloned the first mammal, a sheep named Dolly. All of her DNA came from a single body cell. Dolly lived for 6 years. **Why might the practice of cloning raise concerns about its future use?