18/02/2016 Science 30 Unit A: Biology – DNA DNA Review - DNA: Name: _______________ Date: _______________ - contains genetic code for making ______________ that make up organisms - found in ______________ - specific parts are called ________________ - makes a double-____________ shape DNA is made long chains of ____________________. Each nucleotide is made up of three parts (two of which never change)... - Deoxyribose (_____________) ____________________ ____________________ base Each and every nucleotide contains the sugar and phosphate. But the nitrogen base can be one of four molecules. The Four Nitrogen base pairs are: A - _________________ T - _________________ G - _________________ C – _________________ These four bases differ on each nucleotide. Note that the bases only bond (through hydrogen bonds) with one other base: Adenine always pairs with _____________________. (_______) Guanine always pairs with ____________________ (_______) From these four base pairs come all of the instructions for building the amino acids that make up the proteins that make up life. ex) Determine the complementary strand to ATTGCCGATGC. www.ldindustries.ca 18/02/2016 DNA Replication Recall that in both ____________ and _____________, DNA makes an exact ___________ of itself to start the cell division process. This replication is possible because of the structure of DNA. During DNA replication, the double helix _______________ (as the _____________ bonds between the base pairs break). The unzipped base pairs then pair up with ____________________ complementary base pairs, making two ________________ daughter copies of DNA. If you take any three of these base pairs, you get the instructions for the making a particular _________________________ (the building blocks of proteins which are the building blocks of pretty much everything else). We get a code-book to determine what each DNA triplet corresponds to: This table on page 13 of your data booklet lets you figure out what triplet codes for which amino acid. Note that some triplets tell where a particular _______ and _____: So that, when reading the gene, your body has a defined start and endpoint for each set of amino acids produced. Protein Mutations Most of the time, this process of replication works perfectly. But there can be __________ in the base pairs: this leads to mutations. Just one change in the DNA sequence can have significant effect. Some disorders in humans caused by genetic mutations include: - Hemophilia: inability to ______ blood Sickle-cell _____________ Huntington`s Disease: ______________ condition leading to motor impairment By knowing which parts of DNA code for which traits, scientists can sometimes cause _________________ mutations as well. This creates _____________________ DNA. This genetic engineering has led to genetically modified food: Gene Therapy - replacing a _______________ gene with a non-defective gene - e.g. Cystic fibrosis, hemophilia - Issues: How do we get the genes in the body and control them? Practice: page 115 1-4 www.ldindustries.ca 18/02/2016 www.ldindustries.ca