DNA Notes - Cornell Style PDF

Topic: DNA & DNA Replication EQ: How does DNA control cell activities and cell function? Learning Targets: 1. Explain how the structure of DNA allows for its function of inheritance. 2. Draw and explain the relationships among DNA, genes, and chromosomes. 3. Create a model that explains...

Topic: DNA & DNA Replication EQ: How does DNA control cell activities and cell function? Learning Targets: 1. Explain how the structure of DNA allows for its function of inheritance. 2. Draw and explain the relationships among DNA, genes, and chromosomes. 3. Create a model that explains how and why cells copy DNA before mitosis. Date: DNA (Deoxyribonucleic Acid) Structure of DNA o Nucleotide- building blocks of DNA a. Deoxyribose sugar (Side of ladder) b. Phosphate (Side of ladder) c. Nitrogen Base – 4 types (Rungs of ladder) Adenine Thymine Guanine Cytosine o Nitrogen base pairs- two nitrogen bases bond to form the rungs of the ladder (each is bonded with a deoxyribose sugar, as well) ▪ Adenine and Thymine bond together ▪ Cytosine and Guanine bond together ▪ Base pairs are held together with hydrogen bonds o Nucleotides form the double helix (twisted ladder) ▪ Order and # of bases makes organisms different  Function of DNA- molecule that contains heredity information o DNA contains sections of nucleotides called genes o Each gene has the information to make a protein o Proteins do a wide variety of jobs within cells (ex: enzymes, transport proteins, cellular respiration proteins, structural proteins, hormones, antibodies, etc.) DNA Packaging – DNA molecules are long “strands” or molecules in eukaryotic organisms. To fit in cells, they must be wrapped around proteins called histones. o Chromatin- “Long and thin” ▪ Less coiled DNA in a non-dividing cell ▪ Can be “unzipped and read” to make a new protein ▪ Not visible in nucleus o Chromosomes ▪ Coiled up strand of DNA in a dividing cell ▪ Compact strands line up and move apart- so they don’t tangle ▪ Visible in cell (no nuclear membrane) DNA Replication Definition – process by which a full copy of DNA is made in a cell. Why important – needed when organisms make new body cells through mitosis. Each cell needs a full set of DNA. Process- 1. Helicase breaks hydrogen bonds between the complementary base pairs 2. DNA Polymerase complementary base pairs new nucleotides to the exposed nucleotides of each strand of the DNA molecule 3. Steps 1 & 2 continue until the entire molecule is copied. Each DNA molecule is made of one parent (“old”) strand and one daughter (“new”) strand. Summary: