1Materials Agenda Notebook Pen/Pencil Packet Cell Book-74 01/12/2015- NO GUM PLEASE!Materials Agenda Notebook Pen/Pencil Packet Cell Book-74AgendaDaily questionDNA PPTBrain popObjective: Today we will learn about DNA, RNA, and protein SynthesisDaily Question: What does DNA stand for?
2DNA STRUCTUREEACH CELL IN YOUR BODY CONTAINS DNA…BUT WHAT IS IT? WHAT DOES IT LOOK LIKE?
3What is DNA? DNA- Deoxyribonucleic acid stores and passes on genetic information within cells from one generation to the nextJames Watson, Francis Crick, Maurice Wilkins, and Rosalind Franklin are three of the scientists credited with the discovery of the structure of the DNA molecule.
11The Master Molecule of Life DNAThe Master Molecule of Life
12THE DNA MOLECULEDNA-Deoxyribonucleic acid- stores and passes on genetic information from one generation to the nextMany scientists believe that the discovery of the structure of DNA was the most important biological breakthrough of the 20th centuryJames Watson, Francis Crick, and Maurice Wilkins are three of the scientists credited with the discovery of the structure of the DNA molecule.They discovered that chromosomes are made up of long strands of DNA molecules. It is the DNA molecules in chromosomes that make up genes.A gene is the basic unit of heredity that consists of a segment of DNA on a chromosome
13The Structure of DNAThe DNA molecule looks like a twisted ladder, or spiral staircaseThe sides of the ladder are made up of molecules of the sugar deoxyribose and phosphate groups. The rungs of the ladder are formed by pairs of substances called nitrogen basesThe sugars are chemicals on the outside of the double helix that hold the bases togetherPhosphates are the chemicals that join the sugars togetherThere are 4 nitrogen bases in DNA:Adenine (A) Thymine (T)Guanine (G) Cytosine (C)
14THE Structure of DNA (cont) The order of these substances on the DNA molecule determines what type of gene it is.Adenine always pairs with ThymineCytosine always pairs with GuanineThe order of the nitrogen bases on a DNA molecule determines the particular genes on a chromosomeThe genetic code is actually the order of nitrogen bases on the DNA molecule (ACGGTTCAAG) for example
17When does DNA Replication occur? Before Mitosis begins- InterphaseCell Division: Stage1- Interphase
18Why is DNA Replication an important cell process? Ensures that each daughter cell will have all of the genetic information it needs to carry out its activities.Forming daughter cellDNA (genetic information)Forming daughter cellDNA (genetic information)
19Structure of DNA Sides (DNA Ladder) Rungs (DNA Ladder) PhosphateSides (DNA Ladder)Alternating molecules ofDeoxyribose sugarPhosphateRungs (DNA Ladder)Made up of pairs of nitrogen basesadeninethyminecytosineguanineDeoxyribose sugarNitrogen base
20Ladder Rungs Letters A, T, G, C Used to represent the four bases that make up ladder’s rungsNitrogen bases on one side of ladder “match up” in specific way with bases on the other side.Adenine always pairs with Thymine (A-T)Guanine always pairs with Cytosine (G-C)Nitrogen BaseNitrogen base
21Pairing pattern of the nitrogen bases key to understanding how DNA replication occurs.
22Replication Process Step 1: Two sides of the DNA molecule unwind and separate between paired nitrogen bases on each rung.Like a zipper unzipping
23Replication Process Step 2: Nitrogen bases floating in nucleus pair up with bases on each half of the DNA molecule.A always pairs with TG always pairs with C
24Replication Process Step 3: Once new bases are attached, two new DNA molecules formed.Order of bases in each new DNA molecule exactly matches the order in the original molecule.