DNA: The Molecule of Heredity Bio. B. 1. 2 DNA: The Molecule of Heredity Bio.B.1.2.1 Describe how the process of DNA replication results in the transmission and /or conservation of genetic information.

DNA Determines an Organisms Traits DNA controls the production of proteins All actions like eating, running and thinking depend on proteins called enzymes Enzymes control the chemical reactions needed for life Within the structure of DNA are the instructions for manufacturing proteins

DNA is a polymer composed of many repeating subunits called nucleotides Nucleotides are made of three parts: a simple sugar – deoxyribose 2. a phosphate group – 1phosphorous atom bonded to 4 oxygen atoms 3. a nitrogen base – either adenine(A), cytosine(C), thymine(T) or guanine(G)

Purines and Pyrimidines Single – ring bases: Thymine and Cytosine Double – ring bases: Adenine and Guanine

The phosphate groups and deoxyribose molecules bond covalently forming the backbone of the DNA chain

DNA- Double Helix (twisted zipper) Complimentary base pairs: A&T C&G Like teeth on a zipper, nitrogen bases hold the two strands of DNA together with hydrogen bonds

DNA Replication Two strands separate: Hydrogen bonds between the nitrogen bases are broken 2. Free nucleotides bond with exposed nucleotides

DNA Replication Replication of DNA is semi-conservative. That is, one side of each new DNA strand is "old" and the other side is "new".

Enzymes in Action Helicase – “unzips” DNA DNA polymerase – Adds new DNA nucleotides DNA ligase – bonds new nucleotides into a chain

Three Functions of DNA: ?Error Store Information- cell may not be able to make all the materials needed. Copy Information- cell would have a faulty code & may not have all the information needed to function. Transmit Information- offspring may not get all the information needed to function.

How is DNA Like a Book? 1. DNA & Books contain information. 2. DNA & Books can be copied. 3. Each copy has the same information as the original.

Nucleotide Sequences The sequence of every three nucleotides forms the unique genetic information that is transcribed into a codon. Each codon is translated into an amino acid. A-T-T-G-A-C carries different information than T-C-C-A-A-A

Central Dogma Big Idea: Complementary Base Pairing: A-T, C-G and a Universal Genetic Code ensure that genetic information is conserved from DNA replication through transcription and translation.

The closer the relationship between two organisms, the greater the similarities in the order of DNA nucleotides. DNA is what makes us unique as individuals and as the human species, and yet DNA also illustrates how connected we are to all other living organisms.