August 18, 2015 Bell Work:  What is the purpose of DNA replication? Objective: The student will be able to… 1. Demonstrate his or her knowledge of DNA structure and replication by completing a quiz. 2. Describe the process of transcription.

Today in History  1587 Virginia Dare became the first child of English parents to be born on American soil, on what is now Roanoke Island, NC.  1846 U.S. forces led by Gen. Stephen W. Kearny captured Santa Fe, NM.

DNA Quiz

Crash Course Biology

Proteins  A large molecule formed by linked smaller molecules called amino acids  Amino acids are the building blocks to proteins  There are twenty different amino acids  Some are polar, some are non-polar

Proteins  Some are electrically charged  Proteins fold into compact shapes that determined by how the protein’s amino acids interact with water and each other

Proteins  Functions of proteins:  Enzymes  Catalysts (promote chemical reactions)  Structural proteins  Antibodies  Specialized functions: cell membrane channels, carrying oxygen

Proteins are formed by ___. A. Cells B. Amino Acids C. Carbon D. Nitrogen

Decoding Information in DNA  Traits are built according to instructions in DNA  Traits are determined by proteins  Proteins are not built directly by DNA

How are traits determined? A. RNA B. DNA C. Proteins D. All of these

RNA  RNA (Ribonucleic Acid): a nucleic acid- a molecule of nucleotides linked together  Different from DNA in three ways  Consists of a single strand of DNA  Contain the five carbon sugar ribose  Contains the nitrogen base uracil  No thymine bases are found in RNA  Uracil is the complementary base to adenine

Compare and Contrast DNA and RNA

RNA  Transcription: the process of synthesizing RNA by using one strand of DNA as a template  Translation: the process of protein synthesis that takes place at ribosomes and that uses the codons in mRNA molecules to specify the sequence of amino acids in polypeptide chains

RNA stands for ___. A. Deoxyribonucleic Acids B. Amino Acids Chains C. Polypeptides D. Ribonucleic Acids

Which base if found in RNA but not DNA? A. Uracil B. Cytosine C. Thymine D. Adenine

Transfer of Information  Gene expression: the entire process of by which proteins are made based on the information encoded in DNA  Also known as protein synthesis

Transfer of Information  The first step of making a protein is transferring information from a gene in DNA to a molecule of RNA  This is known as transcription  Transcription: the process in which instructions for making a protein are transferred from a gene to a molecule of RNA  RNA polymerase is required for transcription

Transcription 1. Begins when RNA polymerase binds to the gene’s promoter  A promoter is a specific sequence of DNA that acts as a “start” signal for transcription 2. RNA polymerase unwinds and separates the two strands of the double helix, exposing the DNA nucleotides on each strand. 3. RNA polymerase adds then links complementary nucleotides  Follows the base pairing rules: cytosine/guanine and adenine/uracil

Transcription  This process continues until the RNA polymerase reaches a “stop” gene.  The stop signal is:  A sequence of bases that marks the end of each gene in eukaryotes  A sequence of bases that marks the end of each set of genes in prokaryotes

Transcription  When RNA nucleotides are added during transcription they are linked together with covalent bonds  Behind RNA polymerase, the two strands of DNA close by forming hydrogen bonds between the complementary bases reforming the double helix

Transcription  Uses DNA nucleotides as a template for making a new molecule  In transcription, a part of one strand of DNA (a gene) serves as a template  In DNA replication both strands of DNA serve as a template  Occurs in the cytoplasm of prokaryotes (prokaryotes do not have a nucleus)

Transcription  Occurs in the nucleus of eukaryotic cells  Many identical RNA molecules are made simultaneously from a single gene

Ticket Out  List two ways RNA is different from DNA.