Structure and Role of DNA http://www.youtube.com/watch?v=yiMhG-HAPew

Cells  DNA Organisms are made up of cells. All cells run on a set of instructions spelled out in DNA (Deoxyribonucleic Acid). Cells DNA

Deoxyribonucleic Acid is DNA. DNA is located in the nucleus in Eukarotes. DNA is free floating in the cytoplasm in Prokaryotes. Genetic information = instructions for making proteins Eukaryotic Cell nucleus cytoplasm

DNA Deoxyribonucleic Acid DNA is composed of: Nucleic Acids (1 of the 4 biomolecules). Each nucleic acid is made up of smaller units (monomers) called Nucleotides. Phosphate group Deoxyribose sugar Nitrogen bases Thymine Adenine Cytosine Guanine Nucleotide Deoxyribose sugar

The 4 Nitrogenous Bases: also known as Base Pairs Adenine Thymine Cytosine Guanine

DNA Deoxyribonucleic Acid DNA is shaped like a twisted ladder. This shape is called a double helix OR double stranded. Phosphate and deoxyribose sugar are the backbone of the double helix. The Nitrogen Bases are held together by Hydrogen Bonds. Nitrogen Base Sequencing: Adenine bonds with Thymine Guanine bonds with Cytosine Adenine Thymine Cytosine Guanine

The DNA winds up! DNA is loose in the cell nucleus.

DNA Sequencing Pair the following bases with the correct complementary base: T A C T T A C G T A A A

DNA A nucleotide is the monomer of a nucleic acid. Nucleic Acids are genetic material. What are the components of DNA? Phosphate Deoxyribose sugar Nitrogen Bases (A – T) and (G – C) 4. Which part of the nucleotide is known as the genetic code? The nitrogen bases 5. The structure of DNA is a double helix.

Structure of RNA Ribonucleic Acid

RNA Ribonucleic Acid RNA is composed of? RNA is found in the nucleus of cells. RNA travels from the nucleus of a cell to the ribosome in a cell. Nucleic Acids The monomer of a nucleic acid is a Nucleotide. Label the RNA nucleotide below: Ribose Sugar

RNA Ribonucleic Acid We will answer this question using the venn diagram on number 10. The 4 nitrogenous bases found in RNA are: Uracil bonds with Adenine Cytosine bonds with Guanine 9. RNA is single stranded. Whereas, DNA is double stranded.

RNA vs. DNA Use the following information to complete the venn diagram. ribose sugar nitrogen bases G, C, A, U U : A C : G single stranded DNA deoxyribose sugar nitrogen bases G, C, A, T T : A C : G double stranded

DNA  Cells  Bodies How does DNA code for cells & bodies? (how are cells and bodies made from the instructions in DNA.) DNA has the information to build proteins Genetic code DNA gets all the glory, Proteins do all the work

DNA has the information to build proteins. DNA  Proteins  Cells  Bodies DNA gets all the glory, Proteins do all the work

Protein Synthesis (Making Proteins)

How do proteins do all the work? Enzymes: are catalysts that speed up chemical reactions. Structure: all living organisms are built out of proteins.

Proteins chains of amino acids made by a “protein factory” in cytoplasm protein factory = ribosome nucleus cytoplasm build proteins (amino acids) ribosome

Passing on DNA information. How to get DNA (genetic information) from the nucleus to the cytoplasm? need a copy of DNA messenger RNA cytoplasm nucleus build proteins mRNA ribosome

Replication: How do cells make new copies of DNA for new cells? 1. When DNA needs to be copied, it unwinds in the nucleus 2. An enzyme, DNA Helicase, starts to “unzip” the DNA making a replication fork. 3. As DNA is unzipped, another enzyme, DNA Polymerase, begins to add nucleotides to the now exposed bases of the old strand. 4. The two new DNA strands recoil.

RNA Differs from DNA DNA has a sugar deoxyribose 1. RNA has a sugar ribose DNA has a sugar deoxyribose 2. RNA contains the base uracil (U) DNA has thymine (T) 3. RNA molecule is single-stranded DNA is double-stranded

DNA “codes” for Proteins,…….. But How? 1.Transcription occurs in the nucleus, but the Messenger RNA (mRNA) leaves the nucleus. 2. It attaches to a Ribosome which begins to read the mRNA 3. It reads three (3) letter words called Codons Example: An mRNA that attaches to the Ribosome A U C U G a A c A G a C g U a

Help comes from another type of RNA: Ribosome tRNA – Transfer RNA 1. Transfer RNAs have a group of three bases called the “anticodon” that is the compliment of the mRNA. (Draw the diagram to the right and label the “anticodon”) 2. Each tRNA carries a different Amino Acid: Example: ACG carries the amino acid “Threonine” 3. The process of reading the mRNA code and making Proteins is called: Translation U G C A C G Threonine

Translation 1. The Ribosome doesn’t just read the mRNA, it calls for Amino Acids for each Codon it reads. 2. The codon “U G C” calls for the Amino Acid Cysteine.

Translation U G C A C G 3. The Ribosome moves down the mRNA and calls for the next Amino Acid. 4. The first tRNA goes away when the second amino acid is attached to the first with a Peptide bond. 5. Then the Ribosome moves to the next Codon. U G C Cysteine Threonine

At the “STOP” codon, the ribosome releases the mRNA and the Amino Acid Chain. Proteins ALWAYS start with Methionine. Proteins ALWAYS end with stop.