Journal Entry 1 What do you know about

Journal Entry 1 • What do you know about DNA? • Tell me at least two things you know about DNA.

Journal Entry 2 • Draw a picture of DNA and label… Nucleotide adenine guanine cytosine thymine sugar phosphate hydrogen bond

Journal Entry 3 • Summarize and explain the process of DNA replication.

Chapter 10 Objectives By the end of this unit I will be able to… • Describe three parts of a nucleotide • Relate the role of base pairing rules to the structure of DNA • Summarize and explain the process of DNA replication

Chapter 10 Objectives By the end of this unit I will be able to… • Identify the role of enzymes in the replication of DNA • Outline the flow of genetic information in cells from DNA to protein • Compare the structure of DNA with that of RNA • Summarize the process of transcription.

Chapter 10 Nucleic Acids and Protein Synthesis

What is a nucleic acid? • A complex organic (carbon) macromolecule • DNA= Deoxyribonucleic Acid • RNA= Ribonucleic Acid

What are the two main functions of DNA? 1. To store information and to direct activities of the cell. -tells which proteins to make 2. To copy itself exactly for new cells that are created

What are DNA molecules made of? • • 1. 2. 3. Two strands of repeating nucleotides A nucleotide has three parts: Deoxyribose =a sugar Phosphate =PO 4 Nitrogen Base

What are DNA molecules made of? A= Adenine T= Thymine C= Cytosine G= Guanine Adenine and Guanine have two rings of carbon and are called Purines Thymine and Cytosine have one ring of carbon and are called Pyrimidines

What does the DNA molecule look like? • A twisted ladder (double helix) helical

What are the base pairing rules? • Adenine always bonds with Thymine • Cytosine always bonds with Guanine

Who discovered the structure of DNA? • In 1953 Francis Crick and James Watson • They proposed a model of DNA in which two nucleotide chains wrap around each other to form a double spiralsimilar to a spiral staircase • They called it a Double Helix

Who discovered the structure of DNA? • They relied heavily on scientific evidence reported by other scientists to construct their model. Evidence like the X-ray diffraction photo of DNA studied by Rosaline Franklin and Maurice Wilkins • Crick, Watson, & Wilkins received the Nobel Prize in Medicine in 1962

• http: //www. youtube. com/watch? v=4 PKj F 7 Oum. Yo

What is DNA replication and what happens during it? • The process of copying DNA in a cell is called replication.

What is DNA replication and what happens during it? 1. The two chains of DNA separate at the replication fork by enzymes called Helicase. They break the hydrogen bonds between the complementary base pairs.

What is DNA replication and what happens during it? 2. Enzymes called DNA Polymerase move down each half strands and binds the new nucleotides to the existing DNA chains.

What is DNA replication and what happens during it? 3. When replication is completed, two new exact copies of the original DNA molecule are produced and the cell is ready to divide.

What is a mutation? • A mistake in the nucleotide sequence at even one location will cause a mutation and can have serious effects in new cells. • Chemicals and ultraviolet radiation from the sun can damage DNA which can lead to cancer. • Enzymes called DNA polymerase are constantly proofreading and repairing errors that occur.

What are some differences between RNA and DNA? RNA DNA 1. 2. 3. 4. Sugar is ribose One strand Uracil Can be found in the nucleus or the cytoplasm Sugar is deoxyribose Two strands Thymine Can only be found in the nucleus

What are three kinds of RNA? 1. Messenger RNA 2. Transfer RNA 3. Ribosomal RNA

What is Protein Synthesis and where does it take place? • The making of proteins and it takes place on the ribosomes

How does Protein Synthesis occur? 1. Transcription- genetic information is copied from DNA to m. RNA 2. Messenger RNA’s code is in three base groups called codons 3. Codons attach to ribosomes and each one codes for an amino acid.

How does Protein Synthesis occur? 4. Translation- the process of assembling the protein from information encoded in Messenger RNA. This process begins when the m. RNA leaves the nucleus through pores in the nuclear membrane and then migrates to a ribosome.

How does Protein Synthesis occur? 5. Amino acids floating freely in the cytosol are transported to the ribosome by the t. RNA. 6. The t. RNA has a sequence of three nucleotides called an anti-codon which is complementary to and pairs with its corresponding codons.

Protein Synthesis • http: //www. dnai. org/a/index. html • Let’s watch this in action!

What joins the amino acids together to form a protein? • A peptide bond joins amino acids to make a polypeptide chain.

Where do the amino acids come from floating in the cytosol of our cells? • The food we eat (proteins)

What are some important proteins that we make? Functional Proteins 1. Hemoglobin -found in our red blood cells; function in carrying oxygen 2. Antibodies -help fight off viruses and bacteria that invade the body. 3. Enzymes -control chemical reactions in the body.

What are some important proteins that we make? Structural Proteins 1. Keratin -water proofing protein on our skin. 2. Actin and Myosin -proteins which make up our muscles 3. Collagen- found in cartilage and other connective tissue

The Human Genome • The Human Genome