Materials Agenda Notebook Pen/Pencil Packet Cell Book-74 01/12/2015- NO GUM PLEASE! Materials Agenda Notebook Pen/Pencil Packet Cell Book-74 Agenda Daily question DNA PPT Brain pop Objective: Today we will learn about DNA, RNA, and protein Synthesis Daily Question: What does DNA stand for?

DNA STRUCTURE EACH CELL IN YOUR BODY CONTAINS DNA…BUT WHAT IS IT? WHAT DOES IT LOOK LIKE?

What is DNA? DNA- Deoxyribonucleic acid stores and passes on genetic information within cells from one generation to the next James Watson, Francis Crick, Maurice Wilkins, and Rosalind Franklin are three of the scientists credited with the discovery of the structure of the DNA molecule.

What does DNA look like? What do you think?

What is DNA made up of? The sides are made up of deoxyribose sugar and phosphates. The rungs (steps) are formed by pairs of nitrogen bases

What is DNA made up of? The sugars are chemicals on the outside of the double helix that hold the bases together Phosphates are the chemicals that join the sugars together

What is DNA made up of? There are 4 nitrogen bases in DNA: Adenine (A) Guanine (G) Cytosine (C) Thymine (T) Adenine always pairs with Thymine Cytosine always pairs with Guanine

What is a Nucleotide A unit of DNA that consists of: 1 nitrogen base 1 deoxyribose sugar 1 phosphate

Different Forms of DNA Chromatin- thread like chains of uncoiled DNA Chromosome- rod-shaped coils of chromatin Gene- the basic unit of heredity that consists of a segment of DNA on a chromosome

The Master Molecule of Life DNA The Master Molecule of Life

THE DNA MOLECULE DNA-Deoxyribonucleic acid- stores and passes on genetic information from one generation to the next Many scientists believe that the discovery of the structure of DNA was the most important biological breakthrough of the 20th century James 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

The Structure of DNA The DNA molecule looks like a twisted ladder, or spiral staircase The 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 bases The sugars are chemicals on the outside of the double helix that hold the bases together Phosphates are the chemicals that join the sugars together There are 4 nitrogen bases in DNA: Adenine (A) Thymine (T) Guanine (G) Cytosine (C)

THE Structure of DNA (cont) The order of these substances on the DNA molecule determines what type of gene it is. Adenine always pairs with Thymine Cytosine always pairs with Guanine The order of the nitrogen bases on a DNA molecule determines the particular genes on a chromosome The genetic code is actually the order of nitrogen bases on the DNA molecule (ACGGTTCAAG) for example

A Diagram of the DNA molecule

DNA Replication

When does DNA Replication occur? Before Mitosis begins- Interphase Cell Division: Stage1- Interphase

Why 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 cell DNA (genetic information) Forming daughter cell DNA (genetic information)

Structure of DNA Sides (DNA Ladder) Rungs (DNA Ladder) Phosphate Sides (DNA Ladder) Alternating molecules of Deoxyribose sugar Phosphate Rungs (DNA Ladder) Made up of pairs of nitrogen bases adenine thymine cytosine guanine Deoxyribose sugar Nitrogen base

Ladder Rungs Letters A, T, G, C Used to represent the four bases that make up ladder’s rungs Nitrogen 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 Base Nitrogen base

Pairing pattern of the nitrogen bases key to understanding how DNA replication occurs.

Replication Process Step 1: Two sides of the DNA molecule unwind and separate between paired nitrogen bases on each rung. Like a zipper unzipping

Replication Process Step 2: Nitrogen bases floating in nucleus pair up with bases on each half of the DNA molecule. A always pairs with T G always pairs with C

Replication 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.

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