DNA Chapter 8 Section 3 p

A. DNA A Chemical that contains the information that an organism needs to grow and functionA Chemical that contains the information that an organism needs to grow and function

1. Watson and Crick made the first accurate model of DNA in Watson and Crick made the first accurate model of DNA in A. DNA

2. The Structure of DNA is similar to a Twisted Ladder (a double helix)2. The Structure of DNA is similar to a Twisted Ladder (a double helix) A. DNA

A. DNA 2.The Structure of DNA is similar to a Twisted Ladder (a double helix) a. The sides of the ladder are made up of sugar-phosphate moleculesa. The sides of the ladder are made up of sugar-phosphate molecules

a. The sides of the ladder are made up of sugar- phosphate molecules b. The rungs of the ladder are made up of nitrogen basesb. The rungs of the ladder are made up of nitrogen bases A. DNA 2.The Structure of DNA is similar to a Twisted Ladder (a double helix)

There are 4 Nitrogen Bases that make the Rungs (steps) of the ladder –There are 4 Nitrogen Bases that make the Rungs (steps) of the ladder – –IN DNA, –Adenine always bonds to Thymine –Guanine always bonds to Cytosine A. DNA 2.The Structure of DNA is similar to a Twisted Ladder (a double helix)

3. Before a Cell divides, its DNA duplicates itself by unwinding and separating its sides, then forming new sides. A. DNA 2.The Structure of DNA is similar to a Twisted Ladder (a double helix)

B. Genes Sections of DNA on a chromosomeSections of DNA on a chromosome

B. Genes 1. Contain instructions for making specific proteins1. Contain instructions for making specific proteins

B 2. RNA Carries the codes for making proteins from the nucleus to the ribosomes in the cytoplasmCarries the codes for making proteins from the nucleus to the ribosomes in the cytoplasm Three types: –Messenger RNA (mRNA) –Transfer RNA (tRNA) –Ribosomal RNA (rRNA)

B 2. RNA There are 4 Nitrogen Bases that make the Rungs (steps) of the ladder –There are 4 Nitrogen Bases that make the Rungs (steps) of the ladder – –IN RNA, –Adenine always bonds to Uracil –Guanine always bonds to Cytosine

B 2. RNA 2a. Messenger RNA (mRNA) copies the code that directs the order in which the Amino acids bond2a. Messenger RNA (mRNA) copies the code that directs the order in which the Amino acids bond

2b. Ribosomal RNA makes up the ribosomes where the proteins are built2b. Ribosomal RNA makes up the ribosomes where the proteins are built B 2. RNA

2c. Transfer RNA brings amino acids to the ribosomes to build the proteins2c. Transfer RNA brings amino acids to the ribosomes to build the proteins B 2. RNA

3. Cells use only the genes that direct the making of proteins needed by that cell3. Cells use only the genes that direct the making of proteins needed by that cell B. Genes

A theatrical example: DNA is like letters that make upDNA is like letters that make up Genes which are like words or sentences which make upGenes which are like words or sentences which make up Chromosomes like paragraphs or chapters which work together withChromosomes like paragraphs or chapters which work together with All the Chromosomes which makes the script of the play that is YOU!All the Chromosomes which makes the script of the play that is YOU!

C. Mutations Any permanent change in the DNA sequence of a cell’s genes or chromosomesAny permanent change in the DNA sequence of a cell’s genes or chromosomes

1. Can be caused by outside factors like x-rays, Sunlight, and some chemicals.1. Can be caused by outside factors like x-rays, Sunlight, and some chemicals. C. Mutations

2. A change in a gene or chromosome can change the traits of an organism.2. A change in a gene or chromosome can change the traits of an organism. C. Mutations