DNA! DNA! DNA!  Catalyst:  What is a trait?  How are traits related to genes?  What are genes made out of?  Where is DNA stored in a eukaryotic cell? How is this different from where DNA is stored in a prokaryotic cell? Write in complete sentences! Don’t talk during the Catalyst!

Have you ever wondered…  How the genetic code in DNA actually tells your body what to do?

Objectives By the end of today, SWBAT…  Describe the structure and function of a DNA molecule

Agenda  Catalyst  DNA, Gene, Chromosome review  Figure it out yourself  Rules of Base Pairing  Exit Question

Trait  What is a trait?  Characteristic of an organism  How are traits related to genes?  Genes codes for traits!  Where are genes made of?  DNA  Where is DNA located?  Eukaryotic: in the nucleus  Prokaryotic: in the cytoplasm

Peep this Picture  Think-Pair-Share  Think for 30 seconds, turn to your neighbor and explain what this picture shows

Remember  Chromosomes are made of genes. Genes are made of DNA.  CHROMOSOMES  GENES  DNA

Remember also  Genes code for proteins, while proteins cause traits.  GENE  PROTEIN  TRAIT

Question  Key Point #1:  Genes are codes for proteins. The function of DNA is to store the instructions for how to make proteins.  DNA is the code for making proteins!  DNA is the code for making proteins!!  DNA is the code for making proteins!!!

Figure it out YOURSELF! (15 mins)  You each have a picture of the structure of DNA.  On the bottom of the sheet, make AS MANY observations about the DNA as you can.  You should be able to come up with at least 3  On the back side, fill in the other half of the DNA molecule.

Nucleotides  Key Point #2:  DNA is made up of two strands of nucleotides.  A nucleotide is a unit of DNA.  Sugar and phosphate make up the backbone of DNA. The nitrogenous bases is the code.

Identify parts!  Where is the backbone?  Where are the nitrogenous bases? What do they do?  Where is one nucleotide?

DNA  Key Point #3:  DNA has two strands twisted into a double helix. These strands are complimentary to each other.  What did you notice about the pairings? What letters go with what letters?  Adenine (A) ALWAYS pairs with Thymine (T) and Guanine (G) ALWAYS pairs with Cytosine (C).

Guided Practice 1 One strand of DNA has the nitrogenous bases of GCTAATCG What is the complimentary strand of DNA? CGATTAGC

Guided Practice 2 One strand of DNA has the nitrogenous bases of TTAGGCAC What is the complimentary strand of DNA? AATCCGTG

Guided Practice 3  Where is the chromosome?  Where is the gene?  Where is the double helix?

Guided Practice 4  Fill in these terms:  ________________ is made of units called nucleotides.  ________________ are coiled pieces of DNA.  ________________ are sections of chromosomes. DNA Chromosomes Genes

Guided Practice 5  Fill in these terms:  One trait is determined by a _________________.  A gene contains the instructions for making a _________. gene protein

Guided Practice 6 Label the three parts of a nucleotide. phosphate sugar nitrogenous base

Guided Practice 7  What color is the backbone of the DNA molecule?  The backbone of DNA is made of ____________ and ___________.  If purple is Adenine (A) and Guanine (G) is red, then Cytosine (C) must be __________ and Thymine (T) must be ______________. sugarphosphate green yellow

Key Point Wrap-Up  Key Point #1: Genes are codes for proteins. The function of DNA is to store the instructions for how to make proteins.  Key Point #2: DNA is made up of two strands of nucleotides. Sugar and phosphate make up the backbone of DNA. The nitrogenous bases is the code.  Key Point #3: DNA’s strands are twisted into a double helix. These strands are complimentary to each other.  Adenine (A) ALWAYS pairs with Thymine (T) and Guanine (G) ALWAYS pairs with Cytosine (C).

Exit Question  Write the complimentary base sequence to this DNA sequence:  AGTCATGATCCGATAGAA  Order chromosome, DNA, and gene from largest to smallest. Write in complete sentences! Don’t talk during the Exit Question!