Create a worksheet with DNA split in half. This is called unzipping the DNA. Draw a bold vertical line on the left side of the sheet of paper and draw 11 tags on the right side of the line in rows. Write a DNA letter for each tag as follows: CATGGGCTCCA. Then, draw another bold vertical line on the right of the other line and write each letter of the DNA on the left side of the line as follows: GTACCCGAGGT. These are your DNA bases strands that are unzipped and pulled apart.
Demonstrate the DNA molecules replication. Give each student 10 tags for each color. Demonstrate one example of how DNA copies itself. Have the student look at the right DNA strand and pick the top DNA base (G). Tell each student to hold a blue tag (G) and choose its complement which is the orange tag (C). Allow the students to do the same for both DNA strands. This will give the students an idea of how DNA molecules replicate itself. Each human chromosome contains millions of pairs.
Match DNA and RNA (ribonucleic acid) bases to make a mRNA strand for protein synthesis. Allow the students to look at the worksheet again. Have students concentrate on the right DNA strand of GTACCCGAGGT. Ignore the G above and the T below the strand. Only pay attention to:TACCCGAGG. Have each student pair the RNA bases: U, A, G and C with the DNA strand TACCCGAGG using tags. Remember uracil (U) replaces thymine (T) to complement (A). An RNA molecule transcribed from DNA is called messenger RNA (mRNA) which moves from the DNA and leaves the cell's nucleus.
Pair a tRNA anticodon to mRNA codon for protein synthesis. Have students create five tRNA anticodon. Each student will do as follows: staple (G)(C)(A) tags together to create arginine, (C)(A)(U) tags together to create valine, (U)(A)(C) tags together to create methionine, (C)(C)(G) together to create glycine and (A)(G)(G) together to create serine.
Create a horizontal line on the board and create a mRNA codon and then write the letters as follows in a row: (AUG), (GGC), (UCC). Have students match their tRNA tags with the mRNA pair on the board by placing their tags underneath the first three letters to see if their tags complement the first three letters in the row. Once a match is found, erase the first three letters. Then do the same for the next three letters. This demonstrates that ribosomes move to the right and then disappears, leaving behind a polypeptide chain.