Prior Knowledge (Anticipation Guide): DAY 1
• Identify what students already know about DNA from earlier previous grade(s)
i. What is DNA?
1. DNA is the material that makes up chromosomes
2. Deoxyribonucleic acid
3. Genetic material
ii. What is the function of DNA?
1. Controls inherited traits
2. Contains the genetic instructions used in the development and functioning of living organisms
iii. What is the structure of DNA?
1. It is a double helix, like a spiral staircase
2. Contains two strands running in opposite direction (anti-parallel)
Inform students they will learn more about DNA in this lesson.
Lesson Steps (2 days or 2 x 60 min classes)
DAY 2 (following anticipation guide)
• Review genes, chromosomes, and inherited traits
- Visit http://learn.genetics.utah.edu/content/begin/tour/
• Ask students to compare the structures of DNA (Figures 1 and 2)
• Ask for volunteer(s) to explain how the two figures are related to one another
- Figure 2 shows larger, more detailed version of a short section of the DNA molecule that is shown in Figure 1
- Make sure students can identify the sugar-phosphate backbones and bases in each figure
- Review the rules for base pairing (adenine or A always bonds with thymine or T; guanine or G always bonds with cytosine or C).
- In Figure 2, point out the hydrogen bonds that hold together complementary base pairs in the two DNA strands so students will understand why adenine always bonds with thymine and guanine always bonds with cytosine.
• Play for students animated movie clips from YouTube on the structure of DNA:
- http://youtu.be/cwfO6SzGaEg: DNA: Key to Life Clip (1:29)
- http://youtu.be/qy8dk5iS1f0: DNA Structure (1:20)
- http://youtu.be/N8B7zdmPL8w: 3D View of DNA Model Animation (5:00)
- http://youtu.be/d0S9qsgIg3E: DNA Atomic Structure Animation (1:20)
• Start class with a cool animation video demonstrating The Central Dogma of Biology
- http://youtu.be/J3HVVi2k2No: The Central Dogma (10:48)
• Summarize with students what they covered last day on the Structure of DNA
• Use Figure 3 to explain how DNA replication occurs.
- Have students find each enzyme or other structure in the figure as you describe its role in replication.
- Emphasize to students how the lagging strand is built.
- Describe all the steps of replication aloud to the students.
- Call on volunteers to summarize the entire process in their own words and ask students
- Ask students to summarize the DNA Replication process in their own words in their notes.
- Emphasize for students and make sure they understand that the end result of DNA Replication is a pair of identical DNA molecules, each of which incorporates one strand of the original DNA molecule.
• Introduce RNA Structure to students
- Hand out Figure 4 to students, showing A) RNA strand for ribonucleic acid; point out that it is single stranded unlike DNA; and has Uracil instead of Thymine as one of its bases. B) RNA curls up on itself forming a double- and single-stranded regions.
- Point out that looped-hairpin structures form because of the double-stranded regions
- Show a larger, more detailed version of a short section of the RNA molecule that is shown in Figure 4 (Figure 5 handout); point out that one nucleotide consists of a phosphate, base, and the sugar ribose; and that base in RNA is uracil (U) instead of thymine (T)
- Show YouTube video presentation comparing DNA and RNA structures:
• Ask students to pair up and make a Venn diagram comparing and contrasting the structure and function of DNA and RNA
- Students should use Table 1 and Figure 5 as a guide.