UTPA STEM/CBI Courses/Introduction to STEM/DNA Extraction

Course Title: Introduction to STEM

Lecture Topic: DNA Extraction

Instructor: Javier Macossay

Institution: University of Texas - Pan American

Backwards Design

Course Objectives

• Primary Objectives- By the next class period students will be able to:
  • Possess a basic understanding of the DNA structure.

• Sub Objectives- The objectives will require that students be able to:
  • Understand the presence of DNA in living organisms.
  • Learn how to isolate DNA from onions.

• Difficulties- Students may have difficulty:
  • Students will encounter problems understanding the DNA structure.
  • Students will encounter problems performing some of the laboratory techniques.

• Real-World Contexts- There are many ways that students can use this material in the real-world, such as:
  • DNA is a large organic molecule that is responsible for genetic information. Furthermore, errors in the DNA structure can generate diseases (from genetic to cancer).

Model of Knowledge

• Concept Map
  • Learn the structure of DNA.
  • Understand the importance of DNA in life and how its alterations can cause diseases.
  • Isolation of DNA from onion cells.
  • Use of laboratory techniques to grind onion cells, which will permit DNA extraction.
  • Use of laboratory techniques to isolate DNA from other organic materials present in onions and their cells.

• Content Priorities
  • Enduring Understanding
    • Understand the importance of DNA in life.
  • Important to Do and Know
    • Learn the structure of DNA.
  • Worth Being Familiar with
    • Learn the isolation technique of DNA.

Assessment of Learning

• Formative Assessment
  • In Class (groups)
    • Discussion of the importance of DNA in life.
    • Discussion of the DNA structure.
    • Discussion of individual laboratory procedures.
    • Discussion of results and conclusions.

• Homework (individual)
  • Internet based search of DNA.
  • Internet based search of the DNA structure.
  • Isolation technique of DNA from different organisms.
  • Analysis of data and interpretation

• Summative Assessment
  • Discussion of their conclusions in front of the group.

Legacy Cycle

LOOK AHEAD AND REFLECT BACK

• Goals
  • Students should be able to understand the interaction between science and technology and real world applications and impact.
• Objectives
  • Students should learn the structure of DNA and understand its importance in genetics and life.

THE CHALLENGE As a successful researcher, you have been asked to decode the DNA structure of onions seeded and harvested in South Texas. After you have isolated the DNA, its sequence will be decoded and compared against onions from other parts of the USA. Your studies will allow understanding and correlating the medicinal effects that onions consumed in South Texas have to prevent diseases. Therefore, your initial task in this important project will be to isolate DNA, how do you do it?

GENERATE IDEAS

• Students will research independently the DNA structure.
• Students will research independently the role of DNA in life.
• Students will investigate how to isolate DNA.

MULTIPLE PERSPECTIVES students will discuss their ideas through brain storming before performing the experiment.

RESEARCH & REVISE students will learn how to interpret laboratory data and draw conclusions based on their experiments’ results.

TEST YOUR METTLE students will compare their results against their peers’ observations.

GO PUBLIC students will discuss among themselves and in front of the class their results.

LOOK AHEAD AND REFLECT BACK based on students’ conclusions and interpretations, the experiment could be expanded into using different types of vegetables. This will also allow the students to learn the similarities and differences between DNAs from different sources.

Test Your Mettle Quiz

True or False? (50 points)

1. Water is an active chemical in sunscreens

2. Hydroxyacetone is an active chemical in sunscreens

3. The mechanisms of action in sunscreens are absorption and dispersion

4. Ethyl alcohol is an active chemical in sunscreens

5. Paraben is an active chemical in sunscreens

6. Zinc oxide is an active chemical in sunscreens

7. Mineral oil is an active chemical in sunscreens

8. The acronym PF means protection factor

9. Different sunscreen formulations might contain different chemicals but work as effective as one another

10. Hydroxyquinone is an active chemical in sunscreens

Multiple choice (50 points)

11. UV sensitive beads are a good way to test sunscreen lotions because:

a) Beads are not useful

b) Beads do contain sunscreen lotion already

c) Beads contain UV-sensitive dyes

d) Beads interact with UV radiation

e) More than one of the above

12.- UV sensitive beads change colors at the same rate (time) under the sun and in the lab, because:

a) It does not matter, UV radiation will reach the beads

b) The statement is not true, the beads change faster under the sun

c) The beads will change colors regardless of where they are placed

d) The statement is not true, the beads change faster in the lab

e) None of the above

13.- Sunscreen lotions DO retard the time it takes the beads to change colors because:

a) No difference was observed experimentally with or without the use of sunscreen lotions

b) Lotions contain inactive chemicals that interact with radiation

c) Lotions contain active chemicals that interact with radiation

d) Lotions did not retard the time in any case

e) More than one of the above

14. Higher PF values ALWAYS results in lower UV absorption by the beads (longer times for the beads to change colors)

a) The statement is true

b) The statement is true for some PF values, but after a certain value, there is no difference

c) The statement is not true

15. Can the information learned in these experiments be used to understand how to prevent skin cancer?

a) Yes, because UV sensitive beads can be viewed as the skin

b) Yes, because the skin reacts with UV radiation similar to the way the beads react

c) No, because you cannot compare plastic beads to human skin

d) No, because the mechanisms of interaction between UV-beads and UV-skin are quite different

e) More than one of the above