Students often have difficulty understanding that the entire DNA code for an organism is located in almost every cell of the organism, but only the genes necessary to build the particular cell are utilized in the cell. The blueprint analogy has worked well to help clarify this concept.
Related concepts include gene expression, transcription, and translation. In fact, this simple explanation serves as a good introduction to the concept of gene expression.
- For print students, print a blueprint showing various types of rooms.
- For braille students, build a tactile drawing of several different rooms using the Wheatley kit.
- Find the “Cell Sizes and Shapes” from the APH Life Science Tactile graphics set.
- Explain what a blueprint is and provide large print images or tactile graphics, if possible. Tell students that blueprints are made by architects who design buildings and that they are used by builders to construct the different rooms in a building. As we recently moved into new buildings at TSBVI, I had a convenient real-life example to use.
- Considering different types of rooms in a school (classroom, lab, kitchen, gym, etc.), ask the students if they think the plans for these rooms will be the same. Students will understand that because the rooms are so different in both function and structure that the plans must be different.
- Ask the students to imagine that the blueprint for each type of room in the school is stored in every room (and not just the blueprint for that room). This is similar to what happens in the cells of living organisms. Almost every cell stores all of the “blueprints” to make all of the different types of cells that an organism has.
- Ask: “Where does a cell stores its DNA?” the nucleus of the cell
- Have the students think back to the blueprint analogy. Each specific room in the house has a plan designed just for it, but all of the plans are stored in each room. Only the correct blueprint is used by the builders to make each room.
- Introduce the tactile/LP image from the APH Life Science Tactile Graphics about different cell shapes and sizes. Ask the student to take a look at the human red blood cell, muscle cell, and nerve cell as they consider this question. Do they look like the same pattern was used to make them? Discuss.
- Ask the students to consider whether they think that all of the information from ALL of these “blueprints” in the cell is used for each cell type. No, this doesn’t make sense as their are so many cells in the human body with very different structure and function.
- Explain to the students that the manner by which the cell uses only the genes necessary for that particular kind of cell is called “Gene Expression”. This activity provides a good intro to Gene Expression including transcription and translation. Please see links to the following excellent APH kits utilized to teach Gene Expression:
If gene expression will be taught after this introduction, see links to the APH kits above.
- The APH DNA/RNA Kit can also be used to teach transcription.
- The Genetic Code Chart can also be used to teach translation.
Middle School – Growth, Development and Reproduction of Organisms
LS3.A: Inheritance of Traits
- Genes are located in the chromosomes of cells, with each chromosome pair containing two variants of each of many distinct genes. Each distinct gene chiefly controls the production of specific proteins, which in turn affects the traits of the individual. Changes (mutations) to genes can result in changes to proteins, which can affect the structures and functions of the organism and thereby change traits. (MS-LS3-1)
High School : Structure and Function
LS1.A: Structure and Function
- Systems of specialized cells within organisms help them perform the essential functions of life. (HS-LS1-1)
- All cells contain genetic information in the form of DNA molecules. Genes are regions in the DNA that contain the instructions that code for the formation of proteins, which carry out most of the work of cells. (HS-LS1-1)
High School – Inheritance and Variation of Traits
LS3.A: Inheritance of Traits
- Each chromosome consists of a single very long DNA molecule, and each gene on the chromosome is a particular segment of that DNA. The instructions for forming species’ characteristics are carried in DNA. All cells in an organism have the same genetic content, but the genes used (expressed) by the cell may be regulated in different ways. Not all DNA codes for a protein; some segments of DNA are involved in regulatory or structural functions, and some have no as-yet known function. (HS-LS3-1)
By Laura Hospitál
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