Chapter 3- Section 4 The DNA Connection



Chapter 3- Section 4 The DNA Connection/Protein Synthesis

AGENDA Mon. April 16, 2007

STUDENTS

1. Warm up

2. Review DNA Replication

3. Read pp. 91-96 The DNA connection

4. DNA connection Lecture

CALIFORNIA STATE STANDARDS

1.0, 1.a, 1.c, 2.0, 2.b, 2.c, 2.d, 2.e, 7.0, 7.c, 7.d, 7.e

OBJECTIVES

• Explain the term genetic code

• Describe the process by which a cell produces proteins

• Describe different types of mutations and how they affect an organism.

TEACHER

1. Warm up

a. Define the following words:

i. Messenger RNA

ii. Transfer RNA

2. The DNA Connection Lecture

a. Overhead transparenies

Title: The DNA Connection

|Main Ideas |Notes |

|What are the 4 nitrogen bases found in DNA? |“A” (adenine) joins with “T” (thymine) |

| |“C” (cytosine) joins with “G” (guanine) |

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|What is important about the order of nitrogen bases? | |

| |The order of the nitrogen bases along the DNA form a genetic code that specifies the type of |

| |amino acid to be produced. |

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| |Amino Acids are the building blocks of proteins. There are 20 amino acids. |

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| |3 nitrogen bases code for 1 amino acid. |

|How many nitrogen bases code for an amino acid? |For example, think of it as THREE letter words: |

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| |dogheryouhimcat |

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| |These words ALL mean something different. |

| |If there was a mistake made in the sequence, the cell can produce proteins that should not |

| |appear or make any sense. |

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|What are these nitrogen base mistakes called? |These mistakes are called |

| |MUTATIONS. For example: |

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| |dogherrouhimcat (1 mutation) |

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| |dogherryouhimca(3 mutations) |

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Agenda- Tue April 17, 2007

STUDENTS

1. Warm up

2. Protein Synthesis lecture

AGENDA – Wed April 18, 2007 and Thurs April 19, 2007

Protein Synthesis Lesson Plan

|California State Standards: |

|7th grade Life Science |

|All living organisms are composed of cells, from just one to many trillions, whose details usually are visible only through the microscope. |

|1.c The nucleus is the repository for genetic information in plant and animal cells. |

|A typical cell of any organism contains genetic instructions that specify its traits. Those traits may be modified by environmental influences. |

|2.e DNA is the genetic material of living organisms, and is located in the chromosomes of the |

|cell. |

|Learning Objectives: |

|Students should be able to explain the term genetic code. |

|Students will be able to describe the process by which a cell produces proteins. |

|Goals: |

|Goal for Lesson: Identify how DNA and RNA produce proteins inside the cell. |

|Goal for Unit: Understand that DNA plays many important roles within the cell, and is needed for the cell to function. |

|Goal for Subject Matter: Develop scientific ways of thinking such as asking questions, observations, and use evidence to support your findings or |

|theory. |

|Goal for Long Term: DNA is an important element of life. |

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|Lesson Design: |

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|Warm-up: |

|As a review from our previous lecture, students will individually write down the answer to the following question: In your own words, compare and |

|contrast DNA and RNA. You may draw a Venn Diagram if you choose, however do not forget to compare as well. Use key terms when answering. |

| |

|Whole group discussion: |

|After five minutes, students will be allowed to list results obtained for both the similarities and differences between DNA and RNA. The teacher |

|will write responses down in a Venn diagram on the overhead projector, as the students present them. |

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|Lesson Questions: |

|Based on what we discussed previously, who can tell me how nitrogen bases along a gene serve as a genetic code? How is this gene sequence important |

|in determining proteins? |

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|Whole group discussion: |

|Students will brainstorm for a few minutes and present reasons. The teacher will display manipulatives, and gene sequences in order to promote |

|student understanding of codons (three-letter code words that make up DNA). Students should also be able to express in their discussion, some |

|knowledge of how these codons represent an amino acid. |

| |

|Introduction to Activity: |

|Based on information previously discussed about protein synthesis, students should have some general knowledge about the key elements involved in the|

|production of proteins. In order to help understand and visualize this process, students will be shown various manipulatives demonstrating protein |

|synthesis. As these manipulatives are being shown, students will be directed to their textbooks (Prentice Hall Focus on Life Science pp. 94-95) |

|where a diagram of protein synthesis is displayed. Students will be asked to produce a “Protein Synthesis Booklet” that represents how the messenger|

|RNA, transfer RNA, DNA, ribosomes, nucleus, and amino acids all function together to produce proteins. |

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|Activity: |

|Each student will work individually to produce their own protein booklet, but will be able to collaborate with peers during the activity. |

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|Students will be given two strips of un-lined copy paper (one paper cut in half). They will be instructed to place one strip inside the other and |

|fold it “hamburger style” in order to make a booklet with six pages, not including the front and back. The front of the book (page 1) will be the |

|title page “Protein Synthesis” and their name, date, period. The back of the book (page 8) will be “THE END” |

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|Students will be instructed that for pages 2-7 they must fill in each page by drawing, IN ORDER, a process of protein synthesis that occurs, and |

|explain that process in their own words using key terminology. The teacher will instruct students that they are allowed to use the diagram in their |

|books to help them determine the drawings. However, the teacher will also point out that there are only four drawings in the book and students must |

|draw six. Students are encouraged to use their knowledge of protein synthesis to determine where the two additional drawings should go, and what |

|they should look like. Students will also be informed that not all of the drawings will be the same, but that the process and explanations should |

|all clearly explain and demonstrate the steps of protein synthesis. |

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|Students are directed to color and label their diagrams, remembering that colors representing nitrogen bases and organelles must remain the same |

|throughout their drawings. |

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|Students that require a higher level reasoning skills and more in depth challenge are provided a section of the DNA with specific nitrogen bases. |

|They will also be provided with an answer key that identifies the three-letter codons that represent each amino acid. Given this section of DNA and |

|amino acid key, these students must identify the strand of RNA that will match up with the section of DNA given, and what amino acids will join to |

|form the protein chain as a result. Finally, students must incorporate these additional factors into their diagrams and explanations. |

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|Homework: |

|Students will individually write a one-paragraph answer explaining how a change in one nitrogen base on the DNA strand can lead to a mutation, and |

|what could be some possible consequences or advantages of this occurring? |

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Protein Synthesis- the production of protein

|Main ideas |Notes |

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|Where are proteins found? |Proteins are found inside the ribosomes, which are located in the cytoplasm on the cell. |

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| |REMEMBER: Chromosomes are located in the nucleus of the cell. |

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| |RNA is a genetic messenger that carries the genetic code from the DNA inside the nucleus to the |

|How do ribosomes and chromosomes come |cytoplasm. |

|together to produce proteins if they are |This type of RNA is called messenger RNA |

|located in different parts of the cell? | |

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|Compare and Contrast RNA and DNA. | |

| |Unlike DNA, RNA is only single stranded NOT double stranded. |

| |Like DNA, RNA also has four nitrogen bases. |

| |However, instead of the base Thymine, RNA has a base called Uracil. |

| |For RNA the nitrogen bases join as followed: |

| |Adenine joins with Uracil |

| |Cytosine joins with Guanine |

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| |The DNA molecule “unzips” and the messenger RNA strand base pairs with the DNA strand and copies |

|How does protein synthesis begin? |the coded messages inside the NUCLEUS of the cell. The messenger RNA strand then continues into |

| |the cytoplasm. |

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| |Once in the cytoplasm, messenger RNA attaches to a ribosome and translation begins. The ribosome |

| |reads the three letter code and |

|What “reads” the codes to produce proteins? |allows a transfer RNA to enter into the ribosome. |

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| |The transfer RNA carries an amino acid into the ribosome to match up the three letter code and form|

| |a protein chain. |

|What is the function of transfer RNA? | |

| |The ribosome moves down the messenger RNA reading new codes and allowing |

| |new amino acids to form the protein |

| |chain. |

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| |Once the ribosome reads a three letter STOP code, it releases the protein chain and protein |

| |synthesis ends. |

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|How does protein synthesis end? | |

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