Dna unit Plan

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DNA Unit Plan

Class and grade level: Biology 2, 11th and 12th Period: 5



A pre-assessment will be given to the students before the unit is delivered. The teacher will set the stage with a series of questions for students to think about: What is it that tells our cells to produce saliva? What directs a tiny embryo to develop into a baby? What tells skin cells to grow after cutting your hand? The teacher will present a series of historical experiments and the resulting data. Students will be asked to think critically and use the data to make inferences as to what the hereditary material is and its structure. The teacher will represent DNA replication and protein synthesis using a constructed model. In groups, students will analyze original and mutated DNA segments to discover the importance and effects of mutations on protein synthesis. As a class, the causes and effects of genetic disorders will be discussed. Students will also extract DNA from an onion, cut it with restriction enzymes, and analyze it using gel electrophoresis. They will also use their understanding of restriction enzymes and gel electrophoresis to analyze real world problems, such as paternity and crime scene investigations.

Knowledge: Big Ideas

Past experiments and observations have led to the development of many modern scientific theories and a large scientific knowledge base. Previous work done by Griffith, Avery, Hershey, Chase, Chargaff, Franklin, Watson, and Crick has contributed to the understanding of the hereditary material, DNA.

DNA allows heritable traits to be passed from parent to offspring in sexual or asexual reproduction. The parent DNA must first be replicated to create an identical copy of itself, which can then be passed on to an offspring. DNA, being made of two complementary strands, uses each strand to serve as a template for a new complementary strand. Thus, every time DNA replicates, each product contains one old strand of DNA and one new strand of DNA.

DNA resides in the nucleus of every cell and is the hereditary material that dictates all cellular activity. In order to fit inside of the nucleus, the DNA is highly compressed. It contains the instructions for assembling proteins. Many proteins are enzymes, which catalyze and regulate chemical reactions within organisms. A gene contains DNA that controls a particular trait, such as blood type or eye color. Therefore, the DNA of a particular gene codes for a specific protein that performs a certain function.

DNA undergoes a series of steps in order to be coded into a specific protein. This is known as the central dogma, which says that DNA codes for the production of mRNA, which is processed before leaving the nucleus to be translated into a specific protein by a ribosome. Any alteration in the DNA sequence may lead to an alteration in the amino acid sequence and possibly change the protein that is produced. Since different proteins perform different functions, the trait expressed by an individual will be different.

Knowledge: Experiences, Patterns, and Explanations

Observations or experiences (examples, phenomena, data)

Patterns (laws, generalizations, graphs, tables, categories)

Explanations (models, theories)

  • Transformation (Griffith experiment)

  • No transformation in deoxyribonuclease experiment (Avery experiment)

  • Radioactive phosphorous found in cell (Hershey-Chase experiment)

  • Radioactive sulfur found outside cell (Hershey-Chase experiment)

  • [A] = [T] and [C] = [G] (Chargaff’s observations)

  • X-ray diffraction pattern (Franklin’s observations)

  • Hybrid 14N and 15N DNA (Meselson- Stahl experiment)

  • “Old” students and “new” students are a part of each daughter DNA molecule (Student model activity)

  • How do you go from gene to protein (class activity)

  • Radioactive phosphorous of bacteriophage found inside host cell (Hershey – Chase experiment)

  • Host cell lyses and new virus are released

  • Alzheimers

  • Muscular Dystrophy

  • Cystic Fibrosis

  • Sickle cell anemia

  • How do you go from gene to protein (class activity)

  • Genetic mutation activity

  • These observations collectively provide a clear picture of the DNA and RNA structures.

  • DNA and RNA structures compatible to the transformation material.

  • DNA contains an “old” and “new” strand after replication.

  • DNA tells the cell what proteins to make

  • Genetic disorders

  • Changes in one or more bases may change the protein coded for

DNA is the hereditary material

Semi-conservative DNA replication

DNA transcription mRNA translation protein (Central dogma)

Mutations have the potential to alter the physical expression of an organism.

Application: Model-based Reasoning

Inquiry: Finding and Explaining Patterns in Experience

Practices: Objectives for Student Learning



Michigan Objectives

1. Describe how genetic material is passed from parent to young during sexual and asexual reproduction.


Specific Topic Objectives

1. Explain how DNA replicates.

Telling the story

2. Explain how specific proteins are constructed from DNA.


3. Explain how a mutation in a nucleotide sequence may show up as a change in the trait of an individual (U, III. 3. H. 3: Explain how new traits may be established in individuals/populations through changes in genetic material (DNA)).


4. Describe the historical discoveries and experimental data about DNA that led to the discoveries of its role and structure (R, II.1. H. 7: Describe the historical, political, and social factors affecting developments in science).


Daily Lessons

Before Unit Begins (1/19/05): (Pre-assessment)

Pre-assessment (20-25 minutes)

WEEK 1: Monday (2/7/05) - Friday (2/11/05)

Monday (2/7/05): (DNA note pack, DNA overheads, overhead markers, dye electrophoresis lab)

Series of questions about real world phenomenon: (10 minutes)

  • What is it that tells our cells to produce saliva?

  • What directs a tiny embryo to develop into a baby?

  • What tells your skin cells to grow after you cut your hand?

Introduction into the history of DNA: (45 minutes)

Homework: Dye electrophoresis background questions – due Wed (2/9/05)

Wednesday (2/9/05): (DNA note pack, DNA overheads, overhead markers, lab equipment & materials, DNA extraction overhead)

Check off HW

Historical DNA discoveries & DNA structure: (60 minutes)

Extraction explanation of procedure, preparation, & distribution of materials (10 minutes)

DNA extraction (20 minutes)

Homework: Read 10.1 – 10.3 (quiz coming up after break)

Friday (2/11/05): (Dye electrophoresis lab, lab overheads, overhead markers, lab equipment)

Dye electrophoresis purpose, procedure, & distribution of materials (30 minutes)

Student groups

Dye electrophoresis lab (60 minutes)

  • Run lab

  • Analyze gels & answer questions – TURN IN TODAY

Homework: Read 10.4 – 10.6

Monday (2/14/05 - Friday (2/18/05): NO SCHOOL- Winter break

WEEK 2: Monday (2/21/05) - Friday (2/25/05)

Monday (2/21/05): (Computer with internet, projector & hookups, Journey Into DNA handout)

Interactive DNA website (55 minutes)

  • Representative drawing, title, & notes

  • Recap

Homework: Study for quiz on Wed (2/23/05) on DNA history, DNA structure, & dye electrophoresis

Wednesday (2/23/05): (DNA quiz, DNA model, tape, DNA note pack, DNA overheads, overhead markers)

Quiz (15 minutes)

Class discussion about cell division (5 minutes)

DNA replication (70 minutes)

  • Model (visual)

  • Notes (auditory)

Homework: Read 10.7 – 10.14

Friday (2/25/05): (DNA model, tape, DNA note pack, DNA overheads, overhead markers)

Review DNA replication (5 minutes)

  • Model

Protein synthesis – Transcription, splicing, translation (70 minutes)

  • Model (visual)

  • Notes (auditory)

DNA personal ads in groups of 2 or 3 (15 minutes)

Homework: How do you go from gene to protein? HW - due Mon (2/28/05)

WEEK 3: Monday (2/28/05) - Friday (3/4/05)

Monday (2/28/05): (DNA gel electrophoresis lab, lab overheads, overhead markers)

Collect HW

Restriction enzymes & restriction sites (20 minutes)

DNA electrophoresis significance, background, lab set up, & example gel (25 minutes)

Homework: DNA gel electrophoresis practice questions - due Wed (3/1/05)

Wednesday (3/2/05): (DNA gel electrophoresis lab, lab overheads, overhead markers, lab equipment & materials, review for exam)

Check off HW

Pass out exam review

DNA gel electrophoresis procedure & distribution of materials (10 minutes)

DNA gel electrophoresis lab (30 minutes)

How do you go from gene to protein? HW review (20 minutes)

Protein synthesis review – the bigger picture (30 minutes)

*** stain gels after 1-1 ½ hours and de-stain gel for 24 hours***

Friday (3/4/05): (DNA gel electrophoresis lab, lab overheads, overhead markers, stained gels from Wed (3/2/05))

Purpose and procedure to analyze DNA gel (30 minutes)

Gel analysis & questions (60 minutes)

Homework: Finish gel analysis questions due – Mon (3/7/05) & read 10.15 – 10.16

WEEK 4: Monday (3/7/05) - Friday (3/11/05)

Monday (3/7/05): (DNA note pack, DNA overheads, overhead markers)

Collect HW

Mutation group activity (20 minutes)

Mutation & genetic disorder discussion (25 minutes)

Homework: Study for exam on Fri (3/11/05)

Wednesday (3/9/05): (Board markers, overheads, DNA model, computer, jeopardy program)

Review – Q/A

Snowballs review activity (if time remains)

Homework: Study for exam on Fri (3/11/05)

Friday (3/11/05): (DNA exam)

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