DNA, Replication and Transcription

Robert JesbergFETC Conference

Orlando, FLJanuary 28 – 31, 2014

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Workshop Agenda

• Looking at DNA and Forensics• The DNA, Replication and Transcription Set• DNA Ladder• The Double Helix and Replication • Transcription, Translation and Mutation• Forensics Challenge

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The DNA, Replication and Transcription Set

• 521 K’NEX Pieces

• Builds 19 color-coded models

• Supports a team of 2-3 students

• Models DNA and mRNA

• Models can be in the form of

ladders, on stands or with a

flexible central core.

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The Teacher Guide• DNA Structure

– Building the DNA Ladder

– Forming the Double Helix Structure

• Replication and Transcription– The Basic Replication Process

– mRNA Production

• Coding, Translation, and Mutations– Coding Glucagon: A Small Protein

– Translation of a mRNA Transcript

– DNA Mutations

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Key Concepts

• Molecular Basis of Heredity

• Chemistry of DNA

• DNA Structure

• The Double Helix

• Enzymatic Control of DNA

Processes

• Semi Conservative Replication of

DNA

• Transcription and mRNA Production

• Translation of the DNA Code

• Deletion, Substitution, and Insertion

Mutations

• Nuclear and Cytoplasmic Processes of

DNA

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NSES Science Content Standards• Unifying Concepts and Processes

- Evidence, models and explanation

• Science as Inquiry

- Abilities necessary to do scientific inquiry

- Understanding about scientific inquiry

• Life Science

Grade 5-8 Grade 9-12

- Structure and function of living systems - Molecular basis of heredity

- Reproduction and heredity - Biological evolution

- Diversity and adaptations of organisms

• Science and Technology

– Understanding about science and technology6

Next Generation Science Standards• Develop and use a model to describe why structural changes to genes

(mutations) located on chromosomes may affect proteins and may result in harmful, beneficial, or neutral effects to the structure and function of the organism.

• Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.

• Ask questions to clarify relationships about the role of DNA and chromosomes in coding the instructions for characteristic traits passed from parents to offspring.

• Make and defend a claim based on evidence that inheritable genetic variations may result from: (1) new genetic combinations through meiosis, (2) viable errors occurring during replication, and/or (3) mutations caused by environmental factors.

Building the DNA Ladder

• Refer to pages 2 - 3 in the Instructions Booklet.

• Each of the pieces in the set is color-coded to represent the various

chemical components of DNA.

• Turn to pages 4 – 5 to construct a DNA ladder.

• The chart at the bottom of the page indicates the nucleotides you will

need for this activity.

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Twisting the DNA Ladder to form a Helical Molecule!

• Your challenge is to twist the ladder to form a

double helix and mount it on a display stand.

Refer to pages 6 and 7 in your instruction booklet.

• Keep in mind that DNA is a right-handed molecule.

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Replicating DNA

• The replication process provides the cell

with two exact copies of an original DNA

molecule.

• The original DNA is the parent molecule

and the newly formed DNA are the

daughter molecules.

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Transcription

• The model of mRNA shown on the

left carries the code from a DNA

template strand.

• If you refer to pages 18 and 19 of

the instruction booklet, you will see

how the model is formed and the

code transcribed.

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Translation and Mutations

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• You can place the mRNA transcripts on large sheets of paper to translate the

mRNA.

– You can bracket the codons and use a key from the Teacher Guide to

determine the appropriate amino acid sequence.

• Mutation activities in the teacher guide demonstrate how the amino acid

sequence changes when an insertion, deletion, or substitution mutation

occurs.

– Each of these mutation scenarios can be modeled with the materials in

the DNA, Replication and Transcription Set.

DNA and Forensics

• “CSI” type television programs have certainly brought crime scene forensics

and DNA fingerprinting into vogue with students! How do we tap that

growing interest to help students better understand the science behind the

TV screen?

• DNA models that can be coded to any nucleotide sequence can provide

endless opportunities for teachers to simulate molecular level crime scene

investigations and provide materials for further investigation of DNA and

mRNA.

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Let’s get down to work!

• Each group has been provided with a DNA sample from a crime suspect.

• Our first task is to list the sequence of nucleotides found on your molecules.

Refer to page three in your Instruction Booklet to determine the color codes

used for the various nucleotides.

• There are two standard conventions we can use to transfer the sequence to

paper.

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Representing Your Molecule on Paper!

- GCCAGATCATTT CGGTCTAGTAAA –

-OR-

5’ GCCAGATCATTT 3’

3’ CGGTCTAGTAAA 5’

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Finding your Molecule

• I am going to collect all of the DNA molecules and place them on the floor.

• Your task is to review the molecules on the floor and determine which one is

yours.

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Forensics Challenge• Follow the directions given and see if your group can identify the subject.

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Forensics Activity Summary

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• Participants had to use a variety of science skills to identify the DNA match.

- Observation - Analysis

- Record keeping - Data collection

- Critical thinking - Logical thinking

• The activity can serve as a spring board to further research related to DNA

fingerprinting, crime scene science, polymerase chain reaction, and forensic

investigational techniques.