Teaching the Concept Teaching the Concept ofof

Protein SynthesisProtein SynthesisRebecca LostraccoRebecca LostraccoJacqueline McCannJacqueline McCann

Introduction to Protein Introduction to Protein SynthesisSynthesisIf you asked any body builder,

theywould tell you that muscles are

builtfrom protein. But have they everwondered how proteins areactually made in our body?

It all starts with one thing: DNA!

Now you just create protein from DNA. Sounds simple, right?Wrong!

To understand this concept, you’ll

need to learn about the central dogma of transcriptionand translation.

Really, really

Important!!

Lesson SequenceLesson SequenceLesson 1: Protein Synthesis: An Overview

The Central Dogma, RNA, The Genetic CodeLesson 2: Transcription

Initiation, Elongation, TerminationLesson 3: Translation

The Ribosome, Transfer RNA, Elongation of the Polypeptide Chain, Termination

Lesson 4: Control Mechanisms The lac Operon, the trp Operon

Lesson 5: Mutations Types of Mutation, Causes of Mutation

Lesson 6: Differences Between Eukaryotes and Prokaryotes

Curriculum ExpectationsCurriculum ExpectationsD2.4 investigate and analyse the cell components

involved in the process of protein synthesis,

using appropriate laboratory equipment and

techniques, or a computer simulation

D3.2 compare the structures and functions of

RNA and DNA, and explain their roles in the

process of protein synthesis

D3.3 explain the steps involved in the process of

protein synthesis and how genetic expression is

controlled in prokaryotes and eukaryotes by

regulatory proteins (e.g., the role of operons in

prokaryotic cells; the mechanism of gene expression

in eukaryotic cells)

The Central Dogma:The Central Dogma:Teaching ApproachTeaching Approach

Video demonstration of Protein Synthesis

The Central Dogma:The Central Dogma:Teaching ApproachTeaching Approach

Protein Synthesis Virtual Lab Students use an inquiry-based approach to

transcribe a DNA molecule into RNA, and then translate the mRNA into a protein

Students interactively learn more about transcription and translation

Transcription and Translation Virtual Lab

The Central Dogma:The Central Dogma:Teaching ApproachTeaching Approach

Protein Synthesis Role-Play Teacher ropes off a designated area as the nucleus where

transcription must occur. The rest of the classroom is the cytoplasm where translation will occur.

8 students are assigned to DNA sequences (24 nucleotides in each)

8 students are assigned to complementary mRNA sequences

8 students are assigned to complementary tRNA anticodons with corresponding amino acids (polypeptide chain)

8 special learning opportunity messages (Ex. “Ribosomes move along the mRNA in a 5’ to 3’ direction, while reading the coding sequence.”) are posted around the classroom corresponding to amino acid polypeptide chains

The Central Dogma:The Central Dogma:Teaching ApproachTeaching Approach

Protein Synthesis Role Play Continued DNA students and mRNA students remain in nucleus during

transcription. After transcription, mRNA students move into cytoplasm, where tRNA students are waiting for translation.

DNA students begin by writing down the complimentary RNA sequence to their DNA sequence (transcription). They then search the nucleus for their matching mRNA student.

mRNA student then leaves the nucleus and uses the genetic code to write down the corresponding amino acids to their RNA sequence (translation). They then search the cytoplasm for their matching tRNA student.

The tRNA student then searches for the special message associated with their polypeptide chain, thus completing the task.

Potential Student Potential Student DifficultiesDifficulties• Abstract concept – may be hard for students to picture

• Remembering that in RNA, Thymine is replaced with Uracil

• Recognizing the matches between nucleotide bases and

amino acids (i.e., using the genetic code table)

• Distinguishing between DNA and RNA as well as between the roles

of mRNA and tRNA mRNA carries coded DNA message tRNA carries amino acids

• Recognizing a stop codon which

signals for translation to end

• Only 2 tRNA molecules can

attach to the ribosome at a time

• Polypeptide chain is transferred from

one tRNA to the other before tRNA

leaves the ribosome

Solutions to Student Solutions to Student DifficultiesDifficulties• Role-play activity will help to make concept more concrete

• Students can make their own mnemonics

for remembering stop codons

(UAU, UAG, UGA)

• Having an anchor chart with

nucleotide bases and their

corresponding amino acids

• During role-play activity, emphasize the distinction between mRNA and tRNA by having the students in those groups wear a label

• Create a T-Chart/Venn Diagram to compare roles of DNA & RNA and mRNA & tRNA

• Model translation in role-play activity slowly and clearly for the students

• Have students proceed step-by-step, explaining their role in the process

Safety ConsiderationsSafety Considerations• This unit includes a virtual lab, which makes the main safety concern appropriate internet conduct• To safely implement the role-play activity, the classroom will need to be free from clutter with space for students to move around• Students will be given explicit instructions on the role play activity so they are aware of the expectations how to execute their role

Practical ApplicationsPractical Applications

“What makes a Firefly Glow?” • demonstration of how protein synthesis is involved in making a firefly glowFoods and Protein Synthesis• examples of foods that increase protein synthesis to support muscle buildingExercise and Protein Synthesis• discuss the rate of protein synthesis in relation to exercise

Differentiated AssessmentDifferentiated Assessment• Students would have a choice for their culminating task assessment on protein

synthesis. The following tasks are targeted to students’ multiple intelligences:

A poster displaying the process of protein synthesis (Visual) A song about the concept of protein synthesis (Musical) A 3-D model showing the main “players” in protein synthesis (Kinesthetic) A videotaped oral story about the process of protein synthesis (Linguistic) A journal entry on what they learned about protein synthesis (Intrapersonal) A lesson on protein synthesis that is taught to the class (Interpersonal) A lab activity involving transcription of provided DNA nucleotide sequences

into mRNA, splicing of the mRNA, and translation of the mRNA into a

protein (Logical)

• Students’ understanding of the concepts of protein synthesis would also be

evaluated on a unit test

• Formative assessment would be completed based on students’ contributions to

class discussions during role-play and participation in the online lab