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T E AC H ER /FAC I L I TATOR’S GUIDE DNA: The Master Molecule of Life AGC / United Learning 1560 Sherman Ave., Suite 100 Evanston, IL 60201 800.323.9084 www.agcunitedlearning.com D N A: T h e M a s t e r M o l e c u l e of Life Video and Guide Produced by: Ancient Lights Educational Media Published and Distributed by: AGC/United Learning 1560 Sherman Avenue, Suite 100 Evanston, IL 60201 800-323-9084 FAX 847-328-6706 www.agcunitedlearning.com All material in the program is the exclusive property of the copyright holder. Copying, transmitting, or reproducing in any form, or by any means, without prior written permission from the copyright holder is prohibited. (Title 17, U.S. Code Sections 501 and 506.) ©2001 Ancient Lights Educational Media AGC /United Learning 1560 Sherman Ave., Suite 100 Evanston, IL 60201 800.323.9084 wwww.agcunitedlearning.com CONTENTS Introduction and Summary 1 Curriculum Standards 1 Teacher Preparation/Instructional Notes 2 Student Preparation 2 Pre-test 2 Student Objectives 3 Introducing the Video 3 Follow-Up Discussion 4 Extended Learning Activities 4 Blackline Master Descriptions 5 Answer Key 5 Script of Video Narration 7 Video Quiz 11 This video is closed captioneda2 The purchase of this video program entitles the user to the right to reproduce or duplicate, in whole or in part, this teacher’s guide and the blackline master handouts that accompany it for the purpose of teaching in conjunction with this video, DNA: The Master Molecule of Life ™.This right is restricted only for use with this video program. Any reproduction or duplication in whole or in part of this guide and the blackline master handouts for any purpose other than for use with this video program is prohibited. AGC /United Learning 1560 Sherman Ave., Suite 100 Evanston, IL 60201 800.323.9084 wwww.agcunitedlearning.com CLASSROOM/LIBRARY VIEWING CLEARANCE This program is for instructional use. The cost of each program includes public performance rights as long as no admission charge is made. Public performance rights are defined as viewing of a video in the course of face-to-face teaching activities in a classroom, library, or similar setting devoted to instruction. Closed Circuit Rights are included as a part of the public performance rights as long as closed-circuit transmission is restricted to a single campus. For multiple locations, call your AGC/United Learning representative. Television/Cable/Satellite Rights are available. Call your AGC/United Learning representative for details. Duplication Rights are available if requested in large quantities. Call your AGC/United Learning representative for details. Quantity Discounts are available for large purchases. Call your AGC/United Learning representative for information and pricing. Discounts, and some special services, are not applicable outside the United States. Your suggestions and recommendations are welcome. Feel free at any time to call AGC/United Learning at 1-800-323-9084 AGC / United Learning 1560 Sherman Ave., Suite 100 Evanston, IL 60201 800.323.9084 wwww.agcunitedlearning.com 1 D N A: THE MASTER MOLECULE OF LIFE Grades 5-9 Viewing Time: 14 minutes Lesson Three: Religion INTRODUCTION AND SUMMARY The diverse life forms that inhabit the earth share the common bond of being based on DNA. This program explores the structure of the DNA molecule. It demonstrates how DNA subunits are used to create genetic code words and sentences. Students also discover how the instructions stored in genes are transcribed into messenger RNA and then, with the help transfer RNA, are translated into proteins which perform myriad tasks inside cells. CURRICULUM STA N DA R D S The design of this program was guided by the curriculum standards of the States of Texas, California and Illinois. The American Association for the Advancement of Science recommendations for improving biological science content were followed throughout this series: "Biology: The Science of Life". In accordance with these guidelines we have attempted to help students: 1. Understand the molecular basis of heredity. 2. Develop an increased understanding of how cells work. 3. Recognize and investigate problems and propose solutions based on reason, experimentation, and evidence. 4. Express and interpret information and ideas. 5. Use computer networks and library research to access information. 6. Relate biological science to everyday life experience. AGC /United Learning 1560 Sherman Ave., Suite 100 Evanston, IL 60201 800.323.9084 wwww.agcunitedlearning.com 2 TEACHER PREPARATION/INSTRUCTIONAL NOTES Before presenting this program to your students, we suggest that you review the subject of cell structure and function. We also advise you to preview the video and review the guide and accompanying blackline masters in order to familiarize yourself with their content. As you review the materials presented in this guide, you may find it necessary to make some changes, additions, or deletions to meet the specific needs of your class. We encourage you to do so, for only by tailoring this program to your class will they obtain the maximum instructional benefits afforded by the materials. It is also suggested that the video presentation take place before the entire group under your supervision. The lesson activities grow out of the context of the video; therefore, the presentation should be a common experience for all students.You should also duplicate selected "hand out" materials from the blackline masters included in this guide. Set up a "Learning Center" with diagrams and models that depict DNA, RNA and proteins. STUDENT PREPARATION Before viewing DNA: The Master Molecule of Life 1. Have students explore the "Learning Center". 2. It is important to have students to read about DNA and RNA in their in their textbooks before viewing this lesson. PRETEST An optional pretest is provided (Blackline Master 1). This test will help you determine the level of student comprehension prior to participating in this lesson. An Answer Key appears on page 5 of this Teachers Guide. AGC /United Learning 1560 Sherman Ave., Suite 100 Evanston, IL 60201 800.323.9084 wwww.agcunitedlearning.com 3 STUDENT OBJECTIVES After viewing the video and participating in the follow-up activities students should be able to: 1. Explain the chemical basis of the genetic code. 2. Describe the relationship between genetic code words and amino acids. 3. Describe the relationship between the linear order of code words in a gene and the order of amino acids in a protein. 4. Explain the role of messenger RNA. 5. Explain the role of transfer RNA. 6. Compare and contrast Replication, Transcription and Translation. 7. Discuss the importance of proteins in living cells. INTRODUCING THE VIDEO 1. Introduce the program by pointing out the following things: DNA is the master molecule of life because it controls nearly all cell activities. Because DNA is self-replicating, genetic information is passed on from cell to cell and from generation to generation. DNA is able to control cell activities because it stores instructions for making proteins. There is a region of DNA or GENE for every protein made by cells. The cell produces proteins only when they are needed. It does this by sending chemical signals to the DNA which activate genes. Most proteins are enzymes. Enzymes control the rates of the chemical reactions that take place inside the cell: In fact very few chemical reactions in cells occur without the help of enzymes.Point out that if only half of the roughly 100,000 human genes coded for enzymes that would mean 50,000 different types of chemical reactions would be under the direct control of DNA. Let students know the program they are about to see presents a "bare bones" glimpse of how transcription and translation occur. The topic has been simplified to make understanding of this difficult subject as easy as possible. 2. Hand out the Crossword Puzzle (Blackline Master 3 ) View the video: Running time of the program is 14 minutes followed by a short (1 minute) optional video quiz. AGC/ United Learning 1560 Sherman Ave., Suite 100 Evanston, IL 60201 800.323.9084 wwww.agcunitedlearning.com 4 FOLLOW-UP DISCUSSION It is recommended that you involve students in a discussion immediately after viewing the video: 1. Discuss how the genetic code works. 2. Discuss how the proteins called enzymes carry out the actual work of regulating the activities of the cell. EXTENDED LEARNING ACTIVITIES A. In order to express and communicate ideas and improve research skills use the INTERNET and other resources to prepare papers or oral reports on the following subjects: 1. The human genome project 2. Deciphering the genetic code 3. DNA fingerprinting 4. Genetic engineering B. Microscope Work: Examine a slide of the salivary gland chromosomes of the fruitfly Drosophilia melanogaster. These chromosomes are actually polyploid meaning that many DNA strands exist in each chromosome. As a result, they are very thick. Look for the bands that may represent genes and the "puffing" that indicates gene activity. AGC / United Learning 1560 Sherman Ave., Suite 100 Evanston, IL 60201 800.323.9084 wwww.agcunitedlearning.com 5 DESCRIPTION OF BLACKLINE MASTERS Blackline Master 1, is a Pre-test that, when compared to the quiz results, will help you gauge student progress. Blackline Master 2, is a Vocabulary Worksheet that will introduce students to unfamiliar words used in the program, or words pertaining to the subject of the program they may encounter in outside reading. Blackline Master 3, is a Crossword Puzzle that challenges students to use some of the words from the vocabulary worksheet that accompanies in this program. Blackline Master 4, is a Test for evaluating student progress. Blackline Master 5, is a printed version of the Video Quiz that appears at the end of this program. The video quiz encourages attentiveness and tests information retention. ANSWER KEY Blackline Master 1, Pre-test 1. True 2. False, it is the same in every organism. 3. False, it is based on the 4 different subunits of DNA. 4. False, all genetic code words are three letters long. 5. True Blackline Master 2, Vocabulary Activities 1. Enzymes 2. Molecule 3. Messenger RNA 4. Transfer RNA 5. Synthesis AGC / United Learning 1560 Sherman Ave., Suite 100 Evanston, IL 60201 800.323.9084 wwww.agcunitedlearning.com 6 Blackline Master 3, Crossword Puzzle 3 N 4 U R C I L B E T C U 2 2 1 R A N S L A T I M I N A S C C R 4 O O N E O A C I D S E P L I C A H R E E R S T I P 5 L O N 5 T G I E C N I M O O M A 1 A D S R 3 O E O 6 N N U C L E O T I D E U L E Blackline Master 4, Test 1. Messenger RNA: Messenger RNA carries protein–making instructions from the DNA in the nucleus to a ribosome. 2. Genetic Code Words: Three DNA nucleotide subunits in a row, such as AAA or AGA, that represent or "code for" amino acids. 3. Anticodon: The three letter genetic code word of a transfer RNA that corresponds to the amino acid it carries and that matches up with that amino acid's codon on the messenger-RNA. 4. Transfer RNA: A small RNA molecule that can pick up amino acids. By matching the transfer RNA anticodon to the messenger RNA codon the amino acid is put into the protein chain correctly. 5. Proteins: Molecules made up of long chains of amino acids. Proteins build living material, fight disease, and help transport substances out of the cell. The proteins called enzymes are especially important because they control the rates of chemical reactions in the cell. 6. Ribosomes: The organelles where proteins are assembled. AGC /United Learning 1560 Sherman Ave., Suite 100 Evanston, IL 60201 800.323.9084 wwww.agcunitedlearning.com 7 7. Amino Acid: The subunits that are chemically bonded together in proteins. The order amino acids follow one another in protein chains is what determines how the protein works. 8. Nucleotide Subunit: The Subunits that make up DNA. Each nucleotide has a phosphate group, a deoxyribose sugar group and a nitrogencontaining base; either Adenine, Thymine, Cytosine or Guanine. 9. Macromolecule: A very large molecule may form thousands of atoms. DNA, messenger RNA and proteins are examples of macromolecules. 0. Replication of DNA: The process that occurs when DNA makes an exact copy of itself before a cell divides. Blackline Master 5, Video Quiz 1. True 2. False, genetic code words represent different amino acids 3. True 4. False, each chromosome may possess thousands of genes 5. True Script of Video Narration DNA: THE MASTER MOLECULE OF LIFE Living things are very diverse and are found in an incredible array of colors, shapes, and sizes. Yet, in spite of their great differences, if you look closely enough they are actually quite similar to one another. As long ago as the 1830s scientists had begun to realize this fact when they discovered that all living things are made from cells. By the middle of the 20th century even more similarities were found when new scientific tools let researchers examine the molecules found inside of cells. One molecule in particular called Deoxyribonucleic Acid or DNA captured their attention. Scientists discovered that DNA uses a genetic code to chemically store the information cells need to perform their many life-supporting activities. Researchers also discovered that this genetic code is truly universal because it is used in every living cell: from lowly bacteria like these, to the complex cells of animals and plants. Now, let us learn more about the amazing DNA molecule... and find out how it works. AGC /United Learning 1560 Sherman Ave., Suite 100 Evanston, IL 60201 800.323.9084 wwww.agcunitedlearning.com 8 DNA: CHROMATIN, CHROMOSOMES, AND NUCLEOTIDE SUBUNITS In the cells of higher organisms almost all the DNA is located inside the nucleus in the substance called chromatin. Before a cell reproduces the chromatin changes into the separate structures seen here that are known as chromosomes. Inside a chromosome the DNA, along with some proteins, is neatly packaged: It is twisted and folded over and over again. Something like this is possible because DNA is a very large molecule: a macromolecule. A closer look shows that the DNA molecule is actually made up of two separate strands that wind around and around one another creating a shape called a double helix. Each of the two DNA strands is made up of smaller chemical subunits called nucleotides which are joined together, one after another, in a very precise order.Only four different subunits are used in DNA but each one can be found tens of thousands of times in the huge molecule. To help visualize molecules, scientists use structural formulas like this one to show how their atoms are bonded together. For example, this structural formula shows that each DNA subunit contains a phosphate group composed of a single atom of the element Phosphorus, P, bonded to 4 atoms of the element oxygen, O, plus a single Hydrogen atom. Each DNA subunit also contains a sugar group called deoxyribose that is made from five carbon atoms, one oxygen atom and several hydrogen atoms all bonded together as shown here. The individual DNA subunits in a strand are linked together by strong chemical bonds between their phosphate and sugar groups these bonds form the "backbone" of the DNA molecule. Each of the four DNA subunits possesses a nitrogen containing base. The chemical names of the bases are thymine, cytosine, adenine, and guanine: abbreviated T, C, A and G. These bases are always found in pairs linked to one another by weak chemical bonds, called hydrogen bonds, that exist between the bases in each strand. The bases always pair up the same way so that if one DNA strand has an A the opposite strand will always have a T in exactly the same place. Likewise a G in one strand is always paired with a C in the same place in the opposite strand. Because of the way base pairing occurs DNA molecules end up having two exactly opposite or complementary strands. As we will soon discover it is the precise order the subunits appear in the DNA strands that is the key to the genetic code: and the genetic code is the key to life itself. AGC /United Learning 1560 Sherman Ave., Suite 100 Evanston, IL 60201 800.323.9084 wwww.agcunitedlearning.com 9 DNA, GENES AND PROTEINS In the last century researchers studying genes, the units of heredity, which determine such things as hair color, eye color, and blood type made two extremely important discoveries. The first was that genes are made from DNA. The second was that each gene holds the coded instructions for making a different protein. Proteins are made up of long chains of amino acids of which there are 20 different kinds. Living organisms use proteins for a lot of different things : They can be used for building cell parts, repairing damage, fighting disease and regulating the speed of the tens of thousands of chemical reactions that take place inside of cells. Each chromosome in a cell has many different genes and genes themselves are simply certain regions of a DNA molecule. Genes determine the order amino acids will appear in a particular protein chain and it is this order which gives the protein the ability to do its job. Now let us see how DNA stores instructions in the unique biological language of the genetic code. THE GENETIC CODE The subunits of a DNA molecule: A, T, C, and G are the four letters of the genetic code alphabet. Of course the subunits are chemical compounds not actual letters. Nevertheless they can be used just like letters to "spell out" genetic code words. Most of the 64 code words used by living things represent, or "code for", amino acids and each of these words is only three letters long. For example A-A-A is a code word for the amino acid phenylalanine, G-C-T for the amino acid arginine, C-T-C for glutamic acid and T-A-C for the amino acid methionine. A protein made from these amino acids could have a gene, or sentence of code words, like this "written" in one of the DNA strands. This sentence informs the cell that this particular protein is to be made using only these four amino acids in this exact order. replication of DNA All the DNA in a cell can be thought of as a LIBRARY containing books of instructions which tell the cell how to make the proteins it needs to stay alive. In fact every time a cell divides its DNA is copied or replicated so that each new cell will have a full library of instructions. AGC / United Learning 1560 Sherman Ave., Suite 100 Evanston, IL 60201 800.323.9084 wwww.agcunitedlearning.com 10 BRIEF REVIEW Let's briefly review how DNA stores instructions: The DNA molecule of a single chromosome can be thought of as one book from the cell's library of instructions. A chromosome can contain thousands of genetic code sentences or genes that determine the order amino acids will appear in proteins. Such sentences are written using genetic code words ...all of which are just three letters long. These words are codes for any of 20 different amino acids and, of course, the letters with which the words are written are the four nucleotide subunits of DNA. MESSENGER RNA, TRANSFER RNA, AND PROTEIN SYNTHESIS Inside living cells the actual process of making proteins involves several different steps because the instructions for making proteins are stored in the nucleus but the proteins themselves are made, or synthesized, in the cytoplasm. This means cells must have a way to move information out of the nucleus and into the cytoplasm. As it turns out cells use a special molecule for this task, called messenger RNA. RNA, or ribonucleic acid, is very similar to DNA but RNA has only a single strand, it contains the sugar ribose instead of deoxyribose, and a base called uracil replaces the Thymine found in DNA: So the RNA alphabet is A-U-C-G not the A-T-C-G used by DNA. Whenever a cell needs more of a certain protein it sends a chemical signal to the nucleus which causes the gene for that protein to be "switched on". When this happens the DNA code words in the gene are copied into the RNA code words, or codons, of messenger RNA: This process is called genetic transcription. After the gene is copied, the messenger-RNA carries the protein making instructions to a ribosome in the cytoplasm: Ribosomes are the organelles where proteins are made. However, just the fact that the messenger RNA has reached a ribosome is not enough for the protein to start being made. In order for the message to be translated a third kind of RNA, called transfer RNA, is needed.Transfer RNAs are small RNA molecules that can pick up amino acids and transfer them to the messenger RNA on the ribosome. There are almost as many transfer RNAs as there are DNA code words. In fact each of the different transfer RNAs has a different anticodon which is basically a DNA code word written using the letters of the RNA alphabet. Transfer RNAs carrying amino acids match-up their anticodons to the messenger RNA AGC /United Learning 1560 Sherman Ave., Suite 100 Evanston, IL 60201 800.323.9084 wwww.agcunitedlearning.com 11 codons as the ribosome moves along the message: As a result the amino acids carried by the transfer RNAs will be put into the protein chain in exactly the right order. Once the protein is finished it is ready to perform its job in the cell and as the protein goes to work a new chemical signal is sent back to the nucleus that "switches off" the gene for that particular protein. CONCLUSION As we have just learned DNA performs an essential role in the lives of all living things. It stores huge amounts of information in the unique biological language called the genetic code. DNA's genetic information is transcribed into messenger RNA which carries it to the ribosomes where, with the help of transfer RNA, new proteins are made that perform thousands of tasks inside of cells. But DNA is even more amazing because it can make exact copies of itself. As a result genes and the instructions they hold are passed on; not just from old cells to new cells but from one generation to the next. VIDEO QUIZ 1. True of False? The four subunits of DNA are used as the "letters" of the genetic code alphabet. 2. True of False? Genetic code words represent different proteins. 3. True of False? Translation takes place on ribosomes. 4. True of False? There is usually one gene on each chromosome. 5. True of False? DNA is transcribed into messenger RNA in the nucleus. AGC / United Learning 1560 Sherman Ave., Suite 100 Evanston, IL 60201 800.323.9084 wwww.agcunitedlearning.com 1 Name DNA: The Master Molecule of Life PRE-TEST Directions: Answer each question TRUE OR FALSE: 1. Genes are made from DNA. 2. The genetic code used in the cells of mushrooms is quite different from genetic code used in human cells. 3. The "alphabet" of the genetic code uses the 20 different amino acids for letters. 4. Genetic code words are of different lengths according to the information they contain. 5. DNA chemically stores instructions for making proteins. AGC / United Learning 1560 Sherman Ave. Suite 100 Evanston, IL 60201 800.323.9084 DNA: The Master Molecule of Life ©2001 Ancient Lights Educational Media Published and Distributed by AGC/United Learning to print materials cleared for classroom duplication and distribution 2 Name DNA: The Master Molecule of Life VO C A B U LA RY WORKSHEET Adenine: A nitrogen containing base found in one of the nucleotide subunits of DNA. Adenine is the "A" of the genetic code alphabet. Cytosine: A nitrogen containing base in a nucleotide subunit of DNA. Cytosine is the "C" of the genetic code alphabet. Amino Acid: The subunits that are chemically bonded together in proteins. The order of amino acids in a protein is what gives it the ability to do its job. Deoxyribonucleic Acid (DNA): A long molecule shaped like a twisted ladder(double helix). The plans for running and reproducing cells are chemically stored in the DNA. DNA is found mostly in the nucleus but small amounts of DNA are found in mitochondia and chloroplasts. Anticodon: The three letter word of a transfer RNA that corresponds to the amino acid it carries. The anticodon matches up with the codon of the messenger–RNA. Bacteria: Simple, one-celled, organisms that lack a nucleus belonging to the kingdom Monera. Cell Division: The process that results in two cells being formed from one cell. Cell reproduction. Chemical: Chemicals are substances made from combinations of different elements. Chemical Bonds: The way in which atoms are joined to one another: For example, in water an atom of oxygen is joined to two atoms of hydrogen by chemical bonds. The subatomic particles called electrons are responsible for creating chemical bonds. Chemical Reactions: Events in which chemical bonds are broken, rearranged and reformed. Matter is changed by chemical reactions: This is what happens when chemical compounds react with one another and new compounds are formed. Chromatin: Chromatin is made up of the tangled, threadlike, coils of chromosomes. Chromatin contains DNA plus certain proteins. Chromosomes: Chromosomes are worm-shaped structures that develop from chromatin before cells divide. Chromosomes contain DNA and protein. Human body cells have two full sets of 23 different chromosomes. Codon: A code word of messenger RNA that represents an amino acid. Complementary: Two parts of a jigsaw puzzle fit together to make a whole: Therefore they are called complementary parts. DNA has two complementary strands because they are exact opposites of one another. Cytoplasm: All the protoplasm located outside the nucleus. AGC / United Learning 1560 Sherman Ave. Suite 100 Evanston, IL 60201 800.323.9084 Deoxyribose: The sugar part of a a DNA nucleotide subunit. Double Helix: The double spiral shape of the DNA molecule. Enzymes: Proteins that control the rates of chemical reactions in cells. Most proteins in a cell are enzymes. Digestive enzymes such as pepsin and trypsin are produced by specialized cells. These enzymes are exported from cells to break down food in the digestive tract. Gene: A region of a DNA molecule that stores the instructions for making a particular protein. Genes are also known as the units of making a particular protein. Genes are also known as the units of heredity. Genetic Code: The chemical language of the cell. DNA stores its instructions in the genetic code. Genetic Code Word: Three DNA nucleotide subunits in a row, such as AAA or AGA, that represent amino acids. Genetic Transcription: The process of copying a gene into messenger-RNA. Guanine: A nitrogen–containing base found in a nucleotide subunit of DNA that is the "G" of the genetic code alphabet. Heredity: Characteristics that are passed on from parents to their offspring. Genes are called the "units of heredity”. Hereditary: Passed on from one generation to the next. Hydrogen Bond: A type of weak chemical bond. Hydrogen bonds exist between the two strands of the DNA molecule and between the messenger RNA codons and the transfer RNA anticodons. Molecule: A combination of two or more atoms bonded together by strong chemical bonds (covalent bonds). continued DNA: The Master Molecule of Life ©2001 Ancient Lights Educational Media Published and Distributed by AGC/United Learning to print materials cleared for classroom duplication and distribution 2a Name DNA: The Master Molecule of Life Macromolecule: A very large molecule made from thousands of atoms. DNA, messenger RNA and proteins are all examples of macromolecules. Messenger RNA (m-RNA): Messenger RNA carries instructions for making proteins from the nucleus to a ribosome. Nitrogenous Bases: The nitrogen containing bases of the DNA nucleotide subunits whose chemical names are Adenine, Thymine, Cytosine, and Guanine. Nuclear: Refers to the nucleus. Nucleic Acids: DNA or RNA nucleus (Plural: Nuclei) A rounded structure located in the cytoplasm. The nucleus is the cell's control center because it is where most of the DNA is located. Nucleolus (New-klee-oh-lus): "Little Nucleus" The area of the nucleus where ribosomes are made. Cells can have more than one nucleolus. Nucleotide Subunit: The Subunits that make up DNA. Each nucleotide has a phosphate group, a deoxyribose sugar group and a nitrogen–containing base; either Adenine, Thymine, Cytosine or Guanine. Organelles: "Little Organs". Structures in the cytoplasm such as mitochondria, ribosomes, chloroplasts, and Golgi bodies where different tasks are performed in the cell. Proteins: Molecules made up of long chains of amino acids(polypeptides). Proteins build living material, fight disease, and help transport things out of the cell. The important class of proteins called enzymes act to control the rates of chemical reactions. Most proteins are enzymes. Replication of DNA: The process that occurs when DNA makes an exact copy of itself before cell division. Ribosomes: The organelles where proteins are assembled. Ribonucleic Acid: A type of nucleic acid that contains the sugar ribose instead of deoxyribose, has one strand and that has the base Uracil instead of Thymine. Ribose: A sugar group found in RNA nucleotide subunits. Structural Formula: A diagram used by chemists that shows how atoms are arranged in molecules. Synthesis: To make complex substances from simpler parts. Proteins are synthesized from amino acid subunits. DNA is synthesized from nucleotide subunits. AGC / United Learning 1560 Sherman Ave. Suite 100 Evanston, IL 60201 800.323.9084 Sugar-Phosphate Bonds: Strong (covalent) bonds between the deoxyribose sugar of one nucleotide and the phosphate group of the adjoining nucleotide is what forms the "backbone" of the DNA molecule. Terminator Codons: Every messenger RNA message ends with one of three different "terminator" codons: UAG, UAA or UGA. Since there are no transfer RNAs with anticodons to match these messenger RNA codons protein synthesis stops whenever a terminator codon is reached. Thymine: A nitrogen containing base found in one of the nucleotide subunits of DNA. Thymine is the "T" of the genetic code alphabet. Transfer RNA (t-RNA): A small RNA molecule that can pick up amino acids. By matching the transfer RNA anticodon to the messenger RNA codon the amino acid is put into the protein chain correctly. Translation: The process of making proteins using the instructions of messenger RNA molecule. Uracil: A nitrogen–containing base used in RNA molecules instead of Thymine. VO C A B U LA RY ACTIVITY From the vocabulary list find the correct word to fill in the blanks. 1. are proteins that control the rates of chemical reactions. 2. Two or more atoms strongly bonded together is called a 3. Instructions from DNA are carried to ribosomes by molecules of 4. Amino acids are picked up by special RNA molecules called 5. The process of making something from simple subunits is called DNA: The Master Molecule of Life ©2001 Ancient Lights Educational Media Published and Distributed by AGC/United Learning to print materials cleared for classroom duplication and distribution 3 Name DNA: The Master Molecule of Life CROSSWORD PUZZLE 3 Across: 1. A messenger-RNA code word is called a 2. 4 . is the process that takes place when proteins are made from the instructions of messenger-RNA. 1 3. Transfer-RNA carries to the messenger-RNA. 4. 2 2 is the process that takes place when DNA makes a copy of itself. 5. All genetic code words have "letters". 1 3 6. Four subunits are needed to make a DNA molecule. Down: 4 1. The DNA molecule is called a because it is very large. is the process by which DNA is copied into messenger RNA. 5 5 3. Most of a cell's DNA is found in its . 4. Proteins are made on organelles called . 6 5. A region of the DNA molecule that stores instructions for a protein is called a . AGC / United Learning 1560 Sherman Ave. Suite 100 Evanston, IL 60201 800.323.9084 DNA: The Master Molecule of Life ©2001 Ancient Lights Educational Media Published and Distributed by AGC/United Learning to print materials cleared for classroom duplication and distribution 4 Name DNA: The Master Molecule of Life PRE-TEST Directions: Define each of the following. 1. Messenger RNA– 2. Genetic code word– 3. Anticodon– 4. Transfer RNA– 5. Proteins– 6. Ribosome– 7. Amino acid– 8. Nucleotide Subunit– 9. Macromolecule– 10. Replication of DNA– AGC / United Learning 1560 Sherman Ave. Suite 100 Evanston, IL 60201 800.323.9084 DNA: The Master Molecule of Life ©2001 Ancient Lights Educational Media Published and Distributed by AGC/United Learning to print materials cleared for classroom duplication and distribution 5 Name DNA: The Master Molecule of Life VIDEO QUIZ Directions: Define each of the following. 1. True or False? The four subunits of DNA are used as the "letters" of the genetic code alphabet. 2. True or False? Genetic code words represent different proteins. 3. True or False? Translation takes place on ribosomes. 4. True or False? There is usually one gene on each chromosome. 5. True or False? DNA is transcribed into messenger RNA in the nucleus. AGC / United Learning 1560 Sherman Ave. Suite 100 Evanston, IL 60201 800.323.9084 DNA: The Master Molecule of Life ©2001 Ancient Lights Educational Media Published and Distributed by AGC/United Learning to print materials cleared for classroom duplication and distribution