DNA, RNA & Protein Synthesis

1. DNA, RNA & Protein Synthesis Packet 7

2. Notes DNA Structure

3. DNA Structure DEOXYRIBONUCLEICACID • DNA stands for – • What group of organic molecules does DNA belong to? • DNA is responsible for storing & transferring from one generation to the next. It also contains the codes for making all the in your body. NUCLEICACIDS GENETIC INFORMATION PROTEINS 1. DNA Structure 2. Journey into DNA 3. DNA to Protein

4. DNA Structure NUCLEOTIDES • The building blocks of DNA are • Look at the 12 different nucleotides given to your group. What are the three parts in a nucleotide? • DEOXYRIBOSE (SUGAR), • PHOSPHATE, • NITROGEN BASE

5. DNA Structure • DEOXYRIBOSE (SUGAR) AND PHOSPHATE • What are the TWO common parts of the nucleotides? In other words what two parts are identical between all the pieces? • Notice one of the words ends in –ose. What type of molecule is this? • What group of organic compounds does this belong to? • What is the ONE part of a nucleotide that is DIFFERENT among the nucleotides in your group? • List the letters for the four nitrogen bases: • SUGAR • CARBOHYDRATE NITROGEN BASE • (A) – ADENINE • (G) – GUANINE • (C) – CYTOSINE • (T) - THYMINE

6. DNA Structure Your completed model should look like a ladder. Besides being shaped like a ladder, a DNA molecule is twisted. It looks like a spiral staircase. However, your paper model cannot show this shape. • This shape is known as a • If DNA is “ladder like,” which two molecules of a nucleotide form the sides or upright portion of the ladder? • Which molecules form the rungs of the ladder? • What is the pairing arrangement of the nitrogen bases? This kind of pairing is called complementary. The base pairing rule states that: • If four guanine bases appear in a DNA model, how many cytosine bases should there be? DOUBLE HELIX • DEOXYRIBOSE (SUGAR) AND PHOSPHATE NITROGEN BASE __A____ pairs with ___T___ ___C___ pairs with ___G____ • FOUR

7. Purinesvspyrimidines • Notice that the nitrogen bases are different sizes. • are larger and are made of 2 rings or units and are called purine bases. • are smaller and are made of only 1 ring or unit and are called pyrimdine bases. • A purine base always pairs with a base. ___A____ and ___G___ ___T____ and ___C___ PYRIMIDINE

9. D P D P D P D P D P D P D P D P D P D P D P D P D P D P D P D P D P D P DNA Structure HYDROGEN 2 3 • The bases pairs in the double helix are held together by weak bonds. • A and T are held together by (#)_________ hydrogen bonds • C and G are held together by (#)_________ hydrogen bonds • The backbone of DNA is made up of alternating (D) and (P) molecules which are held together by strong bonds. • The two opposing strands are said to be since by knowing one half you can figure out the other) • What is the same about DNA between all organisms? • What is different about DNA between all organisms? DEOXYRIBOSE PHOSPHATE COVALENT COMPLEMENTARY THE SAME 4 NUCLEOTIDES ARE IN ALL ORGANISMS. THEY ARE MOSTLY THE SAME EXCEPT FOR THE ORDER OF THE NUCLEOTIDES, THE NUMBER OF CHROMOSOMES AND THE EXPRESSION OF THE GENES.

10. DNA Replication

11. 1. DNA Replication 2. Short Clip of Replication DNA Replication 3. DNA to Protein 4. DNA Replication • Use the puzzle pieces to construct a strand of DNA 6 nucleotides long. • Write down the sequence of the strands here. You can just list the letters of the bases. • Original Strand 1: T T G C G C • Original Strand 2: A A C G C G • Since the strands are complementary each strand can serve as a for a new DNA molecule. • Separate the two strands of DNA between the base pairs. You will get 12 new nucleotides. Manipulate these nucleotides to find the best fit with the 12 nucleotides in your Parental Strands. (Unzip DNA) TEMPLATE

12. DNA Replication COMPLEMENTARY • The new strand of the six nucleotides you just joined together is called a copy of your Parental Strand. Daughter Strand #1 is base-pairing to Parental Strand #1 and Daughter Strand #2 is base-pairing to Parental strand #2. (Enzyme helps with this chemical reaction) • In the space below, write the sequence of your nucleotides in each strand. (Your sequence will not be the same as below. P#1 & D#2 = Identical; D#1 & P#2 = Identical) • Parental strand #1: • Daughter strand #1: • Parental strand #2: • Daughter strand #2: • Do the two new molecules contain the same number of rungs? • Are the two DNA molecules exact copies of each other? T T G C G C A A C G C G A A C G C G T T G C G C • YES • YES

13. DNA Replication SEMICONSERVATIVE • This mode of replication is called replication because each parental strand is used as a model (or template) for the generation of the new daughter (or complementary) strand. Color the backbone of original strand blue and the newly formed strand red. Identify the parts of the DNA molecule below as the original strand or the new strand. 4. ORIGINAL 5. NEW 6. ORIGINAL 7. NEW

14. Steps of DNA Replication • An ENZYME (called comes in and breaks the bonds between the base pairs which causes the strand of DNA to split or “unzips” (what is left looks like a ladder cut in two). • The appropriate NUCLEOTIDE are then matched up (by another enzyme called . • What you are left with is identical strands of DNA. HELICASE HYDROGEN POLYMERASE TWO

15. DNA Replication • Why are the bonds between the nitrogen bases in DNA weak? • Specifically when and why would DNA have to replicate? SO DNA CAN SPLIT TO REPLICATE. WHEN NEW CELLS ARE MADE SO EACH NEW CELL HAS A COPY OF DNA

17. DNA vs RNA & Protein Synthesis

18. DNA vs RNA & Protein Synthesis NUCLEIC ACID NUCLEOTIDES • RNA also belongs to the group of organic molecules. • The building blocks of RNA are 1. RNA Structure 2. Transcription

19. DNA vs RNA & Protein Synthesis

20. DNA vs RNA & Protein Synthesis Three types of RNA: • RNA (mRNA)– carriers the code from the DNA in the to the in the cytoplasm. • Every three mRNA nucleotides is a How many are in the mRNA pictured below? MESSENGER NUCLEUS RIBOSOME CODON FOUR mRNA Codon

21. DNA vs RNA & Protein Synthesis • RNA (rRNA) combines with proteins to make up the • Made up of two subunits that snap together around the mRNA. RIBOSOMAL RIBOSOME rRNA (& protein)

22. DNA vs RNA & Protein Synthesis • RNA (tRNA) is the complement to the mRNA. • Its job is to bring to the ribosome to make the protein. • The 3 letters on the tRNA is called an • How are codons related to anticodons? TRANSFER AMINO ACIDS tRNA ANTICODON THEY ARE COMPLEMENTS OF EACH OTHER

23. Protein Synthesis

24. Protein Synthesis 1. DNA & Protein Synthesis 2. Translation AMINO ACIDS • ProteinSynthesis is the joining of in a specific sequence in order to form a protein or . There are only different amino acids. 20 POLYPEPTIDE

25. What does an amino acid look like? There are 20 different R groups. This is what makes each amino acid different.

26. So why do we even need to make proteins???? Here are several important proteins. Enzymes • ________________ - help with the chemical reactions in your body (metabolism). • __________________ - covers the red blood cells and helps carry oxygen to all the cells in your body. Remember your body needs oxygen to undergo __________________________ to produce 38 __________ molecules giving your body energy. • ________________ - helps maintain blood sugar homeostasis. Excess glucose is stored as glycogen in the muscles and liver. • ______________________ - Forms channels in the cell membrane to help transport substances in and out of the cell • ________________ - These help with growth and development • Makes up your muscles that help your body move. Is every protein made at all times within an organism? Hemoglobin Cellular Respiration ATP Insulin Integral proteins Hormones No, this would be a waste of time & energy. Proteins are made when needed.

28. Flow chart of Protein Synthesis (Label the arrows with the 2 steps). TRANSCRIPTION TRANSLATION protein DNA mRNA The DNA contains the code for making proteins. But DNA cannot leave the safety of the ______________. Therefore, mRNA is formed from the DNA and leaves the nucleus taking the message out to the ___________________ where proteins are made. NUCLEUS RIBOSOME

30. Protein Synthesis 1. DNA & Protein Synthesis Rap 2. Interactive DNA Replication & Protein Synthesis NUCLEUS First Step = Transcription • Occurs in the • is used to form Second Step = Translation • Occurs at the • The tRNA picks up a specific in the cytoplasm and ‘travels’ to the mRNA (which is attached to the ). • The tRNA attaches to the mRNA. When 2 tRNA molecules are next to one another at the ribosome a bond forms between the 2 amino acids. DNA mRNA RIBOSOME AMINO ACID RIBOSOME PEPTIDE

31. Result – long chain of amino acids making the protein or ________________________. The protein is functional when it folds and changes shape. (See your teachers telephone cord demo). POLYPEPTIDE

33. H Diagram of Protein Synthesis (Transcription + Translation)

34. Protein Synthesis C A G G U C Glutamine

35. Protein Synthesis

36. Mutations

37. Mutations • Mutation – A CHANGE IN THE DNA Sentence Analogy: Represents the Normal sequence: The red cat ate the fat rat. SILENT The red cat ate the fat rat. MISSENSE The red hat ate the fat rat. NONSENSE The red hat ate the INSERTION The reb dca tat eth efa tra t DELETION The rec ata tet hef atr at

38. 1. DNA Mutation Causing Cancer 2. How Mutations Work Mutations 3. Mutations 4. Mutations - sickle shaped cells Causes of Mutations: • Random errors in DNA replication • mutagens – physical or chemical agents that cause mutations • Ex: x-rays, UV rays • Mutations are not always bad –they are a source of genetic diversity