DNA & PROTEIN SNTHESIS(Words to Know)

• 1. Transfer RNA• 2. Peptide Bond• 3. Dipeptide Bond• 4. ATP• 5. Translation• 6. Anticodon• 7. Transcription• 8. Messenger RNA• 9. Codon• 10. Ribosomal RNA• 11. Ribosomes

•12. Nucleus•13. Protein Synthesis•14. Replication•15. Hydrogen Bonds•16. Complementary Base Pairs•17 Amino Acids•18 Nucleotide •19. DNA•20. Proteins•21. Double Helix•22. Watson & Crick•23. Purines•24. Pyrimidines•25. RNA

• CHAPTER 11

• relating the structure of DNA to its function• the role of DNA in protein production• distinguish amongst different types of mutations.

• Proteins are important components of living cells.

• Metabolism of cells is controlled by proteins called enzymes.

• Proteins are essential for life.

• Every cell is capable of making all the thousands of different kinds of proteins it may need.

• DNA of the chromosomes is the genetic material that is passed from generation to generation.

• Genes are sections of DNA.

• DNA controls cellular activities by controlling the production of enzymes.

Think On This…

• How does the cell synthesize proteins?

• What determines the kinds of enzymes present in each cell?

• The molecule that controls the production of proteins is a nucleic acid called Deoxyribonucleic Acid (DNA).

• DNA is found in the chromosomes in the nucleus.

• DNA carries information for running the cell.• DNA is made of nucleotides.

DNA StructureDNA is made up of nucleotides

Nucleotides Have Three Parts

1. Simple Sugar (5-carbon sugar)

2. Phosphate group

3. Nitrogen Base

Looking at the Structure of DNA

• In 1953 Watson and Crick solved the puzzle (p. 290 Fig. 11:3)

• These two scientists viewed x-ray images of DNA crystals that were created by Rosalind Franklin and Maurice Wilkins.

• DNA Structure• Resembles a ladder

– sides: sugar and phosphate– rungs (steps): complementary pairs

of nitrogen bases

The structure (shape) of the DNAis referred to as a double helix.

•In DNA, there are four possible nitrogen bases:

•adenine (A)

•guanine (G)

•cytosine (C)

•thymine (T)

• Purines– Adenine (A)– Guanine (G)

• Pyrimidines– Thymine (T)– Cytosine (C)

Adenine (A) to Thymine (T)And

Guanine (G) to Cytosine (C)

DNA Replication

Replication of DNA

• DNA molecules can build an exact copy of itself.– This is called Replication. (ATP is the energy source)

• Replication is important for reproduction and must occur every time a cell divides.– That way each cell has a complete set of instructions

for making proteins.

:

REMEMBER: DNA is in the Nucleus Proteins are synthesized in the Ribosomes“ How can the information get to the ribosomes?”

By coping a near message >>mRNA (messenger RNA)The process of transferring the information from

DNA to RNA is called transcription

Transferring the info….

• To carry the genetic message from the nucleus into the cytoplasm we have

mRNA.• Any RNA strand is a

direct order from the DNA.

RNA Structure(looks like one half of a

zipper)• The Sugar is Ribose

• Single Strand

• Bases are:

• Adenine (A) to Uracil (U)

• Guanine (G) to Cytosine (C)

**Thymine is NOT found in RNA **

Thymine is substituted with Uracil

3 Types of RNA

• mRNA (messenger RNA) *Carries genetic information from nucleus to ribosomes.• rRNA (ribosomal RNA) *Found in ribosomes *binds to mRNA and uses instructions to assemble the amino acids in the correct order• tRNA (transfer RNA) * Found in the cytoplasm * Carries amino acids in the cytoplasm to the ribosomes

DNA….to Proteins

• DNA Replicates….mRNA carries message to the Ribosome…

The Genetic Code• There are 4 bases• There are 20 different kinds of

– amino acids in cells(A.A. are the building blocks of proteins)• The groups of three bases (3 letter code) in

mRNA are called codons or triplets.

UUU,Codon

Or triplet

AUA,Codon

OrTriplet

ACG,Codon

OrTriplet

• Each codon codes for a particular A.A.• Each codon always codes for the same A.A• The sequence can be different…this gives rise to

different proteins.• There are 64 possible 3 letter code words.• Only 20 common A.A.• Some codons do not code for A.A., they provide

instructions for making the proteins Example: UAA (is a stop codon) this indicates that the protein ends at this point

Example:AUG (is a start codon and codes for an A.A.)

TRANSLATION(see p. 294)

• Bonding A. A. to form proteins is called• Translation (from mRNA to Protein)• tRNA: * Is shaped like a cloverleaf (Fig. 11:8) *one end has an attached site for an A.A. * the other end has an exposed base triplet called and anticodon

* If a codon (3 bases on mRNA) is AUC …..then Its’ anticodon (3 bases on tRNA) is UAG *In the cytoplasm are the A. A. necessary for building proteins. tRNA will carry the proper A.A. to the mRNA and line them in the correct order. * Once the RNA attaches to its’ specific A.A. the combination moves toward a ribosome (protein factory)

Translation: Information is

decoded

Transfer RNA (tRNA) (p. 293)

Three base anticodon

Amino Acid Codons

Genetic Changes (11:3)

• Mutation: any change in the DNA sequence. Mutagen: any agent that can cause a change in DNA…(radiation, chemicals, and even high

temperatures.Effects of Mutation: (p. 298)

• Point mutation: Change in a single base pair in DNA• Frameshift Mutation: A single base is added or

deleted from DNA

Four Kinds of Chromosomal Mutations (see.p. 300)

• Deletion: part of the chromosome is left out

• Insertion: part of the a chromatid breaks off and attaches to its sister chromatid

• Inversion: part of a chromosome breaks off and reattaches backwards

• Translocation: part of one chromosome breaks off and is added to a different chromosome

Terms1. Protein: A complex chain of amino acids

essential in cell structure.2. DNA: A nucleic acid “molecule of life”3. Nucleus: Control center of the cell4. Protein Synthesis: the making of

proteins5. Double Helix: the shape of DNA6. Watson & Crick: Constructed DNA model7. Ribosomes: Protein factory8. ATP: Energy used to break chemical bonds

More Terms9. Hydrogen Bonds: holds nitrogen bases together (they are weak)10. Replication: ability to build an identical copy of itself11. Messenger RNA (mRNA): Brings the code from the DNA to the ribosomes (sets of 3 are codons)12. Transcription: Process by which the DNA code is copied onto a

strand of mRNA.13. Nucleotide: contains a 5-carbon sugar, nitrogen base and phosphate14. Amino Acid: the building blocks of proteins15. Purines: Adenine and Guanine16. Pyrimidines: Cytosine and Thymine

More Terms17. Complementary Base Pair: A (to) T C (to) G18. RNA: Ribonucleic Acid

19. Ribosomal RNA (rRNA): makes up the major part of ribosomes20. Codon: a sequence of 3 nucleotide bases that code for 2 amino acid in a protein…(found on mRNA)

21. Anticodon: An exposed base triplet at the end of the RNA (found on tRNA)

22. Translation: Process of bonding A.A. in a sequence to form a protein

23. Dipeptide Bond: 2 or more A. A. joined

24. Peptide Bond: the bond that forms between A.A. to join another25. Transfer RNA (tRNA): “Picks up” and carries A.A. to the ribosomes

DNA Worksheet1. Name the molecule of life.2. What are proteins essential for?3. What are the building blocks for proteins?4. Who studied the structure of DNA?5. Where do you find DNA?6. What is the job DNA?7. Name the 4 bases in DNA.8. How do these bases pair?9. What does the DNA structure look like?10.What is the protein factory of the cell?11.Name three types of RNA..12.Name two jobs of RNA..13.What base does adenine bond with? How many bases does it take to

make one amino acid?14.How many amino acids are common?15.What is the anticodon for ACG?16.If DNA read A-T-T-A-C-G-G-C-C what would the RNA read? Why is

DNA replication important?

1. What is the shape of the DNA molecule?2. Who are the two men that proposed DNA?3. What base will pair with cytosine?4. What base will pair with adenine?5. The shape of the DNA structure is twisted, it is better

known as ___.6. What is the process called when DNA copies itself?7. Name the three types of RNA.8. What is transcription?9. What is translation?10. What kind of information does the DNA contain?

DNA StoryIn the living world there are millions of different kinds of (1)

____. How are these made by cells? It has been found that protein synthesis in a cell is controlled by a complex macromolecule called (2)_____. This compound is not a protein but a (3)______. A nucleic acid is made up of 3 parts. A 5-Carbon (4)____ molecule, nitrogen containing (5)____, and a (6)____ group. DNA looks like a ladder twisted into a shape known as (7)____. Each side of the “ladder” is a long strand made of connecting nucleic acids.

Each base is joined by a weak (8) ___ to a base on the other strand forming “rungs” in the ladder. The bases form complementary pairs. Adenine bonds with (9) ____; cytosine bonds with (10)___. During DNA (11)_____, the hydrogen bonds break and each strand finds new complimentary bases.

DNA Story cont.• In the nucleic acid RNA, adenine

always pairs with (12)______. • There are three kinds of RNA.

(13)______ RNA carries genetic information from the nucleus to the cytoplasm.

• During (14)____. Information is transferred from DNA in the nucleus to mRNA.

• The DNA molecule opens up and the mRNA forms a single complementary (15)_____.

• The four bases of RNA can be combined into 64 different (16)______ combinations.

• Each triple, known as a (17)___, codes for one specific (18)____.

• The order of the triples will determine the order of the amino acids in the ______ (19) synthesized.

Word Bank

• PROTEIN• AMINO ACIDS• SUGAR• BASE• HYDROGEN• MESSENGER• PROTEINS• THYMINE• REPLICATION• STRAND• THREE BASE• CONDON• GUANINE• PHOSPHATE• DNA• DOUBLE HELIZ• URACIL• TRANSCRIPTION• NUCLEIC ACID