Chapter 10: DNA, RNA, and Protein Synthesis

Words on Chapter 10 Quiz

• Transformation• Nucleotide• Deoxyribose• Nitrogen base• Purine• Pyrimidine• Helicase• DNA replication• DNA polymerase• Mutation

• Transcription• Translation• Ribose• Messenger RNA• Ribosomal RNA• Transfer RNA• RNA

polymerase• Promotor• Codon• anticodon

Section1: Discovery of DNA

• Griffith’s Experiments: involved working with bacteria that reproduce using binary fission, pneumonia has a strand of bacteria that attacks mammals.

• Transformation: was discovered from the experiments done by Griffith with the R and S strands of pneumonia. There is a relationship between how cells communicate (genetic material).

The Work of Oswald Avery

• He continued Griffith’s work by testing whether the transformation happened due to protein, RNA, or DNA.

• He concluded that DNA was responsible for the transformation in bacteria. The RNA and protein tests did not respond correctly.

Hershey-Chase Experiment

• Martha Chase and Alfred Hershey (1950’s)• Worked with bacteriophages (phages)• Used radioactive sulfur to discover that DNA is

the hereditary molecule in viruses.

Section 2: DNA Structure• Base pairs: AT –Adenine/Thymine, CG—Cytosine/Guanine• Watson & Crick: credited with discovering that DNA is a

double-helix or winding staircase• DNA Nucleotides: 5 Carbon Sugar, Phosphate group

(phosphorous), and nitrogen base• Rosalind Franklin helped with the structure of DNA• AT and CG are held together by Hydrogen bonds (glue

that holds both sides of the helix together)• D deoxyribose, N nucleic, A acidDEE OXY RYE BOWS

Nitrogen Bases

• The base pairs on the “left” of the helix: Adenine and Guanine are the group PURINES

• The base pairs on the “right” of the helix: Thymine and Cytosine are the PYRIMIDINE group.

Complimentary Bases

• A-T C-G

A A A G G G C C TT T T C C C G G A

Section 3: DNA replication

• Replication-is when DNA copies itself • Occurs when all living cells divide either

during MEIOSIS (gametes) OR MITOSIS (autosomes)

Steps on How DNA Reproduces

• Helicase separate the DNA strands (helicase enzyme “unzips” the helix)

• DNA polymerase add the complimentary nucleotides that match the original strand of DNA. (New DNA must match the Original)

• Yield two identical DNA molecules

TYPES OF RNA

• Ribonucleic Acid (RNA) helps DNA copy itself• mRNA (Messenger RNA): Deliver the genetic

“message” to the ribosomes in the cytosol of eukaryotic cells.

• rRNA (Ribosomal RNA): is step 2 of the process where the ribosomes create proteins using the protein synthesis

• tRNA (Transfer RNA): is where the amino acids help create proteins

Transcription

• Promotors give the signal to start copying the genes

• Termination Signals give the signal to stop when that part of the genome is complete.