DNA was identified as the genetic material through a series of experiments. Griffith found that a transforming principle in dead bacteria could make live bacteria deadly. Avery purified this principle and identified it as DNA through chemical and enzyme tests. Hershey and Chase showed that viral DNA, not proteins, entered bacteria during infection. Watson and Crick determined that DNA is a double helix with nucleotides pairing according to base pairing rules. DNA replication copies genetic information by unwinding the DNA helix and using it as a template to produce two identical DNA molecules. Transcription produces RNA copies of genes which then direct protein production.

1. KEY CONCEPT DNA was identified as the genetic material through a series of experiments.

2. Griffith finds a ‘transforming principle.’ Griffith experimented with the bacteria that cause pneumonia. He used two forms: the S form (deadly) and the R form (not deadly). A transforming material passed from dead S bacteria to live R bacteria, making them deadly.

4. Chemical tests showedthe chemical makeupmatched that of DNA.

6. They tagged viral proteins with radioactive sulfur.

8. phosphate group nitrogen-containing base deoxyribose (sugar) DNA is composed of four types of nucleotides. DNA is made up of a long chain of nucleotides. Each nucleotide has three parts. a phosphate group a deoxyribose sugar a nitrogen-containing base

11. Franklin’s x-ray images suggested that DNA was a double helix of even width.

13. C pairs with G

16. Replication copies the genetic information. A single strand of DNA serves as a template for a new strand. The rules of base pairing directreplication. DNA is replicated during theS (synthesis) stage of thecell cycle. Each body cell gets acomplete set ofidentical DNA.

17. nucleotide The DNA molecule unzips in both directions. Proteins carry out the process of replication. DNA serves only as a template. Enzymes and other proteins do the actual work of replication. Enzymes unzip the double helix. Free-floating nucleotides form hydrogen bonds with the template strand.

22. RNA carries DNA’s instructions. The central dogma states that information flows in one direction from DNA to RNA to proteins.

24. Replication

25. Transcription

26. Translation

28. RNA has a ribose sugar.

29. RNA has uracil instead of thymine.

32. RNA polymerase and other proteins form a transcription complex.

34. RNA polymerase bonds the nucleotides together.

36. Messenger RNA (mRNA) carries the message that will be translated to form a protein.

37. Ribosomal RNA (rRNA) forms part of ribosomes where proteins are made.