Section 2 Objectives – page 288

1. Section 2 Objectives – page 288 **Section Objectives **Relate the concept of the gene to the sequence of nucleotides in DNA. **Sequence the steps involved in protein synthesis.

2. Section 11.2 Summary – pages 288 - 295 Genes and Proteins • The sequence of nucleotides in a gene on DNA • contains information. • Information = production of proteins. • Proteins fold into 3D shapes to become either: • 1. Protein structures • 2. Enzyme regulators of cell functions.

3. Section 11.2 Summary – page 288 - 295 • Enzymes control all the chemical reactions • of an organism. • By encoding the instructions for making • proteins and enzymes, DNA controls cells.

4. Section 11.2 Summary – page 2888- 295 • Proteins are polymers of amino acids. The sequence of nucleotides in each gene contains information for assembling the string of amino acids that make up a single protein.

5. Section 11.2 Summary – pages 288 - 295 RNA • RNA like DNA, is a nucleic acid. RNA structure differs from DNA structure in three ways. 1. RNA is single stranded—whereas DNA is double stranded.

6. Section 11.2 Summary – pages 288 - 295 Ribose 2. The sugar in RNA is ribose DNA’s sugar is deoxyribose.

7. Section 11.2 Summary – pages 288 - 295 3. DNA and RNA contain four nitrogenous bases. But rather than thymine, RNA contains a base called uracil (U). Uracil forms a base pair with adenine in RNA, just as thymine does in DNA. Uracil Adenine Hydrogen bonds

8. Section 11.2 Summary – pages 288 - 295 DNA provides: 1. workers with codes for making proteins 2. workers synthesize the proteins. 3. The workers for protein synthesis are RNAmolecules. RNA helps assemble a protein – amino acid by amino acid – as directed by the code it carries from the DNA

9. Section 11.2 Summary – pages 288 - 295 • There are three types of RNA that help build proteins: 1. Messenger RNA (mRNA), brings instructions from DNA in the nucleus to the cell’s factory floor, the cytoplasm. • In the cytoplasm, mRNA moves to the assembly line, a ribosome.

10. Section 11.2 Summary – pages 288 - 295 2. The ribosome, made of ribosomal RNA (rRNA), binds to the mRNA and uses the instructions to assemble the amino acids in the correct order. 3. Transfer RNA (tRNA) is the supplier. Transfer RNA delivers amino acids to the ribosome to be assembled into a protein.

11. Section 11.2 Summary – pages 288 - 295 Transcription • In the nucleus, enzymes make an RNA copy of a portion of a DNA strand in a process called transcription.

12. Section 11.2 Summary – pages 288 - 295 Transcription

13. Transcription

14. Section 1 Check Which of the following correctly comprises a complimentary base pairing in RNA? DNA RNA A. adenine – thymine B. thymine – guanine C. guanine – adenine D. cytosine – thymine E. adenine – uracil The answer is E.

15. Section 11.2 Summary – pages 288 - 295 Transcription • The difference between transcription and DNA replication is that: DNA Replication = double-stranded DNA DNA Transcription = single-stranded RNA

16. Transcription Game