Nucleic Acids Big Idea 3: Living systems store, retrieve, transmit, and respond to info essential to life processes.

Essential Knowledge 3A1: DNA, and in some cases RNA, is the primary source of heritable information.

Nucleic Acids Store and transmit hereditary information Amino acid sequence of a polypeptide is programmed by a unit of inheritance called a gene Genes are found on chromosomes.

Nucleic Acids Large, complex molecules composed of C, O, H, N, and P. 2 types are RNA, ribonucleic acid and DNA, deoxyribonucleic acid.

DNA

RNA

Prokaryotes Earliest cells Smaller than Eukaryotes! No nucleus (home for DNA)

Is housed in a region called the nucleoid Prokaryotic DNA Is housed in a region called the nucleoid

Prok. DNA Is usually small and circular Has plasmids: small, extra-chromosomal, double stranded, and circular DNA

Viruses and Eukaryotes can have plasmids too…

Led to double helix shape discovery by Watson and Crick Herstory Rosalind Franklin: British scientist (working in Maurice Wilkins lab) who took an X ray diffraction image of DNA, 1952 Led to double helix shape discovery by Watson and Crick Photo 51

Double Helix Structure HIStory Watson and Crick used Franklin’s image to create the double helix DNA model in 1953. Won Nobel Prize in 1962,w/ Wilkins. Double Helix Structure

Nucleic Acid Structure Made of nucleotides; both RNA and DNA. Each nucleotide contains: 1 Phosphate Group 1 Sugar 1 Nitrogen Base

Makes up a part of the DNA/RNA backbone Phosphate PO4 Makes up a part of the DNA/RNA backbone

Sugar In DNA, sugar is deoxyribose In RNA, sugar is ribose Binds to Nitrogen Base Is in backbone of DNA/RNA

(c) Nucleoside components: sugars Fig. 5-27c-2 Sugars Figure 5.27 Components of nucleic acids Deoxyribose (in DNA) Ribose (in RNA) (c) Nucleoside components: sugars

Conserved Through Evolution! DNA Nitrogen Bases Adenine Thymine Guanine Cytosine Conserved Through Evolution!

DNA Base Pairing Rules (Chargaff’s Rules) A only binds with T C only binds with G H bonds hold Nitrogen bases together

RNA Nitrogen Bases Adenine Cytosine Guanine Uracil NO Thymine!

Pyrimidines: Single Ring Structure: CTU Fig. 5-27c-1 Nitrogenous bases Pyrimidines Cytosine (C) Thymine (T, in DNA) Uracil (U, in RNA) Pyrimidines: Single Ring Structure: CTU Purines Figure 5.27 Components of nucleic acids Adenine (A) Guanine (G) Purines: Double Ring Structure, GA (c) Nucleoside components: nitrogenous bases

DNA: Double Stranded, RNA Single Stranded

DNA is AntiParallel

3’ carbon and 5’ carbon bind to PO4 phosphodiester linkage Fig. 5-27ab 3’ carbon and 5’ carbon bind to PO4 phosphodiester linkage 5' end 5'C 3'C Nucleoside Nitrogenous base 5'C Phosphate group Figure 5.27 Components of nucleic acids 3'C Sugar (pentose) 5'C 3'C (b) Nucleotide 3' end (a) Polynucleotide, or nucleic acid

DNA Replication DNA provides directions for its own replication  ensure continuous inheritance of DNA

DNA Replication Before a cell divides  must duplicate its DNA. Each strand of DNA will serve as a template/model for a new strand of DNA (semiconservative).

DNA Replication 1st Step DNA Helicase Enzyme called DNA helicase unzips and unwinds a portion of DNA. Enzyme helps breaks apart H connect N bases. (A,T,C,G)

DNA Replication: 2nd Step 2nd enzyme called DNA polymerase III comes along and begins to add complementary base pairs to nitrogen bases. Works in 5’ to 3’ fashion… Video Clip!

Other Enzymes Involved: DNA Replication Other Enzymes Involved: Ligase: Glues back sugar-phosphate backbone Topoisomerase: Regulates overwinding/ underwinding of DNA by cutting backbone

http://highered. mcgraw-hill http://highered.mcgraw-hill.com/sites/9834092339/student_view0/chapter14/dna_replication.html

Practice! If one side of DNA reads CTCT, what would the complement side of DNA read? Write down on paper!

GAGA!

Then, The Cell Divides… Mitosis: Makes 2 identical diploid (2 copies of chromosomes) cells from 1 parent cell: IPMAT