DNA Replication: Key Processes and Implications

1. BIOLOGY NOTESGENETICS PART 6 PAGES 230-238

2. Standards: 4.9 _____ Describe the basic processes of DNA replication and how it relates to transmission and conservation of genetic information _____ Evaluate the impact of biotechnology on the individual, society, and the environment including medical and ethical issues 4.12

3. Essential Questions: Why is the sequence of nucleotides on DNA molecules so important? 1.

4. living • Deoxyribose Nucleic Acid (DNA) = the genetic material that composes all ______ organisms • nucleic acids are highly complex _________ made up of smaller monomer subunits called ____________ • nucleotide = monomer of nucleic acids composed of a 5-carbon ______, a phosphate group, and a nitrogenous ______ polymers nucleotides sugar base

6. DIAGRAM:

7. sugar • Deoxyribose is the name of the ______ in DNA • DNA has 4 possible nitrogenous bases: 1. Adenine (A) 2. Thymine (T) 3. Cytosine (C) 4. Guanine (G)

8. 2 adenine, guanine 1 • purine = a nitrogenous base with __ rings e.g. • pyrimidine = a nitrogenous base with __ ring e.g. thymine, cytosine

9. 2 A. DNA Structure • In DNA, nucleotides join together to form ___ long chains which together compose the polymeric nucleic acid • the chains of nucleotides in DNA are joined by _________ bonds between the bases resulting in a _______ shape • the chains twist together to form a _______ helix hydrogen ladder double

12. Watson Crick • the double helix shape was first discovered in 1953 by James _______ and Francis ______

13. Chargaff • Erwin ________ discovered that specific bases will pair together in DNA. This became known as Chargaff’s rules and later the principle of base pairing. • base pairing principle = principle that hydrogen bonds in _____ can only form between adenine and ________ or guanine and _________ DNA thymine cytosine

14. DIAGRAM:

15. B. DNA Sequence • How can organisms be different from each other if their genetic material is made of the same molecules (DNA)? **WORD JUMBLE** Answer: the _________ of ___________ in the DNA strands of organisms is _________ • The __________ of nucleotides forms the unique genetic information of an organism. The more closely related two organisms are, the more _____ the order of nucleotides in their DNA will be. sequence nucleotides different sequence alike

16. sequence species • Human Genome Project = research project that led scientists to discover the exact _________ of nucleotide bases for the human ________ • begun in _____ and completed in _____ • documented the exact nucleotide sequence for over __ billion base pairings 1990 2003 3

17. C. DNA vs. Chromosome vs. Chromatin • All cells contain DNA • prokaryotic DNA is contained in the __________ of the cell • eukaryotic DNA is contained in the _______ of the cell cytoplasm nucleus

18. long meter • DNA is extremely _____. The nucleus of each human cell contains more than 1 ______ of DNA. How does it fit??? • histones = proteins inside of the nucleus that _____ wraps itself around tightly • nucleosomes = the beadlike structure formed from several _________ wrapped together in _____ • when nucleosome are supercoiled but not organized in structure, __________ is present DNA histones DNA chromatin

19. chromosomes • when nucleosomes are supercoiled into organized structures that are tightly packed, _____________ are present

21. replication genetic meiosis D. DNA Replication • During cell __________, exact copies of cells are made including all _______ information. During cell ________, copies of gametes are made which also include copying of genetic information. • DNA replication = the production of a genetically identical copy of DNA made prior to cell ________ • made during the ___ phase of interphase division S (synthesis)

22. survive grow • without replication, a species could not _______ and individuals could not successfully _____ and reproduce STEPS OF DNA REPLICATION: • The double helix ________ and _________ break the hydrogen bonds holding together the paired bases. This is known as ___________ the DNA. • replication fork = the point at which the 2 chains of DNA are separated unwinds enzymes “unzipping” ** helicases are enzymes that unwind**

24. nucleotides base complementary 2. Free floating ___________ in the nucleus bond to the single strand by _____ pairing. The added bases are known as ______________ bases and the new strands are _______________________ to the original strands. • DNA polymerase = the principle enzyme involved in DNA replication because it bonds the free ______ to the original bases and __________ each new DNA strand. complementary (mates) bases proofreads

26. chromosomes 2 3. Replication continues until all of the DNA in all of the _____________ of the cell have been copied. The results are __ copies of the organism’s genetic material. • each new copy consists of ___ original copy of DNA and ____ new, complementary strand. 1 1

28. A T G C A A G QUESTION: What would be the complementary base sequence of DNA for TACGTTC? ANSWER: ______________________________________