BIOLOGY NOTES GENETICS PART 6 PAGES 230 238

BIOLOGY NOTES GENETICS PART 6 PAGES 230 -238

Standards: 5. 9 _____ Describe the basic processes of DNA replication and how it relates to transmission and conservation of genetic information 5. 12 _____ Evaluate the impact of biotechnology on the individual, society, and the environment including medical and ethical issues

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

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

DIAGRAM:

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)

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

A. DNA Structure 2 • 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 hydrogen ladder resulting in a _______ shape v the chains twist together to form a _______ helix double

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

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. v base pairing principle = principle that DNA hydrogen bonds in _____ can only form thymine between adenine and ____ or guanine cytosine and _____

DIAGRAM:

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

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

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

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

Ø when nucleosomes are supercoiled into organized structures that are tightly packed, _______ are present chromosomes

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

v without replication, a species could not survive _______ and individuals could not successfully grow _____ and reproduce STEPS OF DNA REPLICATION: unwinds enzymes 1. The double helix ____ and _____ break the hydrogen bonds holding together the “unzipping” paired bases. This is known as ______ the DNA. v replication fork = the point at which the 2 chains of DNA are separated ** helicases are enzymes that unwind**

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

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

QUESTION: What would be the complementary base sequence of DNA for TACGTTC? ANSWER: AT G CAA G ___________________