BIOLOGY NOTES GENETICS PART 6 PAGES 230-238

Standards: _____ 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 5.9 5.12

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

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 ______ living polymers nucleotides sugar base

DIAGRAM:

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) sugar

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

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 2 hydrogen ladder double

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

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 _________ Chargaff DNA thymine cytosine

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** 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

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 sequence species 1990 2003 3

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

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 long meter DNA histones DNA chromatin

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

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 replication genetic meiosis division S (synthesis)

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 survive grow unwinds enzymes “unzipping” ** helicases are enzymes that unwind**

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. nucleotides base complementary complementary (mates) bases proofreads

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. chromosomes 2 1 1

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