dna intro. & replication (s phase) dna = deoxyribonucleic acid objective: d3 - identify the...
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C. Chargaff, Erwin Discovered a relationship in the nitrogenous bases ADENINE (A) = THYMINE (T) GUANINE (G) = CYTOSINE (C) D. Rosalind Franklin (1952) TOOK AN X-RAY OF THE DNA STRUCTURE SO THE PATTERNS COULD BE SEEN THE X-RAYS SHOW THAT DNA IS TWISTED AROUND EACH OTHER LIKE A HELIX AND HAS 2 STRANDSTRANSCRIPT
DNA Intro. & Replication (S phase)
DNA = deoxyribonucleic acidObjective: D3 - Identify the components of DNA and describe…DNA replication
I. History of DNAA. Avery, Oswald (1944)
Discovered that the nucleic acid, DNA, stores and transmits the genetic information from one generation of an organism to the next
B. HERSHEY & CHASE (1952)CONCLUDED THAT THE GENETIC
MATERIAL OF THE BACTERIOPHAGE WAS DNA, NOT PROTEIN
C. Chargaff, ErwinDiscovered a relationship in the nitrogenous bases
ADENINE (A) = THYMINE (T) GUANINE (G) = CYTOSINE (C) D. Rosalind Franklin (1952)
TOOK AN X-RAY OF THE DNA STRUCTURE SO THE PATTERNS COULD BE SEEN
THE X-RAYS SHOW THAT DNA IS TWISTED AROUND EACH OTHER LIKE A HELIX AND HAS 2 STRANDS
E. Watson and Crick (1953) Studied the structure of the DNA by
building a 3-D model AFTER using clues from Franklin’s x-ray of DNA
proposed that DNA is made up of 2 chains of nucleotides & that the 2 strands are twisted together in a shape called a double helix
Nucleus
II. Overview of DNA
*Chromosomes are made up of super coiled DNA*
Histone ProteinsDNA
(double
helix)
Base pairs
Sugar-phosphate backbone
Structure of DNA
Made up of nucleotides
Nucleotides have 3 parts:o Phosphateo Sugaro Nitrogen base
Traits are carried in the sequence of nitrogen bases
Common to all organisms
Adenine always pairs with Thymine
Cytosine always pairs with Guanine
DNA Base Pairing Rules
Copying process by which a cell duplicates its DNA
DNA molecule separates into two strands, then produces two new complementary strands following the rules of base pairing Each strand of the double helix of
DNA serves as a template for the new strand
DNA – Genetic Information DNA – Deoxyribonucleic acid
III. DNA Replication (S phase)
How Replication OccursEnzymes unzip DNA by breaking the weak hydrogen bonds between the base pairs, which produces two replication forksDNA polymerase Joins individual nucleotides
to make a new strand Proofreads each new strand
Chromosome Number The number of chromosomes are the same at the end of mitosis
Practice: If one strand of DNA looks like this, ATC GTA CCG, what will the complementary side look like?
TAG CAT GGC If the number of chromosomes in a human skin cell is 46, how many chromosomes will there be in a skin cell after mitosis? 46
ATC GTA CCG___________