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This overview explores the significance of DNA in defining individual characteristics and ensuring trait inheritance across generations. From the groundbreaking discoveries by Hershey and Chase in the 1940s to Watson and Crick's 1953 DNA model, we delve into the molecular structure of DNA, including its nucleotides, sugar-phosphate backbone, and nitrogen bases (A, T, C, G). We highlight DNA's essential functions, such as protein synthesis and genetic replication. Understanding these concepts is vital for appreciating genetics and cellular biology.
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What Makes You…You? DNA!
HISTORY • 1940’s – Hershey and Chase – concluded that DNA was the genetic material. • 1953 – Cambridge University – Great Britain • James Watson – American scientist and Francis Crick – British scientist – developed a model of DNA. • 1962 – Nobel Prize
IMPORTANCE OF DNA • Provides all the instructions that: 1. make you different from other species 2. make you different within your species • Ensures the transmission of traits from one generation to the next. • Provides the template for protein manufacture.
SIDES • Alternating sugar and phosphate molecules • Sugar = Deoxyribose • Held together by bonds
BASES • 4 DNA nitrogen bases • Adenine = A • Thymine = T • Cytosine = C • Guanine = G
MIDDLE / RUNGS OF THE LADDER • composed of nitrogen bases • nitrogen bases attach to the sides by bonds at the sugar • nitrogen bases held together by hydrogen bonds
OVERALL STRUCTURE CODON GROUP – any group of 3 nitrogen bases in a row. NUCLEOTIDE – basic subunit of DNA. Composed of sugar, phosphate, and nitrogen base.
BASE PAIRING RULES • A – T • T – A • G – C • C – G GCAT………CGAT
MAKING COMPLEMENTARY STRANDS OF DNA Given: A C T G C G T T A G C A T G A C G C A A T C G T Make the complementary strand of DNA
A C C G T A T C G T G G C A T A G C Let’s Try Another One! Given:
DNA REPLICATION • The process in which DNA is replicated (copied/duplicated) • Replication occurs at the end of Interphase I. • Ensures that each daughter cell gets the correct number of chromosomes necessary for that cell to be what it’s supposed to be (skin cell, muscle cell, nerve cell, sperm cell, egg cell (ovum), etc.
MITOSIS DNA REPLICATION A T nterphase 1 C G G C POLYMERASE
A T A T C G C G G C G C