DNA Structure Nucleotide s and Replication DNA Consists

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DNA Structure, Nucleotide %s, and Replication

DNA Structure, Nucleotide %s, and Replication

DNA Consists of Nucleotides Nucleotide= Sugar Phosphate backbone: • Deoxyribose sugar (Ribose sugar in

DNA Consists of Nucleotides Nucleotide= Sugar Phosphate backbone: • Deoxyribose sugar (Ribose sugar in RNA) • Phosphate Group Nitrogenous Base (4 types): • Adenine, Thymine, Guanine, and Cytosine. • Purines: Adenine and Guanine • Pyrimidines: Thymine and Cytosine

What is DNA’s form? • Double helix- Looks like a spiral stair case. •

What is DNA’s form? • Double helix- Looks like a spiral stair case. • Sugar phosphate backbone never changes, so what part of DNA changes from organism to organism? • Nitrogenous Base order: what causes all of life’s diversity.

Building a DNA Model • First thing: – Color all the like pieces the

Building a DNA Model • First thing: – Color all the like pieces the same color. – So this means that all the adenine is the same color, guanine is a different color, etc. – Then cut out your pieces and prepare for assembly.

DNA STRUCTURE • WHAT ARE THE PARTS OF A NUCLEOTIDE? CONNECTED WITH STRONG BONDS

DNA STRUCTURE • WHAT ARE THE PARTS OF A NUCLEOTIDE? CONNECTED WITH STRONG BONDS PHOSPHATE SUGAR BASE These are covalent bonds.

DNA STRUCTURE • CONNECTED WITH WEAK BONDS (dotted line) These are called hydrogen bonds.

DNA STRUCTURE • CONNECTED WITH WEAK BONDS (dotted line) These are called hydrogen bonds.

DNA STRUCTURE • How many bases? • How many base pairs?

DNA STRUCTURE • How many bases? • How many base pairs?

BASE-PAIRING

BASE-PAIRING

DNA LOOKS LIKE A LADDER

DNA LOOKS LIKE A LADDER

DNA LOOKS LIKE A LADDER SUGAR-PHOSPHATE BACKBONE BASES: • ADENINE • THYMINE • CYTOSINE

DNA LOOKS LIKE A LADDER SUGAR-PHOSPHATE BACKBONE BASES: • ADENINE • THYMINE • CYTOSINE • GUANINE

Base Pairing • • • • Hydrogen bonds connect particular base pairs. Adenine bonds

Base Pairing • • • • Hydrogen bonds connect particular base pairs. Adenine bonds with Thymine (A=T) Guanine bonds with Cytosine (G=C) So purines bond to pyrimidines Label the DNA strand Deoxyribose Sugar Phosphate Group Nitrogenous Bases Adenine Thymine Guanine Cytosine Purines Pyrimidines

How many C’s? How many G’s? How many A’s? How many T’s?

How many C’s? How many G’s? How many A’s? How many T’s?

If they bond together they must be in equal percentages. Q: If there is

If they bond together they must be in equal percentages. Q: If there is 30% Thymine and 20% Cytosine, how much Guanine and Adenine is there? A: 20% Guanine A: 30% Adenine

If we know 1 percentage can we determine the rest? • If there is

If we know 1 percentage can we determine the rest? • If there is 14% Adenine, what percent Thymine will there be? • Thymine= 14% • What percent Guanine and Cytosine? • Total 100% - (A%+T%) = (C%+G%) • 100% - 28% = 72%(G+C) • 72%/2 = 36%G and 36%C

Sample Question • If the is 28% Guanine, what percent Adenine, Thymine, and Cytosine

Sample Question • If the is 28% Guanine, what percent Adenine, Thymine, and Cytosine will there be? • Find Cytosine first (if BP’s with Guanine) • Cytosine = 28% • 100% - (28%+28%) = 100% - (56%)= 44% • 44%/2 = 22%A and 22%T

DNA Replication • Follow along and fill in the blanks during this video. •

DNA Replication • Follow along and fill in the blanks during this video. • https: //tn. pbslearningmedia. org/resource/t dc 02. sci. life. gen. dnaanimation/how-dnareplicates/

DNA Replication • Helicase is the enzyme that unwinds DNA. • The parent DNA

DNA Replication • Helicase is the enzyme that unwinds DNA. • The parent DNA is used as a template. • DNA polymerase is used to connect complimentary base pairs to the template strand. • New nucleotides join together to make semiconservative DNA.

Meselson-Stahl: Semiconservative Replication Semi: Like a semicircle. What does it mean? Conservative: To conserve

Meselson-Stahl: Semiconservative Replication Semi: Like a semicircle. What does it mean? Conservative: To conserve (like the environment). What does it mean? Why is DNA replication called this?