DNA DNA DNA DNA Structure Diagram DNA DNA
DNA What is DNA? • Nucleic acid polymer made by a sequence of nucleotides What is a nucleotide? • Smaller that makes up a nucleic acid • Has three parts: 1. Sugar (deoxyribose) 2. Phosphate group 3. 1 of 4 nitrogen bases
DNA What are the 4 nitrogen bases? 1. Adenine (A) 2. Guanine (G) 3. Cytosine (C) 4. Thymine (T) **ALL organisms have the same 4 nucleotides
DNA What is DNA’s structure? • Made of 2 strands • Strands are twisted like a spiral staircase/twisted ladder • This is called a DOUBLE HELIX How are the sides of ladder formed? • by the bonding of the sugar from one nucleotide to the phosphate group of another nucleotide How are the steps of the ladder formed? By the bonding of one nucleotide N-base on strand #1 to another nucleotides N-base on strand #2
Purines Adenine
Pyrimidines
Guanine
Cytosine
Phosphate group
Thymine
Deoxyribose
DNA Structure Diagram Nucleotide Hydrogen bonds
Sugar-phosphate backbone Key Adenine (A) Thymine (T) Cytosine (C) Guanine (G)
DNA
DNA
How the nucleotide N-bases pair up? • Adenine to Thymine ONLY (A-T) • Guanine to Cytosine ONLY (G-C) If all organisms have the same four nucleotides, then how do we get so many different organisms? • The sequence of the nucleotides is different for each organisms DNA strand • The more similar the sequence the more similar the organism
What is the Human Genome Project? • A project where scientists are trying to figure out the entire sequence of a human DNA strand • This will map out the genes for a human • They can use this to find cures or treatments for genetic disorders and some cancers
1
DNA
DNA in Chromosomes Chromosome
Nucleosome DNA double helix Coils
Supercoils
Histones
DNA Replication (Drawing)
What is DNA replication? • How DNA will make a copy of itself to put into each new cell which is made How does it work? • The 2 strands of DNA unzip by an enzyme • Free floating nucleotides in that enzyme will attach to the newly detached nucleotides on both DNA strands • The enzyme will run through the entire DNA strand • Result: 2 new DNA molecules **Each new DNA molecule has one original strand and one new complementary strand
DNA Replication Diagram New strand
Original strand
DNA polymerase
Growth DNA polymerase
Growth
Replication fork
Replication fork
New strand
Original strand
2
DNA What are the 4 nitrogen bases? 1. Adenine (A) 2. Guanine (G) 3. Cytosine (C) 4. Thymine (T) **ALL organisms have the same 4 nucleotides
DNA What is DNA’s structure? • Made of 2 strands • Strands are twisted like a spiral staircase/twisted ladder • This is called a DOUBLE HELIX How are the sides of ladder formed? • by the bonding of the sugar from one nucleotide to the phosphate group of another nucleotide How are the steps of the ladder formed? By the bonding of one nucleotide N-base on strand #1 to another nucleotides N-base on strand #2
Purines Adenine
Pyrimidines
Guanine
Cytosine
Phosphate group
Thymine
Deoxyribose
DNA Structure Diagram Nucleotide Hydrogen bonds
Sugar-phosphate backbone Key Adenine (A) Thymine (T) Cytosine (C) Guanine (G)
DNA
DNA
How the nucleotide N-bases pair up? • Adenine to Thymine ONLY (A-T) • Guanine to Cytosine ONLY (G-C) If all organisms have the same four nucleotides, then how do we get so many different organisms? • The sequence of the nucleotides is different for each organisms DNA strand • The more similar the sequence the more similar the organism
What is the Human Genome Project? • A project where scientists are trying to figure out the entire sequence of a human DNA strand • This will map out the genes for a human • They can use this to find cures or treatments for genetic disorders and some cancers
1
DNA
DNA in Chromosomes Chromosome
Nucleosome DNA double helix Coils
Supercoils
Histones
DNA Replication (Drawing)
What is DNA replication? • How DNA will make a copy of itself to put into each new cell which is made How does it work? • The 2 strands of DNA unzip by an enzyme • Free floating nucleotides in that enzyme will attach to the newly detached nucleotides on both DNA strands • The enzyme will run through the entire DNA strand • Result: 2 new DNA molecules **Each new DNA molecule has one original strand and one new complementary strand
DNA Replication Diagram New strand
Original strand
DNA polymerase
Growth DNA polymerase
Growth
Replication fork
Replication fork
New strand
Original strand
2
