240 likes | 340 Views
What is a nucleic acid? What is the nucleus and what is its function inside the cell?. Griffith. Deoxyribonucleic Acid DNA is how your body stores information Most everything about you is determined, at least in part, by your DNA. DNA. DNA is double stranded DNA is wound up into a helix
E N D
What is a nucleic acid? What is the nucleus and what is its function inside the cell?
Deoxyribonucleic Acid DNA is how your body stores information Most everything about you is determined, at least in part, by your DNA DNA
DNA is double stranded DNA is wound up into a helix Thus DNA is known as a double helix Features of DNA
Rosalind Franklin – used X-ray crystallography to take a picture of DNA Francis Crick and James Watson are credited with the double helix model of DNA. Watson, Crick, Franklin
Each segment is a “nucleotide” DNA has 4 kinds of nucleotides DNA is divided into segments
How many strands does DNA have? What does DNA store? Where is DNA found in a cell? What are the 3 parts of DNA? MIDLESSON REVIEW:
Deoxyribose – a sugar Deoxyribose is the same for all nucleotides DNA is made up of 3 parts
Every nucleotide has a phosphate group These link the sugars together
Every nucleotide has a nitrogenous base • 4 kinds • Adenine • Guanine • Cytosine • Thymine
The amount of adenine in a molecule of DNA always equals the amount of thymine The amount of guanine in a molecule of DNA always equals the amount of cytosine. Chargaff’s Rule
An “A” on one strand always pairs with a “T” on the other strand. A “G” on one strand always pairs with a “C” on the other strand.
The sugar and phosphates of DNA are the same for all organisms It is only the order of the nitrogen bases that change Importance of Nitrogen bases
What 3 things does all DNA contain? What are the 4 nitrogenous bases? What is the function of the phosphate group in DNA? What nitrogenous base does A pair with? What nitrogenous base does C pair with? MIDLESSON REVIEW
When DNA coils around proteins it makes a substance called chromatin When chromatin coils around itself it forms chromosomes Prokaryotes have one circular chromosome Eukaryotes have multiple linear chromosomes, located in the nucleus Chromosomes
DNA copies itself with the enzyme “polymerase” • DNA unzips, then both strands have matching nucleotides added to make a new strand • Known as semiconservative replication DNA Replication
Describe how DNA replicates What is the enzyme needed for replication of DNA? Where is DNA found in a eukaryote? What does DNA store? End of lesson review