Biology Unit 6 - DNA Structure and Replication
Which 2 nitrogen bases are the purines?
Adenine and Guanine
What are the base pairings (complementary bases)?
Adenine pairs with Thymine (in RNA Uracil replaces thymine, so Uracil pairs with Adenine) Cytosine pairs with Guanine
What are the 4 nitrogen bases in DNA?
Adenine, Thymine, Cytosine, Guanine
What does Uracil replace?
Thymine
What is DNA replication?
When DNA makes a copy of itself
How does DNA polymerase work?
catalyzes (starts/causes) the covalent bond between the phosphate of one nucleotide and the deoxyribose of the next nucleotide
Which nitrogenous bases are pyrimidines?
cytosine, thymine, uracil (in RNA)
What is DNA?
deoxyribonucleic acid; a nucleic acid polymer
`What is the structure of DNA?
double helix (twisted ladder)
What is the monomer of DNA?
nucleotide
What enzyme unzips DNA?
DNA helicase
What enzyme helps match up the new chain of DNA?
DNA polymerase
What forms each part of the DNA structure?
1. Sides of the ladder = sugar/phosphate backbone with covalent bonds 2. Steps of the ladder = nitrogen bases with hydrogen bonds
What are the 3 parts of DNA?
1. Sugar (deoxyribose) 2. Phosphate 3. Nitrogen base (adenine, guanine, cytosine, thymine)
What are the steps of DNA replication?
1. The original strand of DNA is unzipped by an enzyme (helicase) that breaks the hydrogen bonds between the bases. 2. Free nucleotides start to attach to their base pair by forming new hydrogen bonds. (A goes to T, T with A, C with G, and G with C) with the help of the enzyme DNA polymerase, making a chain. 3. This process continues until the entire strand of DNA has been unzipped and copied, resulting in 2 new strands of DNA (each side of the ladder makes a new whole strand including a parent strand and a "daughter" strand.
What is Chargraff's rule?
In any cell of any organism, there is the same amount of C and G and the same amount of A and T. A=T and C=G)
Who did Watson and Crick get xray diffraction photos from that helped them discover the structure of DNA?
Rosalind Franklin and Maurice Wilkins
How does helicase unzip DNA?
breaks hydrogen bonds
