2.6 Structure of DNA and RNA Flashcards
What are nucleotides, and what are their three main components?
Nucleotides are the monomers that make up DNA and RNA, consisting of a pentose sugar, a phosphate group, and a nitrogenous base.
What pentose sugar is found in DNA nucleotides?
Deoxyribose
What pentose sugar is found in RNA nucleotides?
Ribose
Which nitrogenous base is found in DNA but not in RNA?
Thymine
Which nitrogenous base is found in RNA but not in DNA?
Uracil
How are the nucleotides in a single strand of DNA or RNA connected?
Through a phosphodiester bond between the phosphate group of one nucleotide and the hydroxyl (OH) group of another.
What are the two types of nitrogenous bases found in nucleotides based on their structure?
Purines (adenine and guanine) with two rings, and pyrimidines (cytosine, thymine, and uracil) with one ring.
Describe the basic structure of DNA.
DNA is a double helix formed by two antiparallel strands of nucleotides linked by hydrogen bonds between complementary bases: adenine with thymine, and guanine with cytosine.
How did Crick and Watson use model making to elucidate the structure of DNA?
They built a metal model based on DNA’s chemistry and X-ray diffraction patterns, confirming its double helix structure through complementary base pairing and antiparallel strands.
What is the significance of the complementary base pairing rule in the structure of DNA?
It dictates that guanine always pairs with cytosine, and adenine always pairs with thymine, which is crucial for DNA replication and maintaining genetic integrity.