Chp 8 - Nucleic Acids Flashcards
What are the two general types of nucleic acids, and their primary roles?
- DNA: Stores and transfers genetic information; passed during cell division.
- RNA: Involved in protein synthesis and enzymatic activities.
What are the components of a nucleotide?
- A sugar (pentose monosaccharide).
- One (or more) phosphate groups.
- A nitrogenous base.
List three main differences between DNA and RNA.
- DNA contains deoxyribose; RNA contains ribose.
- DNA uses thymine (T), RNA uses uracil (U).
- DNA is double-stranded, RNA is single-stranded.
What are the five nitrogen-containing bases, and which are exclusive to DNA or RNA?
Pyrimidines: Cytosine (C), Thymine (T, only in DNA), Uracil (U, only in RNA).
Purines: Adenine (A), Guanine (G).
How is a nucleoside formed?
A pentose sugar reacts with a nitrogenous base at the anomeric carbon through condensation.
What are the key functions of nucleotides?
- Building blocks of genetic material.
- Carriers of activated intermediates.
- Second messengers.
- Energy sources (ATP).
- Regulate metabolism.
What is the most precise modern definition of a gene?
A segment of genetic material that codes for one polypeptide or RNA product.
What is the sugar component in DNA and RNA called?
DNA: Deoxyribose
RNA: Ribose
What are the two types of nitrogenous bases?
Purines and Pyrimidines.
What are the structural differences between purines and pyrimidines?
Purines (A, G) have two rings; Pyrimidines (C, T, U) have one ring.
What type of bond joins nucleotides together in DNA and RNA?
Phosphodiester bond.
What is the function of a phosphodiester bond?
It links the 3’ carbon atom of one sugar molecule to the 5’ carbon atom of another.
What is the role of ATP as a nucleotide?
ATP acts as an energy source in metabolic processes.
Describe the structure of a DNA double helix.
Two strands of DNA form a double helix, with a sugar-phosphate backbone and nitrogenous bases paired inside.
What are the complementary base pairing rules in DNA?
A pairs with T (2 hydrogen bonds), and G pairs with C (3 hydrogen bonds).