A1.2 DNA and RNA (HL) Flashcards
What is the genetic material of all living organisms?
DNA (deoxyribonucleic acid) is the genetic material of all living organisms.
What are the three components of a nucleotide?
A nucleotide consists of a pentose sugar, a phosphate group, and a nitrogenous base.
How do nucleotides join to form a nucleic acid polymer?
Nucleotides join through phosphodiester bonds between the phosphate of one nucleotide and the sugar of another.
What is the sugar–phosphate backbone?
It is a strong, covalently bonded structure of alternating sugars and phosphates that forms the structural framework of DNA and RNA.
What are the four nitrogenous bases in DNA?
Adenine (A), Thymine (T), Guanine (G), and Cytosine (C).
What are the four nitrogenous bases in RNA?
Adenine (A), Uracil (U), Guanine (G), and Cytosine (C).
What are purines and pyrimidines?
Purines (Adenine and Guanine) have two rings, while Pyrimidines (Thymine, Cytosine, and Uracil) have one ring.
What type of bonding occurs between nitrogenous bases in DNA?
Hydrogen bonding—Adenine pairs with Thymine (A-T) via two hydrogen bonds, and Guanine pairs with Cytosine (G-C) via three hydrogen bonds.
What is the structural difference between DNA and RNA?
DNA has deoxyribose sugar and is double-stranded; RNA has ribose sugar and is single-stranded.
In which direction does DNA replication and nucleotide addition occur?
Nucleotides are added in the 5′ to 3′ direction.
What does it mean that DNA strands are antiparallel?
One strand runs 5′ to 3′, while the complementary strand runs 3′ to 5′.
What is the shape of the DNA molecule?
DNA forms a double helix.
What replaces thymine in RNA?
Uracil (U) replaces thymine in RNA.
What is the function of the sugar-phosphate backbone?
It provides structural stability and support for the nucleic acid strand.
Why is DNA extraction important in biology?
It allows scientists to study genetic material, diagnose diseases, and perform genetic modifications.
