Chapter 4.1.2 (Exam 3) Base Pairing Flashcards
Nucleic Acids Are Informational Macromolecules
What are the DNA bases?
Purines: Adenine (A) & Guanine (G)
Pyrimidines: Cytosine (C) & Thymine (T)
What is complementary base pairing?
Purines pair with pyrimidines by hydrogen bonds
Why can’t purines pair with each other? Why can’t pyrimidines?
Purines are double rings and pyrimidines are single rings
If they pair with themselves, some rows will have 4 rings, and other will have two, causing DNA to be misshapen
Instead, all base pairings have 3 rings
How many H bonds are there between A and T? C and G?
Between A and T, there are 2 H bonds
Between C and G, there are 3 H bonds
Describe RNA.
Single-stranded, but base pairing can occur between different regions of the molecule which results in 3-D structure
RNA has uracil (U) instead of thymine
Complementary base pairing can also take place between RNA and DNA
Describe DNA.
Two strands form a double helix
All DNA molecules have the same structure
DNA can reproduce itself (replication)
What is transcription?
DNA sequences are copied into RNA
What is translation?
RNA sequence specifies the sequence of amino acids in a polypeptide
What is the result of transcription and translation?
Formation of polypeptides results in gene expression
In replication, the entire DNA molecule is replicated. What do DNA replication and transcription depend on?
DNA replication and transcription depend on the base-pairing properties of nucleic acids
What is a genome?
The complete set of DNA in an organism
What are genes?
sequences of DNA that are transcribed into RNA
What are some other roles of nucleotides aside from the formation of DNA and RNA?
ATP—energy transfer in biochemical reactions
GTP—energy source in protein synthesis
cAMP—essential in many processes, including hormone action
Carriers in synthesis and breakdown of carbohydrates and lipids
