nucleic acids structure and function Flashcards
What are the two main types of nucleic acids, and what are their functions?
DNA: Stores genetic information for the development and function of living organisms.
RNA: Plays a role in protein synthesis and has structural, regulatory, and catalytic roles.
What are the three components of DNA?
Deoxyribose Sugar
Nitrogenous Base (Adenine, Thymine, Guanine, Cytosine)
Phosphate Group
What are purines and pyrimidines in DNA?
Purines: Adenine (A) and Guanine (G)
Pyrimidines: Cytosine (C) and Thymine (T)
What is a nucleoside?
A nucleoside consists of a sugar (ribose or deoxyribose) bound to a nitrogenous base via an N-glycosidic bond.
What is the difference between a nucleoside and a nucleotide?
A nucleotide is a nucleoside with one or more phosphate groups attached to the 5’ carbon of the sugar.
What are the biochemical roles of nucleotides?
Provide chemical energy (e.g., ATP).
Act as signaling molecules (e.g., cAMP).
Involved in metabolism, enzyme activity, and biosynthetic reactions.
What is Chargaff’s first rule?
In double-stranded DNA, the amount of adenine equals thymine (A = T), and the amount of guanine equals cytosine (G = C).
What are the differences between DNA and RNA?
DNA has deoxyribose sugar; RNA has ribose sugar.
DNA is double-stranded; RNA is single-stranded.
RNA contains uracil (U) instead of thymine (T).
What are the three main types of RNA and their functions?
mRNA: Encodes proteins.
tRNA: Transfers amino acids to ribosomes during protein synthesis.
rRNA: Forms the core of ribosomes and catalyzes protein synthesis.
What is the structure of chromatin?
Chromatin consists of DNA wrapped around histone proteins, forming nucleosomes, often described as “beads on a string.”
What types of genomes exist based on DNA structure?
Single-stranded DNA (ssDNA): Found in some viruses.
Double-stranded loop DNA (dsDNA): Found in bacteria, mitochondria, chloroplasts.
Double-stranded linear DNA (dsDNA): Found in most eukaryotic cells.
Who were the key scientists involved in discovering the structure of DNA?
James Watson and Francis Crick
Rosalind Franklin and Maurice Wilkins
What is the size of the human genome?
Approximately 3.2 billion base pairs (3 Gb).
What is the primary role of RNA in cells?
RNA is essential for protein synthesis and plays structural, regulatory, and catalytic roles.
What is the “cloverleaf structure” in RNA?
It is the common secondary structure of tRNA.
