Biology 1113L: Lecture 5 (nucleic acids) Flashcards
What are the two main types of nucleic acids?
DNA (Deoxyribonucleic acid) and RNA (Ribonucleic acid).
What are the primary functions of DNA and RNA?
DNA: Storage and transmission of genetic information.
RNA: Protein synthesis and other diverse functions.
What is the monomer of nucleic acids?
Nucleotides.
What are the three components of a nucleotide?
Phosphate group.
5-carbon sugar (ribose or deoxyribose).
Nitrogenous base.
What is the difference between ribose and deoxyribose?
Deoxyribose has one less oxygen atom than ribose.
What are the nitrogenous bases, and how do they differ in DNA and RNA?
DNA: Adenine (A), Guanine (G), Cytosine (C), Thymine (T).
RNA: Adenine (A), Guanine (G), Cytosine (C), Uracil (U).
What are purines and pyrimidines?
Purines: Larger bases (Adenine, Guanine).
Pyrimidines: Smaller bases (Cytosine, Thymine, Uracil).
What is an activated nucleotide?
A nucleotide with extra phosphate groups, increasing stored energy.
What is ATP, and why is it important?
Adenosine triphosphate (ATP) is an activated nucleotide and the main energy source for cells.
How is energy stored in ATP?
In the bonds between its phosphate groups.
How is ATP regenerated?
By adding a phosphate group back to ADP.
What is the structure of DNA?
Two antiparallel strands forming a double helix.
What forms the backbone of DNA?
Alternating sugars (deoxyribose) and phosphate groups connected by phosphodiester linkages.
What stabilizes the DNA structure?
Hydrogen bonds between base pairs.
Base stacking.
Hydrophobic interactions of bases.
Which base pairs are complementary in DNA?
Adenine pairs with Thymine (A-T).
Cytosine pairs with Guanine (C-G).
Why are A-T and C-G pairing important?
They ensure consistent DNA structure due to specific hydrogen bonding and size compatibility.
How does RNA differ structurally from DNA?
RNA contains ribose sugar instead of deoxyribose.
Uracil replaces Thymine as a base.
RNA is usually single-stranded.
What makes RNA less stable than DNA?
The hydroxyl (-OH) group in ribose is more reactive.
How does RNA form structures?
By base pairing within the same strand, leading to diverse shapes.
What are ribozymes?
RNA molecules that act as catalysts, similar to enzymes.
What type of bond links nucleotides?
Phosphodiester linkage.
What is the directionality of nucleic acids?
They are synthesized in the 5’ to 3’ direction.
New nucleotides are added to the 3’ end.
What are the functional differences between DNA and RNA?
DNA: Long-term storage of genetic information.
RNA: Short-term messenger and functional roles like catalysis.
What does DNA’s stability allow?
Reliable storage and replication of genetic information.
How does RNA’s variability affect its function?
It allows RNA to perform multiple roles, including acting as a messenger, structural component, and catalyst.
What is the central dogma of molecular biology?
DNA → RNA → Proteins.
What determines the function of a protein?
The sequence of amino acids, which is determined by the sequence of nucleotides in DNA.
What happens if a DNA mutation affects a gene?
It can lead to a defective or missing enzyme, disrupting macromolecule synthesis.
Why is DNA’s double helix structure critical?
It provides stability and allows accurate replication.
Why is RNA more versatile than DNA?
Its single-stranded nature and structural diversity enable multiple functions.
