a1.2 nucleic acids Flashcards
(25 cards)
What are the two primary functions of nucleic acids?
- Storage of genetic information
- Transmission of genetic instructions
What are the two types of nucleic acids?
DNA and RNA
What does it mean that DNA is the genetic material of all living organisms?
DNA carries hereditary information, determining traits and enabling reproduction.
Why don’t RNA viruses falsify the claim that DNA is the genetic material of all living things?
RNA viruses rely on host DNA-dependent enzymes for replication, reinforcing DNA’s primary role.
What are the three components of a nucleotide?
- Phosphate group
- Pentose sugar (ribose or deoxyribose)
- Nitrogenous base
What is the “backbone” of a nucleic acid?
The sugar-phosphate chain forming structural support for DNA & RNA.
How do nucleotides connect in a nucleic acid polymer?
Via phosphodiester bonds between the phosphate of one nucleotide and the sugar of another.
What are the nitrogenous bases in DNA & RNA?
- DNA: Adenine (A), Thymine (T), Cytosine (C), Guanine (G)
- RNA: Adenine (A), Uracil (U), Cytosine (C), Guanine (G)
Similarity between bases?
Both types consist of purines (A, G) & pyrimidines (C, T/U).
Difference between bases?
RNA uses Uracil (U) instead of Thymine (T).
How does the base sequence serve as a genetic “code”?
The sequence directs protein synthesis through transcription & translation.
What is a gene?
A segment of DNA that encodes a functional protein or RNA molecule.
What is the condensation reaction forming RNA?
Nucleotide monomers join, releasing water and forming phosphodiester bonds.
What are the monomer and polymer of RNA?
Monomer = Nucleotide Polymer = RNA strand
What is the DNA double helix structure?
Two antiparallel strands twisted in a helix shape.
What is the complementary base pairing rule?
- A pairs with T (2 hydrogen bonds)
- C pairs with G (3 hydrogen bonds)
What does “antiparallel” mean in DNA?
Strands run in opposite directions (5’ → 3’ and 3’ → 5’).
How do DNA & RNA structures compare?
- DNA: Double-stranded, deoxyribose sugar, thymine
- RNA: Single-stranded, ribose sugar, uracil
How do DNA & RNA functions compare?
- DNA: Long-term genetic storage
- RNA: Protein synthesis
How do their locations compare in prokaryotic & eukaryotic cells?
- DNA: Nucleus (eukaryotes), nucleoid (prokaryotes)
- RNA: Cytoplasm (both)
How does base pairing maintain the DNA sequence in replication?
Ensures accurate copying by pairing A-T & C-G.
How does base pairing transmit the genetic code?
- Transcription: DNA → RNA (mRNA copy)
- Translation: RNA codons → Protein synthesis
Why is DNA sequence diversity limitless?
- 4 bases can arrange in infinite combinations
- Enables unique genetic traits across all species
What does “universal” mean in the genetic code?
The same codons encode the same amino acids across all life.
