Nucleic Acids Flashcards
Define nucleotide:
The most basic subunit of a nucleic acid; a monomer of DNA or RNA.
Nucleotides are made up of: a sugar, a phosphate group, and a nitrogenous base. (Each nucleotide is identical except for its nitrogenous base.)
What are the nucleic acids in a cell? What’s their function?
Deoxyribonucleic acids (DNA) and ribonucleic acids (RNA)
Nucleic acids are the molecules that cells use to store, transfer, and express genetic information.
DNA stores genetic information in an organism (gives directions like a recipe); RNA translates that information into proteins.
What’s a polynucleotide?
A long chain of nucleotides held together by phosphodiester bonds
What’s a phosphodiester bond?
Bond between the sugar and the phosphate group in a polynucleotide molecule
What’s a diester bond?
A bond between a hydroxyl group in the sugar and one of the oxygen atoms in the phosphate group in a nucleotide
What tells a cell how to make a structural protein, an enzyme, or any other important component?
The order of the bases in a polynucleotide
What are the characteristics of nitrogenous bases in nucleotides?
Pyrimidines (Cytosine and Thymine) are single-ring nitrogenous bases.
Purines (Guanine and Adenine) are double-ring nitrogenous bases.
Explain complementary base pairing:
“Base pairs”:
C bonds (3 H bonds) with G; A bonds (2 H bonds) with T;
It’s always this way in DNA.
Explain antiparallel orientation, as it relates to polynucleotides bonding:
DNA strands are antiparallel to one another to allow for H bonding. This means they are parallel but oriented in opposite directions.
(The 5’ end of one strand pairs with the 3’ end of the other strand.)
What are the 3’ and the 5’ ends in a strand?
These relate to the carbons.
C #3: sugar end of the strand
C #5: phosphate end of the strand
What does DNA code transcription ultimately do to a cell?
It tells a cell how to make proteins that it can use to perform various necessary functions for life.
Who discovered the Transforming Principle?
Frederick Griffith and Oswald Avery discovered that the Transforming Principle in a cell was due to DNA, after getting the subject rid of proteins and RNA.
Their results concluded that the changes brought about in the cell were permanent.
What do James Watson and Francis Crick discovered?
They discovered the complementary base pairing and the antiparallel orientation. By combining their results, they created the double-helix structural model of DNA.
How many nitrogenous base pairs are in each human cell?
3 billion pairs
Describe the double-helix structure of DNA:
DNA is organized as a twisted ladder with phosphate groups and sugars composing the backbone of the strands, and nitrogenous bases linked by hydrogen bonds make up the rungs. Each strand is oriented antiparallel to the other.
