Nucleic Acids, DNA Replication, and Protein Synthesis

Vocabulary flashcards covering the structure and chemical composition of nucleotides, DNA, and RNA, the processes of DNA replication, transcription, splicing, and translation, as well as the procedure and rationale for DNA purification.

Nucleotide

A monomer from which nucleic acids are made, formed from a pentose sugar, a nitrogen-containing organic base, and a phosphate group.

ATP (Adenosine Triphosphate)

A nucleotide formed from a molecule of ribose, a molecule of adenine, and three phosphate groups.

DNA Nucleotide

A monomer made of a deoxyribose sugar, a phosphate group, and one of four organic bases: adenine (A), guanine (G), cytosine (C), or thymine (T).

Purines

The nitrogenous organic bases consisting of Adenine and Guanine.

Pyrimidines

The nitrogenous organic bases consisting of Cytosine, Uracil, and Thymine.

DNA (Deoxyribonucleic Acid)

A double-stranded molecule with a ladder-like structure that twists into a double helix, consisting of two sugar-phosphate backbones held in place by pairs of complementary bases joined by hydrogen bonds.

RNA Molecule Components

Subunits consisting of a ribose sugar, a phosphate group, and one of the organic bases A, C, U, or G (where uracil replaces thymine).

Polynucleotide Formation

A process occurring via a condensation reaction between two nucleotides to form a phosphodiester bond.

Phosphodiester Bond Hydrolysis

A hydrolysis reaction that breaks the phosphodiester bond between two nucleotides.

DNA Replication

The semi-conservative process in which DNA helices break hydrogen bonds between complementary base pairs, the double helix unwinds and separates, free nucleotides bind exposed template bases, DNA polymerase catalyses the condensation reaction joining adjacent nucleotides, and daughter molecules rewind.

DNA Polymerase

The enzyme that catalyses the condensation reaction that joins adjacent nucleotides together during DNA replication.

Protein Synthesis

The multi-step process where a DNA template is transcribed into messenger RNA molecules in the nucleus, and mRNA is subsequently transcribed into an amino acid sequence in association with transfer RNA on ribosomes in the cytoplasm.

Transcription

The process where DNA helices break hydrogen bonds between bases to unzip DNA, and RNA polymerase moves along the DNA template strand attaching free nucleotides to complementary bases (with uracil replacing thymine) until reaching a stop codon.

Splicing

The post-transcriptional processing event where introns are removed and exons are joined together.

DNA Purification Method

A laboratory protocol where blended plant tissue mixed with salt and ice-cold water is filtered through a mesh, treated with detergent and proteases, and mixed with ice-cold ethanol added at a $45^\circ$ angle so DNA precipitates between layers.

Salt (in DNA Purification)

A chemical agent used to help remove DNA-bound proteins during DNA extraction.

Protease Enzymes (in DNA Purification)

Enzymes that hydrolyse proteins during the extraction and purification of DNA.

Detergent (in DNA Purification)

A substance added to disrupt cell membranes during DNA extraction.

Ethanol (in DNA Purification)

Ice-cold alcohol added at a $45^\circ$ angle that causes DNA strands to precipitate between the ethanol and mixture layer.

Features of the Genetic Code

The three key properties of genetic coding: universal, non-overlapping, and degenerate.

Translation

The process where ribosomal RNA forms a ribosome that moves along mRNA, complementary tRNA anticodons carry specific amino acids to codons, energy from ATP forms peptide bonds between amino acids, and the polypeptide is released upon hitting a stop codon.

Codon

A sequence of three DNA bases that carries the genetic code.