Heredity and Continuity of Life Flashcards
Deoxyribonucleic Acid (DNA)
Thread-liek chain of nucleotides carrying the genetic instructions in a double helix of antiparallel strands.
Ribonucleic Acid (RNA)
Thread-like chain of nucleotides carrying the genetic instructions for the forming of protein in a cell.
Sugar-Phosphate Backbone
The structural framework of nucleic acids, composed of alternating sugar and phosphate groups.
Condensation Polymerisation
The formation of a polymer by the reactions between two monomers, with the loss of a small molecule (e.g. water).
Antiparallel
Two biopolymers that run parallel to each other but with opposite alignments, e.g. the two strands of the DNA molecule.
Nucleosome
A length of DNA coiled around a core eight histone protein molecules.
Epigenetic Factors
A chemical tag that determines the degree of coiling around the nucleosome and thus gene expression.
Gene
A region of DNA, made up of nucleotides, that encodes molecule that has a function.
Genetic Code
The code the body uses to convert the instructions in the DNA into the proteins essential for life.
DNA Helicase
An enzyme that breaks down the hydrogen bonds holding two DNA strands together.
Semiconservative Replication
Replication of DNA resulting in two copies that each contain one of the original strands and one new strand.
3’ (Three-Prime) End
One end of a DNA strand in which the C3 carbon atom of the sugar molecule in the DNA’s sugar backbone has a ‘free’ OH (hydroxyl) group that is not linked to another chemical group.
5’ (Five-Prime) End
One end of a DNA strand in which the C5 carbon atom of the sugar molecule in the DNA’s sugar backbone has a ‘free’ phosphate group that is not linked to another chemical group.
DNA Polymerase
A type of enzyme that is responsible for assembling nucleotides to form new copies of DNA.
Origin of Replication
A particular sequence in the DNA molecule at which replication is initiated.
Replication Fork
Structure with two branching sections that is created when DNA helicase break the hydrogen bonds holding the two DNA strands together at a certain point.
Replication Bubble
An unwound and open region of DNA in which DNA replication occurs, created when the enzyme DNA helicase separates the two strands of DNA.
Leading Strand
DNA template from the middle of the replication bubble (point of origin) to the fork.
Lagging Strand
DNA template from the fork to the middle of the replication bubble (point of origin).
Okazaki Fragments
Fragments of DNA that are formed on the lagging strand of replicating DNA.
DNA Ligase
A specific type of enzyme that facilitates the joining of DNA strands together.
Termination Sequence
A section of nucleic acid sequence that marks the end of a gene or replication site.
