Glossary 1-11 Flashcards
gene
the fundamental physical and functional unit of heredity, which carries information from one generation to the next; a segment of DNA.
genotype
the specific allelic constitution of an organism, either of the entire organism or for a certain set of genes or a certain gene.
phenotype
the morphological, biochemical and behavioural properties of an organism resulting from a specific genotype and its interaction with the environment.
genome
The genetic complement in a set of chromosomes
epigenetics
Changes in gene expression without changes in DNA sequence
telomere
The ends of a eukaryotic chromosome
semi-conservative replication of DNA
the method of DNA replication where the new molecule of DNA has one strand which comes from the parent molecule and one strand which is newly synthesised.
complementary base pairing
nucleotides or nucleotide sequences that are able to base pair. For example, G and C are complementary as are A and T.
pyrimidine
one of the two types of nitrogenous base compounds found in nucleotides. The pyrimidine bases in DNA are cytosine and thymine
purine
one of the two types of nitrogenous base compounds found in nucleotides. The purine bases in DNA are guanine and adenine.
polynucleotide
polymer consisting of nucleotide subunits.
phosphodiester bond
the chemical bond that links the adjacent nucleotides in a polynucleotide.
5’ (PO4) end
the end of the polynucleotide that terminates with a phosphate attached to the 5’- carbon of the sugar.
3’ (OH) end
the end of a polynucleotide which terminates with a hydroxyl group attached to the 3’- carbon of the sugar.
leading/ lagging strand
the leading strand is that which is synthesized continuously, whereas the lagging strand is synthesized in a discontinuous fashion during DNA replication.
Okazaki fragment
one of the RNA-primed short segments of DNA synthesized during replication of the lagging strand of the double helix.
DNA heliase
an enzyme that uses energy from ATP to unwind the DNA
topoisomerase
gyrase
an enzyme which can relax DNA by cutting and reforming the polynucleotide backbones
single-strand binding protein
one of the proteins that attaches to single stranded regions of DNA and prevents the reformation of base pairs, particularly in the region of the replication fork.
primase
an enzyme which synthesises the RNA primer
DNA polymerase I
enzyme which adds nucleotides to gaps when primers removed
DNA polymerase III
main polymerase which adds nucleotdes to template in a complementary way
ligase
enzyme which joins sequences of DNA
mutation
a change in the genetic material which can be passed from cell to cell or parent to offspring. A somatic mutation will occur in a somatic cell and hence will not passed to the next generation, compared to a germline mutation which can be passed to offspring.
locus
the position of a gene on a chromosome
haploid
one copy of each chromosome
diploid
two of each type of chromosome the two similar chromosomes are described as homologous
aneuploidy
addition or deletion of a single chromosome or sometimes extra single chromosomes