3C Flashcards
cell differentiation
the process by which a less specialised cell becomes more specialised for a particular function
locus
place on a chromosome where any particular gene is found
multiple alleles
more than two possible variants at a particular locus
codominant
both alleles are expressed in the phenotype
codominant
both alleles are expressed in the phenotype
gene linkage
when genes for two different characteristics are found on the same chromosome and are close together so they are linked and inherited as a single unit
polygenic
phenotypic characters determined by several interacting genes
digenic (dihybrid)
inheritance the inheritance of two pairs of contrasting characteristics at the same time
operon
a unit consisting of linked genes which is thought to regulate other genes responsible for protein synthesis
discontinuous variation
phenotypic features which are either present or not, usually inherited on one or at most a small number of genes.
continuous cariation
phenotypic features which show a huge range of values; they are usually polygenic and are also affected by environmental factors
transcription factor
protein that binds to the DNA in the nucleus and affects the process of transcribing DNA into RNA
promoter sequence
specific region on the DNA to which transcription factors bind to stimulate transcription
enhancer sequence
specific region of DNA to which transcription factors bind and regulate the activity of the DNA by changing the structure of the chromatin
exons
segments of a DNA or RNA molecule containing information coding for a protein or peptide sequence
introns
segments of a DNA or RNA molecule containing information which does not code for a protein or peptide sequence
pre-mRNA
mRNA that is transcribed directly from the DNA before it has been modified
spliceosomes
enzyme complexes that act on pre-mRNA, joining exons together after the removal of the introns
DNA methylation
methylation of DNA (addition of a methyl -CH group) to a cytosine in the DNA molecule next to a guanine in the
DNA chain and prevents the transcription of a gene
DNA demethylation
removal of the methyl group from methylated
DNA enabling genes to become active so they can be transcribed
heterochromatin
densely supercoiled and condensed chromatin where the genes are not available to be copied to make proteins
histone acentylation
addition of an acetyl group (-COCH3) to one of the lysines in the histone structure, which opens up the structure and activates the chromatin, allowing genes in that area to be transcribed
histone methylation
addition of a methyl group (-CHs) to a lysine in the histone; methylation may cause inactivation or activation of the region of DNA, depending on the position of the lysine
non-coding RNA (ncRNA)
98% of the RNA, which does not code for proteins but affects the transcription of the DNA code, modifies the chromatin structure or modifies the products of transcription
totipotent
an undifferentiated cell that can form any one of the different cell types needed for an entire new organism
blastocyst
an early embryo consisting of a hollow ball of cells with an inner cell mass of pluripotent cells that will eventually form a new organism
embryonic stem cells
the undifferentiated cells of the early human embryo with the potential to develop into many different types of specialised cell
morula
an early embryo made up of a solid ball of 10-30 totipotent cells
pluripotent
an undifferentiated cell that can form most of the cell types needed for an entire new organism
adult stem cells (somatic stem cells)
undifferentiated cells found among the normal differentiated cells in a tissue or organ that can differentiate when needed to produce any one of the major cell types found in that particular tissue or organ
multipotent
a cell that can form a very limited range of differentiated cells within a mature organism
therapeutic cloning
an experimental technique used to produce embryonic stem cells from an adult cell donor
induced pluripotent stem cells (iPS cells)
adult cells that have been reprogrammed by the introduction of new genes to become pluripotent again
induced pluripotent stem cells (iPS cells)
adult cells that have been reprogrammed by the introduction of new genes to become pluripotent again
