3.17-3.21 development of organisms unit 2

blastocyst

a fluid filled mass of cells which contains the inner cell mass (ICM) which later becomes the embryo

differential gene expression

the process of switching on or off genes to control functions within a cell by varying the production of proteins

DNA methylation

the epigenetic modification of DNA by the addition of a methyl group which reduces transcription

epigenetics

the study of how gene expression influences traits in an organism

genotype

the genetic makeup of an organism

histone acetylation

the epigenetic modification of histone proteins by the addition of an acetyl group which relaxes the DNA and increases transcription

lac operon

a group of genes that control lactose uptake and metabolism in certain types of bacteria and are all regulated by the binding of the lac repressor to the lac operator

mature mRNA

the final mRNA product that has had introns removed, as well as having undergone other post-transcriptional changes

morula

an early stage embryo consisting of 16 cells (called blastomeres) in a solid ball contained within the zona pellucida

multipotent stem cell

a stem cell that can divide into a limited range of differentiated cells, most somatic stem cells are multipotent

operon

a group of genes which are all under the control of the same operator

phenotype

the observable physical characteristics of an organism which is based on the interaction with genotype and the environent

pluripotent stem cells

a type of stem cell which has the ability to differentiate into any cell type in the body

polygenic inheritance

the inheritance of multiple different alleles at multiple loci that control a single phenotype

post transcriptional control

the level of gene regulation in which primary mRNA can be modified, controlling translation

post translation control

the level of gene regulation in which proteins can be modified post synthesis

pre mRNA

the product of transcription before any post transcriptional regulation

somatic stem cell

another name for an adult stem cell

stem cell

a type of undifferentiated cell which has the ability to divide many times and differentiate into many different cell types