1.15. Epigenetics Flashcards
acetyl group (with and without)
- acetic acids (CH3-COO^-)
- abundant in the nucleus
- with AC - histone tails don’t join together, don’t pull histones closer so level of DNA condensation decreased, increasing gene expression
- without AC (normal) - histones pulled together, higher level of DNA condensation, reduction in gene expression
- it impacts the conformation of histone tails and therefore impacts the expression of genes
modification of histone tails by acetyl groups
acetylation
epigenetics
set of instructions that sit down on the DNA and histones - the chemical environment of the DNA impacts the gene expression
genome (DNA)
proteome (proteins)
transcriptome (mRNA)
___
epigenome (all epigenetic marks of an organism - e.g. alcohol, Me CH3- and Ac CH3COO-)
acetylation of…
methalanation of…
histone tails
the DNA
epigenetic marks
small chemical tags that sit down on the chromosomes and tell the DNA whether to compact or not - the tell the cell wat to do/who to become by controlling the expression of genes: they can condense chromatin (turn some genes off) or stretch it (make genes accessible)
total length of a single cell’s DNA is ___, and the length of the nucleus is ___.
2 meters, 0.0004 cm (around 4 micrometers)
chromatin (definition and role)
combination of DNA and histones - fitting the DNA in the cell nucleus - gene expression reduction
how are cell differentiation and epigenetics connected
selective positioning of epigenetic markers tells certain cells which genes to turn off and which to turn on (cell differentiation is irreversible)
genotype -
phenotype -
all genes of an organism
only expressed genes of one cell (e.g. genes for eyes - contain unexpressed gene for blue eyes)
- all cells of the same organism have the same genotype but different phenotype (different sets of genes activated)
Epigenetics mars are laid down on the cell’s genome during…
…embryonic development (most of it)
On what does laying down of epigenetic markers depend on?
on surrounding cells (they receive signals from other cells and epigenetic markers accumulate) and environment outside of the embryo (food, stress, air… also give out signals for the markers)
transgenerational epigenetic inheritance
epigenetic mark,s can be transmitted to multiple generations (over tens of generations)
epigenetic marks are…
reversible (can be removed from genes - medicine, environmental factors, psychological factors…)
cancer treatment and epigenetics
tumor-suppressor genes have marks on them that can deactivate them - if epig. marks are removed they can protect the cell and prevent formation of cancer cells or restore them to normal cells