eukaryotic gene expression
the phenotype of a cell or organism is determined by a combination of genes that are expressed and the levels that they are expressed
differential gene expression
differences between cell types
eukaryotic gene expression is regulated at
different stages
if DNA is tightly wound it is
less accessible for transcription
DNA can be modified by
histone acetylation and DNA methylation
histone acetylation
adds acetyl groups to histones which loosens DNA
DNA methylation
adds methyl groups to DNA, which causes chromatin to condense
epigenetic inheritance
- chromatin modifications do not alter nucleotide sequence of the DNA, but they can be heritable to future generations
- modifications can be reversed, unlike mutations
- explains why one identical twin may inherit a disease while the other does not
transcription initiation
- once chromatin modifications allow the DNA to be more accessible, specific transcription factors bind to control elements
- sections of non coding DNA that serve as binding sites
- gene expression can be increased or decreased by binding of activators or repressors to control elements
RNA processing
alternative splicing of pre-mRNA
translation initiation
- translation can be activated or repressed by initiation factors
- microRNAs and small interfering RNAs can bind to mRNA and degrade it or block translation
eukaryotic development
- during embryonic development, cell division and cell differentiation occurs
- cells become specialized in their structure and function
morphogenesis
physical process that gives an organism its shape
cells differentiate during early development by
cytoplasmic determinants and induction
cytoplasmic determinants
substances in the maternal egg that influence cells
induction
cell to cell signals that can cause a change in gene expression
both cytoplasmic determinants and induction influence
pattern formation- a “body plan” for the organism
homeotic genes
map out the body structures
as cells differentiate
apoptosis plays a critical role
apoptosis
programmed cell death
allows structures to take their form
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Unit 10
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Unit 20
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Unit 30
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Unit 4 - Cell Communication and Cell Cycle1
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Unit 5 - Heredity39
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Unit 6 - Gene Expression and Regulation - topic 131
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Unit 6 - topic 233
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Unit 6 - topic 336
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Unit 6 - topic 435
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Unit 6 - topic 516
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Unit 6 - topic 620
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Unit 6 - topic 725
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Unit 6 - topic 88
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random4
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Unit 7 - topics 1, 2, 30
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regents review14
