T/F Histone Acetylation is associated with gene activation.
TRUE
Histone tails protrude out from the histone complex,becoming a site for_____
histone modinfication
Histones Can Be Modified by ________ or ___________
Acetylation or Methylation
______ groups can be attached to some lysines in the histones. _______ results in _____ of positive charge
Acetyl, acetylation, loss
______ groups can be attached to some lysines or arginines in the histones. _______ation results in _____ of positive charge
Methyl, methylation, retention
T/F Any particular histone can be acetylated and methylated
False, either-or but not both
______refers to condensed DNA
heterochromatin
Phosphorylation of a serine or threonine results in a ______charge
Negative
Phosporylation during mitosis _______ DNA
Condenses
Phosporylation during _______ results in less condensed DNA
chromatin Remodeling
_______ Decreases transcription by recruiting HDAC.
Sumoylation
______Affects transcription by promoting/inhibiting acetylation and/or methylation of other histone sites.
Ubiquitylation
T/F Histone Ubiquitylation signals for degradation
FALSE
which peptide is bigger? Ubiqutylation or sumoylation?
Sumoylation (100 vs 76)
T/F Most histone modifications occur within the globular domains (not the tails)
FALSE
histone code hypothesis states that the combinations of modifications determines_______
DNA accessibility
2 effects of histone modifications
1) altered DNA accessibility 2) transcriptional protein binding or prevention
_______ bind to a particular sequence in the DNA, and inhibit transcription
repressors
Repressors are a binding site for __________ ________ inhibiting transcription
histone deactylase (HDAC)
_______ are phenotype changes that occur in a cell or organism that are not due to changes in the DNA sequence
epigenetics
4 categories of epigenetics
1) histone modification 2) incorporation of histone protein variants 3) DNA methylation 4) MicroRNAs
T/F epigentic modification are inherited
false (can be)
T/F environmental epigenetic changes may explain phenotypic differences
TRUE
histone protein variants replace ________ to affect DNA interaction
common histone proteins
DNA methylaton occurs on ________
some cytosine nucleotides
5-methylcytosines are found in _______
CpG islands
DNA Methylation Promotes ______ _____
Gene Silencing
DNA methylation promotes gene silencing by:
1. Preventing certain transcription factors from binding to DNA 2. Promotes the binding of methyl binding proteins, which can interact with histone deacetylases (HDACs)
Methyl groups can be added by ________ DNA methyltransferases.
de novo
DNA methylation promotes gene silencing in which 2 ways
1. Preventing certain transcription factors from binding to DNA 2. Promotes the binding of methyl binding proteins, which can interact with histone deacetylases (HDACs)
Methyl groups can be added by ___ _____ DNA methyltransferases.
de novo
Methyl groups can be removed by __________
DNA demethylases.
DNA Methylation Pattern Is Inherited in which 2 ways?
1) parental cell to daughter cell 2) from sperm or egg
T/F micro RNAs code for proteins
false
micro RNA helps the silencing complex recognize its target the _________
untranslated region of mRNA that codes for protein