Chapter Twenty: Epigenetics

Question 1

three techniques to monitor regulation of gene expression

Answer 1

1. northern
2. microarray
3. RT-PCR

Question 2

techniques to monitor gene expression depend on ___

Answer 2

hybridization

Question 3

heritable alterations in gene expression that do not involve a mutation or change in base pairing

Answer 3

epigenetics

Question 4

the DNA sequence in genes is not the only carrier of ___

Answer 4

genetic information

Question 5

write the definition of epigenetics

Answer 5

heritable self-perpetuating changes in gene expression not caused by base pair sequence changes

Question 6

epigenetics usually involves modified ___, ___, or ___

Answer 6

cytosine residues, histone tails, or small RNAs

Question 7

epigenetic factors determine whether a gene is ___ or ___

Answer 7

on or off (expressed or not)

Question 8

phenomenon in which expression of an allele depends on the parent that transmits it

Answer 8

genomic imprinting

Question 9

about ___ imprinted genes have been identified

Answer 9

100

Question 10

paternal allele is not transcribed

Answer 10

paternally imprinted

Question 11

maternal allele is not transcribed

Answer 11

maternally imprinted

Question 12

imprinted means ___

Answer 12

silenced

Question 13

a methyl group is added to the cytosine base in a 5’ CpG 3’ dinucleotide by DNA methyltransferase

Answer 13

DNA methylation

Question 14

regions with a high concentration of CpG dinucleotides

Answer 14

CpG islands

Question 15

CpG islands are usually ___ and located near a ___

Answer 15

unmethylated
promoter

Question 16

an ___ binds to unmethylated CpG islands, the chromatin is ___ and transcription is ___

Answer 16

activator
open
activated

Question 17

DNA methylation at CpG islands ___ gene expression

Answer 17

silences

Question 18

repressors called ___ bind to methylated CpG islands and close the chromatin structure

Answer 18

methyl-CpG-binding proteins (meCPs)

Question 19

cytosine methylation pattern is ___ during DNA replication, so DNA methylation is ___ throughout cell division

Answer 19

copied
maintained

Question 20

special ___ at the replication fork methylates the newly synthesized DNA strand

Answer 20

DNMT

Question 21

sex-specific DNA methylation mediates ___

Answer 21

imprinting

Question 22

imprinting occurs through these two mechanisms

Answer 22

1. insulator mechanism
2. ncRNA mechanism

Question 23

epigenetic imprints remain throughout the ___ of an animal

Answer 23

life span

Question 24

in germ cells, epigenetic imprints ___ each generation

Answer 24

reset

Question 25

during meiosis, imprints are ___ and new ones are set based on the ___ of the organism

Answer 25

erased
sex

Question 26

human ___ show imprinting

Answer 26

pedigrees

Question 27

___ syndrome occurs when a deletion in chromosome 15 comes from the father, ___ syndrome occurs when it is inherited from the mother

Answer 27

prader-wili
angelmans

Question 28

imprinting only occurs in ___

Answer 28

placental mammals

Question 29

most imprinted genes control ___

Answer 29

prenatal growth

Question 30

imprinting is ___ (100 genes identified so far)

Answer 30

rare

Question 31

all cells in multicellular organisms have the same ___

Answer 31

genes

Question 32

cell types are different because of ___ differences

Answer 32

gene expression

Question 33

determines gene expression and potential fates of a cell, often a transcription factor

Answer 33

master regulator

Question 34

cells “remember” their fate from cell generation to generation partly because histone modifications that repress transcription at master regulatory genes are ___

Answer 34

copied at the replication fork

Question 35

drosophila Cox (homebox) genes encode transcription factors that set up animals ___

Answer 35

segmented body plan

Question 36

highly compacted chromatin found in all cells

Answer 36

constitutive heterochromatin

Question 37

constitutive heterochromatin is found at ___, which are enriched in ___; important to prevent ___

Answer 37

centromeres
transposable elements
TE mobilization

Question 38

constitutive heterochromatin is also found at ___

Answer 38

telomeres

Question 39

___ transcribed from centromeres initiates heterochromatin formation

Answer 39

ncRNA

Question 40

ncRNA is converted to ___ which binds to ___

Answer 40

siRNA
argonaute (ago)

Question 41

ago recruits ___ that results in heterochromatin formation

Answer 41

histone methyltransferases

Question 42

plant heterochromatin is ___ after cell division

Answer 42

reformed

Question 43

which base gets methylated in epigenetic control

Answer 43

cytosine

Question 44

mammalian cells ___ which X chromosome was inactivated

Answer 44

remember

Question 45

when an environmentally induced trait (not caused by a base pair mutation) appears in an individual’s descendants whose DNA was not directly exposed to the environmental trigger

Answer 45

transgenerational epigenetic inheritance

Question 46

methylation marks are released during meiosis in ___ but not ___

Answer 46

animals
plants

Question 47

piRNAs transmit memories of ___

Answer 47

TE invasion

Question 48

organisms try to ___ TE mobilization to prevent mutations or chromosomal rearrangements

Answer 48

limit

Question 49

why can TEs move with a minimal effect on phenotype in humans?

Answer 49

only 1% of the human genome codes for proteins that affect phenotype

Question 50

environmentally induced trait that is displayed only in the child, or child and grandchild of an originally exposed female, or child of an exposed male

Answer 50

intergenerational epigenetic inheritance