1-41 Epigenetics Flashcards Preview

MSI Unit I > 1-41 Epigenetics > Flashcards

Flashcards in 1-41 Epigenetics Deck (32):
1

imprinting

results in?

typically controlled by?

differential modification of maternal/paternal genetic contributions to the zygote.

results in differental expression of parental alleles

methylation - a downregulatory modification

2

do you pass down imprinting patterns?

generally no. these patterns are reset in the germline at meiosis

3

prader-willi syndryome

imprinting issue

paternal chromosome 15 has female imprinting pattern

OR(female imprinting or 2 female copies)

individual is isodisomic for chromosome 15 from mother

or portion of fathers chromsone deleted, only expressing mothers

overweight, always incredibly hungry

4

angelman syndrome

an individuals maternal chromosome 15 has a male impriting pattern

man - male pattern

OR (male imprinting or two male copies)

individual is isodisomic for chromosome 15 from father

or deletion on maternal chromosome, leading only for paternal chromosome to be expresed

5

imprinting follows what kind of pattern?

tend to follow certain patterns depending on if an individual is male or female

6

imprinting failure

when germline cells in an individual fail to be imprinted properly for their gender

example) a man's maternal chromosomes remain imprinted with female pattern after meiosis.

associated with - PWS and AS

7

disomy

a state of having a pair of given chromosomes. The normal state for chromosomes to be in 2N cells.

8

isodisomy

type of..

having inherited 2 copies of same chromosome homologue from one parents

type of uniparental disomy (UPD)

9

heterodisomy

having 2 unique homogloes in a pair from the same parent

a type of UPD

10

two types of UPD

having inherited 2 copies of the SAME chromosome homologue from one parent

or

a state of having two UNIQUE homologues in a chromosomal pair from the same parent

11

PWS individuals tend to...

gain weight rapidly, have developmental delay, bad temper

12

AS individuals tend to be..

mentally retarded, hyperactive, seizes, happy/friendly demeanor

13

what are epigenetics

categories?

study of heritble changes in gene function not caused by changes in DNA sequence

DNA methylation, histone modification, and chromatin remodeling

14

hypomethylation

in an oncogene?

can result in a gene being over expressed, as methylation is ussually a down regulator.

if an oncogene is hypomethylated, cancer can ensue

15

hypermethylation

in tumor supressor gene?

can result in gene being underexpressed

in tumor suppressor gene, gene is under expressed, can lead to cancer

16

transcription factors are also part of _____

epigenetics

17

Rett syndrome

neurodevelopmental disorder caused by a failure of MECP2 trancription factor to function. Lack of MECP2 that normally recognizes methylated DNA and ussually helps repress gene expression

18

down regulation of certain miRNAs

due to?

can cause?

due to hypermethylation at their promotor regions

has been reported in a number of tumors

19

offspring of women living in famine during pregnancy?

schizophrenia

20

what determines differentiation?

Genes in all cells are the same, repertoire of which genes expressed or not expressed determines differentiation

21

one genome for..

many different epigenomes

22

what is an epigenome?

the globel epigenetic patterns that distinguish or are variable between cell types.

23

DNA is typically modified by the..

methylation of C-G's in promotors or body of DNA

when promotor gets methylated, it gets turned off

24

describe chromatin

dynamic polymer. able to open up when a gene needs to get expressed, close down when it is not

25

half of the gene sequence are

repeats. all being expressed would overwhelm the cell. the cell has mechanisms to turn off repeats so not constantly creating mRNAS - heterochromatin

26

HPTMs

histone post-translational modifications - acetylation, phosporylation, methylation

27

histone modification is important in (4)

transcriptional regulation, DNA replication, alternative splicing, chromsome condensation

28

ncRNA can do what?

2 examples?

non-coding RNA - can guide specialized regions of the genome into more compacted chromatin states

-imprinting
-x inactivation

29

microRNA's - purpose?

product?

short non coding RNA's, bind to 3'UTR to regulate

product is not a protein, it is RNA that seeks out genes and turns over a gamut of targets.

by expressing miRNA, we can turn off or on a repertoire of genes

30

the peptide bond (w) between the c=o of one aa and the N of another aa has what type of character?

partial double bond character due to delocalization of electrons. It therefor cannot turn.

31

the phi and psi bonds can rotate

+180 to -180

32

ramachandron plot analysis

dark colors - bond angles easily allowed
lighter color - allowed
lightest color - difficult
no color - impossible

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