Block 4 biochem part 2 Flashcards Preview

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Flashcards in Block 4 biochem part 2 Deck (116)
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1

in humans, DNA methylation occurs at the C-__ position of cytosine residues

5

2

CpGs (cytosine-phosphate-guanine) in promoter region of DNA is site of 80% of DNA ______

methylation

3

How would DNA hypermethylation cause cancer?

silence expression of tumor suppressor genes

4

How would DNA hypomethylation cause cancer?

allow increased transcription of oncogenes

5

where do most of our methyl groups for DNA methylation come from?`

folic acid

6

genomic imprinting-

one copy of a gene is epigenetically silenced

7

In genomic imprinting, even though the DNA sequence for a given gene is exactly the same in both copies, it is expressed differently based on:

whether the expressed gene is maternally or paternally derived

8

completion of embryogenesis requires both differential maternal and paternal _________

genomic expressions

9

gynogenote-

female pronuclei + female pronuclei; diploid zygote that has 2 sets of female chromosomes instead of 1 male 1 female

10

gynogenotes fail to develop _______, but _______ develops normally

-extraembryonic tissue
-embryo proper

11

androgenote-

male pronuclei + male pronuclei

12

androgenotes fail to develop ________, but ______ develops normally

-embryo proper
-extraembryonic tissue

13

ovarian dermoid cyst-

all female derived genetic material. Can result from spontaneous ovarian oocyte activation with duplication of maternal genome

14

hydatidiform mole-

all male derived genetic material. An enucleate egg fertilized by haploid sperm, or egg is fertilized by 2 sperm and subsequent loss of maternal pronucleus. A complete mole has little to no fetal tissue and hyperplastic embryonic tissue growth

15

Histone proteins are _______ charged on lysine rich amino terminal tails that neutralize the charge from DNA

positively

16

How does acetylation make DNA more transcribable?

adding acetyl to histone negates positive charge and reduces affinity of DNA for histone

17

the acetylation enzyme-

HAT (histone acetyltransferase)

18

Trichostatin A-

a histone deacetylase inhibitor, activates genes

19

LYON hypothesis-

during embryonic development, one X chromosome in a female embryo is turned off in every cell at random and all progeny from this cell have the same X turned off. Females are mosaics

20

XIC (X inactivation center)

regulates X inactivation

21

_______ gene makes RNA that inactivates one of the two X chromosomes in a normal female

Xist

22

If extra X chromosomes are inactivated anyways, why are Kleinfelter (XXY) abnormal?

there are pseudoautosomal regions on X and Y chromosomes that escape inactivation, so in the case of Kleinfelter, they have normal genetics, but a little extra chromosome input from the pseudoautosomal region of the second X

23

Prader-Willi syndrome-

fat, short, mentally retarded, small hands
caused by loss of paternal 15q11.2-q13.1 expression (due to improper imprinting) and gain of expression of SNRPN

24

Angelman syndrome-

laughing, retardation, motor retardation, no speech, unusual face
caused by loss of paternal 15q11.2-q13.1 expression (due to improper imprinting) and gain of expression of UBE3A

25

behavior/expression of imprinted genes does not depend on _________. It depends on ______________

-sex of individual in which those genes reside
-the sex of the parent from which the particular allele was inherited

26

blunt ends of DNA can be rejoined by:

T4 DNA ligase

27

The frequency with which a specific restriction site is cut is directly correlated with:

the frequency in which that restriction site appears in DNA

28

vector-

DNA molecule used to clone a piece of foreign DNA

29

What does a vector need to successfully produce target DNA?

restriction site identical to that of the target DNA restriction site, its own origin of rep., and a resistance gene for selection

30

________ vectors are used to clone DNA in humans

retroviral and adenoviral