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Flashcards in Exam 3 Deck (133)
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1

primary gene regulation

transcriptional regulation

2

secondary gene regulation

post-transcriptional regulation

3

tertiary gene regulation

translational regulation

4

quaternary gene regulation

protein modification

5

post-transcriptional regulation

secondary-quaternary regulation

6

pre-transcriptional regulation

regulate the number of gene copies

7

prenatal globin regulation

gamma globin produced instead of beta (expression of beta turned off and expression of gamma turned on)

8

postnatal globin regulation

beta globin produced instead of gamma (expression of beta turned on and expression of gamma turned off)

9

temporal and spatial regulation of globin

temporal: different globins produced at different times (prenatal vs postnatal)
spatial: gamma gene in liver great 12 weeks post-conception, but nonexistent in bone marrow and spleen

10

transcriptional regulation

gene is "on" when it's being transcribed and "off" when transcription is blocked
can also be regulated by controlling how much mRNA is made during transcription

11

post-transcriptional regulation

RNA processing
translational control
post-translational control

12

weismann germplasm theory

cells destined to become gametes set aside early in development
basic concept correct except theory assumed that once development occurs, the germplasms retains all genetic material while differentiated cells lose genetic material they don't need

13

steward 1958

early cloning experiment to determine whether differentiation involves gene loss
determined that since organism could be cloned from a single cell then the cell must not lose any genetic material during differentiation

14

exceptions to maintaining genetic material

gene loss
gene gain

15

gene loss types

chromatin diminution
chromosome elimination
cancer cells

16

chromatin diminution

loss of segments of chromosme but NOT whole chromosome
roundworm ascaris

17

roundworm ascaris chromatin diminution

during early development, the somatic cells lose segments of their chromosomes BUT germline cells retain all genetic material
amount of genome lost depends on species
varies from 25%-85%

18

chromosome elimination

entire chromosomes lost (not just segments)
sciarid flies
paramecium and tetrahymena

19

paramecium and tetrahymena

form 2 nuclei: micronucleus (inactive and only for reproductive purposes) and macronucleus (active nucleus with genes being expressed -- transcription occurring)

20

events of macronucleus growth

internal eliminated sequences (IESs) lost and other segments duplicated

21

IES removal process

RNA mediated process similar to RNA interference
post-meiotic micronucleus' entire genome transcribed and compared to old macronucleus genome (that was transcribed before disintegration) to determine which sequences to remove
50,000+ segments removed

22

repeated replication in macronucleus growth

repeated replication of DNA without cell division produces a giant nucleus with around 800 copies of the remaining segments of DNA

23

cancer cells

many chromosomal changes occur in tumors (including chromosome loss) that make them more viable

24

gene gain

increase in number of gene copies
repetitive vs single copy genes

25

repetitive vs single copy genes

some genes normally present in multiple copies
more copies = more gene product

26

3 types of DNA in eykaryotic genomes

single copy DNA
middle-repetitive DNA
highly-repetitive DNA

27

single copy (unique sequence) DNA

50% of human genes only present once in each genome (twice in each cell bc 1 from each parent)
mRNA (genes coding for proteins)
hybridizes slowly (high Cot value)

28

middle repetitive DNA

around 40% of human genes are moderately repeated with 10-1,000 copies
rRNA and tRNA

29

highly repetitive DNA

around 6% of human genes are highly repeated with up to 100,000 copies
segment length of 5-300 nt
aka "satellite DNA" bc it forms a satellite during CsCl centrifugation
transposable elements and repeated segments of centromere and telomere
usually heterochromatin (inactive genes)

30

gene amplification

when DNA segments (or whole genomes) replicated without division
amphibian oocyte
drosophilia
ciliate macronucleus
human liver cells
cancer cells