Chapter 13.4: How Chromosomal Packaging Influences Gene Activity

Front 1

heterochromatin

Back 1

bands that appear dark when stained

Front 2

euchromatin

Back 2

bands that appear light when stained

Front 3

constitutive heterochromatin

Back 3

chromosomal regions that remain condensed in heterochromatin at most times in all cells

Front 4

autoradiograph

Back 4

an image on an x-ray film or nuclear emulsion produced by the pattern of decay emissions (e.g., beta particles or gamma rays) from a distribution of a radioactive substance

Front 5

_______ contains most of the sites of transcription and thus almost all of the genes

Back 5

euchromatin

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variegating

Back 6

to make varied in appearance, as by adding different colors.

Front 7

position-effect variegation

Back 7

variable expression of a gene in a population of cells, caused by the gene's location near highly compacted heterochromatin

Front 8

facultative heterochromatin

Back 8

regions of chromosomes (or even whole chromosomes) that are heterochromatic in some cells and euchromatic in other cells of the same organism

Front 9

Does heterochromatin skip over genes as it spreads along the chromosomes?

Back 9

NO!!!

Front 10

Is it known how heterochromatin invades euchromatin?

Back 10

Not really...

Front 11

Barr bodies

Back 11

darkly stained heterochromatin masses

Front 12

What does Xist stand for?

Back 12

X inactivation specific transcript

Front 13

What's the function of the Xist gene?

Back 13

to produce a unusually large cis-acting RNA transcript