Ch. 9

Question 1

what is a necessary regulation for cells to respond to their environment

Answer 1

gene expression

Question 2

when is gene expression controlled

Answer 2

during differentiation

Question 3

what directs the various proteins and RNA’s encoded in the genome

Answer 3

cell selectivity

Question 4

true or false: cells retain their entire genome?

Answer 4

true

Question 5

the ability of one cell from an organism can make an entire new organism shows that the original had an ______ _______

Answer 5

intact genome

Question 6

________ occurs at every level of gene expression

Answer 6

regulation

Question 7

_______ _______ is a critical step for many genes

Answer 7

transcriptional regulation

Question 8

transcription is controlled at _________, once this is complete transcription is highly __________

Answer 8

initiation, processive

Question 9

the ________ sets the start point or the transcription initiation site

Answer 9

promoter

Question 10

regulatory _____ sequences control the formation of transcriptional regulatory complexes that switch expression on and off

Answer 10

DNA

Question 11

_____ ______, usually within the ______ groove of DNA, determines binding to the base sequence

Answer 11

specific contacts, major

Question 12

transcription factors are often ______

Answer 12

dimers

Question 13

_____ _______ form complexes that stabilize DNA interactions to regulate transcription

Answer 13

transcription factors

Question 14

in bacteria a _____ transcript encodes a set of protein in an ______ structure

Answer 14

single, operon

Question 15

in eukayotes, sets of genes, each encoding a single protein, are coordinately _______ to control _______

Answer 15

regulated, responses

Question 16

the tryptophan biosynthesis is regulated by levels of ______ in the cell

Answer 16

tryptophan

Question 17

in the presence of tryptophan, a ______ protein binds to the ______. what does this block?

Answer 17

repressor, operator; blocks binding of RNA polymerase

Question 18

the tryptophan repressor is an _______ protein

Answer 18

allosteric

Question 19

who discovered the lac operon

Answer 19

jacob and monod

Question 20

when glucose is _____, then there is no cAMP to activate genes like the lac operon

Answer 20

present

Question 21

with _______ present, then the lac repressor dissociates from the lac promoter

Answer 21

lactose

Question 22

glucose has to be ____ ____ and lactose has to be _____ for the lac operon to run efficiently

Answer 22

used up, present

Question 23

activators and repressors (transcription regulators) bind to ______

Answer 23

enhancers

Question 24

true or false: in eukaryotes can be long distances from the transcription start site, but in prokaryotic transcription they need to be close

Answer 24

true

Question 25

regulation from large distances on the chromosome is thought to occur through ______ ______

Answer 25

DNA looping

Question 26

DNA looping then allows the ______ and ______ sequences close

Answer 26

enhancer and promoter

Question 27

a large transcriptional regulatory complex that stabilizes general transcription factors and RNA polymerase with transcription regulators is called?

Answer 27

a mediator

Question 28

transcription regulators _________ the assembly of chromatin-modifying proteins at locations on the chromosome

Answer 28

promote

Question 29

what are two thing chromatin-modifying proteins induce

Answer 29

compaction and decompaction

Question 30

what promotes chromatin decompaction and is recruited by transcription ACTIVATORS

Answer 30

histone acetyltransferases

Question 31

what promotes chromatin compaction and is recruited by transcription RESPRESSORS

Answer 31

histone deacetylases

Question 32

after specialization a cell has _______ which allows it to maintain new functional specialization

Answer 32

memory

Question 33

single transcription regulators have the ability to _______ one cell type to another

Answer 33

convert

Question 34

what is the single transcription regulator that if expressed coverts a fibroblast cell into a muscle cells

Answer 34

MyoD

Question 35

there _______ transcription factors in genes

Answer 35

1,000

Question 36

to maintain their identity, cells must continue to express ________ of the cell type and progeny as well

Answer 36

characteristics

Question 37

a ______ feedback loop can drive characteristic maintenance in a cell

Answer 37

positive

Question 38

_______ memory is used to maintain cell identity in daughter cells ( this is done by methylation mark at cytosine residues in DNA)

Answer 38

epigenetic

Question 39

________ modification can also be maintained through successive cell divisions

Answer 39

histone

Question 40

in prokaryotes, ______ can bind and block translation or ______ can fold and block translation

Answer 40

factors, mRNA

Question 41

small non-coding mRNA's are called

Answer 41

micro or miRNA

Question 42

miRNA's regulate _______ and ________

Answer 42

translation and stability

Question 43

miRNA's are packaged where

Answer 43

RNA-induced silencing complex

Question 44

miRNA's RISC bind _______ inducing is degradation or blocking translation

Answer 44

mRNA

Question 45

there are about ______ miRNA's

Answer 45

500

Question 46

how many long non-coding RNAs are encoded in genomes? what is their function?

Answer 46

8,000, function as scaffold or regulatory proteins

Question 47

X-chromosome inactivation can be caused by

Answer 47

Xist