Alberts, Ch 7 - Control of Gene Expression

Question 1

Cell memory

Answer 1

Retention by cells and their descendants of persistently altered patterns of gene expression, without any change in DNA sequence

Question 2

CG island

Answer 2

Region of DNA in vertebrate genomes with a greater than averagedensity of CG sequences, remains generally unmethylated

Question 3

Cis-regulatory sequence

Answer 3

DNA sequences to which transcription regulators bind to control the rte of gene transcription, in nearly all case these sequences must be on the same chromosome to the genes they control

Question 4

CRISPR

Answer 4

A defense mechanism in bactria using small noncoding RNA molecules (crRNAs) to seek out and destroy invading viral genomes through complementary base-pairing and targeted nuclease digestion

Question 5

Alternative RNA splicing

Answer 5

Production of different RNAs from the same gene by splicing the transcript in different ways

Question 6

crRNA

Answer 6

Small noncoding RNAs that are effectors of DRISPR-mediated immunity in bacteria

Question 7

DNA methylation

Answer 7

Addition of methyl groups to DNA, extensive methlation of cytosine in CG sequences is used in plants and animals to help keep genes in an inactive state

Question 8

Epigenetic inheritance

Answer 8

Inheritance of phenotypic changes in a cell or organism that do not result from changes in the nucleotide sequence of DNA, can be due to positive feedback loops of transcription regulators or to heritable modifications in chromatin such as DNA methylation or histone modifications

Question 9

Gene

Answer 9

Region of DNA that is transcribed as a single unit and carries information for a discrete hereditary characteristic, usually corresponding to a single protein or a single RNA (or set of closely related protein/RNA)

Question 10

Gene control region

Answer 10

The set of linked DNA sequences regulating expression of a particular gene, includes promoter and cis-regulatory sequences required to initiate transcription of the gene and control the rate of transcription

Question 11

Genomic imprinting

Answer 11

Phenomenon in which a gene is either expressed or not expressed in the offspring depending on which parent it is inerited from

Question 12

Induced pluripotent stem cells (iPS cells)

Answer 12

Cells that are induced by artificial expression of specific transcription regulators to look and behave like the pluripotent embryonic stem cells that are derived from embryos

Question 13

Internal ribosome entry site (IRES)

Answer 13

Specific site in a eukaryotic mRNA, other than at the 5’ end at which translation can be initiated

Question 14

Long noncoding RNA (lncRNA)

Answer 14

One of a large group of RNAs longer than 200 nucleotides long not coding for protein, functions of most lncRNAs is unknown but individual lncRNA are known to play important roles in the cell like in telomerase function and in genomic imprinting, in general sense are believed to act as scaffolds, holding together proteins and nucleic acids to speed up a wide variety of reactions in the cell

Question 15

Master transcription regulator

Answer 15

A transcription regulator specifically required for formation of a particular cell type, artificial expression will often convert one cell type into another

Question 16

microRNA (miRNA)

Answer 16

Short RNA, produced by the processing of specialized RNA transcripts coded in the genome, that regulate gene expression through base-pairing with mRNA

Question 17

Monoallelic gene expression

Answer 17

Expression of only one of the two copies of a gene in a diploid genome, occuring for example as a result if imprinting of X-chromosome inactivation

Question 18

mRNA degradation control

Answer 18

Regulation by a cell of gene expression by selectively preserving or destroying certain mRNAs in the cytoplasm

Question 19

Piwi-interacting RNA (piRNA)

Answer 19

A class of small noncoding RNAs made in the germ line that in complex with Piwi proteins keep in check the movement of transposable elements by transcriptionally silencing transposon genes and destroying RNAs produced by them

Question 20

Post-transcriptional controls

Answer 20

Any control on gene expression that is exerted at a stage after transcriptionhas begun

Question 21

Promoter

Answer 21

Nucleotide sequence in DNA to which RNA polymerase binds to begin transcription

Question 22

Protein activity control

Answer 22

The selective activation, inactivation, degradation or compartmentalization of specific proteins after they have been made, one of the means by which a cell controls which proteins are active at a given time or location in the cell

Question 23

Regulated nuclear transport

Answer 23

Mechanisms controlling export of mRNAs from the nucleus to the cytosol that can be used to regulate gene expression, also includes the selective import of proteins and RNA molecules into the nucleus

Question 24

RNA editing

Answer 24

Type of RNA processinf that alters the nucleotide sequence of an RNA transcript after it is synthesized by inserting, deleting or altering individual nucleotides

Question 25

RNA interference (RNAi)

Answer 25

Mechanism by which an experimentally introduces double-stranded RNA induces sequences-specific destruction of complementary mRNAs, often used to include the inhibition og gene expression by miRNAs and piRNAs which are encoded in the cell’s own genome

Question 26

RNA processing control

Answer 26

Regulation by a cell of gene expression by controlling the processing of RNA transcripts which includes splicing

Question 27

RNA transport and localization control

Answer 27

Regulation by a cell of gene expression by selecting which completed mRNAs are exported from the nucleus to the cytosol and determining where in the cytosol they are localized

Question 28

Small interfering RNA (siRNA)

Answer 28

Short double-stranded RNAs that inhibit gene expression by directing destruction of complementary mRNAs, production is usually triggered by exogenously introduced double-stranded RNA

Question 29

Transcription regulators

Answer 29

General name for any protein that binds to a specific DNA sequence to influence the transcription of a gene

Question 30

Transcriptional control

Answer 30

Regulation by a cell of gene expression by controlling when and how often a given gene is transcribed

Question 31

Translational control

Answer 31

Reulation by a cell of gene expressionby selecting which mRNAs in the cytoplasm are translated by ribosomes

Question 32

X-inactivation

Answer 32

Inactivation of one copy of the X chromosome in somatic cells of female mammals

Question 33

X-inactivation center (XIC)

Answer 33

Site in an X chromosome at which inactivation is initiated and spreads outward