CH 18

Question 1

operator

Answer 1

-the entire stretch of DNA that includes the operator, the promoter, and the genes that they control

Question 2

repressor

Answer 2

-switches off the operon

Question 3

regulatory gene

Answer 3

-created the represor

Question 4

corepressor

Answer 4

-a molecule that cooperates with a repressor protein to switch an operon off

Question 5

inducer

Answer 5

-inactivates the repressor to turn the lac operon on

Question 6

activator

Answer 6

-a protein that binds to DNA and stimulates transcription of a gene

Question 7

cyclic AMP (cAMP)

Answer 7

-a common chemical signal as a second messenger in many eukaryotic cells, and as a regulator of some bacterial operons

Question 8

differential gene expression

Answer 8

-the expression of different genes by cells with the same genome

Question 9

histone acetylation

Answer 9

-acetyl groups are attached to an amino acid in a histone tail

Question 10

DNA methylation

Answer 10

-the addition of methyl groups to certain bases in DNA, is associated with reduced transcription in some species

Question 11

epigenetic inheritance

Answer 11

-The inheritance of traits transmitted by mechanisms not directly involving the nucleotide sequence

Question 12

control elements

Answer 12

-segments of noncoding DNA that serve as binding sites for transcription factors that help regulate transcription

Question 13

enhancers

Answer 13

-grouped Distal control elements

Question 14

alternative RNA splicing

Answer 14

-different mRNA molecules are produced from the same primary transcript, depending on which RNA segments are treated as exons and which as introns

Question 15

MicroRNAs (miRNAs)

Answer 15

-small, single-stranded RNA molecules that can bind complementary sequences in mRNA

Question 16

Small interfering RNAs (siRNAs)

Answer 16

-similar to miRNAs in size and function

Question 17

RNA interference (RNAi)

Answer 17

-blocking of gene expression

Question 18

Long noncoding RNAs (lncRNAs)

Answer 18

-200 to hundreds of thousands of nucleotides in length

Question 19

cell differentiation

Answer 19

-the process by which cells become specialized in structure and function

Question 20

morphogenesis

Answer 20

-The physical processes that give an organism its shape

Question 21

Cytoplasmic determinants

Answer 21

-are maternal substances in the egg that influence early development

Question 22

induction

Answer 22

-signal molecules from embryonic cells cause changes in nearby target cells

Question 23

Determination

Answer 23

-irreversibly commits a cell to becoming a particular cell type
-precedes differentiation

Question 24

Pattern formation

Answer 24

-the development of a spatial organization of tissues and organs

Question 25

Positional information

Answer 25

-the molecular cues that control pattern formation, tells a cell its location relative to the body axes and to neighboring cells

Question 26

homeotic genes

Answer 26

-control pattern formation in the late embryo, larva, and adult stages

Question 27

embryonic lethal

Answer 27

-mutations with phenotypes causing death at the embryonic or larva stage

Question 28

Maternal effect genes

Answer 28

-mutant is in the mother
-results in a mutant phenotype in offspring

Question 29

bicoid gene

Answer 29

-affects the front half of the body
-no functional Bicoid gene=no front half of body missing

Question 30

morphogens

Answer 30

-gradients of substances
-establish an embryo’s axes and other features of its form

Question 31

Oncogenes

Answer 31

-cancer-causing genes in some types of viruses

Question 32

Proto-oncogenes

Answer 32

-are the corresponding normal cellular genes that are responsible for normal cell growth and division

Question 33

Tumor-suppressor genes

Answer 33

-inhibit cell division

Question 34

ras gene

Answer 34

-mutations can lead to production of a hyperactive Ras protein and increased cell division

Question 35

p53 gene

Answer 35

-mutations prevent suppression of the cell cycle