18.2 & 18.3

Question 1

Differential gene expression

Answer 1

The expression of different genes by cells with the same genome

Question 2

Histone acetylation

Answer 2

Acetyl groups are attached to lysines in histone tails; deacetylation is the removal of acetyl groups

Question 3

Genomic imprinting

Answer 3

Methylation permanently regulates expression of either the maternal or paternal allele of particular genes at the start of development

Question 4

Epigenetic inheritance

Answer 4

Inheritance of traits transmitted by mechanisms not directly involving the nucleotide sequence

Question 5

Control elements

Answer 5

Segments of noncoding DNA that help regulate transcription by binding certain proteins

Question 6

Enhancers

Answer 6

A DNA sequence that increases the level of transcription of a gene that is located nearby on the same chromosome

Question 7

Alternative RNA splicing

Answer 7

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

Question 8

Proteasomes

Answer 8

Giant protein complexes that recognize ubiquitin tagged proteins and degrade them

Question 9

microRNAs

Answer 9

Single stranded RNA molecules that are capable of binding to complementary sequences in mRNA molecules

Question 10

RNA interference (RNAi)

Answer 10

Researchers found that injecting double stranded RNA molecules into a cell somehow turned off expression in a gene with the same sequence as the RNA

Question 11

Small interfering RNAs

Answer 11

Smaller in size and function to miRNAs