| A | B |
|---|
| * A unit of genetic function common in bacteria and phages, consisting of coordinately regulated clusters of genes with related functions. | operon (below is a diagram of the lac operon and the molecules that regulate its transcription) p310,  |
| * A specific small molecule that inactivates the repressor protein in an operon. | inducer (allolactase, an isomer of lactose that occurs in small quantities when lactose is present, is the inducer in the lac operon system because it's presence ends up inducing the operon to be transcribed, making the instructions for making the enzyme that breaks down lactose; lactase, a.k.a B-galactosidase) p312, |
| * A protein that suppresses the transcription of a gene. | repressor (the repressor protein that stops the trp operon is the red molecule. It requires tryptophan as a corepressor to assume its active form) p311,  |
| * A small molecule that cooperates with a repressor protein to switch an operon off. | corepressor (tryptophan is the corepressor in the trp operon) p311, |
| * In prokaryotic DNA, a sequence of nucleotides near the start of an operon to which an active repressor can attach, preventing the attachment of RNA polymerase to the promoter (which prevents transcription). | operator (the yellow part of the operon below) p310, |
| * A protein that binds to DNA and stimulates transcription of a specific gene. | activator p313 |
| * What are two general strategies for regulating metabolic pathways? | 1) Regulate the enzymes themselves. 2) Regulate the transcription of the enzymes. p310,  |
| * A promoter, an operator, and the genes they control make up a(n) _______. | operon p310, |
| * The lac operon is a(n) _______ operon because it is usually off but can be switched on. | inducible operon p311, |
| * The trp operon is a(n) _____ operon because it is usually on but can be switched off. | repressible operon p311, |
| * The attachment of CRP (a.k.a CAP) to the promoter of the lac operon is an example of _______ regulation because it directly stimulates gene expression. | positive regulation (This is a graphic from the old textbook that still uses the term CAP. I like the term CRP better because it stands for cAMP receptor protein, and if you look at the graphic, that name describes exactly what it does) p313,  |
| * In both prokaryotes and eukaryotes, gene expression is most often regulated at the stage of _______. | transcription (As you can see in the figure below, there are other places that gene expression can be regulated) p315,  |
| * DNA wraps around ________ to form chromatin. | histone proteins p315,  |
| * What affect does the acetylation of histone tails have on the ability of DNA to be transcribed? | makes it easier (because the acetyl group -COCH3 neutralizes the positive charge of the histone protein, loosening the grip of the histone on the negatively charged DNA. It also loosens their attraction to neighboring nucleosomes) p315,  |
| * What affect does the methylation of histone tails have on the ability of DNA to be transcribed? | makes it harder (Keep in mind that not only can histone tails be methylated, DNA itself can be methylated, both resulting in reduced or no transcription) p315 |
| * DNA that is ______ is generally inactive. | methylated p315 |
| * Inheritance of traits transmitted by mechanisms not directly involving the nucleotide sequence is called ____ inheritance. Methylation, which can silence genes even in successive cell divisions, is an example. | epigenetic inheritance p315 |
* What is "A" pointing to in the picture below?,  | histone proteins p315, |
| * Expression of different sets of genes by cells with the same genome is called _____. | differential gene expression p314 |
| * Genes within highly condensed chromatin, called _____, are usually ____ expressed. | heterochromatin, not p315 |
| * A protein that suppresses the transcription of a gene by binding to DNA is called a(n) _____. | repressor p311 |
| * Another term for a biosynthetic pathway is a(n) _____ pathway. | anabolic p310 |
| * The ____ part of an operon (for prokaryotic cells) can be thought of as the "on/off" switch. | operator p310 |
| * A(n) _____ is the site on DNA where RNA polymerase can bind to start transcription. | promoter p310 |
