AP Biology - Unit 6 Review: Gene Regulation

prokaryotes

Operons are ONLY used by __________ for gene regulation.

promoter

site on the DNA strand where transcription begins; RNA polymerase binds to the DNA strand here

operator

the on and off switch on the DNA segment that controls whether or not the gene is turned on or off

repressor

a protein that can turn off a gene by binding to the operator segment on the DNA strand

operon

the group of genes along with the sections of DNA that regulate them in a prokaryote

lac operon

what is an example of an inducible operon?

trp operon

what is an example of a repressible operon?

negative control

a regulatory mechanism that involves a repressor protein that turns the operon "off" is called this

positive control

an operon is said to have this when a protein or enzyme can turn them "on" or enhance their function by making it easier for RNA polymerase to bind to the promoter

inducible operon

this type of operon is usually off but can be stimulated or induced when a small molecule interacts with the repressor protein, causing it to detach from the operator and allowing the RNA polymerase to initiate transcription

repressible operon

this type of operon is usually on but can be inhibited or repressed when a small molecule binds allosterically to a repressor protein, which then binds to the operator on the operon and prevents RNA polymerase from initiating transcription. An example would be the trp operon

regulatory genes

produces repressor proteins and are continuously expressed, but at a slow rate. These are usually located away from the operon and has its own promoter

cAMP

when ATP is scarce or not available, this, which is a type of ligand, will accumulate and activates CAP

CAP

is activated by cAMP and binds to the promoter of a lac operon, which allows the operon to transcribe rapidly

histone

proteins that eukaryotic DNA strands are wound around

acetyl

groups that binds to histone proteins, causing the eukaryotic DNA strands wound around them to be wound loose, which allows for the DNA to be open and transcribable

tightly

without acetyl groups, the eukaryotic DNA would be wound ________ and would not be able to be transcribed.

euchromatin

describes the eukaryotic DNA that is loosely wound and the histones contain the acetyl groups

heterochromatin

describes the eukaryotic DNA that is tightly wound around the histone proteins, which do not have acetyl groups

methylated

when genes are ________ in eukaryotic DNA, they are OFF!

proximal and distal control elements

in eukaryotic gene regulation, what do transcription factors interact with to control what is happening to a particular gene?

RNA polymerase

together, transcription factors and proximal and distal control elements allow for ______ _______ to bind and transcribe the eukaryotic DNA efficiently and effectly

environment

the ________ controls what kind of eukaryotic genes are expressed in different cells, allowing for differentiation in cells and their function

5' capping, 3' poly-A tail

________ and the ________ controls the amount of time that a particular eukaryotic gene is carried out

alternative splicing

where different genes come from the same strand because difference exons and/or introns are left in or expressed on that particular gene

miRNA

also known as siRNA or "micro RNA," these are produced by dicer proteins and then go into a special protein complex, where they tag an mRNA, causing the mRNA to either by degraded or translation of that mRNA is blocked

dicer protein

these chop up mRNA into miRNA

ubiquitin

a molecule that tags a protein that is unnecessary

proteasome

these find proteins that have been tagged by ubiquitin and then chops it up

true

true or false? viruses can have either RNA or DNA as their genetic information

capsid

protein shell enclosing viral genome. It can be many different shapes depending on the virus

phage

what is another name for a virus?

host range

idea that each particular virus can infect cells of only a limited number of host species

host cells

because viruses don't have the mechanisms needed to replicate themselves, they rely on the mechanisms of _______.

bacteriophages

viruses that infect bacteria

virulent phages

phages that replicate by a lytic cycle

temperate phages

phages that replicate by a lysogenic cycle

restriction enzymes

bacterial cellular enzymes that cut up any foreign DNA that enter the cell, restricting infection from a virus

prophage

viral DNA that has been integrated into bacterial chromosomes, but they usually leave the cell

lytic cycle

mode of "reproduction" in viruses where after using the host cell's mechanisms to replicate itself, the newly assembled viruses will burst out from the cell, usually killing it

lysogenic cycle

mode of "reproduction" in viruses where after replicating itself using the host cell's mechanisms, the virus then integrates itself into the host cell's genetic information, remaining there forever

retrovirus

a type of virus that have RNA genomes, but then they are able to get the host cell's mechanisms to make viral DNA using reverse transcriptase, which then is used to make viral proteins to make new viruses. In this way, they go against the central dogma

provirus

these viruses do not leave the cell once they enter because they are integrated into the cell's genes and will never leave

plasmids

small, circular DNA molecules found in yeast and bacteria that are used to trade genes amongst other bacteria and yeast