LO13 Day 3

Question 1

Cell regulation in prokaryotes occurs primarily because of what?

Answer 1

changes in their environment

Question 2

In bacteria genes are organized into what to facilitate regulation?

Answer 2

operons

Question 3

definition: a group of genes with related function and nearby DNA sequences that control the expression of genes

Answer 3

operon

Question 4

What operon is involved in the catabolism of lactose?

Answer 4

lac operon

Question 5

What functional genes are in the lac operon?

Answer 5

LacZ and LacY

Question 6

what does lacZ do?

Answer 6

breaks down lactose

Question 7

what does lacY do?

Answer 7

lets lactose enter the cell

Question 8

definition: where RNA polymerase binds to DNA to transcribe the functional genes

Answer 8

promoter region

Question 9

definition: determines whether or not the functional genes are transcribed?

Answer 9

operator region

Question 10

where is an repressor gene located?

Answer 10

upstream of the operon

Question 11

definition: codes for a protein that binds to the operator and block RNA polymerase

Answer 11

repressor gene

Question 12

What does the repressor protein doe?

Answer 12

Keeps the operon turned off under certain environmental conditions

Question 13

definition: controls expression of genes

Answer 13

operon

Question 14

The lac operon is what kind of operon?

Answer 14

inducible

Question 15

What happens when lactose is present in the environment?

Answer 15

it binds to the repressor proteina nd prevents it from binding to the operator

Question 16

lactose is what to the repressor?

Answer 16

an allosteric inhibitor

Question 17

What happens when the repressor protein is not bound to the operator?

Answer 17

RNA polymerase can transcribe to the functional genes…this is so cells can use lactose

Question 18

What happens when lactose is not present in the environment?

Answer 18

the repressor protein stays bound to the operator

Question 19

What happens when the repressor protein is m bound to the operator?

Answer 19

there is no transcription of the functional genes

Question 20

definition: induces the expression of the genes needed

Answer 20

inducible operon

Question 21

Where does lactose bind to the protein since it is an allosteric inhibitor?

Answer 21

To an allosteric site that is separate from an active site

Question 22

Trp Operon is what kind of operon?

Answer 22

repressible operon

Question 23

What happens when tryptophan is low in a bacteria cell?

Answer 23

the repressor protein cant bind to the operator and there is transcription of the functional genes that make the amino acid

Question 24

what is tryptophan?

Answer 24

an amino acid

Question 25

The repressor protein is made in what kind of form?

Answer 25

inactive

Question 26

When tryptophan levels are high what happens?

Answer 26

the excess binds to the repressor protein and activates making it bind to the operator. There is no transcription of the functional genes

Question 27

Tryptophan is an allosteric _______ of the repressor

Answer 27

activator

Question 28

definition: represses the expression of the genes needed to be synthesized

Answer 28

repressible operon

Question 29

inducible operons are part of ________ pathways whose genes need to be expressed only when substances are present in the environment.

Answer 29

catabolic

Question 30

Repressible operons are part of ________ pathways whose genes need to be expressed only when substances are in low quantinty in the cell and need to be synthesized.

Answer 30

anabolic

Question 31

gene regulation allows eukaryotes to do what for their cells?

Answer 31

develop and produce specialized

Question 32

prokaryotes and eukaryotes primarily regulate gene expression at which level?

Answer 32

transcriptional level

Question 33

definition: chromatin that is highly compacted

Answer 33

heterochromatin

Question 34

definition: chromatin that is loosely compacted

Answer 34

euchromatin

Question 35

Which chromatin is transcribed euchromatin or heterochromatin?

Answer 35

euchromatin

Question 36

What is an example of heterochromatin?

Answer 36

The inactivated X chromosome in female mammals which is a Barr body.

Question 37

Chemical modification of chromatin determines what?

Answer 37

chromosome structure

Question 38

examples of chemical modification of chromosome are?

Answer 38

histone acetylation and DNA methylation

Question 39

definition: addition of acetyl groups to histones

Answer 39

histone acetylation

Question 40

histone acetylation is associated with the formation of which type of chromatin?

Answer 40

euchromatin and gene activation

Question 41

DNA methylation is associated with the formation of which type of chromatin?

Answer 41

heterochromatin and gene inactivation

Question 42

definition: addition of methyl groups to certain cytosine nucleotides

Answer 42

DNA methylation

Question 43

Chemical modification are what?

Answer 43

epigenetic

Question 44

definitions: inherited changes to DNA or chromosome structure that do not involve changing nucleotide sequence but do not affect gene expression

Answer 44

epigenetic modifications

Question 45

definition: proteins that bind to DNA and interact with RNA polymerase at the promoter

Answer 45

transcription factors

Question 46

example of transcription factors are?

Answer 46

many steroid hormones bind to intracellular receptors that function as transcription factors

Question 47

definitions: DNA sequences that help form an active transcription comples and increase the rate of transcription

Answer 47

enhancers

Question 48

definition: DNA sequences that decrease the rate of transcription

Answer 48

silencers

Question 49

Are enhancers and silencers transcription factors or region of DNA?

Answer 49

silencer regions of DNA

Question 50

definition: controlling gene expression by determining how or whether an mRNA transcript gets translated or not

Answer 50

posttranscriptional control

Question 51

definition: molecules that bind to mRNAs and degrade them or prevent them from being translated are called what?

Answer 51

microRNAs (miRNA)

Question 52

microRNAs are involves in a type of gene regulation called what?

Answer 52

RNA interference

Question 53

definition: a single protein coding gene can produce different forms of its polypeptide in different tissues

Answer 53

alternative mRNA splicing

Question 54

During alternative mRNA splicing the gene will have at lease one segment that can be either ______________ depending on the tissue

Answer 54

intron or exon

Question 55

The gene created during alternative mRNA splicing produces the same _____ but slightly different ________

Answer 55

pre mRNA; mature mRNA

Question 56

How do microRNAs work?

Answer 56

They block translation or degrade mRNA

Question 57

This control affects translation

Answer 57

posttranscriptional

Question 58

This control regulates proteins

Answer 58

posttranslational

Question 59

chemical modification to already translated protein can do what to them?

Answer 59

activate or deactivate them

Question 60

What do kinases do?

Answer 60

they are enzymes that add P groups to other proteins which activates them

Question 61

What do phosphatases do?

Answer 61

They remove P groups usually deactivating proteins

Question 62

definition: eliminates unneeded proteins from cell.

Answer 62

protein degradation

Question 63

Which proteins are degraded by proteasoemes

Answer 63

the ones bonded to ubiquitin molecules

Question 64

definition: protein-digesting organelles that contain protein degrading enzymes

Answer 64

proteasomes