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Biology I > LO13 Day 3 > Flashcards

LO13 Day 3 Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Cell regulation in prokaryotes occurs primarily because of what?

A

changes in their environment

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2
Q

In bacteria genes are organized into what to facilitate regulation?

A

operons

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3
Q

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

A

operon

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4
Q

What operon is involved in the catabolism of lactose?

A

lac operon

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5
Q

What functional genes are in the lac operon?

A

LacZ and LacY

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6
Q

what does lacZ do?

A

breaks down lactose

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7
Q

what does lacY do?

A

lets lactose enter the cell

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8
Q

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

A

promoter region

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9
Q

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

A

operator region

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10
Q

where is an repressor gene located?

A

upstream of the operon

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11
Q

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

A

repressor gene

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12
Q

What does the repressor protein doe?

A

Keeps the operon turned off under certain environmental conditions

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13
Q

definition: controls expression of genes

A

operon

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14
Q

The lac operon is what kind of operon?

A

inducible

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15
Q

What happens when lactose is present in the environment?

A

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

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16
Q

lactose is what to the repressor?

A

an allosteric inhibitor

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17
Q

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

A

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

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18
Q

What happens when lactose is not present in the environment?

A

the repressor protein stays bound to the operator

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19
Q

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

A

there is no transcription of the functional genes

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20
Q

definition: induces the expression of the genes needed

A

inducible operon

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21
Q

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

A

To an allosteric site that is separate from an active site

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22
Q

Trp Operon is what kind of operon?

A

repressible operon

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23
Q

What happens when tryptophan is low in a bacteria cell?

A

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

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24
Q

what is tryptophan?

A

an amino acid

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25
Q

The repressor protein is made in what kind of form?

A

inactive

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26
Q

When tryptophan levels are high what happens?

A

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

27
Q

Tryptophan is an allosteric _______ of the repressor

A

activator

28
Q

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

A

repressible operon

29
Q

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

A

catabolic

30
Q

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.

A

anabolic

31
Q

gene regulation allows eukaryotes to do what for their cells?

A

develop and produce specialized

32
Q

prokaryotes and eukaryotes primarily regulate gene expression at which level?

A

transcriptional level

33
Q

definition: chromatin that is highly compacted

A

heterochromatin

34
Q

definition: chromatin that is loosely compacted

A

euchromatin

35
Q

Which chromatin is transcribed euchromatin or heterochromatin?

A

euchromatin

36
Q

What is an example of heterochromatin?

A

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

37
Q

Chemical modification of chromatin determines what?

A

chromosome structure

38
Q

examples of chemical modification of chromosome are?

A

histone acetylation and DNA methylation

39
Q

definition: addition of acetyl groups to histones

A

histone acetylation

40
Q

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

A

euchromatin and gene activation

41
Q

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

A

heterochromatin and gene inactivation

42
Q

definition: addition of methyl groups to certain cytosine nucleotides

A

DNA methylation

43
Q

Chemical modification are what?

A

epigenetic

44
Q

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

A

epigenetic modifications

45
Q

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

A

transcription factors

46
Q

example of transcription factors are?

A

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

47
Q

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

A

enhancers

48
Q

definition: DNA sequences that decrease the rate of transcription

A

silencers

49
Q

Are enhancers and silencers transcription factors or region of DNA?

A

silencer regions of DNA

50
Q

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

A

posttranscriptional control

51
Q

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

A

microRNAs (miRNA)

52
Q

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

A

RNA interference

53
Q

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

A

alternative mRNA splicing

54
Q

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

A

intron or exon

55
Q

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

A

pre mRNA; mature mRNA

56
Q

How do microRNAs work?

A

They block translation or degrade mRNA

57
Q

This control affects translation

A

posttranscriptional

58
Q

This control regulates proteins

A

posttranslational

59
Q

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

A

activate or deactivate them

60
Q

What do kinases do?

A

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

61
Q

What do phosphatases do?

A

They remove P groups usually deactivating proteins

62
Q

definition: eliminates unneeded proteins from cell.

A

protein degradation

63
Q

Which proteins are degraded by proteasoemes

A

the ones bonded to ubiquitin molecules

64
Q

definition: protein-digesting organelles that contain protein degrading enzymes

A

proteasomes

Biology I (15 decks)

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