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MolBio & Diagnostics > 04 Gene Regulation in Prokaryotes and Eukaryotes > Flashcards

04 Gene Regulation in Prokaryotes and Eukaryotes Flashcards

1
Q

A_____ is an entire chain of DNA along with a group of stabilizing proteins

A

chromosome

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2
Q

Code for proteins, or stable RNA molecules, each of which carries out a specific function in the cell.

A

Gene

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3
Q

A ______is the observable characteristics of a cell (or organism) at a given point in time and results from the complement of genes currently being used.

A

phenotype

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4
Q

____ refers to how we express a gene or not and it is a process of turning genes on and off. During early development, cells begin to take on specific functions. ensures that the appropriate genes are expressed at the proper times and can also help an organism respond to its environment.

A

Gene regulation

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5
Q

It is the process by which the genetic code, the nucleotide sequence of a gene is used to direct protein synthesis and produce the structures of the cell.

A

Gene expression

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6
Q

genes that code for amino acid sequences

A

Structural genes

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7
Q

______→ code for amino acids and collectively determine the amino acid sequence of the protein product. It is these portions of the gene that are represented in the final mature mRNA molecule.

A

exons

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8
Q

_____→ are portions of the gene that do not code for amino acids, and are removed (spliced) from the mRNA molecule before translation.

A

Introns

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9
Q

is the process of RNA synthesis, controlled by the interaction of promoters and enhancers.

A

Transcription

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10
Q

the mature mRNA molecule is used as a template to assemble a series of amino acids to produce a polypeptide with a specific amino acid sequence.

A

Translation

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11
Q

It is a label for the cellular processes that control the rate and manner of gene expression.

A complex set of interactions between genes, RNA molecules, proteins (including transcription factors) and other components of the expression system determine when and where specific genes are activated and the amount of protein or RNA product produced.

A

Gene regulation

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12
Q

______→ are proteins that play a role in regulating the transcription of genes by binding to specific regulatory nucleotide sequences.

A

Transcription factors

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13
Q

Levels of Gene Regulation:

Chromatin Remodeling
Transcription control
Post-Transcriptional control
Post-Translational control

A
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14
Q

_____→ the region of the chromosome must be opened up in order for the enzymes and transcription factors to access the gene.

A

Chromatin Remodeling

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15
Q

_____ → the most common type of genetic regulation. Turning on and off of mRNA formation.

A

Transcription control

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16
Q

_______→ regulation of the processing of a pre-mRNA into a mature mRNA.

A

Post-Transcriptional control

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17
Q

______→ regulation of the modification of an immature or inactive protein to form an active protein.

A

Post-Translational control

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18
Q

____ is a cluster of functionally related genes that encode enzymes of a certain metabolic pathway that are regulated or controlled coordinately as a group.

A

Operon

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19
Q

Operons constitutes the regulatory sites (____,_____) , the regulatory genes (____,_____), and the structural genes. `Can be controlled positively or negatively

A

(promoter and operator)

activators or repressors

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20
Q

For transcription to begin, an active regulator protein known as activator must bind to the promoter. In ______, the genes are expressed only when the activator is present. Otherwise, the operon will be turned off.

A

positive control

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21
Q

In ______, the operon is turned on and the genes are expressed unless they are switched off by a repressor protein. In this case the repressor inhibits transcription.

A

negative control

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22
Q

When repressors are inactivated, the operon is constitutively turned on and the genes that are always expressed or are active all the time are _____

A

“constituted.”

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23
Q

_____ refers to the expression of genes triggered in response to the presence of an inducer.

The inducer releases the repressor, therefore the operon is turned on and the genes are expressed. ____ are usually used for the breakdown of molecules in the cell.

A

Induction

Inducible enzymes

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24
Q

_______ are regulatory proteins that bind to the operator gene blocking the transcription of structural genes when RNA polymerase attaches to the promoter.

A

Repressors

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25
Q

_______ are regulatory proteins that facilitate transcription by helping the RNA polymerase bind to the promoter.

A

Activators

26
Q

The _____ is found in E. coli and it contains genes that are involved in the metabolism of lactose. This group of genes is only expressed with the condition that lactose is present and glucose is absent.

It contains three genes: ____. These genes are transcribed as a single mRNA, under control of one promoter. This operon can be regulated by positive and negative control.

A

lac operon

lacZ, lacY, and lacA

27
Q

Negative Control: The lac operon is usually turned off but can be turned on in the presence of the inducer allolactose. Therefore, it is an inducible operon.

A
28
Q

Binding site for RNA polymerase

A

promoter

29
Q

Regulatory site where repressor is bound

A

operator

30
Q

Acts as a lactose sensor

A

Lac repressor

31
Q

The ____ is found in E. coli and it contains genes that encode enzymes for tryptophan. This operon responds to the cell environment. If tryptophan levels are low the operon is expressed, on the other hand it is repressed when tryptophan levels are high.

It contains five genes: trpE, trpD, trpC, trpB, trpA, and it is transcribed as a single mRNA

A

trp operon

32
Q

Acts as a sensor and switch

→When tryptophan is present, it acts as a corepressor, making the repressor bind to the DNA of the operator and transcription is blocked.

In the case of low levels of tryptophan, the trp repressor is inactive because there is no tryptophan to bind to it. The RNA polymerase can now transcribe the group of genes in the trp operon.

A

Trp repressor

33
Q

The repression of the synthesis of the lac proteins by glucose is called ______, which involves the two regions in the promoter. One is the binding site for the RNA polymerase and the other is the binding site for another regulatory protein, the catabolite activator protein (CAP).

A

catabolite repression

34
Q

____ → Acts as a glucose sensor. It activates transcription of the operon, but only when glucose levels are low.

A

Catabolite activator protein (CAP)

35
Q

______ → Is a “hunger signal” made by E. coli when glucose levels are low.

→ Without this, CAP cannot bind DNA and is inactive.

A

cAMP

36
Q

When the _____, CAP forms a complex with 3’, 5’-cyclic AMP (cAMP) and binds to the CAP site on the promoter. This binding can help RNA polymerase bind to the promoter and the operon is fully active.

A

glucose is not present

37
Q

In the______, the level of cAMP is low; only very few CAP-cAMP complexes can be formed. It is not enough to activate lac operon.

A

presence of glucose

38
Q

The _____ is active only when the glucose is absent and the lactose is present. As such, the CAP site is an example of an enhancer element, and the CAP-cAMP complex is a transcription factor. The modulation of transcription by CAP is a type of positive regulation.

A

lac operon

39
Q

______ → is the process in which messenger RNA transcripts of genetic material in prokaryotes are produced, to be translated for the production of proteins. occurs in the cytoplasm alongside translation.

A

Transcription

40
Q

Proteins that are needed for a specific function, or that are involved in the same biochemical pathway, are encoded together in blocks called _______

A

operons

41
Q

_____ → protein that binds to the operator of prokaryotic genes to prevent transcription

A

Repressors

42
Q

_____ → protein that binds to prokaryotic operators to increase transcription

A

Activators

43
Q

is a type of operon which gets switched on by a substrate chemical i.e., an inducer.

Lac Operon → encodes enzymes for metabolism of the sugar lactose. The inducer in this case is allolactose, a modified form of lactose.

A

Inducible

44
Q

→ is a type of operon which gets switched off in the presence of a co-repressor.

Trp operon → encodes enzymes for synthesis of the amino acid tryptophan. This operon is expressed by default, but can be repressed when high levels of the amino acid tryptophan are present. The co-repressor in this case is tryptophan.

A

Repressible

45
Q

Gene regulation is the process of turning genes on and off by using transcription factors. Gene regulation in eukaryotes is more complex than in prokaryotes.

A
46
Q

Problems in eukaryotic gene regulation:

  • Movement of DNA or interaction with other proteins that causes transcriptional factors to dislodge.
  • When the transcription factor lands on another segment of DNA that short hops become a big jump, may result that chromosomes are far from it and cannot generate genes.
A
47
Q

usually found in DNA upstream of the gene; for example the TATA Box.

A

Regulatory sequence

48
Q

a gene on the DNA that codes for a regulatory protein; for example the TATA-binding protein

A

Regulatory gene

49
Q

Gene regulation in ______ → Occur at the nucleus has a single promoter for a single gene and has multiple protein molecules.

A

eukaryotes

50
Q

Gene regulation in _____ → Occurs at cytoplasm, it requires a single promoter per operon (group of genes), and they only have 1 or 2 protein molecules.

A

prokaryotes

51
Q

→ the region of the chromosome must be opened up in order for the enzymes and transcription factors to access the gene. The cellular genome is packed together with the histones and if the promoter region is part of that nucleosome, transcription is inhibited.

A

Chromatin Remodeling

52
Q

_____ is located in the nucleus and made up of DNA that is wrapped up in histones proteins. It has 2 types:

_____ are genes that are not tightly coiled and usually expressed.
_______ are genes that are tightly coiled and not usually expressed.

A

Chromatin

Euchromatin
Heterochromatin

53
Q

_____ promotes acetylation by opening the chromatin structure. It has 2 process:

o ____ → when acetyl is added to heterochromatin, its structure changes to euchromatin turning on transcription.
o ______ → when the acetyl group is removed then it turns back into the heterochromatin structure and turns off the gene transcription.

A

Histone Acetylation

Acetylation
Deacetylation

54
Q

______ condenses the DNA and forms heterochromatin, blocking transcription or turning off the transcription.

A

DNA Methylation

55
Q

it is the most common type of genetic regulation. In this level, transcription is regulated by transcription factors that either enhance or restrict the RNA polymerase from binding to the promoter.

A

Transcription Control

56
Q

.Post-transcription Control → it is the regulation of the processing of a pre-mRNA into a mature mRNA

introns are being removed in the RNA and the only left are all exons that are combined together making the mRNA, and this is called the ____.

A

splicing

57
Q

_______ → regulation occurs during the modification of an immature or inactive protein to form an active protein by changing the activity of rate-limiting protein factors that take part in the process of translation.

A

Post-translational Control

58
Q

The model of _____ in Eukaryotes sums up all the events that happened in a eukaryotic gene regulation. First, both coding and noncoding regions of DNA are transcribed into mRNA. Some regions are removed (introns) during initial mRNA processing. The remaining exons are then spliced together, and the spliced mRNA molecule is prepared for export out of the nucleus through addition of an endcap (sphere) and a polyA tail. Once in the cytoplasm, the mRNA can be used to construct a protein.

A

Gene Regulation

59
Q

Uncontrolled cell growth. Genes in the human genome are made of DNA. Upon gene expression, a segment of DNA is copied into another molecule called RNA. When gene regulation goes wrong, diseases like cancer can occur. Therefore, knowing how enzymes, highly efficient protein nanomachines, work to switch genes on and off enables the development of new drugs and diagnostics.

A

Cancer

60
Q

These are like security guards that prevent you from developing cancer. However, as time passes by, these genes could either be inactivated or turned off. When this happens, the cell will divide beyond their normal division and may lead to death.

A

Tumor Suppressor Genes and Proto-Oncogenes

MolBio & Diagnostics (7 decks)

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