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INTRGEN > MOD 6: Regulation of Expressions in Prokaryotes > Flashcards

MOD 6: Regulation of Expressions in Prokaryotes Flashcards

1
Q

TRUE OR FALSE: Prokaryotic cells are generally larger than eukaryotic cells

A

FALSE; They are smaller

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2
Q

TRUE OR FALSE: Eukaryotic cells are round because they do not have cell walls

A

TRUE

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3
Q

What do you call the enzyme that deteriorates cell walls?

A

Cellulase

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4
Q

What factors affect the occurrence of transcription?

A
  1. Environment
  2. Cellular activities
    • Replication
    • Recombination
    • Repair of DNA
    • Cell division
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5
Q

This type of enzyme can be induced and it requires specific factors for it to do its job

A

Inducible enzyme

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6
Q

This type of enzyme is always functioning

A

Constitutive enzyme

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7
Q

This type of enzyme binds to the operator and tells it to stop working. It is produced by a repressor gene

A

Repressible enzyme

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8
Q

Genetic expression occurs unless it is shut off by a regulator molecule. What control is this?

A

Negative control

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9
Q

Transcription occurs only if a regulator molecule directly stimulates RNA production

A

Positive control

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10
Q

These refer to the genes coding for the primary structure of an enzyme

A

Structural genes

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11
Q

What are the three structural genes in the lac operon?

A
  1. lacZ (B-galactosidase)
  2. lacY (permease)
  3. lacA (transacetylase)
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12
Q

TRUE OR FALSE: Bacterial DNA have introns as well

A

FALSE; They do not

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13
Q

TRUE OR FALSE: Proteins are products of genes that will be operons

A

FALSE; Operons are products of genes that will be proteins

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14
Q

Lactose related genes are expressed when lactose is __________ and repressed when __________

A

Present; absent

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15
Q

These are genes that code for similar functions. They tend to be organized in clusters

A

Operons

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16
Q

This type of operon is affected by the presence of lactose

A

Lac operon

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17
Q

Which two scientists discovered the genetic regulatory mechanism, regulation of transcription, and obtain the 1965 Nobel Prize in Medicine?

A

Francois Jacob and Jacques Monod (Jacob Monod Lac Operon)

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18
Q

With lactose, the disaccharide is broken down into 2 monosaccharides. What are they?

A

Glucose and galactose

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19
Q

Lac operon produces an enzyme to break down lactose. What is this enzyme?

A

B-galactosidase

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20
Q

What are the two binding sites of the repressor protein?

A

Operator gene and lactose

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21
Q

What process does the repressor protein block?

A

Transcription

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22
Q

With the absence of lactose, it is repressed. Where does the repressor protein bind to?

A

It binds to the operator gene

23
Q

With the presence of the repressor protein, its conformation is changed. Where does the repressor protein bind to?

A

It binds with the lactose

24
Q

TRUE OR FALSE: The repressor protein can bind to the operator region with or without the presence of lactose.

A

FALSE; The repressor protein cannot bind to the operator region with the presence of lactose

25
Q

Which does a cell prefer, lactose or glucose? What happens to the other?

A

The cell prefers glucose for glycolysis. Lactose then shuts down.

26
Q

What type of control does the catabolite-activating protein (CAP) exert over the lac operon?

A

Positive control

27
Q

What is the condition of glucose and lactose when:
- cAMP levels increase
- cAMP forms complex with cAP
- binds with cAP-binding site
- transcription and translation
- structural genes are expressed

A

Without glucose, with lactose

28
Q

What is the condition of glucose and lactose when:
- cAMP levels decrease
- cAMP does not form complex with cAP
- no binding with cAP-binding site
- glucose cannot bind efficiently
- translation is diminished

A

With glucose, with lactose

29
Q

TRUE OR FALSE: Lactose metabolism requires fewer steps and less energy compared to glucose metabolism.

A

FALSE; By using glucose first the cell maximizes energy efficiency

30
Q

TRUE OR FALSE: The cell avoids unnecessary production of enzymes involved in lactose metabolism when glucose, a more readily metabolizable sugar, is available.

A

TRUE

31
Q

TRUE OR FALSE: The CAP-cAMP system ensures that the lac operon is only fully activated when glucose levels are low and lactose is present.

A

TRUE

32
Q

What happens to the repressor with the presence of tryptophan?

A

Tryptophan binds to the repressor, activating it

33
Q

TRUE OR FALSE: Tryptophan is produced in the cell and cannot be obtained from the environment.

A

TRUE

34
Q

TRUE OR FALSE: The DNA plays diverse roles in regulation gene expression in bacteria.

A

FALSE; RNA

35
Q

What are the three types of regulation that fine-tune levels of gene expression in bacteria?

A
  1. Attenuation
  2. Riboswitches
  3. Small noncoding RNAs (sRNA)
36
Q

TRUE OR FALSE:
DNA —> Transcribed to __________ —> decides if it will be converted to __________ or not

A

mRNA; protein

37
Q

Which groups of scientist discovered attenuation?

A

Charles Yanofsky, Kevin Bertrand, and their colleagues

38
Q

What is the condition of tRNA when:
- tRNA is uncharged
- transcription is slow
- 1-3 stem-loop is formed

A

tRNA is unavailable

39
Q

What is the condition of tRNA when:
- tRNA is charged
- 1, 2, and 3 are separated
- 4 forms a loop
- termination hairpin is formed

A

tRNA is available

40
Q

What is the condition of tryptophan levels when:
- ribosome translates slowly
- antiterminator is formed

A

Low tryptophan level

41
Q

What is the condition of tryptophan levels when:
- ribosome translates quickly
- terminator hairpin and associated hairpin are formed

A

High tryptophan levels

42
Q

This hairpin prevents the formation of the terminator and allows transcription to continue

A

Antiterminator (Non-terminating hairpin)

43
Q

This begins at the ligand-binding site of the RNA

A

Riboswitches

44
Q

Riboswitches involve short ribonucleotide sequences present in the __________ of __________

A

5’-untranslated regions; mRNAs

45
Q

TRUE OR FALSE: The terminator conformation of riboswitches interfaces directly with the transcriptional machinery and shuts it down

A

TRUE

46
Q

These play regulatory roles in bacteria

A

Small noncoding RNAs (sRNA)

47
Q

These are involved in gene regulation and the modification of protein function

A

sRNAs

48
Q

These are transcribed from the opposite strand of DNA and in the opposite direction, making them complementary to mRNAs transcribed from that locus

A

sRNA

49
Q

Positive or negative regulation?

  • sRNA binds to the ribosome binding site
  • no translation
A

Negative regulation

50
Q

Positive or negative regulation?

  • ribosome binding site is now open for attachment of the ribosome
  • translation proceeds, as RBS is unmasked
A

Positive regulation

51
Q

CRISPR-Cas is an __________ in bacteria

A

Adaptive Immune System

52
Q

CRISPR-Cas is an __________ in bacteria

A

Adaptive Immune System

53
Q

Who first discovered nucleotide excision repair in 1964?

A

Paul Howard-Flandres

54
Q

Who discovered attenuation?

A

Charles Yanofsky and Kevin Bertrand

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