Gene Expression Flashcards

1
Q

What are the three possible levels of gene regulation?

A
  1. Transcription
  2. Post-transcription
  3. Post-translation
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2
Q

Bacterial genes are usually organised into clusters called…

A

Operons.

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3
Q

Genes within an operon are usually involved in the same pathway. True or false?

A

True.

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4
Q

What is polycistronic mRNA?

A

A single mRNA molecule with multiple genes transcribed.

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5
Q

What are the four main components of operons?

A
  1. Regulator
  2. Promoter
  3. Operator
  4. Genes
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6
Q

Each operon has multiple promoters. True or false?

A

False.

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7
Q

What type of operon can be easily turned off by regulatory proteins?

A

Repressible operons.

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8
Q

What type of operon can be easily turned on by regulatory proteins?

A

Inducible operons.

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9
Q

What type of molecule turns on/off the regulatory proteins?

A

Effector molecules.

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10
Q

In the lac operon, what acts as the effector molecule?

A

Lactose.

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11
Q

What does the lacZ structural gene encode?

A

The enzyme beta-galactosidase.

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12
Q

What does the lacY structural gene encode?

A

The enzyme lactose permease.

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13
Q

What does the lacA structural gene encode?

A

The enzyme transacetylase.

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14
Q

What is the regulatory component lacI?

A

The lac repressor.

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15
Q

What induces lacI?

A

Allolactose or IPTG.

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16
Q

What is the function of regulatory component O?

A

Operator site - where the lac repressor binds.

17
Q

What term explains how there can be lactose in the cell to induce the lac operon, while the operon is inactive?

A

Operon leakiness.

18
Q

What is the trp operon responsible for?

A

Synthesising tryptophan.

19
Q

Attenuation occurs at the leader sequence. True or false?

A

True.

20
Q

Attenuation occurs before transcription initiation. True or false?

A

False.

21
Q

If tryptophan is present, is the repressor bound in the trp operon?

A

Yes.

22
Q

What are two similar features of bacterial and eukaryotic gene regulation?

A
  1. Regulatory DNA regions.
  2. Regulatory proteins.
23
Q

Name three regulatory sequences in eukaryotes.

A
  1. TATA box
  2. CAAT box
  3. GC box
24
Q

What are the three key components of eukaryotic gene regulation?

A
  1. Regulatory sequences
  2. Transcription factors
  3. Chromatin remodelling
25
Q

What do basal transcription factors do?

A

Form the transcription pre-initiation complex.

26
Q

What do activator transcription factors do?

A

Help RNA polymerase and other TFs.

27
Q

What do repressor TFs do?

A

Repress RNA polymerase and other TFs.

28
Q

What is the predominant DNA motif in bacteria?

A

Helix-turn-helix.

29
Q

What is the ‘DBD’ in transcription factors?

A

DNA-binding domain.

30
Q

What is the ‘SSD’ in transcription factors?

A

Signal-sensing domain.

31
Q

What is the ‘TAD’ in transcription factors?

A

Trans-activation domain.

32
Q

Name the gene regulation complex containing helicase, ATPase and kinases.

A

TFIIH.

33
Q

If histone tails are methylated, are genes expressed?

A

No.

34
Q

If nucleosomes are packed tightly, histone tails are likely…

A

Methylated.

35
Q

Histone tail acetylation forms what type of chromatin?

A

Euchromatin.

36
Q

Heterochromatin has what nucleosome packing?

A

Tight.