Exam 4 - Chapter 18 Flashcards

1
Q

gene expression

A
  • nearly all somatic cells contain an individuals entire genome
  • differences in gene expression result in different types of cells with different structions and fucntion
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

gene regulation in prokaryotes

A

-control mostly at the transcription level

operon = promoter + operator = genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

repressor

A

produced in the cell, binds to operator and prevents transcription by blocking RNA polymerase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

activator

A

produced in the cell, binds to promoter and increases transcription

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

inducer

A

may be produced by the cell or available in the environment, can activate or repress transcription

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Negative gene regulation

A

operons switched off by active form of repressor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Repressible operon

A

usually on, binding of repressor to operator shuts off transcription

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

trp operon

A

controls the synthesis of the amino acid tryptophan

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

trp reporessor

A

only active in the presense of its corepressor tryptophan

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

inductible operon

A

usually off, an inducer inactivates the repressor and turns on transcription, example is the lac operon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

positive gene regulation

A

regulatory protein binds to control region and turns on transcription

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

eukaryotic gene regulation - access to genes

A
  • dna loosely wraps around histone proteins to form chromatin
  • histone package and order dna into units within chromatin called nucleosomes
  • regions of chromatin can be condensed into heterchromatin
  • epigenetic modifications are when gene expression is altered by the dna itself is not
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Histone modifications

A
  • acetyl groups loosen chromatin
  • phosphate groups (-) loosen chromatin
  • methyl groups condense chromatin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

DNA methylation

A
  • addition of methyl groups (condenses DNA) reduces transcription
  • can cause long-term gene inactivation/silencing
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

eukaryotic gene regulation - transcriptional controls

A
  • transcription factors bind to the promoter to bring in RNA ploymerase
  • control elements regulate transcription
  • transcription factors and activators bind increasing transcription through enhancers
  • repressors can bind to promoter or enhancer for a gene to block transcription
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

eukaryotic gene regulation - post transcriptional mRNA modifications

A
  • alternate RNA splicing where different mRNA transcripts are produced from the starting DNA
  • mRNA degradation is that each mRNA has a defined lifespan and decays at a specific rate
  • RNA interface (RNAi) are when molecules inhibit gene expression
  • Small interfering RNA (siRNA) and microRNA (miRNA) centgral to RNAi
17
Q

eukaryotic gene regulation - translational controls

A

-initiation factors are required for formation of the translation initiation complex
-Regulatory proteins can bind to mRNA and block the translational machinery from assembling
-Translation of all mRNAs in a cell may be regulated by
increasing/decreasing the amount of initiation factors that would increase/decrease all translation

18
Q

eukaryotic gene regulation - Post-Translation Protein Modification & Degradation

A

-Proteins can be chemically modified by the addition of methyl,
phosphate, acetyl, and ubiquitin groups
-The addition or removal of these groups can regulate protein activity,location in the cell, or lifespan
-Modifications occur in response to stimuli like stress, lack of nutrients, heat, or UV light