5a slides Flashcards

1
Q

what do prokaryotes and eukaryotes do in response to cellular and environmental cues

A

regulate gene expression

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2
Q

in multicellular eukaryotes what does gene expression regulate

A

development and is responsible for differentiation of cell types

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3
Q

promoter

A

specific nucleotide sequence of a gene that binds RNA polymerase

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4
Q

what binds to a specific DNA sequence called a promoter

A

RNA polymerase

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5
Q

where does the promoter position the RNA polymerase and in what direction does it point the enzyme

A

at the start of the gene and points the enzyme in the right direction to transcribe a given gene

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6
Q

what do proteins recognize and bind to

A

discrete sites

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7
Q

what is the most likely consequence of the DNA binding site for a particular protein is mutated

A

mutations can enhance and decrease binding affinity between proteins and DNA

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8
Q

downregulation

A

less protein made

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9
Q

upregulation

A

more protein made

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10
Q

domains of proteins that bind DNA in a nucleotide fit in where

A

in the groove of the doubke standard helix where it can form non covalent bonds with the correct base pairs

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11
Q

how does bacteria respond to environmental changes

A

by regulating gene expression

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12
Q

Natural selection has favored bacteria that produce only the gene products needed to live in a particular environment. Why?

A

a cell can regulate the production of enzymes by gene regulation

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13
Q

what is the operon a mechanism for

A

the coordinate control of multiple genes that affect a single bacterial trait

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14
Q

operon

A

the entire stretch of DNA that incldues the oeprator, the promoter, and all the genes they control

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15
Q

what does it mean when you see a word before operon in italic

A

that it is a gene

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16
Q

what does the trp operon code for

A

all the enzymes required to synthesize the amino acid, tryptophan

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17
Q

what is the switch in a segment of DNA called, what does it often overlap with

A

an operator and often overlaps the promoter region

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18
Q

what are encoded within a single mRNA

A

multiple polypeptides

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19
Q

what can the trp operon be switched off by

A

a protein repressor

20
Q

what does the repressor prevent

A

gene transcription by binding to the operator and blocking out the RNA polyermase

21
Q

what is the repressor the product of, where is it located

A

a seperate regulatory gene, located some distance away from the operon itself

22
Q

qualites of trp present in the environment

A

-bacterium does not need to make tryptophan
-repsenting trp operon saves energy required to synthesize the enzymes of the pathway to make trp

23
Q

qualities of tryptophan absent in the environment

A

-bacterium needs tryptophan for synthesis of proteins
-removing repression of trp operon allows synthesis of the enzymes of the pathway to synthesize trp

24
Q

what form can you find the repressor

A

in active or inactive form depending on the presence of other molecules

25
Q

what does a corepressor cooperate with

A

a repressor protein to switch an operon off by affectin protein conformation

26
Q

corepressor

A

a small molecule that binds to a bacterial repressor protein and changes the proteins shape allowing it to bind to the operator and switch an operon off

27
Q

what are operators blocked by

A

repressor binding

28
Q

default trp operon are….

A

on and the genes for tryptophan synthesis are transcribed

29
Q

in what way is trp operon expression self regulating

A

The tryptophan (trp) operon in bacteria is an example of a self-regulating pathway. It is self-regulating because the concentration of tryptophan itself acts as a corepressor, directly influencing the operon’s activity.

30
Q

what type of pathway is trp synthesis

A

anabolic pathway

31
Q

anabolic pathway

A

metabolic pathway that consumes energy to synthesize a complex molecule from simpler molecules

32
Q

what are anabolic pathways controlled by

A

repressible operon

33
Q

what are ctabolic pathways controlled by

A

inducible operson

34
Q

catabolic pathway

A

a metabolic pathway that releases energy by breaking down complex molecules to simpler molecules

35
Q

transcription with recessible operon

A

transcription is usually on but can be inhibited when a specific molecule binds to a repressor

36
Q

transcription for inducible operon

A

transcription is ually off by can be stimulated when a specific molecule binds to a repressot

37
Q

example of inducible operon

A

lac operon

38
Q

lac operon is part of what pathwat

A

catabolci pathway to metabolize lactose

39
Q

example of repressible operon

A

trp

40
Q

effect of repressible operon type

A

repressor attaches to operator ->transcription off (repressed)

41
Q

what is repressible operon in presence of

A

corepressor

42
Q

effect of inducible operon type

A

repressor does not attach to operator -> transcription on (inducded)

43
Q

inducer

A

a specific small molecule that binds to a bacterial repressor protein and changes the repressor’s shape so that it cannot bind to an operator, thus switching an operon on

44
Q

examples of upregulation include

A

immune response (increase antibodies)
-tissue repair (growth factors)
-increased fertility (increase in genes associated with gamete production and fertilization)

45
Q

examples of downregulation

A

-developmental defects
-cognitive impairment (synaptic proteins)

46
Q

what does anabolic consume

A

consumes energy (ATP) to synthesize large molecules from simple ones

47
Q

catabolic releases what

A

releases energy by breaking down molecules