BIOL Chapter 18 Flashcards


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1

[Identical] What molecule binds to promoters in bacteria and transcribes the coding regions of the genes?

RNA polymerase

2

Which of the following statements best defines the term operon?

An operon is a region of DNA that codes for a series of functionally related genes under the control of the same promoter.

3

[Identical] What is allosteric regulation?

In allosteric regulation, a small molecule binds to a large protein and causes it to change its shape and activity.

4

[Identical] Under which conditions are the lac structural genes expressed most efficiently?

No glucose, high lactose

5

[Identical] What happens to the expression of the lacI gene if lactose is not available in the cell?

There is no change—the lacI gene is constitutively expressed.

6

[Identical] What is the function of the lacZ gene?

This gene encodes an enzyme, b-galactosidase, which cleaves lactose into glucose and galactose.

7

[Identical] Which of the following enzymes converts ATP to cAMP?

Adenylyl cyclase

8

[Identical] True or false? The mechanism by which glucose inhibits expression of the lac structural genes is known as catabolite stimulation

whereas the mechanism by which lactose stimulates expression of the lac structural genes is known as allosteric regulation., False

9

[Identical] The operon model of the regulation of gene expression in bacteria was proposed by _____.

Jacob and Monod

10

[Identical] Which of these is NOT a component of the lac operon?

regulatory gene only

11

[Identical] Regulatory proteins bind to _____.

the operator

12

[Identical] In the presence of a regulatory protein the lac operon is _____.

not transcribed

13

[Identical] Which of these is a regulatory gene? 1827q.jpg

D

14

[Identical] If a mutation deactivated a regulatory gene of a repressible operon in an E. coli cell which of the following describes the most likely outcome?

continuous transcription of the structural gene controlled by that regulator

15

[Identical] Which of the following predictions about the survival of a lactose intolerant E. coli cell is most likely correct?

The cell will survive if the environment has sufficient glucose.

16

[Identical] Under which condition do high levels of transcription of structural genes occur in an inducible operon?

It starts when the pathway's substrate is present.

17

[Identical] A mutation in E. coli results in a molecule known as a "super-repressor" because the operon is permanently repressed. Which of the following describes the most likely effect of the mutation on the repressor protein?

It cannot bind to the inducer.

18

[Identical] How are the processes shown in the figure below examples of feedback mechanisms regulating biological systems in bacterial cells? Campbell12_table18_2.jpg Regulation of enzyme activity

Inhibition by the final product

19

[Identical] How are the processes shown in the figure below examples of feedback mechanisms regulating biological systems in bacterial cells? Campbell12_table18_2.jpg Regulation of enzyme production

- a longer term response

- turn off expression of genes encoding pathways enzymes

20

[Identical] How are the processes shown in the figure below examples of feedback mechanisms regulating biological systems in bacterial cells? Campbell12_table18_2.jpg BOTH

- ensures efficient useof resources and energy

- important for systhesis regulation of compounds that bacteria are able to obtain from the environment

21

[Identical] How are the processes shown in the figure below examples of feedback mechanisms regulating biological systems in bacterial cells? Campbell12_table18_2.jpg NEITHER

- - important for systhesis regulation of compounds that bacteria are NOT able to obtain from the environment

22

[Identical] Bacterial cells__ molecules that can be __ by other bacterial cells. Sensing the concentration of such signalling molecules allows bacteria to monitor the local __ of cells

a phenomenon called __ . There is a group of genes in the genome of the described bacterium, called luxlux genes, which are organized in an __ . Reaching a certain concentration, molecules involved in this process __ the luxlux genes. As a result, the population of the bacteria needs to reach an optimal level to __ the luxlux genes and, thus, __ light production., - Bacterial cells secrete molecules that can be - detected by other bacterial cells. Sensing the concentration of such signalling molecules allows bacteria to monitor the local - density of cells, a phenomenon called quorum sensing. - There is a group of genes in the genome of the described bacterium, called luxlux genes, which are organized in an operon. - Reaching a certain concentration, molecules involved in this process activate the luxlux genes. - As a result, the population of the bacteria needs to reach an optimal level to activate the luxlux genes - and, thus, activate light production

23

[Identical] A rise in extracellular glucose results in which of the following changes at the lac operon?

cAMP receptor protein (CRP) detaches from the lac promoter

24

[Identical] The cAMP receptor protein (CRP) is said to be responsible for positive regulation of the lac operon because ________.

CRP bound to the CRP-binding site stimulates the transcription of the lac operon

25

[Identical] _____ bind(s) to DNA enhancer regions.

Activators

26

[Identical] Which of these indicates an enhancer region? 1810q.jpg

A

27

[Identical] Which of these directly bind(s) to the promoter? 1811q.jpg

C and D

28

[Identical] Enzyme complexes that break down protein are called _____.

proteasomes

29

[Identical] The nuclear membrane's role in the regulation of gene expression involves _____.

regulating the transport of mRNA to the cytoplasm

30

[Identical] What is the function of a spliceosome?

RNA processing

31

[Identical] Protein-phosphorylating enzymes' role in the regulation of gene expression involves _____.

protein activation

32

[Identical] Which of the following terms describes the DNA–protein complexes that look like beads on a string?

Nucleosome

33

[Identical] Which of the following regulatory elements is not composed of DNA sequences?

Activators

34

[Identical] True or false? Regulatory and basal transcription factors regulate transcription by binding to the promoter.

False

35

[Identical] Which of the following regulatory DNA sequences might be located thousands of nucleotides away from the transcription start site of a gene?

Enhancer

36

[Identical] Which of the following events in transcription initiation likely occurs last?

RNA polymerase binds to the promoter of the gene.

37

[Identical] True or false? One possible way to alter chromatin structure such that genes could be transcribed would be to make histone proteins more positively charged.

False

38

[Identical] The functioning of enhancers is an example of

transcriptional control of gene expression.

39

[Identical] Which of the following is an example of post-transcriptional control of gene expression?

the removal of introns and alternative splicing of exons

40

[Identical] Within a cell

the amount of protein made using a given mRNAmRNA molecule depends partly on, the rate at which the mRNAmRNA is degraded.

41

[Identical] DNA sequences can act as "tape measures of evolution". Scientists analyzing the human genome sequence were surprised to find that some of the regions of the human genome that are most highly conserved (similar to comparable regions in other species) don't code for proteins. What is a possible explanation for this observation?

Such regions play a significant role in gene regulation. That is why they remain conserved under the influence of natural selection.

42

[Identical] Which of the following mechanisms is commonly used to coordinate the expression of multiple

related genes in eukaryotic cells?, Groups of genes that are expressed together have specific combinations of control elements.

43

[Identical] DNA methylation and histone acetylation are examples of which of the following processes?

epigenetic phenomena

44

[Identical] Which of the following describes how steroid hormones regulate gene expression?

They bind to intracellular receptors and alter transcription of specific genes.

45

[Identical] miRNAs can control gene expression by what action?

binding to mRNAs and degrading them or blocking their translation

46

[Identical] Which of the following methods are used by eukaryotes to control gene expression but are not used by bacteria?

control of both RNA splicing and chromatin remodeling

47

[Identical] Which of the following is not a body segment of the fruit fly embryo?

Antenna

48

[Identical] Which of the following statements about a gene that shows maternal effect inheritance is true?

Offspring will show a mutant phenotype if the mother has a mutant genotype.

49

[Identical] True or False? Pattern formation refers to events that organize embryonic cells in space

True

50

[Identical] Where is bicoid mRNA translated?

Fertilized egg

51

[Identical] Which body part develops in regions with a low concentration of Bicoid protein?

Abdomen

52

[Identical] Which of the following statements about the Bicoid protein is true?

The Bicoid protein is a regulatory transcription factor.

53

[Identical] If bicoid mRNA is injected at the anterior end of an egg from a bicoid mutant mother

what would the phenotype of the resulting larva be? , The larva would be normal with one head at the anterior pole.

54

[Identical] A high concentration of bicoid protein at the opposite ends of a developing Drosophila embryo would result in the development of a _____.

two-headed fly

55

[Identical] The bicoid gene product is directly responsible for _____ in a developing Drosophila embryo.

the establishment of the anterior-posterior axis

56

[Identical] The region of a Drosophila embryo with the highest concentration of bicoid protein will develop into the _____.

head

57

[Identical] What triggers the translation of bicoid mRNA?

fertilization of the egg

58

[Identical] The bicoid gene is a type of _____ gene.

egg-polarity

59

[Identical] The region of a Drosophila embryo with a low concentration of bicoid protein will develop into the _____.

abdomen

60

[Identical] What process produces the gradient of bicoid protein in a fertilized egg?

diffusion

61

[Identical] Bicoid mRNA is translated in _____

the fertilized egg

62

[Identical] Which of these regions is most likely to develop into the Drosophilia's head? 1841q.jpg

A

63

[Identical] The bicoid gene is transcribed by _____.

nurse cells

64

[Identical] How do master regulatory genes function in cell differentiation?

- they produce proteins that act as transcription factors to produce proteins specific to the function of the particular cell type- they are often capable of changing some fully differentiated cells of different types into their particular cell type- they may produce proteins that stimulate production of more of the master regulatory gene- the transcription factors they produce coordinately control related genes

65

[Identical] If a mutation alters a maternal effect gene in a female Drosophila zygote

which of the following is most likely to occur?, All of her offspring will show the mutant phenotype, regardless of their genotype.

66

[Identical] Proto-oncogenes can change into oncogenes that cause cancer. Which of the following best explains the presence of these potential time bombs in eukaryotic cells?

Proto-oncogenes normally help regulate cell division.

67

[Identical] Prostate cells usually require testosterone and other androgens to survive. But some prostate cancer cells thrive despite treatments that eliminate androgens. One hypothesis is that estrogen

often considered a female hormone, may be activating genes normally controlled by an androgen in these cancer cells.Choose the experiments to test this hypothesis, - Use a treatment to eliminate estrogen, and note the effect on the proliferation of prostate cancer cells.- Look for the presence of an estrogen-receptor complex in the nuclei of prostate cancer cells.- Look for evidence of transcription or translation of the genes of interest in the absence of androgens.

68

[Identical] Which of the following describes the normal function of the p53 gene product?

It inhibits the cell cycle.

69

[Identical] Which of the following statements correctly describes a characteristic of tumor-suppressor genes?

They encode proteins that help prevent uncontrolled cell growth.

70

[Identical] Which of the following characterizes BRCA1 and BRCA2 as tumor-suppressor genes?

Their normal products participate in repair of DNA damage.