Question

In: Biology

1. When glucose and lactose are both present a. the activator and repressor do not bing...

1. When glucose and lactose are both present

a. the activator and repressor do not bing the DNA

b. the operon is not expressed

c. the operon is expressed

d. only the repressor binds the DNA

e. only the activator binds the DNA

f. the activator and repressor do not bind DNa

2. match the following

cAMP

lactose

operator

DNA sequences where regulatory proteins bind

binds and inactivates the repressor

binds and activates the activator

binds and activates the repressor

bind and inactivate the activator

3.the tryptopan operon

a. is activated when tryptophan levels are low

b. contains genes involved in tryptophan digestion

c. requires a repressor which is always expressed at low levels

d.is controlled by an activator that is turned off by tryptophan

4.whicn of the following is not true about operons

a. they produce a polycystronic mRNA molecule

b. are regulated by two or more allosteric proteins

c. multiple genes are under the control of one promoter

d. operons are only found in eukaryotes

5. transcriptional regulators can either activate or repress gene expression

a. true

b. false

6. which of the following is not true about transcription regulatory proteins?

a. they form covalent bonds with the bases

b. they bind upstream of the transcription start site

c. most bind the DNA at the minor groove

d. they bind using homeodomains, leucine zippers, or zinc fingers

7.these are many steps from DNA to protein. each step can be regulated but the most important step for controlling gene expression is

a. initiation of translation

b. initiation of transcription

c. splicing

d. mRNA export

8. which of the following is true about neuronal cells and muscle cells?

a. they contain a different set of proteins

b. they contain the same genome

c. they contain a differentset of genes

d. they express a different set of genes

Expert Solution

Answer:

1. When glucose and lactose are both present

a. the activator and repressor do not bind the DNA
b. the operon is not expressed
c. the operon is expressed
d. only the repressor binds the DNA
e. only the activator binds the DNA
f. the activator and repressor do not bind DNA

2. match the following

cAMP
lactose
operator
DNA sequences where regulatory proteins bind - Operator
binds and inactivates the repressor - lactose
binds and activates the activator - cAMP
binds and activates the repressor
bind and inactivate the activator

3.the tryptopan operon

a. is activated when tryptophan levels are low
b. contains genes involved in tryptophan digestion
c. requires a repressor which is always expressed at low levels - Correct option
d.is controlled by an activator that is turned off by tryptophan

4.whicn of the following is not true about operons

a. they produce a polycystronic mRNA molecule
b. are regulated by two or more allosteric proteins
c. multiple genes are under the control of one promoter
d. operons are only found in eukaryotes - FALSE (Operons occur primarily in prokaryotes but also in some eukaryote)

5. transcriptional regulators can either activate or repress gene expression

a. true - Correct
b. false

6. which of the following is not true about transcription regulatory proteins?

a. they form covalent bonds with the bases
b. they bind upstream of the transcription start site
c. most bind the DNA at the minor groove - FALSE (most bind to major groove)
d. they bind using homeodomains, leucine zippers, or zinc fingers

7.these are many steps from DNA to protein. each step can be regulated but the most important step for controlling gene expression is

a. initiation of translation
b. initiation of transcription - Correct Option
c. splicing
d. mRNA export

8. which of the following is true about neuronal cells and muscle cells?

a. they contain a different set of proteins - Correct Option
b. they contain the same genome
c. they contain a different set of genes
d. they express a different set of genes

gladiator answered 2 years ago

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