Question

For the following questions please also include an explanation why the answer is correct.  

15: Rolling circle replication of the lambda genome differs from replication of a bacterial chromosome in that

a) only a single strand of the genome is copied and no concatamers are formed.

b) bidirectional replication forks are not formed.

c) only a single strand of the genome is copied.

d) no concatamers are formed.

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20: Cyclic AMP is synthesized from ATP by an enzyme called ________ which is involved in ________.

a) adenylate cyclase / catabolite repression

b) adenylate cyclase / transcriptional activation  

c) cAMP receptor protein (CRP) synthase / catabolite repression

d) cAMP receptor protein (CRP) synthase / transcriptional activation

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21: How is the activity of a riboswitch controlled?

a) by other riboswitches

b) metabolite binding can change its structure

c) sigma factor binding alters its structure

d) small RNA complementary binding disrupts its function

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22: The packaging mechanism of T4 DNA involves cutting of DNA from

a) linear genetic elements

b) circular genetic elements

c) DNA concatemers

d) its host cells

Answer 1

20-a)Adenylate cyclase, catabolite repression

Cyclic AMP is synthesized from ATP by adenylate cyclase located on the inner side of the plasma membrane and anchored at various locations in the interior of the cell.

21-b)metabolite binding can change its structure

Such as TPP riboswitch- this binds TPP (Thiamine pyrophosphate) in order to regulate the transport and synthesis of thiamin aa well as other metabolite with similar properties.

Lysine riboswitch-This binds to Lysine and regulate its biosynthesis, catabolism and transport.