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Your
laboratory investigates utilization of the sugar “comatose” by
yeast. This table shows that the
expression of comatose kinase (CK), an enzyme required for comatose
degradation, is negatively regulated by glucose. You’ve isolated four mutations (com-1, com-2,
com-3, com-4) that affect regulation of CK expression. Your genetic analysis indicates that com-1
and com-3 are linked to the CK structural gene, and that com-2 and com-4 are
unlinked to each other and also unlinked to the CK gene. The quantity of comatose kinase expressed by
haploids and by heterozygous diploids is shown in the table.

Part A –
One of the mutations affects an enhancer to which a positive transcription
factor binds. The enhancer is located
upstream of the CK gene and is required for induction of CK expression by
comatose. The mutation destroys function
of the enhancer.

Which
mutation is this?

1)
com-1

2)
com-2

3)
com-3

4)
com-4

Part B – One of the
mutations affects the trans-acting positive transcription factor
discussed in Part A. The mutation destroys function of the transcription
factor.Which
mutation is this?

1)
com-1

2)
com-2

3)
com-3

4)
com-4

Part C -One of the mutations affects a silencer to which a
negative transcription factor binds. The silencer is located upstream of
the CK gene and is required for repression of CK expression by
glucose. The mutation destroys function of the silencer.

1)
com-1

2)
com-2

3)
com-3

4)
com-4

Part D – One of the
mutations affects the trans-acting negative transcription factor
discussed in Part C. The mutation destroys function of the transcription
factor.Which
mutation is this?

1)
com-1

2)
com-2

3)
com-3

4)
com-4

Your laboratory investigates
utilization of the sugar “comatose” by yeast. This table shows
that the expression of comatose kinase (CK), an enzyme required for comatose
degradation, is negatively regulated by glucose. You’ve isolated four
mutations (com-1, com-2, com-3, com-4) that affect regulation of CK
expression. Your genetic analysis indicates that com-1 and com-3
are linked to the CK structural gene, and that com-2 and com-4
are unlinked to each other and also unlinked to the CK gene. The
quantity of comatose kinase expressed by haploids and by heterozygous diploids
is shown in the table