作者yyta (整天打瞌睡)
看板TransBioChem
标题[生物] 生物的问题
时间Wed Nov 9 20:27:23 2005
1 Restricted-transducing particles are classes as P standing for
‘plaue-forming’ or D standing for ‘defective in lysogeny.
Given the proceeding data, Delta-gal phage might be:
a.D and recoversable if mixed infections were made using a P or a wild-type
helper.
b.D and recoversable if mixed infections were made using a D or a wild-type
helper.
c.P and recoversable if mixed infections were made using a P or a wild-type
helper.
d.P and recoversable if mixed infections were made using a D or a wild-type
helper
The following tetrads were observed in a yeast cross:
+ b c + b c + b c a b +
a + + a + + + + c a + +
---------------------- ----------------------
500 25
+ b c + b + + b c a b c
a + c a + + + + + a + +
---------------------- -----------------------
300 100
+ b c a b + + b + a b c
+ + + a + c + + + a + c
---------------------- -----------------------
25 25
2-1. The chromosomal arrangement of these genese is
a. a 10 + 20 + b. a 10 b 20 c c. b 10 a 20 c d. b 10 + 20 c
--------------- -------------- ------------- -------------
+ b c + + + + + + b + +
2-2. The coefficient of conincidence in ther above data is
a. 1.0 b. 1.25 c.0.8 d.0.0
2-3. Is there any indication of either positive or negative chromatid
interference in these data
a. Yes, because there is a shortage of 2-strand double exchange.
b. Yes, because there are fewer double-crossovers than expected.
c. No, because there are as many 2-strand doubles as expected.
d. No, because there are as many double-crossovers as expected.
这几题我不会,劳烦大大们教我...谢谢
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