You have purified DNA from your recently deceased goldfish. Which of the following restriction nucleases would you use if you wanted to end up with DNA fragments with an average size of 70 kilobase pairs (kb) after complete digestion of the DNA?
The recognition sequence for each enzyme is indicated in the right-hand column.
(a) Sau3AI GATC
(b) BamHI GGATCC
(c) NotI GCGGCCGC
(d) XzaI GAAGGATCCTTC
Choice (c) is correct. A restriction nuclease that has a 4-base-pair recognition sequence cuts on average once every 44 or 256 base pairs; one that has a 6-base-pair recognition sequence cuts once every 46 or 4096 base pairs; one that has an 8-base-pair recognition sequence cuts once every 48 or 65,536 base pairs; one that has a 12-base-pair recognition sequence cuts once every 412 or 16 million base pairs. Thus, to obtain fragments of about 70 kb in size, you would cut with a nuclease that recognizes an 8-base-pair site.
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Phenotypically identical bacteria
A. look the same. B. are genetically exactly the same. C. may be told apart by DNA sequence analysis. D. may not be told apart by any means. E. look the same AND may be told apart by DNA sequence analysis.
When a person gets dehydrated while exercising on a hot day, their pituitary gland releases ADH, a hormone that signals the kidneys to retain more water. This is an example of
A) Positive feedback regulation B) Negative feedback regulation C) Chemical cycling D) Emergent properties
Agriculture, industrial use, and domestic use are the largest uses of fresh water supplies, in that order.
a. true b. false
Which of the following apply to the demography of human populations today? (Check all that apply.)A) Our ecological footprint is decreasing.B) We are using distributed resources disproportionately-less than 20% of us use over 80% of the energy.C) We have plenty of resources still untouched.D) We use almost half of the Earth's land.E) We use over half of all renewable fresh water sources.
What will be an ideal response?