Question

You have a linear piece of DNA that can be cut by the restriction nucleases HindIII and EcoRI, as diagrammed in Figure Q10-9. If you were to cut this linear DNA with HindIII, what type of DNA fragments do you predict you will obtain?

(a) three linear pieces of DNA
(b) two linear pieces of DNA, only one of which can be cut by EcoRI
(c) two linear pieces of DNA, both of which can be cut by EcoRI
(d) two linear pieces of DNA, only one of which can be cut by HindIII

Answer 1

If the linear DNA is cut with HindIII, you will get multiple linear DNA fragments corresponding to the number of HindIII sites present in the DNA. HindIII generates sticky ends, allowing fragments to potentially be joined with other complementary sticky ends, often utilized in molecular cloning with vectors like plasmids.

Step-by-step explanation:

If you cut a piece of linear DNA with the restriction enzyme HindIII, the type of DNA fragments you predict you will obtain depends on the number and location of HindIII recognition sites within the DNA sequence. Since the question does not provide information on the number of HindIII sites present, it's not possible to definitively answer. However, generally speaking, if you have one HindIII site, you would end up with two linear fragments of DNA. If more than one HindIII site is present, you'd get additional fragments, respectively.

It's important to note that restriction endonucleases like HindIII and EcoRI recognize specific palindromic DNA sequences and cut at or near these sites, creating either blunt ends or sticky ends (cohesive ends). The sticky ends can base pair with complementary sticky ends on other DNA fragments, which is useful in molecular cloning practices where DNA fragments can be joined to create recombinant DNA molecules.

Furthermore, EcoRI generates sticky ends with a 5' overhang, recognizing the sequence 5'GAATTC3' and cutting between G and A. HindIII, on the other hand, recognizes the sequence 5'AAGCTT3' and also generates sticky ends with a 5' overhang, cutting between A and A. Cutting DNA with either of these enzymes would allow the resulting fragments to potentially be ligated into vectors, such as plasmids, which are commonly used in molecular cloning to propagate DNA sequences of interest.