The restriction enzyme EcoR1 recognizes the DNA sequence GAATTC. Which DNA strands will be cut by EcoR1?
I.
TTCAGGAATTCGGAAACC AAGTCCTTAAGCCTTTGG
II.
TGAATCGAACCTG ACTTAGCTTGGAC
III.
TTAAGCGGCCGAATTCAGTCCA
AATTCGCCCGCTTAAGTCAGGT
IV.
CAGTAGGATTTCTGTGTC
GTCATCCTAAAGACACAG
I and III is the correct solution.
Well, I must say this is a sharp question. But be prepared for a cut above answer. The DNA strands that will be cut by EcoR1 are like those dreadful haircuts we all regret: I and III. They have the GAATTC sequence and are in desperate need of a trim. So, if you're playing matchmaker for EcoR1, swipe right on I and III, and get ready for the snip-snip!
The correct answer is I and III.
The DNA sequence recognized by the EcoR1 restriction enzyme is GAATTC. Let's check each DNA strand to see if it contains this specific sequence:
I. TTCAGGAATTCGGAAACC AAGTCCTTAAGCCTTTGG - This sequence contains GAATTC, so it will be cut by EcoR1.
II. TGAATCGAACCTG ACTTAGCTTGGAC - This sequence does not contain GAATTC, so it will not be cut by EcoR1.
III. TTAAGCGGCCGAATTCAGTCCA AATTCGCCCGCTTAAGTCAGGT - This sequence contains GAATTC, so it will be cut by EcoR1.
IV. CAGTAGGATTTCTGTGTC GTCATCCTAAAGACACAG - This sequence does not contain GAATTC, so it will not be cut by EcoR1.
Therefore, the correct DNA strands that will be cut by EcoR1 are I and III.
To determine which DNA strands will be cut by the restriction enzyme EcoR1, we need to identify DNA sequences that match the recognition site GAATTC.
Let's analyze each of the given DNA strands:
I.
TTCAGGAATTCGGAAACC
AAGTCCTTAAGCCTTTGG
In this case, the sequence GAATTC is present in the first strand, highlighted above. So, this DNA strand will be cut by EcoR1.
II.
TGAATCGAACCTG
ACTTAGCTTGGAC
Here, there is no GAATTC sequence present, so this DNA strand will not be cut by EcoR1.
III.
TTAAGCGGCCGAATTCAGTCCA
AATTCGCCCGCTTAAGTCAGGT
In this DNA strand, the GAATTC sequence is present at the end of the first strand and the beginning of the second strand. Therefore, this DNA strand will also be cut by EcoR1.
IV.
CAGTAGGATTTCTGTGTC
GTCATCCTAAAGACACAG
The GAATTC sequence is not present in this DNA strand, so it will not be cut by EcoR1.
Therefore, the correct answer is I (TTCAGGAATTCGGAAACC AAGTCCTTAAGCCTTTGG) and III (TTAAGCGGCCGAATTCAGTCCA AATTCGCCCGCTTAAGTCAGGT).