Final answer:
The complimentary sequence of the given DNA strand 5'-TTAGCTAGA-3' is 3'-AATCGATCT-5'.
Step-by-step explanation:
The complementary sequence of a DNA strand is formed by pairing the nucleotides according to the base-pairing rule. In DNA, adenine (A) pairs with thymine (T), and guanine (G) pairs with cytosine (C).
So, for the given sequence 5'-TTAGCTAGA-3', the complementary sequence would be 3'-AATCGATCT-5'.
Remember that the 5' to 3' direction refers to the orientation of the DNA strand and indicates the order of nucleotides in the chain.