DNA Reverse Complement Flashcards
Practice finding DNA reverse complements, reading 5′ and 3′ labels, and locating exact matches on either DNA strand.
Bu deste hakkında
Start by pairing DNA bases and labeling the ends of the complementary strand. Then find reverse complements, work backward to the original sequence, and spot when a wrong answer skipped the pairing or the reversal.
Use the same direction check to find exact matches on the + and − strands and give their positions on the printed reference. You’ll also see how a reverse-complement palindrome can match both strands at the same span.
Every sequence example is original and artificial. The cards use A, C, G, and T and exact matches so you can focus on strand direction. RNA, approximate searches, and primer design need additional rules and are outside the scope.
Bu destedeki kartlar
Kart 1
Soru
In double-stranded DNA, which bases pair with adenine (A) and cytosine (C), respectively?
Cevap
Thymine (T) pairs with A. Guanine (G) pairs with C.
Kart 2
Soru
Two DNA strands are aligned base by base. The top strand has its 5′ end on the left. Which end of the bottom strand is on the left?
Cevap
The 3′ end. The strands are antiparallel, so their directions are opposite.
Kart 3
Soru
Write the complementary DNA strand directly below
5′–CATGGA–3′, pairing the bases in the same columns. Label its ends.Cevap
3′–GTACCT–5′The aligned partner runs 3′ to 5′ from left to right.
Kart 4
Soru
A DNA strand is written 5′ to 3′. How do you get its reverse complement?
Cevap
Pair each base, then read the paired bases in reverse order. The result gives the partner strand from its 5′ end to its 3′ end.
Kart 5
Soru
What is the reverse complement of
5′–GTTCA–3′?Cevap
5′–TGAAC–3′The aligned partner is
3′–CAAGT–5′. Read it from the right.Kart 6
Soru
Which two bases fill the blanks in the bottom DNA strand, from left to right?
5′–G C T A G–3′ 3′–C _ A _ C–5′Cevap
G, then T. They pair with C and A in the top strand.
The completed bottom strand is
3′–CGATC–5′.Kart 7
Soru
Write the same DNA strand 5′ to 3′ if it is shown as
3′–TGGAC–5′.Cevap
5′–CAGGT–3′Start from the right. The bases stay the same because you're reading the same strand.
Kart 8
Soru
Write the strand that pairs with
3′–ACCTGA–5′. Give your answer 5′ to 3′.Cevap
5′–TGGACT–3′The aligned partner already has its 5′ end on the left.
Kart 9
Soru
Someone gives
CGTGACas the reverse complement of5′–CAGTGC–3′. What step did they miss?Cevap
They still need to complement each base.
CGTGACis the original sequence read backward. The reverse complement is5′–GCACTG–3′.Kart 10
Soru
A DNA strand ends with G at its 3′ end. What is the first base of its reverse complement, written 5′ to 3′?
Cevap
C. The original 3′ end lines up with the partner's 5′ end, and C pairs with G.
Kart 11
Soru
Write the reverse complement of
5′–ACGCTAA–3′.Cevap
5′–TTAGCGT–3′Pair the bases to get
3′–TGCGATT–5′, then read from the right.Kart 12
Soru
Is
5′–AGCATGCT–3′a reverse-complement palindrome?Cevap
Yes. Its reverse complement is
5′–AGCATGCT–3′again.Kart 13
Soru
Someone gives
AGGCATas the reverse complement of5′–TCCGTA–3′. What step did they miss?Cevap
They still need to reverse the order.
AGGCATis the aligned partner read 3′ to 5′. Read it from the other end to get5′–TACGGA–3′.Kart 14
Soru
A DNA strand's reverse complement is
5′–CGAACTG–3′. What was the original sequence, written 5′ to 3′?Cevap
5′–CAGTTCG–3′Taking the reverse complement a second time restores the original sequence.
Kart 15
Soru
Find the exact + strand match to
5′–GATA–3′on the printed + reference5′–TCGGATACCAA–3′. Count the leftmost reference base as position 1 and include both ends of the match.Cevap
Positions 4–7 (+). Those bases read
GATAfrom left to right.Kart 16
Soru
You split a 5′→3′ DNA sequence into a left block and a right block. Which block provides the 5′ end of the reverse complement?
Cevap
The right block. The original 3′ end is on the right, across from the partner's 5′ end.
Kart 17
Soru
An exact DNA query matches the + strand at reference positions 4–8. Which reference position holds the query's 5′ end?
Cevap
Position 4. The query runs left to right on the + strand.
Kart 18
Soru
To find a − strand match to
5′–GCTAC–3′, what sequence should you look for on the printed 5′→3′ + reference?Cevap
5′–GTAGC–3′That's the reverse complement of the query.
Kart 19
Soru
Can a five-base DNA sequence made from A, C, G, and T equal its own reverse complement?
Cevap
No. Its middle base would have to pair with itself, and each of those four bases pairs with a different base.
Kart 20
Soru
Search the printed + reference
5′–ACTAGGATTCCTAGT–3′for5′–CTAGG–3′on either strand. Give each exact match's strand and 1-based inclusive reference positions.Cevap
Positions 2–6 (+) and 10–14 (−).
The reference has
CTAGGat 2–6 andCCTAG, the query's reverse complement, at 10–14.Kart 21
Soru
One base in the bottom DNA strand is paired incorrectly. Which base should replace it, and at what position from the left?
5′–A T C G C–3′ 3′–T A A C G–5′Cevap
G at position 3. The top strand has C there.
The corrected bottom strand is
3′–TAGCG–5′.Kart 22
Soru
A window on the printed + reference is
5′–CGAG–3′. Does its − strand exactly match the query5′–CTCA–3′?Cevap
No. The − strand at that span reads
5′–CTCG–3′. Its last base differs from the query.Kart 23
Soru
Find the exact − strand match to
5′–CCGA–3′on the printed + reference5′–GACTCGGAATC–3′. Give the 1-based inclusive reference positions.Cevap
Positions 4–7 (−). The printed bases at 4–7 are
TCGG. The opposite strand readsCCGAin the 5′→3′ direction.Kart 24
Soru
An exact DNA query matches the − strand at reference positions 6–10. Which reference position holds the query's 5′ end?
Cevap
Position 10. The query runs right to left on the − strand.
Kart 25
Soru
A query of
5′–CGCG–3′exactly matches the + strand at reference positions 3–6. How many strands match at that same span?Cevap
Two.
CGCGequals its own reverse complement, so positions 3–6 match on both strands.
25 kart
DNA Reverse Complement Flashcards
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