1 for specific request mail
BIOCH 330 Midterm 1 Questions and Correct
Answers | Latest Update
Why are pyrimidines unable to adopt the syn conformation?
Ans: steric hinderance so they remain anti only
What type of helical structure does dsRNA always adopt and why?
Ans: A-DNA
-because of steric hinderance with the 3' OH group
Assignment Expert
-(causes the 3' endo pucker that is the only type of pucker in A-DNA)
Guru01 - Stuvia
When do nucleic acids tend to adopt the Z helix?
Ans: 1. short sequence
2. dehydrated
2026
3. alternating pyrimidines and purines (GCGCGC)
©
-most important one
What evidence exists for a biological function for Z DNA?
Ans: 1. the special sequences required are found upstream of many
genes at a non-random frequency
-possible role in transcription
2. antibodies have been formed against Z DNA
3. natural proteins bind to it
-poxvirus protein that may alter gene expression
What is a hairpin structure in DNA?
, 2 for specific request mail
Ans: -an intrastrand helix that forms a loop at the top
-stabilized by intrastrand H bonding
How is a cruciform different than a hairpin?
Ans: -basically two hairpins right next to each other in a ds nucleic acid
What is the difference between a palindromic and a mirror repeat?
Ans: palindromic: repeats on different strands
mirror: repeats on the same strand
Assignment Expert
What forms a hairpin loop? A cruciform structure?
Guru01 - Stuvia
Ans: hairpin loop: palindromes (typically have a few bp between
sequences)
-because they are self-complementary
2026
cruciform: two palindromic sequences next to each other
When does hairpin loop formation occur in the cell?
©
Ans: during unwinding of the DNA
-because the palindromic sequences are more stable in regular form (no
hairpins)
-during unwinding in transcription or replication, the ss complementary
bases are exposed so they can hybridize together
What are the two types of triple helix structures?
Ans: 1. three separate nucleic acid molecules
2. a triple helix found in a double stranded nucleic acid complex
-aka HDNA
BIOCH 330 Midterm 1 Questions and Correct
Answers | Latest Update
Why are pyrimidines unable to adopt the syn conformation?
Ans: steric hinderance so they remain anti only
What type of helical structure does dsRNA always adopt and why?
Ans: A-DNA
-because of steric hinderance with the 3' OH group
Assignment Expert
-(causes the 3' endo pucker that is the only type of pucker in A-DNA)
Guru01 - Stuvia
When do nucleic acids tend to adopt the Z helix?
Ans: 1. short sequence
2. dehydrated
2026
3. alternating pyrimidines and purines (GCGCGC)
©
-most important one
What evidence exists for a biological function for Z DNA?
Ans: 1. the special sequences required are found upstream of many
genes at a non-random frequency
-possible role in transcription
2. antibodies have been formed against Z DNA
3. natural proteins bind to it
-poxvirus protein that may alter gene expression
What is a hairpin structure in DNA?
, 2 for specific request mail
Ans: -an intrastrand helix that forms a loop at the top
-stabilized by intrastrand H bonding
How is a cruciform different than a hairpin?
Ans: -basically two hairpins right next to each other in a ds nucleic acid
What is the difference between a palindromic and a mirror repeat?
Ans: palindromic: repeats on different strands
mirror: repeats on the same strand
Assignment Expert
What forms a hairpin loop? A cruciform structure?
Guru01 - Stuvia
Ans: hairpin loop: palindromes (typically have a few bp between
sequences)
-because they are self-complementary
2026
cruciform: two palindromic sequences next to each other
When does hairpin loop formation occur in the cell?
©
Ans: during unwinding of the DNA
-because the palindromic sequences are more stable in regular form (no
hairpins)
-during unwinding in transcription or replication, the ss complementary
bases are exposed so they can hybridize together
What are the two types of triple helix structures?
Ans: 1. three separate nucleic acid molecules
2. a triple helix found in a double stranded nucleic acid complex
-aka HDNA
