1. Self Assessment Question 1
Which chemical group is at the 5' end of a single polynucleotide strand?
Hydroxyl group     
Diester group     
Purine base     
Phosphate group   
Nitrogen group

2. Self Assessment Question 1 Answer
Which chemical group is at the 5' end of a single polynucleotide strand?
Hydroxyl group     
Diester group     
Purine base     
Phosphate group CORRECT ANSWER   
Nitrogen group

3. Structure of Nucleic Acid
DNA and RNA consist of only four nucleotides
Adenine (A) and guanine (G) are purines
Cytosine (C), thymine (T) and uracil (U) are pyrimidines
A nucleotides consist of an organic base linked to a five-carbon sugar with a phosphate group attached to carbon 5.
In RNA, the sugar is ribose; in DNA, deoxyribose.
Polynucleotide sequences are read in 5’ -> 3’ direction
All nucleotides consist of an organic base linked to a five-carbon sugar with a phosphate attached to carbon 5. In RNA, the sugar is ribose; in DNA, deoxyribose.
A single nucleic acid strand has a backbone composed of repeating pentose-phosphate units from which the purine and pyrimidine bases extend as side groups. The chemical linkage between adjacent nucleotides is a phosphodiester bond. The nucleic acid strand has an end-to-end chemical orientation; the 5’ end has a hydroxyl or phosphate group on the 5’ carbon of its terminal sugar; the 3’ end usually has a hydroxyl group on the 3’ carbon of its terminal sugar. This directionality, plus the fact that synthesis proceeds 5’ to 3’ has given rise to the convention that polynucleotides sequences are written and read in the 5’ to 3’ direction.

4. Self Assessment Question 2
Which chemical group is at the 3' end of a single polynucleotide strand?
Phosphate group     
Hydroxyl group   
Purine base     
Nitrogen group     
Methyl group

5. Self Assessment Question 2 Answer
Which chemical group is at the 3' end of a single polynucleotide strand?
Phosphate group     
Hydroxyl group CORRECT ANSWER   
Purine base     
Nitrogen group     
Methyl group

6. Structure of Nucleic Acid
DNA and RNA consist of only four nucleotides
Adenine (A) and guanine (G) are purines
Cytosine (C), thymine (T) and uracil (U) are pyrimidines
A nucleotides consist of an organic base linked to a five-carbon sugar with a phosphate group attached to carbon 5.
In RNA, the sugar is ribose; in DNA, deoxyribose.
Polynucleotide sequences are read in 5’ -> 3’ direction
All nucleotides consist of an organic base linked to a five-carbon sugar with a phosphate attached to carbon 5. In RNA, the sugar is ribose; in DNA, deoxyribose.
A single nucleic acid strand has a backbone composed of repeating pentose-phosphate units from which the purine and pyrimidine bases extend as side groups. The chemical linkage between adjacent nucleotides is a phosphodiester bond. The nucleic acid strand has an end-to-end chemical orientation; the 5’ end has a hydroxyl or phosphate group on the 5’ carbon of its terminal sugar; the 3’ end usually has a hydroxyl group on the 3’ carbon of its terminal sugar. This directionality, plus the fact that synthesis proceeds 5’ to 3’ has given rise to the convention that polynucleotides sequences are written and read in the 5’ to 3’ direction.

7. Self Assessment Question 3
The purine bases are:
Thymine and cytosine     
Thymine and guanine     
Cytosine and Adenine     
Cytosine and guanine     
Adenine and guanine   

8. Self Assessment Question 3 Answer
The purine bases are:
Thymine and cytosine     
Thymine and guanine     
Cytosine and Adenine     
Cytosine and guanine     
Adenine and guanine CORRECT ANSWER   

9. Self Assessment Question 4
The pyrimidine bases are:
Thymine and cytosine   
Thymine and guanine     
Adenine and guanine     
Cytosine and adenine     
Cytosine and guanine

10. Self Assessment Question 4 Answer
The pyrimidine bases are:
Thymine and cytosine CORRECT ANSWER   
Thymine and guanine     
Adenine and guanine     
Cytosine and adenine     
Cytosine and guanine

11. student.ccbcmd.edu

12. Self Assessment Question 5
Each new DNA strand is initiated by a:
Short RNA primer   
Single-stranded DNA-binding protein     
Precursor fragment     
Restriction fragment     
Specific DNA primer

13. Self Assessment Question 5 Answer
Each new DNA strand is initiated by a:
Short RNA primer CORRECT ANSWER   
Single-stranded DNA-binding protein     
Precursor fragment     
Restriction fragment     
Specific DNA primer

14. Self Assessment Question 6
The phenomenon where the two complementary strands of duplex DNA have their 5’-to-3’ directions running in opposite directions is called:
Antiparallel   
Nucleic acid hybridization     
Renaturation     
Rolling-circle replication     
Restriction fragment polymorphism  

15. Self Assessment Question 6 Answer
The phenomenon where the two complementary strands of duplex DNA have their 5’-to-3’ directions running in opposite directions is called:
Antiparallel CORRECT ANSWER   
Nucleic acid hybridization     
Renaturation     
Rolling-circle replication     
Restriction fragment polymorphism  

16. DNA forms a Double Helix
The presence of thousands of such hydrogen bonds in a DNA molecule contributes greatly to the stability of the double helix. Hydrophobic and van der Waals interactions between the stacked adjacent base pairs further stabilize the double-helical structure.
Two DNA strands where nucleotides form base pairs are said to be complementary.
The DNA forms a right-handed helix. The two strands form two helical grooves of different widths described as the major groove and the minor groove. The atoms on the edge of each base within these grooves are accessible from outside the helix, forming two types of binding surfaces. DNA binding proteins can “read” the sequence of bases in duplex DNA by contacting atoms in either the major or the minor grooves.
The bases are projected inward whereas the sugar phosphate backbone is on the outside
The two strands are antiparallel
A is paired with T through two hydrogen bonds
G is paired with C through three hydrogen bonds

17. Self Assessment Question 7
The Meselson-Stahl experiment showed that a single round of DNA replication produces:
One DNA molecule made of two parental strands and a second DNA molecule made of two daughter strands.     
Two duplex DNA molecules where all of the strands are partly parental and part new DNA.     
Two duplex DNA molecules each with one parental strand and one daughter strand.   
Many duplex DNA molecules, all with two new daughter strands.

18. Self Assessment Question 7 Answer
The Meselson-Stahl experiment showed that a single round of DNA replication produces:
One DNA molecule made of two parental strands and a second DNA molecule made of two daughter strands.     
Two duplex DNA molecules where all of the strands are partly parental and part new DNA.     
Two duplex DNA molecules each with one parental strand and one daughter strand. CORRECT ANSWER   
Many duplex DNA molecules, all with two new daughter strands.

19. DNA Replication: Meselson-Stahl Experiment Results**
Important points:
The conservative mechanism never generates H-L DNA.
The semiconservative mechanism never generates H-H DNA, but does generate H-L DNA during the second and subsequent doublings.
DNA replicates by which mechanism?
In this experiment, E. coli cells were grown in a medium containing ammonium salts prepared with “heavy” nitrogen (N15) until all the cellular DNA was labeled. After the cells were transferred to a medium containing the normal “light” isotope N14. Samples were periodically removed and the DNA in each was measured by density-gradiant centrifugation. This technique can separate H-H, H-L, and L-L duplexes into distinct bands.

20. Self Assessment Question 8
DNA fragments migrate in an electric field because DNA molecules:
Are positively charged     
Are neutral in charge     
Are negatively charged
Are double stranded     
Contain numerous covalent bonds

21. Self Assessment Question 8 Answer
DNA fragments migrate in an electric field because DNA molecules:
Are positively charged     
Are neutral in charge     
Are negatively charged CORRECT ANSWER   
Are double stranded     
Contain numerous covalent bonds

22. Self Assessment Question 9
Endonucleases:
Break internal phosphodiester bonds in a single- or double-stranded nucleic acid molecule.  
Remove amino acids from the carboxyl end of a polypeptide chain.     
Connect two DNA fragments.     
Remove terminal nucleotides from the 3'-end of a polynucleotide chain.     
Connect two oligopeptides.

23. Self Assessment Question 9 Answer
Endonucleases:
Break internal phosphodiester bonds in a single- or double-stranded nucleic acid molecule. CORRECT ANSWER   
Remove amino acids from the carboxyl end of a polypeptide chain.     
Connect two DNA fragments.     
Remove terminal nucleotides from the 3'-end of a polynucleotide chain.     
Connect two oligopeptides
*Note: restriction enzymes are endonucleases produced by bacteria

24. Self Assessment Question 10
A palindrome is a sequence that:
reads differently when read from either direction     
can be found in multiple origins of replication     
is the same when read from either direction
is used as a primer in DNA replication     
contains only purines

25. Self Assessment Question 10 Answer
A palindrome is a sequence that:
reads differently when read from either direction     
can be found in multiple origins of replication     
is the same when read from either direction CORRECT ANSWER   
is used as a primer in DNA replication     
contains only purines
websters-dictionary-online.com

26. Self Assessment Question 11
Which of the following sequences are palindromes?
5'-CCAG-3'     
5'-CCCC-3'     
5'-CCAGG-3'     
5'-ACCGGA-3'     
5'-CCATGG-3'   

27. Self Assessment Question 11 Answer
Which of the following sequences are palindromes?
5'-CCAG-3'     
5'-CCCC-3'     
5'-CCAGG-3'     
5'-ACCGGA-3'     
5'-CCATGG-3' CORRECT ANSWER   

28. Self Assessment Question 12
Which of the following is a characteristic of restriction enzymes?
Most restriction enzymes recognize a single site.     
The restriction site is recognized regardless of the source of the DNA.     
The number of times a piece of DNA is cut is determined by the number of times the restriction site is present in the DNA.     
Most restriction sites are palindromes.     
A, B, C, and D   
A and C     
B and D

29. Self Assessment Question 12 Answer
Which of the following is a characteristic of restriction enzymes?
*Most restriction enzymes recognize a single site.     
* The restriction site is recognized regardless of the source of the DNA.     
* The number of times a piece of DNA is cut is determined by the number of times the restriction site is present in the DNA.     
* Most restriction sites are palindromes.     
A, B, C, and D CORRECT ANSWER   
A and C     
B and D

30. Questions?