self assessment question 1

Self Assessment Question 1

• Which chemical group is at the 5' end of a single polynucleotide strand?

A. Hydroxyl group

B. Diester group

C. Purine base

D. Phosphate group

E. Nitrogen group

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Self Assessment Question 1 Answer


A. Hydroxyl group

B. Diester group

C. Purine base

D. Phosphate group CORRECT ANSWER

E. Nitrogen group

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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

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A. Phosphate group

B. Hydroxyl group

C. Purine base

D. Nitrogen group

E. Methyl group

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A. Phosphate group

B. Hydroxyl group CORRECT ANSWER

C. Purine base

D. Nitrogen group

E. Methyl group

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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

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• The purine bases are:

A. Thymine and cytosine

B. Thymine and guanine

C. Cytosine and Adenine

D. Cytosine and guanine

E. Adenine and guanine

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• The purine bases are:



C. Cytosine and Adenine

D. Cytosine and guanine

E. Adenine and guanine CORRECT ANSWER

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• The pyrimidine bases are:



C. Adenine and guanine

D. Cytosine and adenine

E. Cytosine and guanine

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• The pyrimidine bases are:

A. Thymine and cytosine CORRECT ANSWER


C. Adenine and guanine

D. Cytosine and adenine

E. Cytosine and guanine

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11student.ccbcmd.edustudent.ccbcmd.edu


• Each new DNA strand is initiated by a:

A. Short RNA primer

B. Single-stranded DNA-binding protein

C. Precursor fragment

D. Restriction fragment

E. Specific DNA primer

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• Each new DNA strand is initiated by a:

A. Short RNA primer CORRECT ANSWER

B. Single-stranded DNA-binding protein

C. Precursor fragment

D. Restriction fragment

E. Specific DNA primer

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• The phenomenon where the two complementary strands of duplex DNA have their 5’-to-3’ directions running in opposite directions is called:

A. Antiparallel

B. Nucleic acid hybridization

C. Renaturation

D. Rolling-circle replication

E. Restriction fragment polymorphism

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• The phenomenon where the two complementary strands of duplex DNA have their 5’-to-3’ directions running in opposite directions is called:

A. Antiparallel CORRECT ANSWER B. Nucleic acid hybridization

C. Renaturation

D. Rolling-circle replication

E. Restriction fragment polymorphism

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•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

DNA forms aDouble Helix

Self Assessment Question 7• The Meselson-Stahl experiment showed that a

single round of DNA replication produces:

A. One DNA molecule made of two parental strands and a second DNA molecule made of two daughter strands.

B. Two duplex DNA molecules where all of the strands are partly parental and part new DNA.

C. Two duplex DNA molecules each with one parental strand and one daughter strand.

D. Many duplex DNA molecules, all with two new daughter strands.

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Self Assessment Question 7 Answer• The Meselson-Stahl experiment showed that a

single round of DNA replication produces:

A. One DNA molecule made of two parental strands and a second DNA molecule made of two daughter strands.

B. Two duplex DNA molecules where all of the strands are partly parental and part new DNA.

C. Two duplex DNA molecules each with one parental strand and one daughter strand. CORRECT ANSWER

D. Many duplex DNA molecules, all with two new daughter strands.

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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?


• DNA fragments migrate in an electric field because DNA molecules:

A. Are positively charged

B. Are neutral in charge

C. Are negatively charged

D. Are double stranded

E. Contain numerous covalent bonds

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• DNA fragments migrate in an electric field because DNA molecules:

A. Are positively charged

B. Are neutral in charge

C. Are negatively charged CORRECT ANSWER

D. Are double stranded

E. Contain numerous covalent bonds

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• Endonucleases:

A. Break internal phosphodiester bonds in a single- or double-stranded nucleic acid molecule.

B. Remove amino acids from the carboxyl end of a polypeptide chain.

C. Connect two DNA fragments.

D. Remove terminal nucleotides from the 3'-end of a polynucleotide chain.

E. Connect two oligopeptides.

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• Endonucleases:

A. Break internal phosphodiester bonds in a single- or double-stranded nucleic acid molecule. CORRECT ANSWER

B. Remove amino acids from the carboxyl end of a polypeptide chain.

C. Connect two DNA fragments.

D. Remove terminal nucleotides from the 3'-end of a polynucleotide chain.

E. Connect two oligopeptides

*Note: restriction enzymes are endonucleases produced by bacteria

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• A palindrome is a sequence that:

A. reads differently when read from either direction

B. can be found in multiple origins of replication

C. is the same when read from either direction

D. is used as a primer in DNA replication

E. contains only purines

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• A palindrome is a sequence that:

A. reads differently when read from either direction

B. can be found in multiple origins of replication

C. is the same when read from either direction CORRECT ANSWER

D. is used as a primer in DNA replication

E. contains only purines

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• Which of the following sequences are palindromes?

A. 5'-CCAG-3'

B. 5'-CCCC-3'

C. 5'-CCAGG-3'

D. 5'-ACCGGA-3'

E. 5'-CCATGG-3'

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• Which of the following sequences are palindromes?

A. 5'-CCAG-3'

B. 5'-CCCC-3'

C. 5'-CCAGG-3'

D. 5'-ACCGGA-3'

E. 5'-CCATGG-3' CORRECT ANSWER

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• Which of the following is a characteristic of restriction enzymes?

A. Most restriction enzymes recognize a single site.

B. The restriction site is recognized regardless of the source of the DNA.

C. 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.

D. Most restriction sites are palindromes.

E. A, B, C, and D

F. A and C

G. B and D

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• Which of the following is a characteristic of restriction enzymes?

A. *Most restriction enzymes recognize a single site.

B. * The restriction site is recognized regardless of the source of the DNA.

C. * 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.

D. * Most restriction sites are palindromes.

E. A, B, C, and D CORRECT ANSWER

F. A and C

G. B and D

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Questions?

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self assessment question 1

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