DNA & RNA

In his transformation experiments, what did Griffith observe?

• Mutant mice were resistant to bacterial infections.

• Mixing a heat-killed pathogenic strain of bacteria with a living nonpathogenic strain can convert some of the living cells into the pathogenic form.

• Mixing a heat-killed nonpathogenic strain of bacteria with a living pathogenic strain makes the pathogenic strain nonpathogenic.

• Infecting mice with nonpathogenic strains of bacteria makes them resistant to pathogenic strains.

• Mice infected with a pathogenic strain of bacteria can spread the infection to other mice.

What does transformation involve in bacteria?

• the creation of a strand of DNA from an RNA molecule

• the creation of a strand of RNA from a DNA molecule

• the infection of cells by a phage DNA molecule

• the type of semiconservative replication shown by DNA

• assimilation of external DNA into a cell

Cytosine makes up 38% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine?

• 12

• 24

• 31

• 38

• It cannot be determined from the information provided.

Why does the DNA double helix have a uniform diameter?

• Purines pair with pyrimidines.

• C nucleotides pair with A nucleotides.

• Deoxyribose sugars bind with ribose sugars.

• Nucleotides bind with nucleosides.

• Nucleotides bind with nucleoside triphosphates.

What kind of chemical bond is found between paired bases of the DNA double helix?

• hydrogen

• ionic

• sulfhydryl

• covalent

• phosphate

What is meant by the description ʺantiparallelʺ regarding the strands that make up DNA?

• The twisting nature of DNA creates nonparallel strands.

• The 5ʹ to 3ʹ direction of one strand runs counter to the 5ʹ to 3ʹ direction of the other strand.

• Base pairings create unequal spacing between the two DNA strands.

• One strand is positively charged and the other is negatively charged.

• One strand contains only purines and the other contains only pyrimidines.

Once the pattern found after one round of replication was observed, Meselson and Stahl could be confident of which of the following conclusions?

• Replication is semi-conservative.

• Replication is not dispersive.

• Replication is not semi-conservative.

• Replication is not conservative.

• Replication is neither dispersive nor conservative.

Tags

NGSS.HS-LS1-1

An Okazaki fragment has which of the following arrangements?

• primase, polymerase, ligase

• 3ʹ RNA nucleotides, DNA nucleotides 5ʹ

• 5ʹ RNA nucleotides, DNA nucleotides 3ʹ

• DNA polymerase I, DNA polymerase III

• 5ʹ DNA to 3ʹ

Which enzyme catalyzes the elongation of a DNA strand in the 5ʹ → 3ʹ direction?

• primase

• DNA ligase

• DNA polymerase III

• topoisomerase

• helicase

What determines the nucleotide sequence of the newly synthesized strand during DNA replication?

• the particular DNA polymerase catalyzing the reaction

• the relative amounts of the four nucleoside triphosphates in the cell

• the nucleotide sequence of the template strand

• the primase used in the reaction

• the arrangement of histones in the sugar phosphate backbone