BIO 202 Mastering Genetics #5

What is the complementary DNA sequence to 5′ ATGCTTGACTG 3′?

5′ CAGTCAAGCAT 3′ This sequence is complementary and in the correct orientation.

In an analysis of the nucleotide composition of double-stranded DNA to see which bases are equivalent in concentration, which of the following would be true? -A + C = G + T -A + T = G + C -A = C -A = G and C = T -A = G and C = T and A + C = G + T are both true.

A + C = G + T

Mutation

The random variation of genetic material that provides the basis for evolution.

RNA differs from DNA in all EXCEPT which of the following ways? -the number of different functions performed -the 5'-3' orientation of the polynucleotide strand -the sugar molecule -the presence of uracil

The 5'-3' orientation of the polynucleotide strand. Both RNA and DNA have the same 5' phosphate group and 3' hydroxyl group chemical orientation.

TRUE OR FALSE: DNA has no sulfur, and proteins have no phosphorus.

True.

TRUE OR FALSE: When considering the structure of DNA, we would say that complementary strands are antiparallel.

True.

Guanine complementarily binds with cytosine and forms __________ __________ bonds.

Guanine complementarily binds with cytosine and forms 3 hydrogen bonds.

In 1928, Frederick Griffith established that _______.

Heat-killed bacteria harbor the constituent(s) necessary to convey genetic properties to living bacteria. Because some of the nonvirulent bacteria acquired properties of the virulent bacteria, instructions for this transformation must be carried by the virulent bacteria.

To be certain that the extract prepared from virulent cells still contained the transforming principle that was present prior to lysis, Avery _______.

Incubated nonvirulent cells with the complete extract. The complete extract possessed the same ability to induce transformation in IIR bacteria as whole heat-killed IIS bacteria.

Adenine, guanine, cytosine and thymine are ___________________.

Nitrogenous bases

Reverse transcriptase is an enzyme found in association with retroviral activity. It has the property of ________.

Synthesis of DNA from an RNA template

What was the result? What conclusions were drawn?

The DNA was proven to be the "transforming principle". Treatment with deoxyribonuclease resulted in the loss of transforming ability.

Storage

The genetic material must be stable enough to maintain information in __________ from one cell to the next and one organism to the next.

Which statement is true? -The more hydrogen bonds between bases, the higher the temperature needed to separate the pair. -The fewer hydrogen bonds between bases, the higher the temperature needed to separate the pair.

The more hydrogen bonds between bases, the higher the temperature needed to separate the pair.

What observation did Griffith make in his experiments with Streptococcus pneumoniae?

The mouse did not survive when injected with a mixture of live, avirulent (rough) Streptococcus pneumoniae and heat-killed, virulent Streptococcus pneumoniae. Something in the heat-killed preparation was able to transform the avirulent strain to a virulent form.

G and C are present in both DNA and RNA.

True.

TRUE OR FALSE: Guanine and adenine are purines found in DNA.

True. Guanine and adenine are indeed purines found in DNA; thymine and cytosine are the pyrimidines found in DNA.

The classic Hershey and Chase (1952) experiment that offered evidence in support of DNA being the genetic material in bacteriophages made use of which of the following labeled component(s)?

phosphorus and sulfur

Which of the following statements about the basic structural features of DNA are true? -In a DNA macromolecule, the two strands are complementary and antiparallel. -The major and minor grooves form in the DNA helix because the DNA strands are antiparallel. -The twisting of the DNA double helix is attributed to the tight packing of DNA bases and base-stacking. -The major and minor grooves prevent DNA binding proteins from making contact with nucleotides.

-In a DNA macromolecule, the two strands are complementary and antiparallel. -The twisting of the DNA double helix is attributed to the tight packing of DNA bases and base-stacking. In a DNA macromolecule, the two strands are complementary and antiparallel. There is an axis of helical symmetry and the double helix twists around this axis. The tight packing of DNA bases causes this twist and causes base-stacking. This base-stacking results in the formation of major and minor grooves in the DNA helix, which expose the underlying nucleotides and allow DNA binding proteins to contact them.

If 15% of the nitrogenous bases in a sample of DNA from a particular organism is thymine, what percentage should be cytosine?

35%

Adenine complementarily binds with thymine and forms _________ __________ bonds.

Adenine complementarily binds with thymine and forms 2 hydrogen bonds.

Which of the following outcomes would be most likely if the Hershey-Chase experiments were repeated without the step involving the blender? -Both preparations of infected bacteria would contain both P32 and S35. -Both preparations of infected bacteria would exhibit radioactivity. -The phage would fail to infect bacteria. -Neither preparation of infected bacteria would exhibit radioactivity.

Both preparations of infected bacteria would exhibit radioactivity. Instead of being removed from the preparation, the "ghosts" would be retained. Because both bacterial preparations would include ghosts as well as viral DNA, both would be radioactive, one with P32, one with S35.

DNA is comprised of four different types of ________. Each one is made up of a pentose ________, a __________ group, and one of four _____________.

DNA is comprised of four different types of nucleotides. Each one is made up of a pentose sugar, a phosphate group, and one of four nitrogenous bases.

Which of the following statements best represents the central conclusion of the Hershey-Chase experiments? -Phage T2 is capable of replicating within a bacterial host. -DNA is the identity of the hereditary material in phage T2. -When radioactive sulfur is supplied in a growth medium, it is primarily DNA that incorporates radioactive label. -Some viruses can infect bacteria.

DNA is the identity of the hereditary material in phage T2. Because phage DNA and not protein was associated with bacteria at the end of the experiment, it could be concluded that DNA - not protein - must be the genetic material.

Deoxyribonucleotides bind together to form polynucleotides. This bond occurs between the phosphate group of one nucleotide and the _________ position of a ___________ of another nucleotide. The type of bond formed in this interaction is called a ___________ bond.

Deoxyribonucleotides bind together to form polynucleotides. This bond occurs between the phosphate group of one nucleotide and the C- 3' position of a sugar of another nucleotide. The type of bond formed in this interaction is called a phosphodiester bond.

Which statement is true? -G-C base pairs have three hydrogen bonds while A-T base pairs have two hydrogen bonds. -A-T base pairs have three hydrogen bonds while G-C base pairs have two hydrogen bonds.

G-C base pairs have three hydrogen bonds while A-T base pairs have two hydrogen bonds.

All EXCEPT which of the following are characteristics of the genetic material? -It contains all the information needed for growth, development, and reproduction of the organism. -It is composed of protein. -It must be replicated accurately. -It must be capable of change.

It is composed of protein. Although early observations favored protein as the genetic material, subsequent experiments demonstrated that the genetic material was nucleic acid.

The Hershey and Chase experiments involved the preparation of two different types of radioactively labeled phage. Which of the following best explains why two preparations were required? -Establishing the identity of the genetic material required observation of two phage generations. -The bacteriophage used in the experiments was a T2 phage. -It was necessary that each of the two phage components, DNA and protein, be identifiable upon recovery at the end of the experiment. -Each scientist had his own method for labeling phage, so each conducted the same experiment using a different isotope.

It was necessary that each of the two phage components, DNA and protein, be identifiable upon recovery at the end of the experiment. Because it was concluded that the component associated with bacteria at the end of the experiment must be the genetic material, it was critical that the component be identifiable as either DNA or protein.

If Avery had observed transformation using only the extracts containing degraded DNA, degraded RNA, and degraded protein, but NOT the extract containing degraded polysaccharides, he would have concluded that _______.

Polysaccharides are the genetic material. Failure to transform suggests that the chemical degraded in that preparation is the one responsible for transformation, in this case polysaccharides.

Adenine and guanine, which have a nine-member double-ring, are called _________.

Purines

Cytosine and thymine, which have a six-member single-ring, are called ___________.

Pyrimidines

What is the physical state of DNA after being denatured by heat?

Single-stranded

The nitrogenous bases of each nucleotide project __________ the double helix. They form complementary base pairs through the formation of _____________ bonds with bases on the opposite DNA strand.

The nitrogenous bases of each nucleotide project into the double helix. They form complementary base pairs through the formation of hydrogen bonds with bases on the opposite DNA strand.

Which of the following statements about DNA structure is true? -The nucleic acid strands in a DNA molecule are oriented antiparallel to each other, meaning they run in opposite directions. -The pentose sugar in DNA is ribose. -Hydrogen bonds formed between the sugar‑phosphate backbones of the two DNA chains help to stabilize DNA structure. -Nucleic acids are formed through phosphodiester bonds that link nucleosides together.

The nucleic acid strands in a DNA molecule are oriented antiparallel to each other, meaning they run in opposite directions. This statement is true; the 5′-3′ orientation of each chain runs in opposite directions.

Replication

The process that leads to the production of identical copies of the existing genetic information.

Expression

The processing of genetic information that results in synthesis of proteins which contribute to the phenotype of the organism.

When Avery and his colleagues had obtained the transforming factor from the IIIS virulent cells, they treated the fraction with proteases, ribonuclease, and deoxyribonuclease, followed by the assay for retention or loss of transforming ability. What was the purpose of these experiments?

To determine the exact molecular species of the "transforming principle"