The chemical structure of DNA and RNA.


  1. Genes are

    heritable units of expression that determine the physical characteristics of a cell.

    things into which one can peek to determine the sex of an individual.

    always present in a cell in two similar copies that may be slightly different, often called alleles.

    present only in very simple organisms like viruses.


  2. Gene function

    is a mathematical equation that predicts the physical traits of offspring.

    is immutable and cannot be changed.

    can be demonstrated only for simple organisms like bacteria.

    describes the mechanism by which parents pass physical traits to offspring.


  3. The general cellular genetic information is stored in structures known as

    chromosomes.

    mitochondria.

    vacuoles.

    endoplasmic reticulum.


  4. Cellular components that play an important role in the structure and function of chromosomes include

    protein.

    deoxyribonucleic acid or DNA.

    ribonucleic acid or RNA.

    membrane.


  5. The most important molecule involved in long-term storage of genetic information is

    protein.

    lipid.

    deoxyribonucleic acid or DNA.

    ribonucleic acid or RNA.


  6. The role of proteins in chromosomal function can involve

    maintaining chromosome structure.

    converting the stored infomation to a more readily accessible format.

    reproducing the genetic information.

    correcting damage to the genetic information.


  7. The association of the molecule RNA with the cellular chromosome is

    of minor genetic importance.

    of key structural significance to maintaining chromosome structure.

    a consequence of control of levels of gene expression.

    caused by the presence of viruses that insert themselves into the chromosome structure.


  8. The chemical structure of DNA is

    of minor importance to chromosomal function.

    is controversial and poorly understood.

    of crucial importance to gene function.

    very different from all other naturally occcuring molecules.


  9. The primary chemical structure of DNA includes

    a phosphorylated sugar backbone.

    individual components called amino acids.

    individual components called nucleotide bases.

    complete structural symmetry.


  10. The nucleotide bases present in DNA include

    only adenine (A) and thymine (T).

    only guanine (G) and cytosine (C).

    both uracil (U) and thymine (T).

    adenine (A), thymine (T), guanine (G), and cytosine (C)

    adenine (A), uracil (U), guanine (G), and cytosine (C)


  11. DNA is most commonly

    single-stranded with little, if any internal base pairing.

    double-stranded.

    single-stranded with extensive internal base pairing.

    polar.


  12. Double-stranded DNA, when it occurs, is

    antiparallel.

    parallel.

    complementary.

    anti-complementary


  13. The base pairing arrangements that occur in double-stranded DNA as determined by hydrogen bonding include

    A with C and G with T.

    A with U and G with C.

    A with T and G with C.

    C with T and A with G.


  14. The base pairing ability of DNA is critical to the function of DNA as a genetic molecule in that

    it facilitates easy introduction of base changes to allow rapid evolution of gene function.

    it allows production of an accurate RNA copy for use by the protein assemby machinery of a cell.

    the pairing of the bases with each other generates a chemical stability that completely protects them from interaction with other cellular components.

    changes that do occur in one strand of a double-stranded DNA molecule can be passed on to progeny.


  15. Cellular RNA is most commonly

    single-stranded with little, if any internal base pairing.

    double-stranded.

    single-stranded with extensive internal base pairing.

    polar.


  16. The nucleotide bases present in RNA include

    only adenine (A) and thymine (T).

    only guanine (G) and cytosine (C).

    both uracil (U) and thymine (T).

    adenine (A), thymine (T), guanine (G), and cytosine (C)

    adenine (A), uracil (U), guanine (G), and cytosine (C)


  17. The most common base pairing arrangements that occur in double-stranded RNA as determined by hydrogen bonding include

    A with C and G with U.

    A with U and G with C.

    A with T and G with C.

    C with U, A, or G.


  18. The key feature that allows the DNA molecule to store genetic information is

    the structure of the sugar-phosphate backbone.

    the order of the nucleotide bases on the sugar-phosphate backbone.

    the specificity with which chromosomal proteins can interact with specific DNA sequences.

    the ability of the DNA molecule to be directly used to produce a protein by attachment of the protein-assembly machinery to the DNA template.


  19. A key feature that facilitates the involvement of RNA in the expression of genetic information is

    the instable chemical nature of RNA.

    the ability of RNA to be recognized by the protein assembly machinery of the cell.

    the ability of amino acids to correctly align along the RNA molecule to assemble the desired gene product.

    the resistance of the RNA molecule to rearrangemnt within a cell.


  20. The conversion of a double-stranded DNA molecule to single strands (denaturation) and the reversal of that process (renaturation) are strongly dependent on

    the temperature of the DNA solution.

    the amount of salt in the DNA solution.

    the pH of the DNA solution.

    the size and base composition of the DNA molecule.


  21. Two single-stranded DNA molecules will only anneal to form a double-stranded region if

    the two molecules have exactly the same sequence.

    the two molecules have exactly complementary sequences.

    the two molecules have sufficient sequence identity to allow extensive double-stranded regions with some mismatched bases.

    the two molecules have sufficient sequence complementarity to allow extensive double-stranded regions with some mismatched bases.

    ©1999 Attotron Biosensor Corporation
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