EXAM 3

BIOLOGY 111

Dr. Richard B. Brugam

2/27/98

 

 1.  When DNA duplicates during interphase

      a.   The double helix uncoils and each strand codes a new strand to form two new helices consisting of half new and half old DNA

      b.   The double helix does not uncoil but codes a new double helix to make two double helices, one old and one new

 

 2.  Which of the following is the best definition for a gene?

      a.   One complete turn of the DNA double helix                 c.  The base sequence that codes for a given protein

      b.   Three bases in a row

 

 3.  Why does the amount of Guanine (G) always equal the amount of cytosine (C) in an organism’s DNA?

      a.   G in one DNA strand is always linked to C in the complementary strand

      b.   G and C make up one nucleotide

      c.   Both G and C are linked to 5-carbon sugars

      d.            Phosphates link bases together

      e.   Each organism has the same amount of G and C as its mother

 

 4.  A “change in the base sequence of the gene” is a definition of:

      a.  Dominance             b.  Test cross               c.  Mutation              d.  Sex-linked inheritance

 

 5.  The gene for human insulin is spliced into a plasmid.  The plasmid is inserted into a bacterium.  The bacterium produce human insulin.  Is it the same as the insulin you produce?

      a.  Yes            b.  No

 

 6.  Bacteria like E.coli have a single long circular chromosome and smaller rings of DNA called

      a.  Protons           b.  Operons            c.  Plasmids             d.  Operators

 

 7.  Restriction endonucleases

      a.   Cut DNA molecules in two                   c.  Make repressor proteins

      b.   Make mRNA                                      d.  Stick DNA molecules together

 

 8.  Ligases are enzymes that join DNA molecules together.

      a.  True              b.  False

 

 9.  What base is present in RNA that is not present DNA?

      a.            Thymine (T)       b.  Cytosine (C)         c.  Guanine (G)          d.  Adenine (A)           e.  Uracil (U)      

     

10.  What is the name of the viruses that infect bacteria?

      a.   HIV        b.  Coprophages        c.  Saprophages             d.  Macrophages            e.  Bacteriophages

 

11.  Where does the assembly of the amino acid sequence of a protein occur?

      a.  Only in the nucleus             c.  Only on ribosomes               e.  None of these

      b.   Only on mitochondria                 d.  Only on lysosomes

 

12.  What is the role of mRNA in protein synthesis?

      a.            Replicating DNA

      b.  Structural material for ribosomes

      c.            Transferring genetic information from one generation to the next

      d.   Carrying a copy of the code for a protein from the nuclei to the ribosome

      e.            Transporting individual amino acids to sites of protein synthesis

 

13.  During translation

      a.   New polypeptides are produced                      c.  New mRNA is produced                e.  New ribosomes are formed

      b.   New tRNA is produced                                  d.  New DNA is produced

 

 

14.  A few codons in DNA do not specify amino acids.  These are called _____.

      a.  Degenerate codons           b.  Anticodons           c.  stop codons

 

15.  All living things have the same genetic code.

      a.  True              b.  False

 

16.  One of your parents has Huntingdon’s disease, the other does not.  Both parents are over 50 years old.  What is the probability that you will have it?

      a.  0%          b.  25%          c.  50%          d.  75%          e.  100%

 

17.  The cause of sickle cell anemia is:

      a.  Racial in origin

      b.  A misplaced sugar in the liver starches of a person

      c.  A wrong protein in the primary structure of hemoglobin

      d.  A wrong amino acid in the primary structure of hemoglobin

 

18.  The Y chromosome in the human male carries less information than the X.

      A.  True           b.  False

 

19.  In humans, an individual with X and Y sex chromosomes is

      a.  Male          b.  Female             C.  I can’t tell from the information given

 

20.     Phenylketonuria is a genetic disease in which a person lacks an enzyme to metabolize phenylalanine.

      a.  True          b.  False

 

21.  The DNA of different species should

      a.  Have different percentages of particular base pairs             c.  Have no base pairs - DNA is a protein

      b.  Have similar percentages of particular base pairs

 

22.  In the experiments, the part of the bacteriophage which was labeled with radioactive sulfur remained outside the bacterium but the part labeled with radioactive phosphorus got into the cell.  What did this prove?

      a.  That protein is the genetic material       c.  That the bacteriophage infected the bacterium

      b.  That DNA is the genetic material                            d.  Nothing at all

 

23.  Beadle and Tatum’s experiments with Neurospora confirmed the

      a.  Theory of Evolution                 c.  The “one gene, one protein” hypothesis

      b.  Relativity                           d.  The vitalist hypothesis

 

24.  The base pair matchings in DNA are

      a.  A-T, G-C          b.  A-G, T-C          c.  A-U, G-C          d.  A-G, U-C

 

25.  A woman has a child with Down’s syndrome.  What is the probability that her second child will also have Down’s syndrome?

      a.  100%                  c.  25% 

      b.  50%                    d.  We cannot tell.  Most Down’s syndrome is not inherited in a Mendelian way.