From the world of genetics

 

 1. Linked genes 

  A    must be immediately adjacent to one another on a chromosome

  B    have alleles that assort independently of one another

  C    never show crossing over

  D    are on the same chromosome

  E    always have multiple alleles.

2. In the F2 generation of a dihybrid cross

 A    four phenotypes in the ratio 9:3:3:1 if the loci are linked

 B    four phenotypes appear in the ratio 9:3:3:1 if the loci are unlinked

 C    two phenotypes appear in the ratio 3:1 if the loci are unlinked

 D    three phenotypes appear in the ratio 1:2:1 if the loci are unlinked.

 E    two phenotypes appear in the ratio 1:1whether or not the loci are linked.

3. The sex of a honeybee is determined by

 A    ploidy, the male being haploid

 B    X and Y chromosomes, the male being XY

 C    X and Y chromosomes, the male being XX

 D    the number of X chromo somes, the male being XO

 E    Z and W chromosomes, the male being ZZ.

4. In epistasis

 A    nothing changes from generation to generation

 B    one gene alters the effect of another

 C    a portion of a chromosome is deleted.

 D    a portion of a chromosome is inverted.

 E    the behavior of two genes is entirely independent.

5. Individual heritable traits

 A    are always determined by dominant and recessive alleles

 B    always vary discontinuously

 C    can sometimes be controlled by many genes

 D    were first studied in the twentieth century

 E    do not exist outside the laboratory

6. Which statement about Mendel’s cross of TT peas with tt peas is not true ?

 A    Each parent can produce only one type of gamete

 B    Fl individuals produce gametes of two types, each gamete being T or t

 C    Three genotypes are observed in the F, generation.

 D    Three phenotypes are observed in the F, generation

 E    This is an example of a monohybrid cross.

7. The phenotype of an individual

 A    depends at least in part on the genotype.

 B    is either homozygous or heterozygous

 C    determines the genotype.

 D    is the genetic constitution of the organism

 D    is either monohybird or dihybrid.

8. Which statement about alleles is not true?

 A    They are different forms of the same gene.

 B    There may be several at one locus

 C    One may be dominant over another

 D    They may show incomplete dominance

 E    They occupy different loci on the same chromosome.

9. Which statement about an individual that is homozygous for an allele is not true?

 A    Each of its cells possesses two copies of that allele

 B    Each of its gametes contains ane copy of that allele.

 C     It is true-breeding with respect to that allele

 D    Its parents were necessarily homozygous for that allele

 E    It can pass that allele to its offspring.

10. Which statement about a test cross is not true?

 A    It tests whether an unknown individual is

           homozygous or heterozygous

 B    The test individual is crossed with a

           homozygous recessive individual

 C    If the test individual is heterozygous,

           the progeny will have a l:l ratio.

 D    If the test individual is homozygous, the progeny will have a 3:1 ratio

 E    Test cross results are consistent with Mendel’s model of inheritance.