Genetics 1 online Test

In the F2 generation of a dihybrid cross
four phenotypes appear in linked condition
four phenotypes appear in the ratio 9:3:3:1 if the loci are unlinked
two phenotypes appear in the ratio 3:1 if the loci are unlinked
three phenotypes appear in the ratio 1:2:1 if the loci are unlinked.
two phenotypes appear in the are linked. ratio 1:1 whether or not the loci
The sex of a honeybee is determined by
ploidy, the male being haploid
X and Y chromosomes, the male being XY
X and Y chromosomes, the male being XX
The number of X chromosomes, the male being XO
Z and W chromosomes, the male being ZZ.
In epistasis
nothing changes from generation to generation
one gene alters the effect of another.
a portion of a chromosome is deleted
a portion of a chromosome is inverted
the behavior of two genes is entirely independent.
Individual heritable traits
are always determined by dominant and recessive alleles
always vary discontinuously
can sometimes be controlled by many genes
were first studied in the twentieth century
do not exist outside the laboratory.
The phenotype of an individual
depends at least in part on the genotype.
is homozygous
determines the genotype.
is the genetic constitution of the organism
is either monohybrid or dihybrid.
Which statement about alleles is not true?
They are different forms of the same gene.
There may be several at one locus
One may be dominant over another
They may show incomplete dominance
They occupy different loci on the same chromosome
Which statement about an individual that is homozygous for an allele is not true?
Each of its cells possesses two copies of that allele
Each of its gametes contains one copy of that allele.
It is true-breeding with respect to that allele
Its parents were necessarily homozygous for that allele
It can pass that allele to its offspring.
Which statement about a test cross is not true ?
It tests whether an unknown individual is homozygous or heterozygous
The test individual is crossed with a homozygous recessive individual
If the test individual is heterozygous, the progeny will have a l : l ratio
If the test individual is homozygous, the progeny will have a 3:1 ratio.
Test cross results are consistent with Mendel's model of inheritance.
Traits that are coded for in autosomes but expressed only in one sex due to effect of sex -hormones are
sex-Linked
sex-limited
sex-Influenced
none above
Traits that are coded for in auto some, but appear more frequently in one of the sexes are_________ traits
sex dominant
sex limited
sex-influenced
sex-Linked
A couple each carries the allele for phenylketonuria ; neither of them has disease ; the probability of their child having disease is
0.25
0.50
0.75
1.00
Rh -ve individuals are
homozygous dominant
heterozygous
homozygous recessive
possess only one gene R or r
Which 6th Amino acid of b chain of hemoglobin is changed when normal hemoglobin HbA is______ changed to Hbs
Leucine
Methionine
Valine
Glutamic acid