PATHOLOGY

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PATHOLOGY MCQ

GENETICS AND DISEASE

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
To determine the genotype of an unknown dominant phenotype (ex. Tall plant) you must perform a ____ and cross it with a ____ organism
A
Test Cross ; Dominant
B
Dominant ; Recessive ; Recessive
C
Test Cross:Recessive
D
None of the above
Explanation: 

Detailed explanation-1: -The tall plants can be homozygous (TT) or heterozygous (Tt), while the dwarf plants are always homozygous recessive (tt). To determine the genotype of a tall plant, we would perform a test cross with a dwarf plant.

Detailed explanation-2: -The unknown genotype can be determined by observing the phenotypes of the resulting offspring. If crossing the unknown dominant phenotype (PP or Pp genotype) individual with the recessive phenotype individual produces only dominant phenotypes (no recessive), then the unknown individual is homozygous dominant.

Detailed explanation-3: -A test cross is used to determine if the genotype of a plant with the dominant phenotype is homozygous or heterozygous.

Detailed explanation-4: -Pea plants are tall if they have the genotype TT or Tt, and they are short if they have genotype tt.

There is 1 question to complete.
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