©JASONMcCONNELL 2025 ALL RIGHTS RESERVED
Bio 121 Exam 2 Purdue Questions and
Answers 100% Pass
What are the three hypothesis of inheritance - ANS 1. There are alternative forms of
"factors"(allels)
2. For each inherited trait, there are 2 allels from each parent
3. Sperm and egg only carry one allel
4. When 2 allels are different in a pair, one is expressed
Principal of segregation - ANS When two allels in a pair are different, 1 is fully expressed
while the other is masked
Locus - ANS Location on a chromosome
Homozygous - ANS Pair of the same allels (RR) or (rr)
Heterozygous - ANS Pair of two different allels (Rr)
Phenotype - ANS Physical expressed traits
Genotype - ANS Actual genetic makeup of an organism
What do you do if there are 4 allels that segregate independently - ANS Dihybrid cross
1
, ©JASONMcCONNELL 2025 ALL RIGHTS RESERVED
Probability - ANS Outcome of that event/ total # of possible outcomes
Incomplete dominance - ANS F1 hybrids are intermediate between parental genotype (pink
flowers)
Complementation - ANS One of the two pairs of allels needs to be homozygous dominant to
express phenotype
Epistasis - ANS One allel pair masks the effect of the other pair (lab dogs)
Modifier gene - ANS Controlled by 1 locus
Polygenics of quantitative traits - ANS Controlled by 5-10 loca,(height/skin/hair color)
Pleitrophy - ANS Single gene has multiple phenotypic effects characteristics (deafness in
white cats)
Penetrance - ANS % of individuals carrying a gene and expressing phenotype
Expressivity - ANS Degree to which a gene is expressed(mild or severe)
Epigenetics - ANS When experiences change the way DNA is expressed, can be passed to
offspring.
Concordance rates - ANS Probability that a pair of individuals both have a certain trait
Autosomal recessive - ANS Harmful gene Inherited by having both carrier parents.
2
Bio 121 Exam 2 Purdue Questions and
Answers 100% Pass
What are the three hypothesis of inheritance - ANS 1. There are alternative forms of
"factors"(allels)
2. For each inherited trait, there are 2 allels from each parent
3. Sperm and egg only carry one allel
4. When 2 allels are different in a pair, one is expressed
Principal of segregation - ANS When two allels in a pair are different, 1 is fully expressed
while the other is masked
Locus - ANS Location on a chromosome
Homozygous - ANS Pair of the same allels (RR) or (rr)
Heterozygous - ANS Pair of two different allels (Rr)
Phenotype - ANS Physical expressed traits
Genotype - ANS Actual genetic makeup of an organism
What do you do if there are 4 allels that segregate independently - ANS Dihybrid cross
1
, ©JASONMcCONNELL 2025 ALL RIGHTS RESERVED
Probability - ANS Outcome of that event/ total # of possible outcomes
Incomplete dominance - ANS F1 hybrids are intermediate between parental genotype (pink
flowers)
Complementation - ANS One of the two pairs of allels needs to be homozygous dominant to
express phenotype
Epistasis - ANS One allel pair masks the effect of the other pair (lab dogs)
Modifier gene - ANS Controlled by 1 locus
Polygenics of quantitative traits - ANS Controlled by 5-10 loca,(height/skin/hair color)
Pleitrophy - ANS Single gene has multiple phenotypic effects characteristics (deafness in
white cats)
Penetrance - ANS % of individuals carrying a gene and expressing phenotype
Expressivity - ANS Degree to which a gene is expressed(mild or severe)
Epigenetics - ANS When experiences change the way DNA is expressed, can be passed to
offspring.
Concordance rates - ANS Probability that a pair of individuals both have a certain trait
Autosomal recessive - ANS Harmful gene Inherited by having both carrier parents.
2
