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4: Mendelian Genetics

Students predict offspring ratios using Punnett squares, apply Mendel's principles of segregation and independent assortment, and trace traits through pedigrees.

LibreTexts reference: Chapter 4: Mendelian Genetics LibreTexts

Matching Genetic Terms to Definitions

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Match each of the following genetic terms with their corresponding definitions.
Note: Each choice will be used exactly once.

Your Choice Prompt
Drop Your Choice Here 1. genetic code
Drop Your Choice Here 2. diploid
Drop Your Choice Here 3. genetics
Drop Your Choice Here 4. single nucleotide polymorphism (SNP)
Drop Your Choice Here 5. locus

Drag one of the choices below:

  • A. the study of heredity and how genes control the inherited characteristics
  • B. a cell or organism that has paired chromosomes
  • C. the set of instructions that tell a cell how to make a specific protein
  • D. variation resulting from a single base pair change
  • E. where on a chromosome a specific gene is located
 

Matching Mendelian Cross Generations to Descriptions

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Match each of the following Mendelian crosses and generational stages with their corresponding descriptions.
Note: Each choice will be used exactly once.

Your Choice Prompt
Drop Your Choice Here 1. backcross
Drop Your Choice Here 2. P generation
Drop Your Choice Here 3. hybrid cross
Drop Your Choice Here 4. F2 generation

Drag one of the choices below:

  • A. a mating event that pairs two homozygous individuals with different characteristics
  • B. the starting generation consisting of true-breeding parents in a hybrid cross
  • C. the generation resulting from the mating of F1 generation hybrids
  • D. a genetic cross that involves the F1 generation generation being mated with one of the parent types
 

Matching Mendel's Principles to Descriptions

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Match each of the following Mendel's Foundational Principles of Genetics with their corresponding descriptions.
Note: Each choice will be used exactly once.

Your Choice Prompt
Drop Your Choice Here 1. Principle of Paired Factors
Drop Your Choice Here 2. Law of Segregation
Drop Your Choice Here 3. Principle of Dominance
Drop Your Choice Here 4. Law of Independent Assortment

Drag one of the choices below:

  • A. A gamete carries just one of the two alleles for each characteristic.
  • B. Traits from separate genes do NOT affect each other during the reproductive process.
  • C. Character is represented in an organism by two alleles.
  • D. In cases where contrasting alleles are present, the dominant allele determines the phenotype.
 

Matching Mendelian Genetics Terms to Definitions

Click to show Matching Mendelian Genetics Terms to Definitions example problem

Match each of the following Mendelian genetics terms with their corresponding definitions.
Note: Each choice will be used exactly once.

Your Choice Prompt
Drop Your Choice Here 1. heterozygous
Drop Your Choice Here 2. phenotype
Drop Your Choice Here 3. genotype
Drop Your Choice Here 4. dominant

Drag one of the choices below:

  • A. different alleles at one or more corresponding chromosomal loci
  • B. all the physical traits of an organism
  • C. allele combinations that specify a trait
  • D. masks another trait's expression when both alleles are present
 

Matching Monohybrid Cross Genotypes to Phenotypes

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Match each of the following parental genotypes in monohybrid crosses with their corresponding descriptions of the progeny.
Note: Each choice will be used exactly once.

Your Choice Prompt
Drop Your Choice Here 1. AA × AA
Drop Your Choice Here 2. AA × aa
Drop Your Choice Here 3. AA × Aa
Drop Your Choice Here 4. Aa × aa
Drop Your Choice Here 5. Aa × Aa
Drop Your Choice Here 6. aa × aa

Drag one of the choices below:

  • A. Yields offspring with 50% homozygous dominant and 50% heterozygous genotypes
  • B. Produces only heterozygotes in progeny
  • C. Produces a 1:2:1 genotype ratio in progeny
  • D. All offspring have the same recessive genotype and phenotype
  • E. Half of the offspring display the recessive phenotype
  • F. All offspring have the same dominant genotype and phenotype
 

Genetic Terms from Definitions

Click to show Genetic Terms from Definitions example problem

Which one of the following genetic terms correspond to the definition 'most common type of genetic variation among people'.

 

Mendelian Cross Types from Generational Descriptions

Click to show Mendelian Cross Types from Generational Descriptions example problem

Which one of the following Mendelian crosses and generational stages correspond to the description 'a type of cross between a homozygous recessive individual with an individual of an unknown dominant genotype'.

 

Mendel's Principles from Descriptions

Click to show Mendel's Principles from Descriptions example problem

Which one of the following Mendel's Foundational Principles of Genetics correspond to the description 'Each trait in an organism is determined by two alleles.'.

 

Mendelian Genetics Terms from Definitions

Click to show Mendelian Genetics Terms from Definitions example problem

Which one of the following Mendelian genetics terms correspond to the definition 'a single feature, such as hair color, noticeable in a particular organismal group'.

 

Parental Genotypes in Monohybrid Crosses from Offspring Outcomes

Click to show Parental Genotypes in Monohybrid Crosses from Offspring Outcomes example problem

Which one of the following parental genotypes in monohybrid crosses correspond to the description of the progeny 'Produces a 1:2:1 genotype ratio in progeny'.

 

Offspring Survival Ratios in Lethal Allele Crosses

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In fruit flies, allele C causes curly wings in heterozygotes (Cc) but is lethal in homozygotes (CC). Two heterozygous individuals are crossed.
What fraction of all conceptions are expected to survive?

 

Dominance Types in Monohybrid Crosses

Click to show Dominance Types in Monohybrid Crosses example problem
Gene 1 Female ♀
G g

Male
♂

 G GG Gg
g Gg gg

Two organisms were crossed in a monohybrid experiment. The offspring phenotypes included blue (■) and white (■), along with an intermediate light blue (■) phenotype.
What type of dominance best explains these results?

 

Monohybrid Cross Outcomes

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Which mating pair would produce offspring that are only one phenotype offspring?
 

Parent Genotypes from Offspring Ratios

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A true-breeding person with straight hairline is crossed with an individual of unknown genotype. In a large litter of 12 offspring, 12 show widow's peak and 0 show straight hairline.
Assume a single gene with A dominant to a. What is the most likely genotype of the unknown parent?

 

Offspring Sex Distribution Using the Binomial Model

Click to show Offspring Sex Distribution Using the Binomial Model example problem

Model: Binomial →

⟮  n  ⟯
k
⋅pk⋅qn-k
In this scenario, assume that each child is born independently with the same chance of being either sex. The event outcomes are mutually exclusive, so we can apply the binomial model to determine the probability of a specific combination.
A woman has seven (7) children. What is the probability that she has exactly three (3) boys ♂ and four (4) girls ♀?
 

Punnett Square Results for Flower Color Inheritance

Click to show Punnett Square Results for Flower Color Inheritance example problem
In his experiments, Mendel discovered that the purple flower phenotype was dominant to the white flower phenotype. Which one of the following Punnett squares represents a backcross between a purple F1 hybrid plant and a true-breeding white flower plant?
 

Inheritance Patterns from Pedigrees (Single Diagram)

Click to show Inheritance Patterns from Pedigrees (Single Diagram) example problem

 
   
   
     
   
   
     
   
   
 
   
   
   
   
   
   
 
   
   
   
   
   
   
 
   
   
   
   
   
   
     
   
   
     
   
   
     
   
   
   
   
   
   
   
 
   
   
   
   
   
   
 
   
   
     
   
   
     
   
   
 
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
                     
 

 
Examine the pedigree above. Which one of the following patterns of inheritance is most likely demonstrated in the above pedigree inheritance?
 

Pedigree Diagrams from Inheritance Patterns (Standard Layout)

Click to show Pedigree Diagrams from Inheritance Patterns (Standard Layout) example problem

Match the following pedigrees to their most likely inheritance type.
Note: each inheritance type will only be used ONCE.

Your Choice Prompt
Drop Your Choice Here 1.

 
   
   
     
   
   
     
   
   
 
   
   
   
   
   
   
 
   
   
   
   
   
   
 
   
   
   
   
   
   
     
   
   
     
   
   
     
   
   
   
   
   
   
   
 
   
   
   
   
   
   
   
 
   
   
     
   
   
     
   
   
 
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
                     

 
Drop Your Choice Here 2.

 
   
   
     
   
   
     
   
   
 
   
   
   
   
   
   
 
   
   
   
   
   
   
 
   
   
   
   
   
   
     
   
   
     
   
   
     
   
   
   
   
   
   
   
 
   
   
   
   
   
   
 
   
   
     
   
   
     
   
   
 
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
                     
 

 
Drop Your Choice Here 3.

 
   
   
     
   
   
     
   
   
 
   
   
   
   
   
   
 
   
   
   
   
   
   
 
   
   
   
   
   
   
     
   
   
     
   
   
     
   
   
   
   
   
   
   
 
   
   
   
   
   
   
   
 
   
   
     
   
   
     
   
   
 
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
                     

 
Drop Your Choice Here 4.

 
   
   
     
   
   
     
   
   
 
   
   
   
   
   
   
 
   
   
   
   
   
   
 
   
   
   
   
   
   
     
   
   
     
   
   
     
   
   
   
   
   
   
   
 
   
   
   
   
   
   
   
 
   
   
     
   
   
     
   
   
 
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
                     

 
Drop Your Choice Here 5.

 
   
   
     
   
   
     
   
   
 
   
   
   
   
   
   
 
   
   
   
   
   
   
 
   
   
   
   
   
   
     
   
   
     
   
   
     
   
   
   
   
   
   
   
 
   
   
   
   
   
   
   
 
   
   
     
   
   
     
   
   
 
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
                     

 

Drag one of the choices below:

  • A. autosomal recessive
  • B. x-linked dominant
  • C. x-linked recessive
  • D. y-linked
  • E. autosomal dominant
 

Pedigree Diagrams from Inheritance Patterns (Randomized Layout)

Click to show Pedigree Diagrams from Inheritance Patterns (Randomized Layout) example problem

Match the following pedigrees to their most likely inheritance type.
Note: each inheritance type will only be used ONCE.

Your Choice Prompt
Drop Your Choice Here 1.

               
   
   
 
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
     
   
   
         
   
   
         
   
   
   
   
   
   
   
   
   
   
   
   
   
   
 
   
   
   
   
   
   
                     

 
Drop Your Choice Here 2.

         
   
   
 
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
     
   
   
       
   
   
 
   
   
   
   
   
   
   
 
   
   
   
   
   
   
   
   
   
   
                     

 
Drop Your Choice Here 3.

         
   
   
 
     
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
           
   
   
 
   
   
   
   
   
   
   
   
   
   
     
   
   
   
   
   
   
                     

 
Drop Your Choice Here 4.

             
   
   
 
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
 
   
   
       
   
   
           
   
   
   
   
   
   
 
   
   
   
   
   
   
   
   
   
   
                 

 
Drop Your Choice Here 5.

         
   
   
 
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
   
           
   
   
         
   
   
 
       
   
   
   
   
   
   
   
   
   
   
 
   
   
   
   
   
   
   
   
   
   
                             

 

Drag one of the choices below:

  • A. autosomal dominant
  • B. autosomal recessive
  • C. y-linked
  • D. x-linked dominant
  • E. x-linked recessive