Maximum Score:  12 Points

This assessment task is to be used after students have had instruction in Mendelian Genetics.
NOTE:  If the student uses symbols, a key must be provided.

Question 1- First Seeds	4 points total
Criteria:

• Genotype identification
  • Allow 2 points if the student identifies all possible crosses using words or symbols (with key)
    Key;

    T=tall allele

    t=short allele
    

    pure tall (TT) X heterozygous tall (Tt)

    pure tall (TT) X pure short (tt)

  • Allow 1 point if the student;

    - identifies both crosses with no key if symbols are used

    - identifies only one (1) cross with a key if symbols are used

• Explanation
  • Allow 2 points if the student provides a correct explanation that describes the presence of the dominant gene as being necessary for the trait to appear in the first offspring. The response should be written in complete sentences.
  • Allow 1 point if the student provides a correct explanation, but it is not in complete sentences.
  • No credit if the student gives an incorrect explanation even if it is in complete sentences.

Question 2- Offspring Seeds	4 points total
Criteria:

• Genotypes present
  • Allow 2 points if the student identifies all possible correct genotypes using words or symbols with a key. (the key from question 1 may be used)

    Both homozygous (pure) tall(TT) and heterozygous(Tt)

  • Allow 1 point if the student;

    - identifies both genotypes with no key if symbols are used

    - identifies only heterozygous tall with a key if symbols are used

  • No credit if the student makes no correct identifications or only one (1) correct identification with no key.
• Explanation
  • Allow 2 points if the student provides a correct explanation that describes the presence of the recessive gene in some of the seeds using complete sentences.
  • Allow 1 point if the student provides a correct explanation, but not in complete sentences.
  • No credit if the student gives an incorrect explanation even if it is in complete sentences.

Question 3- Explanation	2 points total
Criteria:

• Allow 1 point if the student provides a correct explanation that describes the presence of both dominant and recessive genes as being necessary in each parent for both traits (tall and short height) to appear in the offspring. This explanation may be shown by the cross hybrid tall x hybrid tall by using words, or symbols with a key as shown above. The response should be in complete sentences.
• Allow 1 point if the student provides a correct explanation, but it is not in complete sentences.
• No credit if the student gives an incorrect response even if it is in complete sentences.

Question 4- Explanation of Guarantee	2 points total
Criteria:

• Do not score  Student's response to "....can he guarantee that...."

• Allow 2 points if the student provides a correct explanation that describes the possibility of the recessive gene being masked by the presence of the dominant gene in any plant with the tall trait from which seeds are collected. The response should be in complete sentences.
• Allow 1 point for a correct explanation, but not written in complete sentences.
• No credit for an incorrect response even if it is in complete sentences.

Student ID _______________________________	Scoring Form - Ajax Seed Company
Male / Female (circle one)

Circle the student's score for each question. Add the points for each question and write the total score at the bottom of the scoring form.

Student ID _______________________________	Scoring Form - Ajax Seed Company
Male / Female (circle one)

Circle the student's score for each question. Add the points for each question and write the total score at the bottom of the scoring form.