PUNNETT SQUARE PRACTICE KEY

Use a Punnett Square to show the possible offspring from the crosses given and answer the questions:

IN PEAS: R = round T = tall Y = yellow peas P = purple flowers

r = wrinkled t = short y = green peas p = white flowers

MAKING MONOHYBRID CROSSES:

Use colors to circle the offspring with the same phenotype.


Yy
/
Yy

Yy /
Yy

YY

What is the genotype of a HOMOZYGOUS YELLOW SEED plant? = YY

What is the genotype of a HOMOZYGOUS GREEN SEED plant? = yy

What is the genotype of a HETEROZYGOUS YELLOW plant? = Yy

Make a cross between a HOMOZYGOUSGREEN parent and a HOMOZYGOUSYELLOWparent.

yy x YY

POSSIBLE OFFSPRING

GENOTYPE PHENOTYPE

Yyyellow seeds

What is the probability an offspring will show the DOMINANT TRAIT (YELLOW SEEDS)? 100%

What is the probability an offspring will show the RECESSIVE TRAIT (GREEN SEEDS)? 0%

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MAKING MONOHYBRID CROSSES:

Use colors to circle the offspring with the same phenotype.

Pp

Pp / pp
Pp / pp

What is the genotype of a HOMOZYGOUS PURPLE FLOWERED plant ? = PP

What is the genotype of a HOMOZYGOUS WHITE FLOWERED plant? = pp

What is the genotype of a HETEROZYGOUS FLOWERED plant? = Pp

Make a cross between a HETEROZYGOUS PURPLE FLOWERED plant and a HOMOZYGOUS WHITE FLOWERED plant.

Pp X pp

POSSIBLE OFFSPRING

GENOTYPE PHENOTYPE

Pp, pp purple, white

What is the probability an offspring will show the DOMINANT TRAIT (PURPLE FLOWERS)? 50%

What is the probability an offspring will show the RECESSIVE TRAIT (WHITE FLOWERS)? 50%

IN PEAS: R = round T = tall Y = yellow peas P = purple flowers

r = wrinkled t = short y = green peas p = white flowers

MAKING MONOHYBRID CROSSES:

Use colors to circle the offspring with the same phenotype.

Rr

RR / Rr
Rr / rr

What is the genotype of a HOMOZYGOUS ROUND plant ? = RR

What is the genotype of a HOMOZYGOUS WHITE WRINKLED plant? = rr

What is the genotype of a HETEROZYGOUS plant? =Rr

Make a cross between two HETEROZYGOUS plants.Rr X Rr

POSSIBLE OFFSPRING

GENOTYPE PHENOTYPE

RR, Rr, rr round, wrinkled

What is the probability an offspring will show the DOMINANT TRAIT (ROUND)? 75%

What is the probability an offspring will show the RECESSIVE TRAIT (WRINKLED)? 25%

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MAKING MONOHYBRID CROSSES:

Use colors to circle the offspring with the same phenotype.

TT

Tt / Tt
Tt / Tt

What is the genotype of a HOMOZYGOUS TALL plant ? = TT

What is the genotype of a HOMOZYGOUSSHORT plant? = tt

What is the genotype of a HETEROZYGOUS plant? = Tt

Make a cross between a HOMOZYGOUS TALL plant and a HOMOZYGOUS SHORT plant.

TT X tt

POSSIBLE OFFSPRING

GENOTYPE PHENOTYPE

Tt tall

What is the probability an offspring will show the DOMINANT TRAIT (TALL)? 100%

What is the probability an offspring will show the RECESSIVE TRAIT (SHORT)? 0%