Genetics and Punnett Squares Review - HMS Demo Lesson

Genetics and Punnett Squares Review
Hicksville Middle School Demo Lesson

By Miss A. Charles

• I can define vocabulary words associated with Punnett squares.

• ​I can use academic vocabulary words in the context of analyzing Punnett squares.

Language Objective

• I can recall key vocabulary terms to assess my understanding of genetics.

• ​I can analyze a monohybrid cross using a Punnett square.

Monday June 9th Learning Objectives

Content Objective

Monday June 9th Learning Objectives

• Puedo definir palabras de vocabulario asociadas con los cuadrados de Punnett.

• ​Puedo usar palabras de vocabulario académico en el contexto de analizar los cuadrados de Punnett.

Objetivo Del Lenguaje

• Puedo recordar términos clave del vocabulario para evaluar mi comprensión de la genética.

• ​Puedo analizar un cruce monohíbrido usando un cuadrado de Punnett.

Objetivo De La Ciencia

First, let's start our review by defining these key terms necessary for Punnett square analysis.
Direction: After each vocabulary review question, write down the answer on your crossword puzzle. Después de cada pregunta de repaso, escribe la respuesta en tu crucigrama.

• ​Allele/Alelo

• Dominant/Dominante

• Recessive/Recesivo

• Homozygous/Homocigoto

• Heterozygous/Heterocigoto

• Genotype/Genotipo

• Phenotype/Fenotipo

Key Vocabulary - Vocabulario Clave

Multiple Choice

Choose the word that best matches the following definition: This is when both alleles of a gene are the same. Think about a purebred. Esto es cuando ambos alelos de un gen son iguales. Piensa en un caballo de raza pura.

• homozygous

• heterzygous

• dominant

• recessive

• This is when both alleles of a gene are the same. Think about a purebred.

• Esto es cuando ambos alelos de un gen son iguales. Piensa en un caballo de raza pura.

​

1-Down

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Multiple Choice

Choose the word that best matches the following definition: This is an alternative form of a gene. When they are dominant, they are represented with capital letters and when they are recessive, they are represented with lowercase letters. Esta es una forma alternativa de un gen.

• genoptype

• chromosome

• allele

• gene

• This is an alternative form of a gene. When they are dominant, they are represented with capital letters and when they are recessive, they are represented with lowercase letters.

• Esta es una forma alternativa de un gen.

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2-Down

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Multiple Choice

Choose the word that best matches the following definition: This type of allele is only expressed if there are two of the same alleles present. You need two of these alleles to result in the corresponding phenotype. Este tipo de alelo solo se expresa si hay dos alelos iguales presentes.

• dominant

• recessive

• strong

• weak

• This type of allele is only expressed if there are two of the same alleles present.

• Este tipo de alelo solo se expresa si hay dos alelos iguales presentes.

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3-Down

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Multiple Choice

Choose the word that best matches the following definition: This is when the alleles of a gene are different. Think about a hybrid because they carry two forms of the gene. Esto es cuando los alelos de un gen son diferentes. Piense en un híbrido porque porta dos formas del gen.

• homozygous

• heterozygous

• polygenic

• pleiotropy

• This is when the alleles of a gene are different.

• Esto es cuando los alelos de un gen son diferentes.

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4-Across

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​h t r z y g o u s

Multiple Choice

Choose the word that best matches the following definition: This type of allele is always expressed if it is present. You only need one of these alleles to have its corresponding phenotype. Este tipo de alelo siempre se expresa si está presente. Solo necesitas que uno de estos alelos tenga su fenotipo correspondiente.

• Strong

• Weak

• Recessive

• Dominant

• This type of allele is always expressed if it is present. You only need one of these alleles to have its corresponding phenotype.

• Este tipo de alelo siempre se expresa si está presente.

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5-Down

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Multiple Choice

Choose the word that best matches the following definition: This describes the alleles that an organism contains. Describe los alelos que contiene un organismo.

• Genotype

• Phenotype

• Gene

• DNA

• This describes the alleles that an organism contains.

• Describe los alelos que contiene un organismo.

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6-Down

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Multiple Choice

Choose the word that best matches the following definition: This describes the physical characteristics displayed by an organism. This is the physical end result of your genes. Describe las características físicas que muestra un organismo. Este es el resultado final físico del genotipo.

• Genotype

• Phenotype

• Trait

• Characteristic

• This describes the physical characteristics displayed by an organism. This is the physical end result of the genotype.

• Describe las características físicas que muestra un organismo.

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7-Across

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​p h e o y p

1. Use the information given to work out the parent genotypes and fill them in.

2. Each parent can only pass on one allele to their offspring. Split up each parents alleles along the sides of the Punnett square.

3. Read across and down to work out the possible offspring genotypes in each quarter of the square.

4. Now work out the phenotypes for each genotype that is in the square.

5. Finally, work out the probability of each phenotype. This can be given as a percentage, fraction, number, or as a ratio!

​​Follow these steps to use a Punnett square!

Question: Smooth peas are dominant over wrinkled peas. A heterozygous pea plant is crossed with a homozygous recessive pea plant. Work out the probability of each offspring genotype and phenotype for this trait using a Punnett square. Use the letter "S" to represent the alleles.

​​Follow these steps to use a Punnett square!

Categorize

Options (3)

Ss

SS

ss

Match the following genotypes to the phenotype that is produced according to our example about smooth and wrinkled peas. Remember, the smooth allele is dominant!

Smooth

Wrinkled

Question: Smooth peas are dominant over wrinkled peas. A heterozygous pea plant is crossed with a homozygous recessive pea plant. Work out the probability of each offspring genotype and phenotype for this trait using a Punnett square. Use the letter "S" to represent the alleles.
1. Parent 1 is heterozygous; therefore, their genotype is "Ss". This parent is smooth. Parent 2 is homozygous recessive; therefore, their genotype is "ss."
2. Parent 1's alleles will go across the top of the Punnett square and Parent 2's alleles will go down the side of the Punnett square.
3. Bring each of the alleles down and across to fill out the Punnett square.
4. Now we need to work out the phenotypes. Our Punnett square contains two genotypes, "Ss" and "ss." Based on the information from the question, we know that "Ss" results in a smooth pea, since smooth is dominant. "ss" results in wrinkled peas since wrinkled peas are recessive.
5. For the probability, we can see that 2 of the four boxes contain the genotype "Ss" and we can see that two of the four boxes contain the genotype "ss." The probability of smooth peas is 1/2 or 50%. The probability of wrinkled peas is 1/2 or 50%.

​​Follow these steps to use a Punnett square!

​Ss

​ss

​S

​s

​s

​s

​s

​s

​s

​s

​s

​s

​S

​S

Multiple Choice

What is the probability that the new baby peas will be smooth?

• 100%

• 0%

• 50%

• 75%

Multiple Choice

What is the probability that the new baby peas will be wrinkled?

• 100%

• 0%

• 50%

• 75%

1. Work out the parent genotypes.

2. Write the parent alleles along the top and sides of the square.

3. Read across and down to work out the possible offspring genotypes in each quarter of the square.

​

Remember the steps to solving a Punnett Square!

Multiple Choice

According to the problem, two heterozygous pea plants are crossed. What is the genotype of both parent plants?

• YY

• Yy

• yy

Multiple Choice

According to the problem, which allele is dominant?

• Green is dominant!

• Yellow is dominant!

1. Work out the parent genotypes.

2. Write the parent alleles along the top and sides of the square.

3. Read across and down to work out the possible offspring genotypes in each quarter of the square.

​

Remember the steps to solving a Punnett Square!

​Yy

​Yy

​Y

​Y

​y

​y

​Y

​Y

​Y

​Y

​y

​y

​y

​y

4. "YY" and "Yy" produce yellow peas. "yy" produces green peas.

5. "YY" 1/4, "Yy" 2/4 -> 1/2, "yy" 1/4​

Now we need to work out the phenotype and genotype probability.

​Yy

​Yy

​Y

​Y

​y

​y

​Y

​Y

​Y

​Y

​y

​y

​y

​y

Multiple Choice

What is the probability that the new baby peas will be yellow? ¿Cuál es la probabilidad de que los nuevos guisantes tiernos sean amarillos?

• 1/4 or 25%

• 1/2 or 50%

• 3/4 or 75%

• 100% They will all be yellow because its dpminant.

Multiple Choice

What is the probability that the new baby peas will be green? ¿Cuál es la probabilidad de que los nuevos guisantes tiernos estén verdes?

• 1/4 or 25%

• 1/2 or 50%

• 3/4 or 75%

• 100% They will all be yellow because its dpminant.

• Both parents are homozygous. One is homozygous dominant PP and the other is recessive pp.

• Ambos padres son homocigotos. Uno es el PP homocigoto dominante y el otro es el PP recesivo.

​

Solve this Punnett square on a piece of paper

Multiple Choice

There is only one possible genotype for the baby pea plants. What is it? Solo hay un genotipo posible para las plantas de guisantes. ¿Qué es?

• PP

• Pp

• pp

Multiple Choice

What is the probability that the new baby pea plants will have purple flowers? ¿Cuál es la probabilidad de que las nuevas plantas de guisantes baby tengan flores moradas?

• 0%, they will all be white (todos blanco)

• 50%, Some will be white and some will be purple. (algunas morado)

• 75%, most of them will be purple because it's dominant.

• 100%, all of the flowers will be purple! (todos morado)

Multiple Choice

A heterozygous yellow pea plant's genotype would be... El genotipo de una planta de guisante amarillo heterocigótico sería...

• YY
• yy
• Yy
• Yg

Multiple Choice

In the Punnett square shown, what must the genotype of the missing parent be? En el cuadrado de Punnett que se muestra, ¿cuál debe ser el genotipo del progenitor desaparecido?

• BB
• Bb
• bb
• Tt

Multiple Choice

B - black, b - brown.  Two black mice mate and have some black and some brown mice.  What is the genotype of the parents? B - negro, b - marrón.  Dos ratones negros se aparean y tienen algunos ratones negros y otros marrones.  ¿Cuál es el genotipo de los padres?

• BB x Bb
• BB x bb
• Bb x Bb
• Bb x bb

Multiple Choice

What ratio of the offspring from the cross shown will be homozygous recessive for the  trait of tallness? ¿Qué proporción de la descendencia de la cruza mostrada será homocigota recesiva para el rasgo de altura?

• 0 in 4
• 1 in 4
• 2 in 4
• 4 in 4