🌿Ejercicios Leyes de Mendel y cuadro de Punnett [Fácil y Rápido] | BIOLOGÍA |

Summary

In this video, the speaker explains Mendel's laws of inheritance using Punnett squares to solve various genetics problems. The video covers examples like the inheritance of flower color, seed texture, fur color in rabbits, and height in plants. Key concepts, such as dominant and recessive traits, homozygous and heterozygous alleles, are demonstrated through detailed step-by-step Punnett square solutions. The speaker also explains the probability of inheriting specific traits and addresses genetic disorders, including a fatal recessive disease in butterflies. The video concludes with a call to action to like, comment, and subscribe.

Takeaways

• 😀 The script explains how to solve genetics exercises using Mendel's laws and Punnett squares.
• 😀 Red flower color dominates over blue, and the probability of obtaining blue flowers from a cross of two heterozygous plants is 25%.
• 😀 A cross between a homozygous dominant red-flowered plant and a homozygous recessive blue-flowered plant results in 100% red-flowered offspring.
• 😀 Heterozygous pea plants with smooth seeds cross with homozygous recessive plants, producing 50% smooth-seed plants and 50% rough-seed plants.
• 😀 In rabbits, black fur color dominates over brown fur color. Crossing two brown rabbits (homozygous recessive) results in 100% brown offspring.
• 😀 Red flower and tall stem traits dominate over blue flower and short stem traits in a cross between two plants with these characteristics.
• 😀 Punnett squares can be used to predict the phenotypic outcomes of various plant and animal crosses.
• 😀 The script also covers how to handle lethal recessive diseases in genetics, using a cross between two carrier butterflies as an example.
• 😀 In the butterfly example, there is a 25% chance that offspring will inherit the lethal disease if both parents are carriers.
• 😀 The video provides practical examples using Punnett squares to visually represent and solve genetic problems based on Mendelian inheritance.

Q & A

What is the dominant trait for flower color in the first example?

The dominant trait for flower color is red, as it dominates over blue.

How do you represent the dominant and recessive alleles for flower color in the first example?

The dominant allele for red is represented by 'R' (uppercase), while the recessive allele for blue is represented by 'r' (lowercase).

What is the probability of obtaining blue flowers when crossing two plants from the first generation?

The probability of obtaining blue flowers is 25%, as only one of the four possible outcomes from the cross results in a blue flower (rr).

What is the phenotype of the offspring when a red-flowered, heterozygous plant is crossed with a blue-flowered, homozygous recessive plant?

All the offspring will have red flowers because the dominant red allele (R) will always pair with the recessive blue allele (r), making the red trait appear.

What is the genotype of a plant with red flowers and a homozygous recessive blue-flowered plant in the first example?

The genotype of the red-flowered plant is heterozygous (Rr), and the genotype of the blue-flowered plant is homozygous recessive (rr).

In the second example, what is the inheritance pattern for seed texture (smooth vs. wrinkled)?

The smooth seed texture (L) is dominant, while the wrinkled seed texture (l) is recessive.

When crossing a heterozygous smooth-seed plant with a homozygous recessive wrinkled-seed plant, what is the expected offspring phenotype?

The expected phenotype is 50% smooth seeds and 50% wrinkled seeds, as both the smooth and wrinkled seed traits have a 1:1 ratio.

How does the dominant allele for black fur in rabbits affect their offspring?

The black fur trait (N) is dominant, so when two rabbits with brown fur (nn) are crossed, all offspring will have brown fur.

What happens when two rabbits with brown fur are crossed in this scenario?

Since both rabbits have brown fur, their genotypes are homozygous recessive (nn), so their offspring will all have brown fur.

In the example involving plants with red flowers and tall stems crossed with plants with blue flowers and short stems, what are the possible offspring outcomes?

All the offspring will have red flowers and tall stems, as both traits (red and tall) are dominant and will be expressed in all the progeny.

What is the probability of a butterfly offspring inheriting a lethal recessive disease from two carrier butterflies?

There is a 25% chance that the offspring will inherit the lethal disease, as the cross between two carrier butterflies (Ss x Ss) results in a 1:2:1 genotype ratio, with 25% of offspring being homozygous recessive (ss) and thus affected by the disease.