Question 1

What is monohybrid inheritance in the context of Edexcel GCSE Combined Science?

Accepted Answer

Monohybrid inheritance refers to the study of how a single trait, controlled by one gene with two alleles, is passed from parents to offspring. In the Edexcel GCSE Combined Science curriculum, it involves understanding how dominant and recessive alleles influence the phenotype of an organism.

Question 2

How do you use a Punnett square to predict monohybrid inheritance outcomes?

Accepted Answer

A Punnett square is a grid used to predict the possible genotypes of offspring from a genetic cross. For monohybrid inheritance, you place the alleles of one parent on the top and the alleles of the other parent on the side. By filling in the squares, you can determine the probability of each genotype and phenotype in the offspring.

Question 3

What is the difference between genotype and phenotype in monohybrid inheritance?

Accepted Answer

In monohybrid inheritance, the genotype refers to the genetic makeup of an organism, specifically the alleles it possesses for a particular trait. The phenotype is the observable characteristic or trait that results from the genotype. For example, if 'T' is a dominant allele for tall plants and 't' is recessive for short plants, a plant with the genotype 'Tt' will have a tall phenotype.

Question 4

Why are dominant alleles expressed over recessive alleles in monohybrid inheritance?

Accepted Answer

Dominant alleles are expressed over recessive alleles because they mask the effect of the recessive alleles when both are present. In monohybrid inheritance, if an organism inherits a dominant allele from one parent and a recessive allele from the other, the dominant trait will be expressed in the phenotype.

Question 5

Can you explain the concept of homozygous and heterozygous in monohybrid inheritance?

Accepted Answer

In monohybrid inheritance, an organism is homozygous if it has two identical alleles for a trait, such as 'TT' or 'tt'. It is heterozygous if it has two different alleles, such as 'Tt'. Homozygous organisms will consistently pass on the same allele to their offspring, while heterozygous organisms can pass on either allele.

Monohybrid Inheritance

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