How many traits are involved in a monohybrid cross? How many alleles are involved?
What prevents the expression of a recessive allele?
When gametes form, what happens to the alleles for each trait?
To determine how many traits are involved in a monohybrid cross, you need to consider the number of characteristics being studied. In a monohybrid cross, only one trait is under consideration. For example, if you are studying flower color, the monohybrid cross looks at the inheritance of only flower color and not any other trait.
Now, let's move on to the number of alleles involved in a monohybrid cross. Alleles are different versions of a gene that occupy the same position, or locus, on homologous chromosomes. In a monohybrid cross, two alleles are involved. These alleles can be either the same (homozygous) or different (heterozygous) at the corresponding gene locus in the organism's genome. For example, in the case of flower color, the alleles can be represented as "C" for the dominant allele (e.g., purple) and "c" for the recessive allele (e.g., white).
Regarding the prevention of expressing a recessive allele, there is a concept known as dominance. Dominant alleles are expressed over recessive alleles when the organism is heterozygous for that trait. This means that even if an organism carries a recessive allele, it will not be expressed phenotypically (physically observable) if a dominant allele is present. Only when an organism is homozygous for the recessive allele (i.e., carrying two recessive alleles) will the recessive trait be expressed.
When gametes form during the process of gametogenesis (sperm and egg formation), alleles separate from each other, ensuring that each gamete carries only one allele for each trait. This process is known as segregation or Mendel's Law of Segregation. As a result, when gametes fuse during fertilization, the offspring will obtain two alleles for each trait, one from each parent.
To summarize:
- A monohybrid cross involves the study of only one trait.
- In a monohybrid cross, two alleles are involved.
- Dominance prevents the expression of a recessive allele when a dominant allele is present.
- When gametes form, the alleles for each trait separate and are passed on to offspring during fertilization.