17.4 Monohybrid inheritance
- Syllabus
- 0610–2026–2027
- Topic
- 17.4
- Level
- —
17.4.1—Inheritance as the transmission
- Describe inheritance as the transmission of genetic information from generation to generation
17.4.2—Genotype as the genetic make-up
- Describe genotype as the genetic make-up of an organism and in terms of the alleles present
17.4.3—Phenotype as the observable features
- Describe phenotype as the observable features of an organism
17.4.4—Homozygous as having two identical
- Describe homozygous as having two identical alleles of a particular gene
17.4.5—Two identical homozygous individuals
- State that two identical homozygous individuals that breed together will be pure-breeding
17.4.6—Heterozygous as having two different
- Describe heterozygous as having two different alleles of a particular gene
17.4.7—Heterozygous individual will not be
- State that a heterozygous individual will not be pure-breeding
17.4.8—Dominant allele as an allele that is
- Describe a dominant allele as an allele that is expressed if it is present in the genotype
17.4.9—Recessive allele as an allele that is
- Describe a recessive allele as an allele that is only expressed when there is no dominant allele of the gene present in the genotype
17.4.10—Interpret pedigree diagrams
- Interpret pedigree diagrams for the inheritance of a given characteristic
17.4.11—Genetic diagrams to predict
- Use genetic diagrams to predict the results of monohybrid crosses and calculate phenotypic ratios, limited to 1: 1 and 3: 1 ratios
17.4.12—Punnett squares in crosses which
- Use Punnett squares in crosses which result in more than one genotype to work out and show the possible different genotypes
17.4.13—To use a test cross to identify
- Explain how to use a test cross to identify an unknown genotype
17.4.14—Codominance as a situation in which
- Describe codominance as a situation in which both alleles in heterozygous organisms contribute to the phenotype
17.4.15—Inheritance of ABO blood groups
- Explain the inheritance of ABO blood groups: phenotypes are A, B, AB and O blood groups and alleles are IA, IB and Io
17.4.16—Sex-linked characteristic as a feature
- Describe a sex-linked characteristic as a feature in which the gene responsible is located on a sex chromosome and that this makes the characteristic more common in one sex than in the other
17.4.17—Red-green colour blindness
- Describe red-green colour blindness as an example of sex linkage
17.4.18—Genetic diagrams to predict
- Use genetic diagrams to predict the results of monohybrid crosses involving codominance or sex linkage and calculate phenotypic ratios
Objective notes
18 learning objectivesConceptIGCSE Biology