3.4 Inheritance - sl
Essential idea: The inheritance of genes follows patterns.
3.4.U1 Mendel discovered the principles of inheritance with experiments in which large numbers of pea plants were crossed.
3.4.U2 Gametes are haploid so contain only one allele of each gene.
3.4.U3 The two alleles of each gene separate into different haploid daughter nuclei during meiosis.
3.4.U4 Fusion of gametes results in diploid zygotes with two alleles of each gene that may be the same allele or different alleles.
3.4.U5 Dominant alleles mask the effects of recessive alleles but co-dominant alleles have joint effects.
3.4.U6 Many genetic diseases in humans are due to recessive alleles of autosomal genes, although some genetic diseases are due to dominant or co-dominant alleles.
3.4.U7 Some genetic diseases are sex-linked. The pattern of inheritance is different with sex-linked genes due to their location on sex chromosomes. [Alleles carried on X chromosomes should be shown as superscript letters on an upper case X, such as Xh.]
3.4.U8 Many genetic diseases have been identified in humans but most are very rare.
3.4.U9 Radiation and mutagenic chemicals increase the mutation rate and can cause genetic diseases and cancer.
3.4.A1 Inheritance of ABO blood groups. [The expected notation for ABO blood group alleles: O = i, A=IA, B = IB.]
3.4.A2 Red-green colour blindness and hemophilia as examples of sex-linked inheritance.
3.4.A3 nheritance of cystic fibrosis and Huntington’s disease.
3.4.A4 Consequences of radiation after nuclear bombing of Hiroshima and accident at Chernobyl.
3.4.S1 Construction of Punnett grids for predicting the outcomes of monohybrid genetic crosses.
3.4.S2 Comparison of predicted and actual outcomes of genetic crosses using real data.
3.4.S3 Analysis of pedigree charts to deduce the pattern of inheritance of genetic diseases.
3.4 NOS Making quantitative measurements with replicates to ensure reliability. Mendel’s genetic crosses with pea plants generated numerical data.
[Text in square brackets indicates guidance notes]
3.4.U1 Mendel discovered the principles of inheritance with experiments in which large numbers of pea plants were crossed.
3.4.U2 Gametes are haploid so contain only one allele of each gene.
3.4.U3 The two alleles of each gene separate into different haploid daughter nuclei during meiosis.
3.4.U4 Fusion of gametes results in diploid zygotes with two alleles of each gene that may be the same allele or different alleles.
3.4.U5 Dominant alleles mask the effects of recessive alleles but co-dominant alleles have joint effects.
3.4.U6 Many genetic diseases in humans are due to recessive alleles of autosomal genes, although some genetic diseases are due to dominant or co-dominant alleles.
3.4.U7 Some genetic diseases are sex-linked. The pattern of inheritance is different with sex-linked genes due to their location on sex chromosomes. [Alleles carried on X chromosomes should be shown as superscript letters on an upper case X, such as Xh.]
3.4.U8 Many genetic diseases have been identified in humans but most are very rare.
3.4.U9 Radiation and mutagenic chemicals increase the mutation rate and can cause genetic diseases and cancer.
3.4.A1 Inheritance of ABO blood groups. [The expected notation for ABO blood group alleles: O = i, A=IA, B = IB.]
3.4.A2 Red-green colour blindness and hemophilia as examples of sex-linked inheritance.
3.4.A3 nheritance of cystic fibrosis and Huntington’s disease.
3.4.A4 Consequences of radiation after nuclear bombing of Hiroshima and accident at Chernobyl.
3.4.S1 Construction of Punnett grids for predicting the outcomes of monohybrid genetic crosses.
3.4.S2 Comparison of predicted and actual outcomes of genetic crosses using real data.
3.4.S3 Analysis of pedigree charts to deduce the pattern of inheritance of genetic diseases.
3.4 NOS Making quantitative measurements with replicates to ensure reliability. Mendel’s genetic crosses with pea plants generated numerical data.
[Text in square brackets indicates guidance notes]
Play the Blood Typing Game at Nobel prize.org
|
|
10.2 Inheritance - HL
Essential idea: Genes may be linked or unlinked and are inherited accordingly.Understandings, applications and skills
10.2.U1 Gene loci are said to be linked if on the same chromosome.
10.2.U2 Unlinked genes segregate independently as a result of meiosis.
10.2.U3 Variation can be discrete or continuous.
10.2.U4 The phenotypes of polygenic characteristics tend to show continuous variation.
10.2.U5 Chi-squared tests are used to determine whether the difference between an observed and expected frequency distribution is statistically significant.
10.2.A1 Morgan’s discovery of non-Mendelian ratios in Drosophila.
10.2.A2 Completion and analysis of Punnett squares for dihybrid traits. [Alleles are usually shown side by side in dihybrid crosses, for example, TtBb.]
10.2.A3 Polygenic traits such as human height may also be influenced by environmental factors.
10.2.S1 Calculation of the predicted genotypic and phenotypic ratio of offspring of dihybrid crosses involving unlinked autosomal genes.
10.2.S2 Identification of recombinants in crosses involving two linked genes. [In representing crosses involving linkage, show genotypes as vertical pairs seperated by horizontal lines repesenting the chromosomes.]
10.2.S3 Use of a chi-squared test on data from dihybrid crosses.
10.3 NOS Looking for patterns, trends and discrepancies—Mendel used observations of the natural world to find and explain patterns and trends. Since then, scientists have looked for discrepancies and asked questions based on further observations to show exceptions to the rules. For example, Morgan discovered non-Mendelian ratios in his experiments with Drosophila.
[Text in square brackets indicates guidance notes]
10.2.U1 Gene loci are said to be linked if on the same chromosome.
10.2.U2 Unlinked genes segregate independently as a result of meiosis.
10.2.U3 Variation can be discrete or continuous.
10.2.U4 The phenotypes of polygenic characteristics tend to show continuous variation.
10.2.U5 Chi-squared tests are used to determine whether the difference between an observed and expected frequency distribution is statistically significant.
10.2.A1 Morgan’s discovery of non-Mendelian ratios in Drosophila.
10.2.A2 Completion and analysis of Punnett squares for dihybrid traits. [Alleles are usually shown side by side in dihybrid crosses, for example, TtBb.]
10.2.A3 Polygenic traits such as human height may also be influenced by environmental factors.
10.2.S1 Calculation of the predicted genotypic and phenotypic ratio of offspring of dihybrid crosses involving unlinked autosomal genes.
10.2.S2 Identification of recombinants in crosses involving two linked genes. [In representing crosses involving linkage, show genotypes as vertical pairs seperated by horizontal lines repesenting the chromosomes.]
10.2.S3 Use of a chi-squared test on data from dihybrid crosses.
10.3 NOS Looking for patterns, trends and discrepancies—Mendel used observations of the natural world to find and explain patterns and trends. Since then, scientists have looked for discrepancies and asked questions based on further observations to show exceptions to the rules. For example, Morgan discovered non-Mendelian ratios in his experiments with Drosophila.
[Text in square brackets indicates guidance notes]