3 Reproduction and inheritance
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(a) Reproduction
3.1Sexual and asexual reproduction
Understand the differences between sexual and asexual reproduction.
3.2Fertilisation and embryo development
Understand that fertilisation involves the fusion of a male and female gamete to produce a zygote that undergoes cell division and develops into an embryo.
3.3Flower structure and pollination
Describe the structures of an insect-pollinated and a wind-pollinated flower and explain how each is adapted for pollination.
3.4Pollen tube growth and fertilisation
Understand that the growth of the pollen tube followed by fertilisation leads to seed and fruit formation.
3.5Seed germination practical
Practical: investigate the conditions needed for seed germination.
3.6Food reserves in germinating seeds
Understand how germinating seeds utilise food reserves until the seedling can carry out photosynthesis.
3.7Asexual reproduction in plants
Understand that plants can reproduce asexually by natural methods (illustrated by runners) and by artificial methods (illustrated by cuttings).
3.8Human reproductive systems
Understand how the structure of the male and female reproductive systems are adapted for their functions.
3.9Oestrogen and progesterone
Understand the roles of oestrogen and progesterone in the menstrual cycle.
3.10BFSH and LH in the menstrual cycle
Understand the roles of FSH and LH in the menstrual cycle.
3.11Placenta and embryo nutrition
Describe the role of the placenta in the nutrition of the developing embryo.
3.12The developing embryo is protected by amniotic fluid
Understand how the developing embryo is protected by amniotic fluid.
3.13Oestrogen and testosterone roles
Understand the roles of oestrogen and testosterone in the development of secondary sexual characteristics.
(b) Inheritance
3.14Genome and genes
Understand that the genome is the entire DNA of an organism and that a gene is a section of a molecule of DNA that codes for a specific protein.
3.15Chromosomes and genes
Understand that the nucleus of a cell contains chromosomes on which genes are located.
3.16BDNA structure
Describe a DNA molecule as two strands coiled to form a double helix, the strands being linked by a series of paired bases: adenine (A) with thymine (T), and cytosine (C) with guanine (G).
3.17BRNA structure
Understand that an RNA molecule is single stranded and contains uracil (U) instead of thymine (T).
3.18BProtein synthesis
Describe the stages of protein synthesis including transcription and translation, including the role of mRNA, ribosomes, tRNA, codons and anticodons.
3.19Alleles
Understand how genes exist in alternative forms called alleles which give rise to differences in inherited characteristics.
3.20Genetic terminology
Understand the meaning of the terms: dominant, recessive, homozygous, heterozygous, phenotype, and genotype.
3.21BCodominance
Understand the meaning of the term codominance.
3.22Polygenic inheritance
Understand that most phenotypic features are the result of polygenic inheritance rather than single genes.
3.23Monohybrid inheritance
Describe patterns of monohybrid inheritance using a genetic diagram.
3.24Interpreting family pedigrees
Understand how to interpret family pedigrees.
3.25Monohybrid cross probabilities
Predict probabilities of outcomes from monohybrid crosses.
3.26Sex chromosomes
Understand how the sex of a person is controlled by one pair of chromosomes, XX in a female and XY in a male.
3.27Sex determination at fertilisation
Describe the determination of the sex of offspring at fertilisation, using a genetic diagram.
3.28Mitosis and identical diploid cells
Understand how division of a diploid cell by mitosis produces two cells that contain identical sets of chromosomes.
3.29Roles of mitosis
Understand that mitosis occurs during growth, repair, cloning and asexual reproduction.
3.30Meiosis and haploid gametes
Understand how division of a cell by meiosis produces four cells, each with half the number of chromosomes, and that this results in the formation of genetically different haploid gametes.
3.31Random fertilisation and variation
Understand how random fertilisation produces genetic variation of offspring.
3.32Human diploid and haploid chromosome numbers
Know that in human cells the diploid number of chromosomes is 46 and the haploid number is 23.
3.33Variation within a species
Understand that variation within a species can be genetic, environmental, or a combination of both.
3.34Mutation
Understand that mutation is a rare, random change in genetic material that can be inherited.
3.35BDNA mutations and phenotype
Understand how a change in DNA can affect the phenotype by altering the sequence of amino acids in a protein.
3.36BEffects of genetic mutations
Understand how most genetic mutations have no effect on the phenotype, some have a small effect and rarely do they have a significant effect.
3.37BMutagens
Understand that the incidence of mutations can be increased by exposure to ionising radiation (for example, gamma rays, x-rays and ultraviolet rays) and some chemical mutagens (for example, chemicals in tobacco).
3.38Darwin’s theory of evolution by natural selection
Explain Darwin’s theory of evolution by natural selection.
3.39Antibiotic resistance
Understand how resistance to antibiotics can increase in bacterial populations, and appreciate how such an increase can lead to infections being difficult to control.