Singapore JC H2 Biology

This comprehensive guide details the syllabus for the Singapore JC H2 Biology subject, based on the official 2024 syllabus (9744). It covers the core ideas and extension topics, along with learning outcomes and assessment objectives.

I. Core Ideas

1. The Cell and Biomolecules of Life

This topic explores the fundamental building blocks of life, from the cell theory to the intricate structures and functions of biomolecules. It covers:

• Cell theory: Understanding cells as the smallest units of life, originating from pre-existing cells, and forming the basis of all living organisms.
• Membrane systems and organelles: Structure and function of rough and smooth endoplasmic reticulum, Golgi body, mitochondria, ribosomes, lysosomes, chloroplasts, cell surface membrane, nuclear envelope, centrioles, nucleus, and nucleolus. Practical skills involving light microscopy may be assessed.
• Bacterial cell structure: Characteristics of a typical bacterial cell, including its small size, unicellular nature, peptidoglycan cell wall, circular DNA, 70S ribosomes, and lack of membrane-bound organelles.
• Virus structure: Structural components of viruses, including enveloped viruses and bacteriophages, and their implications for the cell theory and the definition of life.
• Biomolecule structure and function: Monomers (glucose, glycerol, fatty acids, amino acids) and polymers (starch, cellulose, glycogen, triglycerides, phospholipids), and the bonds that link them (glycosidic, ester, peptide). The relationship between structure and function is emphasized.
• Membrane structure and function: Fluid mosaic model, roles of constituent biomolecules (phospholipids, proteins, glycolipids, glycoproteins, cholesterol), and mechanisms of transport across membranes (simple diffusion, osmosis, facilitated diffusion, active transport, endocytosis, exocytosis).
• Protein structure and function: Primary, secondary, tertiary, and quaternary structures, the bonds involved, and the effects of temperature and pH. Specific examples include haemoglobin, collagen, and G-protein linked receptors.
• Enzymes: Mode of action, enzyme-substrate complex, activation energy, enzyme specificity (lock-and-key and induced-fit hypotheses), effects of temperature, pH, enzyme concentration, and substrate concentration. Competitive and non-competitive inhibitors and their effects on enzyme activity.
• Stem cells: Unique features of zygotic, embryonic, and blood stem cells (totipotency, pluripotency, multipotency), their normal functions, and the ethical implications of their use in research and medical applications, including the role of human induced pluripotent stem cells (iPSCs).

2. Genetics and Inheritance

This topic delves into the mechanisms of inheritance and the molecular basis of genetics, covering:

• DNA and RNA: Structure and function of DNA, tRNA, rRNA, and mRNA. DNA replication and the end replication problem.
• Central Dogma: Protein synthesis in prokaryotes and eukaryotes, including transcription, mRNA processing, and translation.
• Genome organization: Structure and organization of viral, prokaryotic, and eukaryotic genomes.
• Viral genetics: Inheritance of viral genomes through lytic and lysogenic cycles (T4 phage, lambda phage, influenza virus, HIV), and mechanisms of variation (antigenic shift and antigenic drift).
• Bacterial genetics: Asexual reproduction by binary fission, and mechanisms of variation (transformation, transduction, conjugation).
• Eukaryotic gene regulation: Control of gene expression at the chromatin level (histone modification, DNA methylation), transcriptional level (promoters, silencers, enhancers, transcription factors), post-transcriptional level (splicing, polyadenylation, 5' capping), translational level (RNA half-life, translation initiation), and post-translational level (biochemical modification, protein degradation).
• Molecular techniques: PCR, gel electrophoresis, Southern blotting, and nucleic acid hybridization.
• Mutations: Gene mutations (substitution, addition, deletion, frameshift) and chromosomal aberrations (numerical and structural), and their role in diseases like sickle cell anaemia.
• Cell cycle and cancer: Mitotic cell cycle, stages of mitosis, significance and regulation of the cell cycle, causative factors of cancer, role of tumor suppressor genes (p53) and proto-oncogenes (ras), and the multi-step process of cancer development.
• Meiosis: Meiotic cell cycle, stages of meiosis, and its significance in generating variation.
• Mendelian genetics: Concepts of locus, allele, dominance, recessiveness, codominance, incomplete dominance, homozygosity, heterozygosity, phenotype, genotype, and linkage. Inheritance patterns, including dihybrid crosses, test crosses, and the effects of linkage and crossing over.
• Epistasis: Interaction between loci and its effect on phenotypic ratios.
• Genotype-phenotype interaction: Influence of environment on phenotype.
• Genetic variation: Continuous and discontinuous variation.
• Chi-squared test: Testing the significance of differences between observed and expected results.

3. Energy and Equilibrium

This topic focuses on the energy flow within living organisms, encompassing:

• Photosynthesis: Chloroplast structure, absorption and action spectra of pigments, light-dependent reactions, Calvin cycle, and limiting factors.
• Respiration: Glycolysis, link reaction, Krebs cycle, oxidative phosphorylation, anaerobic respiration, and the role of chemiosmosis.
• Cell signaling: Stages of cell signaling (ligand-receptor interaction, signal transduction, cellular response), second messengers (cyclic AMP), kinases, phosphatases, and the regulation of blood glucose by insulin and glucagon.

4. Biological Evolution

This topic explores the mechanisms and evidence of evolution, covering:

• Natural selection: Importance of variation, environmental factors as selective forces, and the role of natural selection in evolution.
• Evolution: Definition of biological evolution, microevolution, macroevolution, and the preservation of genetic variation.
• Evidence of evolution: Homologies (biochemical and anatomical), fossil record, and biogeography.
• Species concepts: Biological, ecological, morphological, genetic, and phylogenetic concepts.
• Classification and phylogeny: Biological classification, evolutionary relationships, speciation (allopatric and sympatric), and the use of genome sequences in reconstructing phylogenetic relationships.

II. Extension Topics

A. Infectious Diseases

This topic examines the interplay between pathogens and the immune system, covering:

• Immune system: Adaptive (active, passive, naturally acquired, artificially acquired) and innate immunity, roles of B and T lymphocytes, antigen-presenting cells, and memory cells.
• Antibodies: Structure and function of antibodies (IgG), somatic recombination, hypermutation, and class switching.
• Vaccination: Control of disease through vaccination, benefits and risks.
• Viral infections: Mechanisms of viral infection (influenza virus, HIV).
• Bacterial infections: Mode of transmission and infection of bacterial pathogens (Mycobacterium tuberculosis).
• Antibiotics: Modes of action of antibiotics (penicillin).

B. Impact of Climate Change on Animals and Plants

This topic investigates the effects of climate change on living organisms, covering:

• Human activities and climate change: Contribution of human activities to greenhouse gas emissions.
• Effects of climate change: Environmental consequences of climate change.
• Impact on plants: Effects of climate change on plant distribution and adaptations.
• Impact on insects: Effects of temperature changes on insects.
• Dengue fever: Life cycle of Aedes aegypti, development of dengue fever in humans, and the impact of global warming on its spread.
• Impact on biodiversity and food supply: Consequences of climate change for biodiversity, biomedicines, and the global food supply.

This detailed breakdown of the H2 Biology syllabus provides a comprehensive overview of the topics covered, equipping students with the necessary knowledge and understanding to excel in the subject.