International Baccalaureate Diploma Programme (IB) Group 4: Sciences (Biology) Syllabus

Group 4: Sciences (Biology) syllabus — full chapter and topic list

Expand any chapter to see its topics and sub-topics. This is the whole examinable outline for Group 4: Sciences (Biology) in International Baccalaureate Diploma Programme (IB), not a summary of it.

1. 1

   Unity and Diversity

   4 topics

   • Molecules of life
     • Water and its properties
     • Carbohydrates, lipids, proteins and nucleic acids
   • Cells and viruses
     • Cell structure and the origin of cells
     • Prokaryotic and eukaryotic diversity
   • Genetic continuity and variation
     • DNA replication and inheritance
     • Mutation, meiosis and gene pools
   • Classification and biodiversity
     • Taxonomy and cladistics
     • Conservation of biodiversity
2. 2

   Form and Function

   3 topics

   • Molecular and cellular structure-function
     • Membranes and membrane transport
     • Enzymes and metabolic pathways
   • Gas exchange and transport systems
     • Adaptations for gas exchange
     • Circulatory and transport mechanisms
   • Organisms and homeostasis
     • Nutrient and water balance
     • Coordination and control
3. 3

   Interaction and Interdependence

   3 topics

   • Cell signalling and the nervous system
     • Neurons and synaptic transmission
     • Hormonal coordination
   • Ecosystems and ecology
     • Populations and communities
     • Energy flow and nutrient cycling
   • Defence and immunity
4. 4

   Continuity and Change

   3 topics

   • Cell division and reproduction
     • Mitosis, meiosis and the cell cycle
     • Sexual and asexual reproduction
   • Evolution and natural selection
     • Evidence for evolution
     • Speciation and selection pressures
   • Climate change and ecosystem stability
5. 5

   Practical Scheme and Assessment

   4 topics

   • Experimental skills and inquiry
     • Designing controlled investigations
     • Data collection, processing and uncertainties
   • Collaborative Sciences Project
   • Internal Assessment: Scientific investigation
     • Personal engagement and research question
     • Analysis, evaluation and communication
   • External papers structure
     • Paper 1: multiple choice and data-based
     • Paper 2: short and extended response

Group 4: Sciences (Biology) flashcards for International Baccalaureate Diploma Programme (IB)

23 of 52 cards from the Group 4: Sciences (Biology) deck — real questions with worked answers.

1. In the IB Biology context, what four elements make up roughly 99% of the mass of living organisms?

   Oxygen, Carbon, Hydrogen and Nitrogen ($\ce{O}$, $\ce{C}$, $\ce{H}$, $\ce{N}$).

2. What type of bond forms between two monosaccharides during a condensation reaction, and what small molecule is released?

   A glycosidic bond forms, releasing one molecule of water ($\ce{H2O}$).

3. Write the overall balanced equation for aerobic respiration of glucose.

   $$\ce{C6H12O6 + 6O2 -> 6CO2 + 6H2O}$$

4. Write the overall balanced equation for photosynthesis.

   $$\ce{6CO2 + 6H2O ->[\text{light}] C6H12O6 + 6O2}$$

5. What is the general structure of an amino acid?

   A central carbon bonded to an amino group ($\ce{-NH2}$), a carboxyl group ($\ce{-COOH}$), a hydrogen atom, and a variable R (side) group.

6. Name the four levels of protein structure.

   Primary (sequence), secondary ($\alpha$-helices and $\beta$-pleated sheets), tertiary (3D folding) and quaternary (multiple polypeptide subunits).

7. Which property of water allows it to act as a coolant in organisms, and why?

   Its high specific heat capacity and high latent heat of vaporisation, because extensive hydrogen bonding requires large energy input to raise temperature or evaporate water.

8. List the four main classes of biological macromolecules and their respective monomers.

   Carbohydrates (monosaccharides), proteins (amino acids), nucleic acids (nucleotides), and lipids (built from glycerol and fatty acids, though not strictly polymers).

9. State the four key differences between prokaryotic and eukaryotic cells.

   Prokaryotes lack a membrane-bound nucleus, lack membrane-bound organelles, have a single circular DNA molecule, and have 70S ribosomes; eukaryotes have all of these reversed (nucleus, organelles, linear chromosomes, 80S ribosomes).

10. What is the function of the rough endoplasmic reticulum?

    It is studded with ribosomes and synthesises and transports proteins (especially those destined for secretion).

11. Why are viruses generally not considered living organisms?

    They are acellular, cannot reproduce independently (they are obligate intracellular parasites), and lack their own metabolism.

12. State the components of a virus particle (virion).

    A nucleic acid genome (DNA or RNA), a protein coat called a capsid, and sometimes a lipid envelope derived from the host membrane.

13. What does the lytic cycle of a virus produce, and how does it differ from the lysogenic cycle?

    The lytic cycle produces new virions that burst (lyse) the host cell immediately; the lysogenic cycle integrates viral DNA into the host genome (as a provirus) where it replicates passively until activated.

14. State the base-pairing rules in DNA.

    Adenine pairs with thymine ($\ce{A=T}$, two hydrogen bonds) and guanine pairs with cytosine ($\ce{G#C}$, three hydrogen bonds).

15. What is the difference between the structure of DNA and RNA?

    DNA is double-stranded, uses deoxyribose sugar and the base thymine; RNA is single-stranded, uses ribose sugar and the base uracil instead of thymine.

16. Define a gene and an allele.

    A gene is a heritable sequence of DNA that codes for a specific polypeptide or function; an allele is one of the alternative versions (forms) of a gene at a given locus.

17. In Mendelian genetics, what phenotypic ratio results from a monohybrid cross between two heterozygotes ($Aa \times Aa$)?

    A $3:1$ ratio of dominant to recessive phenotype (genotypic ratio $1:2:1$).

18. What is a point mutation, and give an example consequence at the protein level.

    A change in a single base pair; consequences include a silent, missense (changed amino acid, e.g. sickle-cell anaemia) or nonsense (premature stop codon) mutation.

19. Define semi-conservative replication of DNA.

    Each new DNA double helix consists of one original (parental) strand and one newly synthesised strand, so half the original molecule is conserved.

20. What are the three stages by which genetic information flows in the central dogma?

    DNA $\to$ (transcription) $\to$ mRNA $\to$ (translation) $\to$ protein.

21. List the taxonomic hierarchy from broadest to most specific used in classification.

    Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.

22. Name the three domains of life.

    Bacteria, Archaea and Eukarya.

23. State the binomial nomenclature convention for naming species.

    A two-part Latin name: the genus (capitalised) followed by the species epithet (lowercase), both italicised, e.g. $Homo\ sapiens$.

See more Group 4: Sciences (Biology) flashcards →

Planning Group 4: Sciences (Biology) for International Baccalaureate Diploma Programme (IB)

Group 4: Sciences (Biology) (International Baccalaureate Diploma Programme (IB)) FAQ