Engineering and Science Admissions Test (ESAT) Biology Module Syllabus

Biology Module syllabus — full chapter and topic list

Expand any chapter to see its topics and sub-topics. This is the whole examinable outline for Biology Module in Engineering and Science Admissions Test (ESAT), not a summary of it.

1. 1

   Cells and Cellular Processes

   4 topics

   • Cell Structure
     • Prokaryotic and eukaryotic cells
     • Animal and plant cell organelles
     • Specialised cells and differentiation
   • Transport Across Membranes
     • Diffusion and facilitated diffusion
     • Osmosis
     • Active transport
   • Cell Division
     • Mitosis and the cell cycle
     • Stem cells and their uses
   • Enzymes
     • Enzyme action and the lock-and-key model
     • Effect of temperature, pH and concentration
2. 2

   Physiology and Organ Systems

   4 topics

   • Digestion and Nutrition
     • Digestive enzymes and absorption
     • Food tests
   • Circulation and Gas Exchange
     • The heart and blood vessels
     • Blood components
     • The lungs and gas exchange
   • Respiration
     • Aerobic respiration
     • Anaerobic respiration and fermentation
   • The Nervous and Endocrine Systems
     • Reflex arcs and neurones
     • Hormonal coordination
3. 3

   Homeostasis and Response

   3 topics

   • Principles of Homeostasis
     • Negative feedback control
     • Receptors, coordination centres and effectors
   • Control of Internal Conditions
     • Blood glucose regulation and diabetes
     • Osmoregulation and the kidneys
     • Thermoregulation
   • Plant Responses and Hormones
     • Tropisms in plants
     • Plant hormones and their uses
4. 4

   Genetics, Inheritance and Variation

   3 topics

   • DNA and Inheritance
     • Structure of DNA and genes
     • Genotype, phenotype and alleles
     • Monohybrid crosses and Punnett squares
   • Variation and Evolution
     • Genetic and environmental variation
     • Natural selection and evolution
     • Selective breeding and genetic engineering
   • Reproduction
     • Sexual and asexual reproduction
     • Meiosis
5. 5

   Ecology and the Environment

   4 topics

   • Ecosystems and Interdependence
     • Food chains, webs and trophic levels
     • Energy transfer through ecosystems
   • Cycling of Materials
     • The carbon cycle
     • The water cycle
   • Human Impact and Biodiversity
     • Pollution and land use
     • Conservation and maintaining biodiversity
   • Photosynthesis
     • The photosynthesis reaction and limiting factors

Biology Module flashcards for Engineering and Science Admissions Test (ESAT)

25 of 52 cards from the Biology Module deck — real questions with worked answers.

1. What is the function of the cell membrane (plasma membrane), and what model describes its structure?

   It controls the entry and exit of substances (selectively permeable / partially permeable barrier). Its structure is described by the fluid mosaic model: a phospholipid bilayer with embedded proteins, cholesterol, and glycoproteins that can move laterally.

2. Compare the key structural differences between a prokaryotic and a eukaryotic cell.

   Prokaryotic: no membrane-bound nucleus (DNA is a free circular loop in the cytoplasm, plus plasmids), no membrane-bound organelles, ribosomes are smaller ($70S$), typically $1$–$5\,\mu m$. Eukaryotic: true nucleus with linear DNA, membrane-bound organelles (mitochondria, ER, etc.), larger $80S$ ribosomes, typically $10$–$100\,\mu m$.

3. State the function of mitochondria, ribosomes, and the rough endoplasmic reticulum.

   Mitochondria: site of aerobic respiration / ATP synthesis. Ribosomes: site of protein synthesis (translation). Rough ER: studded with ribosomes; transports and processes proteins made for secretion.

4. What is the function of the chloroplast and which pigment does it contain?

   The chloroplast is the site of photosynthesis. It contains the green pigment chlorophyll, which absorbs light energy; reactions occur in the thylakoid membranes (light-dependent) and the stroma (light-independent).

5. Define magnification and resolution in microscopy, and give the magnification formula.

   Magnification = how many times larger an image appears than the real object. Resolution = the minimum distance at which two points can still be distinguished as separate. $$\text{magnification} = \frac{\text{image size}}{\text{actual size}}$$

6. Define diffusion and list three factors that increase its rate.

   Diffusion is the net movement of particles from a region of higher concentration to a region of lower concentration, down a concentration gradient, until evenly distributed. Rate increases with a steeper concentration gradient, higher temperature, larger surface area (and shorter diffusion distance).

7. Define osmosis precisely.

   Osmosis is the net movement of water molecules from a region of higher water potential (dilute solution) to a region of lower water potential (concentrated solution) across a partially permeable membrane.

8. What is active transport, and how does it differ from diffusion?

   Active transport is the movement of substances against their concentration gradient (low to high) using carrier proteins and energy from ATP. Unlike diffusion, it requires metabolic energy and can accumulate substances, e.g. mineral ion uptake by root hair cells.

9. Explain the terms hypertonic, hypotonic, and isotonic with respect to a cell.

   Hypertonic solution: higher solute concentration than the cell, so water leaves (cell shrinks/plasmolyses). Hypotonic: lower solute concentration, so water enters (cell swells/lyses or becomes turgid). Isotonic: equal concentrations, so no net water movement.

10. List the stages of the cell cycle in order, including the phases of mitosis.

    Cell cycle: Interphase ($G_1$, $S$ — DNA replication, $G_2$), then mitosis. Mitosis phases (PMAT): Prophase, Metaphase, Anaphase, Telophase, followed by cytokinesis (cytoplasm division).

11. Compare mitosis and meiosis in terms of products and chromosome number.

    Mitosis: one division producing $2$ genetically identical diploid daughter cells (for growth/repair). Meiosis: two divisions producing $4$ genetically different haploid gametes; chromosome number is halved from $2n$ to $n$, with genetic variation from crossing over and independent assortment.

12. What are stem cells, and what distinguishes embryonic from adult stem cells?

    Stem cells are undifferentiated cells able to divide and differentiate into specialised cells. Embryonic stem cells are pluripotent (can form almost any cell type); adult (tissue) stem cells are multipotent (limited to certain cell types, e.g. bone marrow forming blood cells).

13. What is an enzyme, and why is it described as a biological catalyst?

    An enzyme is a protein that speeds up the rate of a biochemical reaction by lowering the activation energy, without being used up or permanently changed itself, so it can be reused.

14. Explain the lock-and-key model of enzyme action.

    Each enzyme has a specific active site with a complementary shape to its substrate. The substrate binds like a key in a lock to form an enzyme–substrate complex, the reaction occurs, and products are released, leaving the enzyme unchanged.

15. Describe the effect of temperature on enzyme activity, including denaturation.

    Rate increases with temperature up to an optimum (more frequent successful collisions). Above the optimum, heat breaks bonds holding the tertiary structure, changing the active site's shape so the substrate no longer fits — the enzyme is denatured and activity falls sharply.

16. How does pH affect enzyme activity?

    Each enzyme has an optimum pH at which activity is maximal. Moving away from the optimum disrupts hydrogen and ionic bonds, altering the active site's shape and reducing the rate; extreme pH denatures the enzyme. E.g. pepsin works best at acidic $pH \approx 2$.

17. Match each digestive enzyme to its substrate and products: amylase, protease, lipase.

    Amylase: starch $\rightarrow$ maltose (sugars). Protease (e.g. pepsin): proteins $\rightarrow$ amino acids. Lipase: lipids (fats) $\rightarrow$ fatty acids + glycerol.

18. What is the role of bile in digestion, and where is it made and stored?

    Bile is made in the liver and stored in the gall bladder. It neutralises stomach acid (alkaline, providing optimal pH for enzymes in the small intestine) and emulsifies fats into small droplets, increasing surface area for lipase action.

19. Describe how the small intestine (ileum) is adapted for absorption.

    It has a very large surface area from villi and microvilli, a thin (one-cell-thick) epithelial wall for a short diffusion distance, a rich capillary network maintaining a steep concentration gradient, and lacteals to absorb fatty acids and glycerol.

20. Name the components of blood and give one function of each.

    Red blood cells: transport oxygen (contain haemoglobin). White blood cells: defence/immunity (phagocytosis and antibody production). Platelets: blood clotting. Plasma: liquid that transports cells, nutrients, $\ce{CO2}$, hormones, and urea.

21. Write the reversible reaction by which haemoglobin transports oxygen.

    $$\ce{Hb + 4O2 <=> Hb(O2)4}$$ Haemoglobin binds oxygen in the lungs (high $\ce{O2}$) to form oxyhaemoglobin and releases it in respiring tissues (low $\ce{O2}$).

22. Describe the double circulation of the human heart and why it is advantageous.

    Blood passes through the heart twice per circuit: the pulmonary circuit (heart $\rightarrow$ lungs $\rightarrow$ heart) and the systemic circuit (heart $\rightarrow$ body $\rightarrow$ heart). This maintains high blood pressure to the body, allowing efficient, rapid delivery of oxygen.

23. Compare arteries, veins, and capillaries.

    Arteries: thick muscular/elastic walls, narrow lumen, carry blood at high pressure away from the heart, no valves. Veins: thinner walls, wide lumen, low pressure, valves to prevent backflow, carry blood to the heart. Capillaries: one-cell-thick walls for exchange of substances between blood and tissues.

24. Describe how the alveoli are adapted for efficient gas exchange.

    Large total surface area (millions of alveoli), thin (one-cell-thick) walls for a short diffusion distance, moist lining for gases to dissolve, and a dense capillary network that maintains steep concentration gradients for $\ce{O2}$ and $\ce{CO2}$.

25. Write the word and balanced symbol equations for aerobic respiration.

    Glucose + oxygen $\rightarrow$ carbon dioxide + water (+ energy). $$\ce{C6H12O6 + 6O2 -> 6CO2 + 6H2O}$$

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