Every question IB students actually ask.

How Do Channel Proteins vs Pump Proteins Work?

Compare how channel and pump proteins transport substances across cell membranes, including gradients, ATP use, selectivity, and IB exam terminology.

What's the Difference Between Integral and Peripheral Membrane Proteins?

Learn how integral and peripheral membrane proteins differ in position, interactions and functions for IB Biology membrane exam questions at SL and HL.

What Do Glycoproteins and Glycolipids Do in the Membrane?

Learn how membrane glycoproteins and glycolipids enable cell recognition, signalling and adhesion, with precise IB Biology exam terminology and tips.

What's the Difference Between Endocytosis and Exocytosis? (AHL)

Compare endocytosis and exocytosis in IB Biology AHL, including vesicle formation, membrane fusion, energy use, examples, and exam terminology.

Why Does Cholesterol Affect Membrane Fluidity? (AHL)

Learn how cholesterol stabilizes animal cell membranes by limiting phospholipid movement at high temperatures and preventing stiffening at low temperatures.

Why Are Unsaturated Fats More Fluid Than Saturated Fats in Membranes? (AHL)

Learn why unsaturated fatty acid tails increase membrane fluidity, how double bonds affect packing and what IB Biology AHL exam answers require.

How Do Voltage-Gated Ion Channels Work in Neurons? (AHL)

Learn how voltage-gated sodium and potassium channels generate action potentials in neurons, with precise IB Biology AHL terminology for exams.

Why Do Cells Have Organelles Instead of One Big Compartment?

Learn why organelles improve cell efficiency by concentrating enzymes and separating incompatible reactions, with SL and HL IB Biology B2.2 guidance.

How Does Sodium-Glucose Cotransport Work in the Small Intestine and Kidney? (AHL)

Learn how sodium-glucose cotransport uses sodium gradients to absorb glucose in the small intestine and reabsorb it in the kidney nephron.

How Does the Sodium-Potassium Pump Work? (AHL)

Learn how the sodium-potassium pump uses ATP to move three sodium ions out and two potassium ions in, helping generate membrane potentials in cells.

What Are Cell Adhesion Molecules (CAMs)? (AHL)

Learn what cell adhesion molecules (CAMs) are, how they form cell to cell junctions and tissues, and the precise AHL points required for IB Biology exams.

Why Are the Nucleus and Cytoplasm Separated?

Learn how the nuclear envelope separates transcription from translation, allowing mRNA processing and controlled gene expression in eukaryotic cells.

What Are the Advantages of Compartmentalizing the Cytoplasm?

Learn how cytoplasmic compartmentalization concentrates enzymes and metabolites, separates incompatible reactions, and improves cell efficiency for IB exams.

How Is the Chloroplast Adapted for Photosynthesis? (AHL)

Learn how thylakoid membranes, a small thylakoid lumen and the stroma adapt chloroplasts for photosynthesis in IB Biology AHL exam answers.

What Does the Golgi Apparatus Do? (AHL)

Learn how the Golgi apparatus modifies, sorts and packages proteins into vesicles for transport or secretion in IB Biology AHL exam answers.

How Do Vesicles Form (Role of Clathrin)? (AHL)

Learn how clathrin assembles a protein coat, bends membranes into buds, helps vesicles form, and is removed before targeting in IB Biology AHL exams.

Why Does the Nucleus Have a Double Membrane With Pores? (AHL)

Learn why the nuclear envelope has two membranes and pores, how it separates transcription from translation, and what IB Biology AHL answers require.

What's the Difference Between Free Ribosomes and Rough ER? (AHL)

Learn the AHL difference between free ribosomes and rough ER, including protein destinations, secretion pathways, and key IB exam misconceptions.

How Does One Fertilized Egg Become Different Types of Cells? (Differentiation)

Learn how mitosis, chemical gradients and differential gene expression turn one fertilized egg into specialized cells for IB Biology B2.3 exam questions.

What Are Stem Cells and What Makes Them Special?

Learn what stem cells are, why self-renewal and differentiation make them special, and how IB Biology compares the main types of stem cell.

Where Are Stem Cell Niches in the Human Body?

Learn where human stem cell niches occur, especially bone marrow and hair follicles, and how each microenvironment controls stem cells in IB Biology.

How Is the Mitochondrion Adapted for Making ATP? (AHL)

Learn how cristae, mitochondrial compartments, electron carriers and ATP synthase enable efficient ATP production for IB Biology AHL exam questions.