IB Biology Topic 2 Videos

This video explores the conditions of early Earth and the Miller-Urey experiment, introducing how organic molecules may have formed. It also explains the criteria used to define life and why viruses are not considered living.

This video introduces the RNA world hypothesis and explains how the first cells may have formed. It also discusses evidence for a last universal common ancestor shared by all life forms.

This video introduces the cell theory, highlights key exceptions to it, and explores the seven functions of life using Paramecium and Chlamydomonas as examples.

This video compares the structures of prokaryotic and eukaryotic cells, emphasizing differences in organelles, DNA structure, and ribosome size.

This video outlines the structural differences and similarities between animal, plant, and fungal cells, focusing on unique organelles in each type.

This video traces the evolution of microscopy, introduces types of microscopes, and explains the structure and use of the light microscope, including magnification and resolution.

This video explains how eukaryotic cells evolved through endosymbiosis and how multicellular organisms developed through differentiation and cell communication.

This video outlines the structure of viruses and examines specific examples, with a focus on the rapid mutation of influenza and HIV and their implications for vaccine development.

This video discusses theories about the origin of viruses and explains how viruses replicate using the lytic and lysogenic cycles.

This video explores membrane structure, the fluid mosaic model, and the roles of phospholipids, proteins, glycoproteins, and glycolipids in membrane function.

This video explains passive and active transport, osmosis, and the role of transport proteins like aquaporins in maintaining homeostasis

This video explains how different lipids affect membrane fluidity and introduces the types of cell adhesion molecules involved in tissue formation.

This video describes passive transport processes, focusing on voltage-gated and ligand-gated ion channels involved in neural signalling.

This video explores active transport mechanisms including the sodium-potassium pump and sodium-glucose co-transporter, and explains how vesicular transport moves large molecules across membranes.

This video details the main organelles in eukaryotic cells and emphasizes the advantages of compartmentalization in enhancing cellular efficiency.

This video describes the structure and function of mitochondria and chloroplasts, highlighting their adaptations for cellular respiration and photosynthesis.

This video explains the roles of vesicles, nuclear membrane, ribosomes, and the Golgi apparatus in protein synthesis, modification, and transport within cells.

This video covers stem cell types, differentiation, and sources, with a focus on therapeutic uses and ethical considerations surrounding embryonic stem cells.

This video explains how surface area-to-volume ratio affects cell size and function, and how organisms adapt to maintain efficient exchange of substances.

This video explores how cell structure relates to function, using examples like alveoli and gametes, and highlights adaptations that maximise surface area-to-volume ratio for efficient exchange.

This video compares skeletal and cardiac muscle cells, focusing on their structure, function, and specialized adaptations for contraction and coordination.

This video introduces chemical signalling through ligands like hormones and neurotransmitters, comparing localized and systemic effects on target cells.

This video explains intracellular and extracellular receptors, the basics of signal transduction, and bacterial communication through quorum sensing.

This video outlines the mechanisms of ion channel, G-protein coupled, and enzyme-linked receptors, with key examples like adrenaline and insulin signalling.

This video describes how steroid hormones activate intracellular receptors and explains how positive and negative feedback regulate signalling, using the menstrual cycle as an example.

This video introduces neurons and explains how nerve impulses are generated and propagated, including the roles of axon diameter and myelination in impulse speed.

This video explains how signals are transmitted across synapses via neurotransmitters like acetylcholine and details the full process of synaptic transmission in cholinergic synapses.

This video examines the ionic mechanisms of action potentials, local currents, and saltatory conduction in neurons for rapid signal transmission.

This video explores how synaptic transmission is influenced by substances like cocaine and pesticides, and explains how excitatory and inhibitory inputs are integrated through summation.

This video explores nociceptors and reflex pathways involved in pain perception, and presents major theories explaining the phenomenon of consciousness.

This video covers the stages of mitosis and cytokinesis, differences between animal and plant cytokinesis, and how to identify mitotic phases in micrographs and calculate mitotic index.

This video explores the concept of ploidy and outlines the stages of meiosis I and II, comparing equal and unequal cytokinesis in spermatogenesis, oogenesis, and budding.

This video explains how non-disjunction during meiosis can lead to chromosomal abnormalities like Down, Klinefelter, and Turner syndromes, and compares diagnostic sampling methods.

This video highlights meiosis as a source of genetic variation, explaining the mechanisms and effects of crossing over and random orientation during gamete formation.

This video introduces the stages of the cell cycle and explores how stem cells drive cell proliferation for tissue growth, development, and repair.

This video explains how cyclins regulate the cell cycle and how mutations in proto-oncogenes can lead to tumour formation and cancer.

This video explains gene expression through nucleosome structure, transcriptional regulation, and post-transcriptional mechanisms like mRNA degradation.

This video explores how environmental and biochemical factors modify gene expression through epigenetic changes, and how some of these modifications can be inherited.

This video covers how stress, diet, pollution, hormones, and biochemicals influence gene expression, with examples like air pollution, spaceflight, and bacterial operons.

This video introduces osmolarity and its role in osmosis, using the potato core practical to illustrate the effects of hypertonic, hypotonic, and isotonic solutions on cells.

This video contrasts osmosis in plant and animal cells, explaining turgor pressure and plasmolysis in plants, and the importance of isotonic solutions in medical and physiological contexts.

This video explains the concept of water potential in plant cells and how solute and pressure potential affect the direction and function of osmosis.