This 5-minute video lesson introduces this short series on human preshistory. [Biology playlist: Lesson 63 of 71].

This 15-minute video provides an overview of the inflammatory response. [Biology playlist: Lesson 58 of 71].

This 18-minute video lesson provides an overview of the Krebs or Citric Acid Cycle. [Biology playlist: Lesson 25 of 71].

This 10-minute video lesson shows how how myosin and actin interact to produce mechanical force. [Biology playlist: Lesson 47 of 71].

This 16-minute video lesson looks at how one neuron can stimulate (or inhibit) another neuron at a chemical synapse. [Biology playlist: Lesson 46 of 71].

This 17-minute video lesson looks at oxidation and reduction in cellular respiration. It Reconciles the biology and chemistry definitions of oxidation and reduction. [Biology playlist: Lesson 23 of 71].

This 5-minute video lecture looks at oxidative phosphorylation and chemiosmosis (along with slight correction of previous video). [Biology playlist: Lesson 27 of 71].

This 27-minute video lesson looks at the phases of Meiosis. [Biology playlist: Lesson 11 of 71].

This 21-minute video explains the phases of mitosis. [Biology playlist: Lesson 10 of 71].

This 17-minute video lesson provides more detail on the Calvin Cycle and Photorespiration. [Biology playlist: Lesson 32 of 71].

This 14-minute video lesson presents an overview of photosythesis. [Biology playlist: Lesson 28 of 71].

This 13-minute video lesson covers the Calvin Cycle or the light-independent (dark) reactions of photosythesis. [Biology playlist: Lesson 31 of 71].

This 20-minute video lesson presents details on the light-dependent reactions of photosynthesis. [Biology playlist: Lesson 29 of 71].

This 12-minute video lesson looks at how professional antigen presenting cells present parts of engulfed pathogens on MHC II complexes (major histocompatibility complexes). [Biology playlist: Lesson 54 of 71].

This 16-minute video looks at oxygen uptake by hemoglobin in red blood cells. [Biology playlist: Lesson 38 of 71].

This 11-minute video lesson provides a review of B cells, CD4+ T cells and CD8+ T cells. [Biology playlist: Lesson 57 of 71].

This 16-minute video lesson looks at the role of phagocytes in innate or nonspecific immunity. It also discusses neutrophils, macrophages, and dendritic cells. MHC II. [Biology playlist: Lesson 51 of 71].

This 15-minute video lesson looks at the role of the sarcoplasmic reticulum in controlling calcium ion concentrations within the muscle cell. [Biology playlist: Lesson 49 of 71].

This 14-minute video lesson looks at secondary active transport in the Nephron. [Biology playlist: Lesson 60 of 71].

This 14-minute video lesson covers the chromosomal basis for gender and sex-linked traits. [Biology playlist: Lesson 17 of 71].