A level | biology | Topic 5A | Photosynthesis | Pearson Edexcel

Summary

A comprehensive review of the photosynthesis topic for A-Level Biology, covering ATP, chloroplast structure, light-dependent and light-independent reactions, and factors limiting photosynthesis.

Highlights

Introduction to ATP and Metabolism00:00:00

Overview of autotrophs and heterotrophs, the role of ATP in metabolism, and the difference between hydrolysis and condensation reactions in ATP synthesis and breakdown.

Chloroplasts and Photosynthetic Pigments00:04:18

Detailed explanation of chloroplast structure, the function of chlorophyll, and how absorption and action spectra measure light capture. Included is a guide on using paper chromatography to separate pigments and calculate Rf values.

Biochemistry of Photosynthesis: Light-Dependent Stage00:11:40

Covers photolysis of water and the distinction between cyclic photophosphorylation (using only PS1) and non-cyclic photophosphorylation (using PS1 and PS2) to produce ATP and reduced NADP.

The Calvin Cycle: Light-Independent Stage00:19:37

Explanation of the Calvin cycle, involving carbon fixation by rubisco, the conversion of GP to GALP using ATP and reduced NADP, and the regeneration of RuBP.

Factors Limiting Photosynthesis00:21:07

Analysis of how temperature, CO2 concentration, and light intensity act as limiting factors in the rate of photosynthesis, illustrated through experimental data graphs.