Summary Selected iGCSE Edexcel Biology Paper Two Notes

Notes covering the following specification points: 2.5B explain the importance of cell differentiation in the development of specialised cells 2.6B understand the advantages and disadvantages of using stem cells in medicine 2.72B understand how the kidney carries out its roles of excretion and osmoregulation 2.73B describe the structure of the urinary system, including the kidneys, ureters, bladder and urethra 2.74B describe the structure of a nephron, including the Bowman’s capsule and glomerulus, convoluted tubules, loop of Henle and collecting duct 2.75B describe ultrafiltration in the Bowman’s capsule and the composition of the glomerular filtrate 2.76B understand how water is reabsorbed into the blood from the collecting duct 2.77B understand why selective reabsorption of glucose occurs at the proximal convoluted tubule 2.78B describe the role of ADH in regulating the water content of the blood 2.79B understand that urine contains water, urea and ions 2.95B understand the sources, roles and effects of the following hormones: ADH, FSH and LH 3.10B understand the roles of FSH and LH in the menstrual cycle 3.16B describe a DNA molecule as two strands coiled to form a double helix, the strands being linked by a series of paired bases: adenine (A) with thymine (T), and cytosine (C) with guanine (G) 3.17B understand that an RNA molecule is single stranded and contains uracil (U) instead of thymine (T) 3.18B describe the stages of protein synthesis including transcription and translation, including the role of mRNA, ribosomes, tRNA, codons and anticodons 4.11B describe the stages in the nitrogen cycle, including the roles of nitrogen fixing bacteria, decomposers, nitrifying bacteria and denitrifying bacteria (specific names of bacteria are not required) 4.18B understand the effects of deforestation, including leaching, soil erosion, disturbance of evapotranspiration and the carbon cycle, and the balance of atmospheric gases 5.17B describe the process of micropropagation (tissue culture) in which explants are grown in vitro 5.18B understand how micropropagation can be used to produce commercial quantities of genetically identical plants with desirable characteristics 5.19B describe the stages in the production of cloned mammals involving the introduction of a diploid nucleus from a mature cell into an enucleated egg cell, illustrated by Dolly the sheep 5.20B understand how cloned transgenic animals can be used to produce human proteins