As Level Edexcel Biology Study Guide Graded A+

Prophase {Ans: The chromosomes condense Effectively two chromosomes joined at one region called the centromere Microtubules form spindle and the centrioles move around the nuclear envelope at the opposite side of the cell The nuclear envelope breaks down}Hydrolysis {Ans: Water added to split molecule in two}Cardiac cycle {Ans: 1) Atrial systole- The atria contract and blood flows from the left and right atria into the ventricles through the atrioventricular valves 2) Ventricular systole- The ventricles contract to push blood into the pulmonary arteries and aorta through the semilunar valves. Atrioventricular valves close 3) Cardiac diastole- The atria and ventricles relax drawing blood into the heart. Blood under high pressure in the pulmonary arteries and aorta is drawn towards the ventricles, closing the semilunar valves. Coronary arteries fill during diastole.}CF Thalassaemia Albinism Phenylketonuria {Ans: Caused by recessive alleles}Chorionic villus sampling {Ans: Placental tissue is removed so need to wait for amniotic fluid to develop}Translation {Ans: mRNA attaches to a ribosome and amino acids are linked together in the correct order according to the sequence of codons on the mRNA The mRNA attaches to the smaller subunit of the ribosome so the two codons face the