EDEXCEL IAL BIOLOGY 1: - PAST PAPER QUESTIONS AND VERIFIED ANSWERS

Bonding in unsaturated lipids - Anshave double bonds between C atoms and between C and O atoms. method of amniocentesis and how it's used to detect CF. - Ans1) amniotic fluid removed (from the amniotic sac of the mother) / eq. 2) {fetal/embryonic} cells present in amniotic fluid /{fetal / embryonic} cells needed. 3) DNA can be analysed/ eq. 4) to detect {defective/eq} gene(s) (in sample)/ eq. method of chorionic villus sampling and how it's used to detect CF. - Ans1) placental tissue removed (from the womb of the mother) / eq. 2) fetal cells present in {placenta/placental tissue / chorionic tissue} / fetal cells are needed. 3) DNA can be analysed / eq. 4) to detect {defective / eq} gene(s) (in sample) / eq. benefits, to a pregnant woman, of prenatal testing. - Ans1) it gives information about abnormalities in the fetus/eq. 2) {opportunity for choice/eq} OR {consider termination/eq} OR time for {preparation/treatment/eq}. risks, to a pregnant woman, of prenatal testing. - Ans1) possibility of miscarriage due to procedure/eq. 2) potentially a healthy baby would be lost/eq} / {risk to mother / eq}. OR 3) idea of a false positive/negative result. 4) a wrong decision made. OR 3) damage/harm to the fetus. 4) subsequent health issues/miscarriages/eq. Ethical and social issues relating to the use of prenatal testing. - Ans1) idea that fetus is living 2) abortion is wrong/murder/eq. 1) who has the right to decide id tests should be performed/eq. 2) implications of medical costs/disagreements over the next step. 1) who has the right to make the decision for the fetus/ fetus has rights. 2) the fetus is being denied the opportunity to live/ fetus has a right to live. Describe the roles of the atrioventricular valves during the cardiac cycle. - Ans1) valves separate atria from ventricles. 2) opens during atrial systole/contraction / eq. 3) so that blood can pass through to the ventricles / eq. 4) closed during ventricular systole/contraction / eq. 5) to prevent back flow into atria + to maintain pressure in ventricles. 6) open during diastole. 7) so that ventricles can start to fill up as atria are filling. Suggest reasons for the difference in the maximum pressures of the left and right ventricles. - Ans1) pressure in left is higher than right. 2) left ventricles pumps blood all around body / eq. 3) right ventricles pumps blood to lungs / eq. 4) if blood from right ventricle at high pressure there would be damage to lungs/capillaries / eq. 5) lots of muscle/thick wall of left ventricle. Define causation - Answhen a change in one variable is responsible for a change in another variable. define correlation - Ansrelationship between 2 variables such that a change in one of the variables is reflected by a change in the other variable / eq. define gene - Ansa section of DNA/ sequence of bases that codes for a polypeptide / eq. and occupies a particular locus on a chromosome.