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BIOLOGY EDEXCEL IAL UNIT 1 - PAST PAPER QUESTIONS
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BIOLOGY EDEXCEL IAL UNIT 1 - PAST PAPER QUESTIONS
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BIOLOGY: EDEXCEL IAL UNIT 1 - PAST PAPERQUESTIONS
Bonding in unsaturated lipids - Answers- have double bonds between C atoms and
between C and O atoms.
method of amniocentesis and how its used to detect CF. - Answers- 1) amniotic fluid
removed (from 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 its used to detect CF. - Answers- 1)
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. - Answers- 1) 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. - Answers- 1) 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.
Define causation - Answers- when a change in one variable is responsible for a change
in another variable.
define correlation - Answers- relationship between 2 variables such that a change in
one of the variables is reflected by a change in the other variable / eq.
define gene - Answers- a section of DNA/ sequence of bases that codes for a
polypeptide / eq. and occupies a particular locus on a chromosome.
define allele - Answers- different/variant form of a gene.
,define recessive allele - Answers- allele that is only expressed in the phenotype of an
organism if the dominant allele is not present / eq.
define homozygous - Answers- alleles of a particular gene are the same / eq.
amylose is an example of a: - Answers- polysaccharide
The three dimensional structure of a protein is held together by: - Answers- . disulphide
bridges.
. hydrogen bonds.
. ionic bonds.
What blood vessel carries deoxygenated blood to the lungs? - Answers- pulmonary
artery.
Define activation energy - Answers- 1) energy needed for a reaction to occur.
2) by causing bonds to break/weaken/form.
2) by increasing the number of collisions / eq.
Explain why it is necessary to measure the initial rate of reaction when investigating the
effect of enzyme concentration on the rate of reaction. - Answers- 1) there should be
enough substrate molecules to saturate the enzyme.
2) to endure that the substrate is not a limiting factor / eq.
Factors that increase the risk of CVDs - Answers- 1) genetics.
2) diet.
3) increasing age.
4) male.
5) high BP.
6) smoking.
7) inactivity/lack of exercise.
advantages of the human circulatory system - Answers- 1) blood flows {faster/at higher
pressure/eq} (to the body).
2) blood flows {slower/at lower pressure/eq} to the lung.
3) idea that this reduces risk of damage to lungs.
4) correct ref. to more efficient {exchange/ transport} of gases / eq.
Describe the structure of an enzyme. - Answers- 1) ref to an enzyme as a protein.
2) ref. to {3D/tertiary/globular} structure.
3) ref. to named bonds (holding structure in place).
4) between the R groups.
5) ref. to active site.
6) idea of specificity of active site.
, Describe the blood clotting process. - Answers- 1) idea that there is a cascade of
events (leading to blood clotting).
2) ref. to thromboplastin (starting the cascade).
3) ref. to conversion of prothrombin into thrombin.
4) idea that {thromboplastin/thrombin} is {an
enzyme / a catalyst} ;
5) ref. to conversion of fibrinogen into fibrin.
6) ref. to formation of mesh of {fibres/fibrin}.
7) ref. to requirement of {calcium ions/ Ca2+ / vitamin K} ;
8) ref. to {platelets/blood cells} getting trapped (in the mesh) ;
Ethical and social issues relating to the use of prenatal testing. - Answers- 1) 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. - Answers- 1)
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. - Answers- 1) 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.
Suggest why cells from mouth swabs or blood samples are used rather than gametes -
Answers- 1) idea that these cells are {easy/painless } to collect.
2) idea that a relatively {large amount of DNA / large number of cells} can be collected.
3) they {contain diploid cells/have (23) pairs of chromosomes}.
4) cells {are genetically identical/have same DNA / have same alleles}.
5) any {recessive allele/mutated (CF) gene} will be present in them / eq.
6) idea that if the gametes were tested they may not contain the {recessive
allele/mutated (CF) gene} (as they are haploid).
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