BIOLOGY: EDEXCEL IAL UNIT 1 - PAST
PAPER QUESTIONS
Advantages of CVS and amniocentesis. - ANS CVS:
1) cvs can be performed earlier in pregnancy. (10 and 13 weeks)
2)cvs allows earlier decision to abort / termination less physically traumatic.
3) cvs results available sooner.
AMNIO-:
4) amniocentesis there is a lower risk / 1% risk of miscarriage.
5) can detect gene problems on X chromosomes.
\advantages of the human circulatory system - ANS 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.
\amylose is an example of a: - ANS polysaccharide
\Assess 2 graphs... - ANS 1) general correlation.
2) the individual pieces of data.
3) pieces of data in each graph that stands out.
4) application of your own knowledge to explain data.
\benefits, to a pregnant woman, of prenatal testing. - ANS 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}.
\blood clots form only when requires because the clotting factors used are... - ANS
present in an inactive form in the blood.
\Bonding in unsaturated lipids - ANS have double bonds between C atoms and between
C and O atoms.
\Compare and contrast exocytosis and endocytosis. - ANS SIMILARITIES:
º both used to transport large particles / large
quantities of material (1)
º both involve (phospholipid) membrane vesicles (1)
DIFFERENCE:
º exocytosis is export and endocytosis is import of
material (1)
\Compare and contrast the procedures used in amniocentesis and chorionic villus
sampling to obtain fatal cells in prenatal tests. - ANS DIFFERENCES:
1) fetal cells obtained from amniotic fluid in amniocentesis, fetal cells obtained from
placental cells in CVS.
2) amniocentesis via abdomen and cvs either via abdomen or vagina.
,SIMILARITES:
1) use of needle in both amniocentesis and CVS.
\Compare and contrast the structures of globular and fibrous proteins. - ANS 1) both are
chains of amino acids joined by peptide bonds.
2) both contain named bonds (holding molecule in its three dimensional shape).
3) globular proteins have hydrophilic groups on the outside whereas fibrous proteins
have hydrophobic groups on the outside.
4) globular have tertiary or quaternary structures whereas fibrous have little or no tertiary
structure.
5) globular are folded into compact shapes whereas fibrous have long chains.
\Compare and contrast the structures of glycogen and starch. - ANS SIMILARITIES:
º both polysaccharides / formed from many (alpha) glucose monomers (1)
º joined by glycosidic bonds (1)
DIFFERENCES:
º starch is composed of two polysaccharides, glycogen only one (1)
º amylose is a {straight / helical} chain, amylopectin and glycogen are both branched
molecules (1)
\Define activation energy - ANS 1) energy needed for a reaction to occur.
2) by causing bonds to break/weaken/form.
2) by increasing the number of collisions / eq.
\define allele - ANS different/variant form of a gene.
\Define causation - ANS when a change in one variable is responsible for a change in
another variable.
\define correlation - ANS 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 - ANS a section of DNA/ sequence of bases that codes for a polypeptide / eq.
and occupies a particular locus on a chromosome.
\define homozygous - ANS alleles of a particular gene are the same / eq.
\define recessive allele - ANS allele that is only expressed in the phenotype of an
organism if the dominant allele is not present / eq.
\Describe how a blood clot forms in large veins. - ANS 1) Idea of slow blood flow in
(large) veins.
2) initiates clotting cascade.
3) prothrombin converted to thrombin.
4) leading to conversion of fibrinogen to fibrin.
5) fibrin is insoluble.
6) trapping red blood cells / platelets to form a clot.
\Describe how a triglyceride is synthesised. - ANS 1) one glycerol molecule and three
fatty acid molecules (1)
, 2) which react via a condensation reaction (1)
3) and are joined by ester bonds (1)
\Describe how sucrose is formed from monosaccharides. - ANS 1) glucose and fructose.
2) joined by condensation reaction / water produced.
3) forming a glycosidic bond/link.
\Describe how the primary structure of a protein results in a protein with a 3D structure. -
ANS 1) primary structure is the sequence of amino acids.
2) idea that amino acids each have different R groups.
3) idea that bonds form between R groups.
4) bonding determines the folding of the polypeptide.
\Describe how the structure of glycogen is related to its function as a storage molecule. -
ANS 1) branched molecule for more rapid hydrolysis.
2) compact so more can be stored.
\Describe how the two strands of DNA forming the double helix in a gene are held
together. - ANS 1) complementary bases / named pair of complementary bases (1)
2) it enables the formation of two hydrogen bonds between adenine and thymine / three
hydrogen bonds between cytosine and guanine (1)
\Describe the blood clotting process. - ANS 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) ;
\Describe the correct location for the CFTR protein. - ANS 1) in the cell surface
membrane.
2) of mucus producing cells.
\describe the location of the elastic fibres and explain its function. - ANS 1) middle layer
of wall of vessel/eq/tunica media / in the muscle layer.
2) ref. to allows stretching/recoil/ description.
3) to prevent damage of the aorta/eq. /to maintain the pressure of the blood / eq.
\Describe the process of protein synthesis that occurs in the cytoplasm. - ANS 1)
reference to ribosome (attaches to mRNA).
2) idea that tRNA carries an amino acid.
3) idea of{ anti codon codon interaction/complementary base pairing } between tRNA and
mRNA.
4) formation of hydrogen bonds (between the tRNA and mRNA).
PAPER QUESTIONS
Advantages of CVS and amniocentesis. - ANS CVS:
1) cvs can be performed earlier in pregnancy. (10 and 13 weeks)
2)cvs allows earlier decision to abort / termination less physically traumatic.
3) cvs results available sooner.
AMNIO-:
4) amniocentesis there is a lower risk / 1% risk of miscarriage.
5) can detect gene problems on X chromosomes.
\advantages of the human circulatory system - ANS 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.
\amylose is an example of a: - ANS polysaccharide
\Assess 2 graphs... - ANS 1) general correlation.
2) the individual pieces of data.
3) pieces of data in each graph that stands out.
4) application of your own knowledge to explain data.
\benefits, to a pregnant woman, of prenatal testing. - ANS 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}.
\blood clots form only when requires because the clotting factors used are... - ANS
present in an inactive form in the blood.
\Bonding in unsaturated lipids - ANS have double bonds between C atoms and between
C and O atoms.
\Compare and contrast exocytosis and endocytosis. - ANS SIMILARITIES:
º both used to transport large particles / large
quantities of material (1)
º both involve (phospholipid) membrane vesicles (1)
DIFFERENCE:
º exocytosis is export and endocytosis is import of
material (1)
\Compare and contrast the procedures used in amniocentesis and chorionic villus
sampling to obtain fatal cells in prenatal tests. - ANS DIFFERENCES:
1) fetal cells obtained from amniotic fluid in amniocentesis, fetal cells obtained from
placental cells in CVS.
2) amniocentesis via abdomen and cvs either via abdomen or vagina.
,SIMILARITES:
1) use of needle in both amniocentesis and CVS.
\Compare and contrast the structures of globular and fibrous proteins. - ANS 1) both are
chains of amino acids joined by peptide bonds.
2) both contain named bonds (holding molecule in its three dimensional shape).
3) globular proteins have hydrophilic groups on the outside whereas fibrous proteins
have hydrophobic groups on the outside.
4) globular have tertiary or quaternary structures whereas fibrous have little or no tertiary
structure.
5) globular are folded into compact shapes whereas fibrous have long chains.
\Compare and contrast the structures of glycogen and starch. - ANS SIMILARITIES:
º both polysaccharides / formed from many (alpha) glucose monomers (1)
º joined by glycosidic bonds (1)
DIFFERENCES:
º starch is composed of two polysaccharides, glycogen only one (1)
º amylose is a {straight / helical} chain, amylopectin and glycogen are both branched
molecules (1)
\Define activation energy - ANS 1) energy needed for a reaction to occur.
2) by causing bonds to break/weaken/form.
2) by increasing the number of collisions / eq.
\define allele - ANS different/variant form of a gene.
\Define causation - ANS when a change in one variable is responsible for a change in
another variable.
\define correlation - ANS 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 - ANS a section of DNA/ sequence of bases that codes for a polypeptide / eq.
and occupies a particular locus on a chromosome.
\define homozygous - ANS alleles of a particular gene are the same / eq.
\define recessive allele - ANS allele that is only expressed in the phenotype of an
organism if the dominant allele is not present / eq.
\Describe how a blood clot forms in large veins. - ANS 1) Idea of slow blood flow in
(large) veins.
2) initiates clotting cascade.
3) prothrombin converted to thrombin.
4) leading to conversion of fibrinogen to fibrin.
5) fibrin is insoluble.
6) trapping red blood cells / platelets to form a clot.
\Describe how a triglyceride is synthesised. - ANS 1) one glycerol molecule and three
fatty acid molecules (1)
, 2) which react via a condensation reaction (1)
3) and are joined by ester bonds (1)
\Describe how sucrose is formed from monosaccharides. - ANS 1) glucose and fructose.
2) joined by condensation reaction / water produced.
3) forming a glycosidic bond/link.
\Describe how the primary structure of a protein results in a protein with a 3D structure. -
ANS 1) primary structure is the sequence of amino acids.
2) idea that amino acids each have different R groups.
3) idea that bonds form between R groups.
4) bonding determines the folding of the polypeptide.
\Describe how the structure of glycogen is related to its function as a storage molecule. -
ANS 1) branched molecule for more rapid hydrolysis.
2) compact so more can be stored.
\Describe how the two strands of DNA forming the double helix in a gene are held
together. - ANS 1) complementary bases / named pair of complementary bases (1)
2) it enables the formation of two hydrogen bonds between adenine and thymine / three
hydrogen bonds between cytosine and guanine (1)
\Describe the blood clotting process. - ANS 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) ;
\Describe the correct location for the CFTR protein. - ANS 1) in the cell surface
membrane.
2) of mucus producing cells.
\describe the location of the elastic fibres and explain its function. - ANS 1) middle layer
of wall of vessel/eq/tunica media / in the muscle layer.
2) ref. to allows stretching/recoil/ description.
3) to prevent damage of the aorta/eq. /to maintain the pressure of the blood / eq.
\Describe the process of protein synthesis that occurs in the cytoplasm. - ANS 1)
reference to ribosome (attaches to mRNA).
2) idea that tRNA carries an amino acid.
3) idea of{ anti codon codon interaction/complementary base pairing } between tRNA and
mRNA.
4) formation of hydrogen bonds (between the tRNA and mRNA).
