biology

1. which row describes the membranes surrounding each cell structure?
[| eroroniast [mitochondrion [nucleus |
a single single double
b double single single
cc single double single
d double double double

2 the mean width of mitochondria in an electron micrograph is 6 mm.
the magnification of the electron micrograph is x9600.
what is the actual mean width of the mitochondria?
a 6x10°mm b 6x10%mm c 6x107nm d 6x 10°um

3 which sequence shows the correct order of some of the stages in the production and secretion of
an enzyme?
a golgi body — ribosome — rough endoplasmic reticulum — mrna
b mrna — smooth endoplasmic reticulum — golgi body — vesicle
c ribosome -— rough endoplasmic reticulum — vesicle — golgi body
d_ smooth endoplasmic reticulum + mrna —> vesicle > ribosome

4 different antibiotics function in different ways. ideally, the antibiotic kills the bacteria, but does not
harm the infected human.
one type of antibiotic, tetracycline, can affect the way in which human mitochondria function.
what explains the effect of tetracycline on human mitochondria?
1 the antibiotic prevents the synthesis of peptidoglycan cell walls.
2 the antibiotic prevents synthesis of linear dna.
3. the antibiotic prevents translation by binding to 70s ribosomes.
a 1and2 b 2and3 c 2only d= 3only

5  aprokaryotic cell is 5.0 um in length.
a virus particle is 300 nm in length.
how many times larger is the prokaryotic cell compared to the virus particle?
a 2 b 17 cc 60 d 167

6 a student carries out a semi-quantitative test with benedict’s solution.
which statement about this procedure is correct?
a_ it detects only the presence or absence of glucose.
b it provides an indication of relative reducing sugar concentrations.
c_ the precipitate needs to be filtered, dried and weighed to give the reducing sugar
concentration.
d_ a colorimeter needs to be used to determine the glucose concentration.

8 which shows the correct general formula for glycogen?
a (csh1005)n b  (csh1006)n c  (ceh1005)n d  (c6h1206)n

9 chitin is a structural polysaccharide found in the hard, outer shells of animals such as crabs.
chitin is made of chains of amino sugars that contain nh groups.
the diagram shows two sugars in the chain of a chitin molecule.
ch,oh h nhcoch,
h oh h
oh h h
6 74 a , o—
h nhcoch, ch,oh
which polysaccharide is most like chitin?
a amylopectin
b- amylose
c_ cellulose
d_ glycogen

10 four fatty acids and their formulae are listed.
caprylic acid ch3(ch2)scooh
lauric acid ch3(ch2)10 cooh
oleic acid ch3(ch2)7 ch=ch(ch2)7 cooh
palmitoleic acid ch3(ch2)sch=ch(ch2)7cooh
which fatty acids are saturated?
a caprylic acid and lauric acid
b_caprylic acid and oleic acid
c _lauric acid and palmitoleic acid
d oleic acid and palmitoleic acid

11. which molecule contains the smallest number of hydrogen atoms?
a a-glucose
b glycine, an amino acid in which the r group is h
c glycerol
d_ asaturated fatty acid containing eight carbon atoms

12 the diagram shows sucrose and sucralose.
ch,oh ch,oh ch,oh ch,cl
(0) oo cl (e) o
oh ho oh ho
oh ie) ch,oh o ch,cl
oh oh oh oh
sucrose sucralose
the enzyme sucrase breaks down sucrose but cannot break down sucralose. four students were
asked to suggest why sucrase can break down sucrose but not sucralose.
three of the students gave correct suggestions.
which suggestion cannot be correct?
a the clatoms change the shape of the sucralose molecule so it is not the same shape as the
active site of sucrase.
b_ the clatoms of the modified fructose cannot bind to the active site of sucrase.
c the cl atoms cannot cause an induced fit, so sucralose does not enter the active site of
sucrase.
d the clatoms cause fewer temporary hydrogen bonds between sucralose and the active site
of sucrase.

13 the graph shows the energy levels involved in an enzyme-catalysed reaction. substrate
molecules x and y combine to give product z.
which arrow shows the reduction in activation energy due to the enzyme?
f* ,
energy ky a
lo seeming icin nis
d
zz
0
0 time/s

14 which roles of the cell surface membrane result from the properties of the phospholipids?
1 to allow cytokinesis to occur in mitotic cell division
2 to allow entry and exit of oxygen and carbon dioxide
3. to allow the phagocytosis of a bacterium into a cell
a 1,2and3 b 1tand2only c 1and3only d = 2and3only

15 which factors can be changed to affect the rate of facilitated diffusion across a cell surface
membrane?
1 the surface area of the membrane
2 the concentration gradient
3. the number of specific protein channels
a 1,2and3 b 1tand2only c 1and3only d_= 3only

16 the diagram shows an experiment using a model cell to investigate the movement of substances.
(f
ie e6il j } membrane permeable
modened | to monosaccharides
| and water
solution containing fr
0.03 mol dm sucrose
0.02 moldm~ glucose ; acts
solution containing
¥ 0.01 moldm- sucrose
0.01 mol dm glucose
which statements are correct?
1 there is net movement of sucrose out of the model cell.
2 there is net movement of glucose out of the model cell.
3 there is net movement of water into the model cell.
a 1,2and3 b 1tand2only c 1and3only d 2and3only

17 human chromosomes have different parts. some parts are more numerous than others.
which parts are listed in order from most numerous to least numerous in a human white blood
cell?
a centromere — nucleotide — histone protein
b dna molecule > telomere > centromere
c histone protein + telomere + dna molecule
d_ telomere > centromere — nucleotide
a

18 the diagram represents the cell cycle of a human cell. during the cell cycle the number of
chromatids changes.
mitosis
which row is correct for the number of chromatids in m, g;, and g2?
pf fw | ew | & |
a 46 46 92
b 46 92 92
cc 92 46 92
d 92 92 92

19 asingle skin cell was isolated and transferred to growth medium in a sterile petri dish. the petri
dish was incubated for 16 days. during this time, the number of skin cells multiplied as a result of
repeated mitotic divisions.

one of the chromosomes in the nucleus of each skin cell has a telomere that contains many
repeats of the base sequence ttaggg. on each of days 4, 8, 12 and 16 of the incubation
period, a single cell was removed from the petri dish. the total number of bases in the telomere
of this chromosome was determined for each cell. each of the four cells had a different total
number of telomere bases for this chromosome: 5548, 5580, 5645 and 5700.

what was the total number of telomere bases in the chromosome from the cell that had
undergone the most mitotic divisions?

a 5548 b 5580 c 5645 d 5700

20 ashort piece of dna, 18 base pairs long, was analysed to find the number of nucleotide bases in
each of the polynucleotide strands.
some of the results are shown in the table.
|| number of nucleotide bases
adenine | cytosine thymine

strand 1 4 7

strand 2 5
how many nucleotides containing thymine were present in strand 2?
a 2 b 4 cc 5 d7

21 the diagram shows a strand of dna and mrna during transcription.
1 (>) 2
©) ©)
©) ®)
om
which row correctly identifies 1, 2 and 3?
ee ee
a purine deoxyribose two hydrogen bonds
b purine ribose three hydrogen bonds
cc pyrimidine deoxyribose two hydrogen bonds
d pyrimidine ribose three hydrogen bonds

22 two students were discussing the involvement of dna and rna in transcription and translation.
e student 1 always stated correct facts.
e student 2 gave further information, which was sometimes correct.
| | correct facts given by student 1 further information given by student 2
1 a length of mrna is 747 nucleotides this mrna can produce a polypeptide
long, including stop and start codons. that is 249 amino acids long.
2 adjacent mrna codons of aau there is a total of 14 hydrogen bonds
and cug bind to complementary formed between these two codons and
trna anticodons. their anticodons.
3 | rna polymerase catalyses the formation during translation, an rna adenine
of the mrna from the template strand nucleotide will pair with a dna thymine
of dna. nucleotide.
4 | adna adenine nucleotide is structurally the difference is in the hexose sugars;
different to an rna adenine nucleotide. dna is deoxyribose and rna is ribose.
which further information, given by student 2, is correct?
a iand4 b 2and3 c 2only d 4only

23 which descriptions of the adaptations of xylem vessel elements to their function are correct?
1 they have pits between vessels allowing water to pass from one vessel to another.
2 they are thickened with lignin to stop them collapsing when the column of water is
under tension.
3 they form a continuous hollow tube through the plant providing little resistance to
water movement.
a 1,2and3 b 1tand3only c= 2only d = 2and 3 only

24 the diameter of a tree trunk usually decreases slightly during the day.
which changes in environmental factors during the day could cause the diameter to decrease
even more?
increased
humidity
increased increased
wind speed light intensity

25 a student wanted to find out the rate of transpiration using a potometer as shown.
cut shoot
reservoir
air bubble capillary tube
volume beaker
scale of water

the student was told to work out a value for transpiration using the units mm?, m~ and hour”.
which measurements would the student need to take?
a_ volume of water in the reservoir, length of the capillary tubing, temperature and how many

leaves are on the shoot
b_ volume of water in the reservoir, radius of the capillary tubing, time and surface area of the

leaves
c_ distance air bubble moves, radius of the capillary tubing, time and surface area of the leaves
d_ distance air bubble moves, length of the capillary tubing, temperature and how many leaves

are on the shoot

26 in plants, assimilates such as sucrose are loaded from source cells into sieve tube elements. the

assimilates are then transported from source to sink.
what is needed to transport sucrose from source cells through phloem tissue to sink cells?

water potential

gradient between atp
the source and
the sink vj
hydrostatic pressure gradient
between the source and the sink

27 the sinoatrial node initiates the cardiac cycle.
what is the correct order in which the chambers of the heart contract?
a atria and ventricles at the same time
b both atria then both ventricles
c left atrium, then left ventricle, then right atrium, then right ventricle
d right atrium, then right ventricle, then left atrium, then left ventricle

28 the graph shows pressure changes in different parts of the heart during a mammalian cardiac
cycle. w, x, y and z indicate when a valve opens or closes.
a> y
i \ /
/ os
x |] a
pressure key
/kpa ——-— aorta
— ventricle
ww j atrium
0 0.2 0.4 0.6 0.8
time/s
which row is correct?
ee
a opens closes closes opens
b opens opens closes opens
cc closes opens closes opens
d closes closes opens opens

29 what can combine with the haem group of a haemoglobin molecule?
1 oxygen
2 carbon dioxide
3. carbon monoxide
a 1,2and3 b 1tand3only c 1 only d 2 and 3 only

30 what is the main reaction occurring in blood capillaries at the gas exchange surface in a human
lung?
a_ carbonic acid dissociates into carbon dioxide and hydrogen ions.
b carbonic anhydrase converts carbon dioxide into hydrogencarbonate ions.
c carbon dioxide combines with haemoglobin to form carbaminohaemoglobin.
d_ carbon dioxide is produced from hydrogencarbonate ions by carbonic anhydrase.

31 which reactions take place in blood that is passing through active tissues?

1 hbos > hb + 40,
2 hbo, + h* — hhb + 40,
3 hco; + h* + h,co3
4 ho + cos > hco;

a 1,2,3and4

b 1,2 and 4 only

c 1,3 and 4 only

d 2and 3 only

32 which row shows the tissues that are present in the wall of the trachea and in the wall of the
bronchus?
[oe [ai [ona
a v jv jv key
b v v x jv = present
cc v x v x = not present
d x v x

33 in some cases where a person has lung disease, the partial pressure of oxygen in the pulmonary
veins is less than the partial pressure of oxygen in the alveoli.
what could explain the difference in partial pressure of oxygen?
1 a high proportion of alveoli are collapsed and do not have enough alveolar
capillaries.
2 the partial pressure of oxygen in the pulmonary arteries is lower than in the alveolar
air.
3 the rate of diffusion of oxygen from the alveolar air to the surrounding alveolar
capillaries is too slow.
a 1,2and3 b 1tand2only c 1and3only d 2and3 only

34 how many times must a molecule of carbon dioxide pass through a cell surface membrane as it
diffuses from the plasma, through a cell in the capillary wall, into an alveolus?
a 1 b 2 cc 3 d 4

35 which disease is spread by a vector?
a aids/hiv
b_ cholera
cc malaria
d_ measles

36 which statement explains why a one-dose vaccination programme for measles has not yet
eliminated the disease?
a many infants under the age of eight months have passive immunity.
b some children need several booster doses to develop full immunity.
c_ the one-dose measles vaccine has a success rate of 93%.
d_ the virus does not often change its antibodies.

37 what has contributed to the increase in antibiotic resistance in bacteria?
1 increased use of vaccines for animal diseases
2 mutations in bacterial dna
3. patients not completing their antibiotic treatment
a 1,2and3 b 1tand2only c 1and3only d = 2and3only

38 what explains why monoclonal antibodies can be used to target cancer cells?
a cancer cells have different antigens from normal body cells.
b_ specific cancer drugs can be attached to the monoclonal antibody.
c_ they secrete a type of antigen that binds to a specific antibody.
d_ they are secreted by hybridomas of cancer cells and b-lymphocytes.

39 which statements correctly describe lymphocytes?

1 each b-lymphocyte has the ability to make several types of antibody molecules.
2 some b-lymphocytes and t-lymphocytes become memory cells.
3 plasma cells secrete antibodies into the blood plasma.
4 some t-lymphocytes stimulate macrophages to kill infected cells.

a 1,2,3and4

b 1, 2 and 3 only

c 1and4 only

d 2,3 and 4 only

40 a country introduced a measles vaccination during a measles epidemic.

later, it was realised that vaccinated children were more likely to survive childhood than

unvaccinated children, even when there were no measles epidemics.

the vaccine had given the children some protection against other pathogenic infections.

which statement could account for this extra protection?

a_ b-lymphocytes produced memory cells which gave the children passive immunity to these
infections.

b memory cells produced plasma cells which secreted anti-measles antibodies that bound to
antigens that closely resembled measles antigens.

c memory cells produced plasma cells which secreted anti-measles antibodies that bound to
any antigen.

d_ t-lymphocytes produced memory cells which gave the children natural immunity against
these other infections.

Solve 9700_s21_qp_12