biology

1. the photomicrograph shows the ultrastructure of part of a cell.
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which statement about the type of cell shown in the photomicrograph is correct?
a_ltis a plant cell because it has both chloroplasts and a nucleus.
b_itis a plant cell because it has chloroplasts.
c_itis an animal cell because it has a cell membrane.
d_itis an animal cell because it has mitochondria.

2 which structures are found in typical eukaryotic cells?

1 70s ribosomes
2 80s ribosomes
3 linear dna (chromosomes)
4 circular dna

a 1,2,3and4

b 1,2 and 3 only

c 1and4only

d 2and3 only

3 a student examined a slide of human blood with a light microscope and made a careful drawing
of the different cell types. the student used an eyepiece graticule so that the relative sizes of the
different cell types were drawn accurately.

in the drawing:
e red blood cells were 7mm in diameter
e lymphocytes were 6mm in diameter
e neutrophils were 14mm in diameter.
what is the linear magnification of the drawing?
a x10 b x40 cc ~x100 d  ~x1000

4 the diagram shows a graduated slide, with divisions of 0.1mm viewed using an eyepiece
graticule.
il adalat onlaedintut
pollen grains were grown in a sugar solution and viewed using the eyepiece graticule.
diagram 1 shows the pollen grains at the start. diagram 2 shows the pollen grains after four
hours.
diagram 1 diagram 2
q pollen o
o tube \ >
o ° s o= ~
finn [fa i
0 10 20 30 40 50 60 70 80 90 100} 0 10 20 30 40 50 60 70 80 90 100)
at start after 4 hours
what is the growth rate of the pollen tubes?
a 5umh"* b  10umh"* c 5mmh* d 10mmh*

5 the table shows a comparison between two features of a typical eukaryotic cell and a typical
prokaryotic cell.
which row shows the correct comparison between these cells?
roatan
cell cell cell cell

a jv v x x key

b v x v x jv = present

cc x v x v x = not present

d x x v v

6 the flow diagram shows the results of a number of tests on a solution of biochemicals.
solution of biochemicals
benedict's test non-reducing iodine test biuret test
blue sugar test blue-black purple
yellow
which substances are present in the solution?
a amylose, amylopectin and lipid
b_ glucose, starch and catalase
c sucrose, amylase and triglyceride
d_ sucrose, starch and catalase

7  maltose and sucrose are disaccharides. maltose is formed from two molecules of glucose, whilst
sucrose is formed from fructose and glucose.
which row shows the molecular formulae of the two disaccharides?
[| matose | sucrose
a cy2h22014 cy2h 22014
b cy2h 22014 ci2h24012
cc cy2h24012 cy2h22014
d cy2h24012 cy2h24012

8 the diagrams show short sections of some common polysaccharides and modified
polysaccharides.
ch,oh h nhcoch, ch,oh h oh
[e) 0
oo noh h_/| as jd on oh h_/| a= va

9 which molecules contain at least two double bonds?
1 unsaturated fatty acid
2 collagen
3 haemoglobin
a 1,2and3 b 1tand2only c iand3only d = 2and3only

10 the diagram shows a protein molecule.
a mi globular
ve | head
ni ad
key
y oy
ase — long polypeptide
ma ls. ---- short polypeptide
two long polypeptides each form a-helices for much of their length and these twist together into a
fibre.
at one end, each of these polypeptides coils into a globular head.
two short polypeptides bind to each globular head.
what describes the protein structure of this molecule?
a quaternary structure because each molecule consists of six polypeptides
b_ secondary structure because the long polypeptides form a-helices
c tertiary structure because the a-helices form a fibre
d tertiary structure because the heads form globular proteins

11 which types of bond will keep a folded protein in its precise shape for the longest time as the
temperature rises?
a disulfide
b_ hydrogen
c hydrophobic interactions
d ionic

12 protease enzymes are found in many locations inside and outside the cells. four of these
locations are listed.
1 lysosomes
2 lumen of the stomach
3 ata telophase spindle
4 mucus in the trachea
which of these locations are sites of intracellular hydrolysis?
a 1,2,3and4
b 1,2 and 4 only
c 1and3 only
d 2and4only

13 an enzyme is modified for industrial use. it has a lower michaelis-menten constant (km) than the
unmodified enzyme.
what is true of the modified enzyme?
a itis more specific.
blt has a higher affinity for its substrate.
c_ it has a lower maximum rate of reaction (vmax).
d_ itneeds more substrate to become saturated.

14 adecrease in some factors will increase the fluidity of the cell surface membrane.
which pair of factors, when decreased, will increase the fluidity of the cell surface membrane?
[aes ss~*d

a |e distance between phospholipid molecules
e proportion of short fatty acid chains
b |e distance between phospholipid molecules
e temperature
c |e proportion of phospholipids with saturated fatty acid chains
e proportion of long fatty acid chains
d |e proportion of phospholipids with unsaturated fatty acid chains
e temperature

15 the diagram shows a cell surface membrane.
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ry id qs y a * ¢ boo ( “ap
hat \/ betittete «— atorihintain «ah
| : nts fanning
oe 0a
al vas wu ou ve
4
which statements about the labelled molecules in the membrane are correct?
e 1 is involved in the diffusion of ions.
e 2is involved in facilitated diffusion.
e 3s involved in the recognition of antigens.
e 4is involved in membrane fluidity.
a 1,2and3 b 1and3only c 1and4 d 2and 4 only

16 equal sized potato pieces were placed into test-tubes containing equal volumes of different
concentrations of sucrose solution and left for 30 minutes. all other variables were controlled.
after 30 minutes, the potato piece in one of the concentrations of sucrose solution had not
changed in size.

what can be concluded from this result?
1 there is no net movement of water into or out of the potato.
2 the water potential of the potato is the same as the water potential of the sucrose
solution.
3. the concentration of sucrose in the potato is the same as the concentration of the
sucrose solution.
a 1,2and3 b 1and2only c 1and3only d 2only

17 which feature of stem cells enables them to replace cells in tissues such as the skin?
a_ they are undifferentiated cells that are present at birth.
b_ they differentiate to form skin cells.
c_ they divide by mitosis to supply some cells that can differentiate.
d_ they have the full number of chromosomes.

18 during prophase, a scientist stains the chromosomes of a diploid animal cell with a fluorescent
dye to stain telomeres. this cell has 32 chromosomes.
how many telomeres will the scientist observe?
a 32 b 64 c 96 d 128

19 the diagram shows the cell cycle.
during which phase do chromosomes condense and become visible?
cytokinesis

20 what is correct for thymine?
has a single rin joins its
chee 9 is a pyrimidine complementary base
with 3 hydrogen bonds
a sf v v key
8 “ v x ¥ = correct
@ od x x x = incorrect
d x x v

21 a short piece of dna 15 base pairs long was analysed to find the number of nucleotide bases in
each of the polynucleotide strands. some of the results are shown below.
|| number of nucleotide bases
a cc g t
strand 1 6 3
strand 2 4
how many nucleotides containing guanine were present in strand 1?
a 2 b 3 cc 4 d 6
ss ee ee ee eee ee

22 scientists grew bacteria in a medium containing heavy nitrogen, °n, as the only source of
nitrogen.
after many generations, all of the bacterial dna contained heavy nitrogen.
these bacteria were then moved from the heavy nitrogen medium into a medium with only light
nitrogen, “4n.
some bacteria were collected from each of the next three generations and their dna was
analysed.
hybrid dna contains both heavy and light nitrogen.
which row shows the correct dna of the first and third generations?
| | dna of first generation dna of third generation
a all hybrid half hybrid, half light
b all hybrid one quarter hybrid,
three quarters light
cc half hybrid, half heavy half hybrid, one quarter
heavy, one quarter light
d half hybrid, half light one quarter hybrid,
three quarters light

23 a population of bacteria is exposed to the antibiotic penicillin. most of the bacteria die.
however, some bacteria in the population have an allele coding for an enzyme that breaks down
penicillin. these bacteria are able to survive.
which could explain how these bacterial cells acquired this allele?
1 anerror during dna replication.
2 anerror during transcription.
3. anerror during translation.
a 1,2and3 b 1and3only c= 1only d 2and 3 only

24 a dicotyledonous leaf has a palisade mesophyll layer that is approximately twice as thick as the
spongy mesophyll layer.
which plan diagram is correct?
a b
upper surface upper surface
of leaf of leaf
-_— xylem -__— phloem
—~—~ phloem ~~ xylem
cc d
upper surface upper surface
of leaf of leaf
-_— xylem -__— phloem
~~~ phloem ~~ xylem

25 a number of processes contribute to maintaining a water potential gradient in plants allowing
water to reach the highest parts of a plant.
which processes are responsible for maintaining this water potential gradient?
1 capillarity
2 osmosis
3. transpiration
a 1,2and3 b 1tand2only c t1and3only d = 2and3only

26 what is a correct statement about the movement of substances absorbed by roots?
a ions have to pass through cell walls to cross the endodermis.
b_lons move through the symplastic pathway only until they reach the casparian strip.
c_ soil water has a more negative water potential than the xylem sap.
d_ water passes through the symplastic pathway along a water potential gradient.

27 which arrangement of four molecules of water shows how water may cohere when moving up a
xylem vessel?
a b
z xn > _ key
1e) » o> ~ se; = @) oxygen atom
— be)
od © hydrogen atom
—-—-— hydrogen bond
cc d
-$--< d2
: 2

28 which statement about sucrose loading into companion cells and then into the phloem sieve tube

element is not correct?

a_ hydrogen ions and sucrose molecules move into the companion cells using a carrier protein.

b_ hydrogen ions are pumped out of the companion cells by active transport.

c sucrose molecules are carried into the companion cells down the concentration gradient for
sucrose.

d sucrose molecules move from a companion cell into the sieve tubes of the phloem through
plasmodesmata.

29 what explains why the left and right sides of the heart contract simultaneously?
a_ both atria have a sinoatrial node.
b_ both sides of the heart are supplied by the same coronary artery.
c_ purkyne tissue links the two sides of the heart.
d_ there is no barrier to electrical excitation between two sides of the heart.

30 the statements list some of the events in the cardiac cycle. they are not in the correct order.

1 the impulse travels through purkyne tissue.
2  awave of excitation sweeps across the atria.
3. the atrioventricular node delays the impulse for a fraction of a second.
4 the sinoatrial node contracts.
5 the wave of excitation sweeps upwards from the base of the ventricles.
6 the ventricles contract.
7 the atria contract.

which statement describes the third of these events to occur in the cardiac cycle?

a 1 b 3 cc 4 d7

31 the diagram shows pressure changes in different parts of the heart during one cardiac cycle.
during which period are the semilunar valves open and the atrioventricular valves closed?
a b cc d
pressure key

+++ aortic pressure
— ventricle pressure
—-—-— atrial pressure

ao

see
time

32 which diagram shows the events that occur during transport of carbon dioxide by the blood?
a b
co, co,

33 which structures are found in bronchi?
smooth muscle
cartilage goblet
cells

34 which tissue in the respiratory system is correctly linked to its function?
pf tees
a cartilage stretch and recoil to force air out
b | ciliated epithelium | gives protection from suspended particles in the air
cc elastic fibres contract and relax to adjust diameter of bronchioles
d smooth muscle keeps trachea and bronchi open

35 chronic obstructive pulmonary disease (copd) includes emphysema.
which effects does emphysema have on gaseous exchange?
1 surface area to volume ratio of lungs decreases
2. distance of the diffusion pathway decreases
3. volume of oxygen diffused per unit time decreases
a 1,2and3 b 1tand2only c ‘1and3only d = 2and3 only

36 the diagram shows some of the pathogens that cause disease in humans and some of the ways
they are transmitted.
xx
1 2 contaminated
bacterium protoctist y
pathogen method
of
transmission
3 , we ee ,
vitus using a coughs and
vector sneezes
which row matches the correct number for the pathogen with the correct letter for their mode of
transmission for cholera and measles?
[chats [meas |
a 1 and x 3 and y
b 1andy 3 and y
cc 2 and x 2andz
d 3 andz 1 and x

37 which factors would increase the global distribution of malaria?
1 a fall in annual rainfall
2. anincrease in the use of antibiotics
3 arise in global air temperatures
4 increasing irrigation of land for farming
a 1,2and3 b 1tand2only c 2,3and4 d 3and 4 only

38 the antibiotic teixobactin was discovered in january 2015. teixobactin kills some bacteria such
as staphylococcus and mycobacterium.
most antibiotics work by binding to proteins. teixobactin binds to lipids that are used in the
synthesis of bacterial cell walls. this means that it is unlikely that bacteria will quickly develop
resistance to teixobactin.
which statements explain why bacteria are unlikely to quickly develop resistance to teixobactin?
1a mutation in the gene coding for a protein allows selection for resistance.
2 teixobactin binds to a lipid rather than to a protein.
3. the structure of a lipid is not encoded by dna.
a 1,2and3 b 1tand2only c ‘1and3only d = 2and3only

39 which row correctly describes the type of immunity gained from being injected with an antitoxin?
[| eetne | anitcat [possi [naturel |
a v v x x key
b v x x v v =correct
cc x v v x x =not correct
d x x v v

40 where are antibodies found during an immune response?
seen sn
pathogen plasma
a v v key
b v x v¥ = antibodies found
cc x v x = antibodies not found
d x x

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