biology

1. which organelles are enclosed in a single phospholipid bilayer and contain hydrolytic enzymes?
a endocytotic vesicles
b~ golgi body
c_ lysosomes
d_ mitochondria

2 ~the dna of prokaryotes is naked and circular.
which statement describes how the dna of eukaryotes differs from that of prokaryotes?
a it has anuclear envelope around it and is a double helix.
b_ it has a nuclear envelope around it and is circular.
c_ithas proteins attached to it and is a double helix.
d_ it has proteins attached to it and is linear.

3 the recently discovered pandoravirus measures 1000 nm in diameter.
the mimivirus has a diameter of 400 nm.
what can be detected using a light microscope with a maximum resolution of 0.25 um?
a both the mimivirus and the pandoravirus
b_ neither the mimivirus nor the pandoravirus
c_ the mimivirus, but not the pandoravirus
d_ the pandoravirus, but not the mimivirus

4 what are found in chloroplasts and mitochondria?
1 dna
2 70s ribosomes
3 mrna
a 1,2and3 b 1tand2only c 1 only d = 2and 3 only

5 boiling the bones and teeth from dead animals can be used to produce a type of glue.
the glue is formed from the collagen fibres present in bones and teeth.
which statement describes the changes to collagen that occur when the glue is produced?
a the fibres of collagen become more coiled.
b_ the fibres of collagen become more flexible.
c_ the helices of collagen molecules unwind.
d_ the molecules of collagen dissolve in water.

6 what describes the primary structure of a protein?
a a-helix
b= adipeptide
c  aglobular structure
d_ the specific order of amino acids

7 the diagrams show four monosaccharides with the formula cgh120¢.
which diagram shows a-glucose?
a b cc d
ch,oh ch,oh ch,oh ch,oh
h ooh h oh h oh h oh

h h h h
oh h oh h h h oh ho

ho h ho oh ho oh ho oh
h oh h oh oh oh h h

8 complete digestion of polysaccharides requires all the glycosidic bonds between the monomers
to be broken.
amylase only breaks a-1,4 glycosidic bonds.
which row shows how completely amylase can digest molecules of cellulose, amylopectin or
amylose?
polysaccharide

a = ++ + key

b _ a ee — no digestion

cc + ++ = + some digestion

d 4 = + ++ most digestion

9 the diagram shows the results of tests on four solutions containing biological molecules.
which shows the solution that contains only starch and protein?
biuret test, iodine test,
purple blue black
benedict's test,
orange

10 the enzyme invertase catalyses the breakdown of sucrose to glucose and fructose.
three different enzyme inhibitors of invertase x, y and z were investigated. the percentage
inhibition of invertase was measured at different concentrations of inhibitor.
the graph shows the result of the investigation.
inhibitor x
inhibitor y
percentage
inhibition
inhibitor z
0 2 4 6 8
inhibitor concentration
/arbitrary units
which are valid conclusions from these results?
1 the higher the concentration of inhibitor x, the less sucrose is broken down.
2 the production of glucose and fructose using inhibitor y is higher than when
inhibitor z is used.
3 the production of glucose and fructose at an inhibitor concentration of 2 arbitrary
units is lower than at an inhibitor concentration of 4 arbitrary units, for all inhibitors.
a iand2 b= 1only c 2and3 d 3only

11 the following statements are about enzymes.
1 folding of an enzyme molecule causes the formation of the active site.
2 the shape of the active site changes to enable the substrate to bind.
3 temporary bonds hold the substrate in the active site.
4 more enzyme-substrate complexes are formed at the optimum temperature.
which statements are correct for the induced fit hypothesis?
a 1and2 b 1and3 c 2,3and4 d 2and 4 only

12 how is the michaelis-menten constant (km) used?
a _toassess the efficiency of an enzyme in catalysing a reaction
b_ to compare the affinity of enzymes for their substrate
c to find the maximum velocity of an enzyme (vmax)
d to find the rate at which substrate is loaded by an enzyme

13 proteins in the cell surface membranes of human cells and mouse cells were labelled with
fluorescent dyes. the human cells were labelled with a red dye and the mouse cells were
labelled with a green dye.

a human cell and a mouse cell were then fused to form a hybrid cell.

at first the different dyes remained separate. after 40 minutes the two dyes were evenly

distributed in the hybrid cell surface membrane.

what explains this observation?

a_ all protein molecules in the cell surface membrane are fixed to structures within the cell, but
phospholipid molecules move freely between them.

b_ groups of protein and phospholipid molecules in the cell surface membrane are attached to
each other and move together.

c only protein molecules in the outer layer of the cell surface membrane can move freely
between phospholipid molecules.

d_ protein molecules in the outer layer of the cell surface membrane and those which span the
bilayer can move freely between phospholipid molecules.

14 the diagram shows a plant cell.
the plant cell is put into a solution with a water potential less negative than the cell contents.
what will happen to the appearance of the cell?
a b cc d
<>

15 the diagram shows the fluid mosaic model of membrane structure.
2 23
i
4
which molecules in the membrane are identical?
a 1,2and3 b 1and4 c 2and3only d 4only

16 the photomicrograph shows a stage of mitosis.
what would be correct for the next stage in mitosis?
paired chromatids nuclear membrane
a absent absent
b absent re-forming
c present absent
d present breaking down

17 the diagram shows part of the organisation of a dna molecule and the associated histones.
&
ie) ge
rny
ow ae nie
orgy —_
dog) ye s —
ge q se, pp
oo |
q
wy
we
g
r
which statement about the features labelled p, q and r during prophase of mitosis is correct?
a_ the coiled dna molecule forms q and wraps around the histones of r to form small clusters
held in place by histone p.
b_ the groups of histones, p, and its associated dna, q, move closer together as the
chromosome condenses around r.
c_ the histones p and r are made of protein around which the dna molecule, q, is wrapped so
that the dna molecule can fit inside the nucleus.
d_ the linked groups of histones p and r and the associated dna, q, form strands that fold
and twist together to form a chromatid.

18 the bacterium escherichia coli divides once every 50 minutes at 36°c.
e. coli were grown on a medium containing only heavy nitrogen, ‘°n, until all of the bacterial dna
contained heavy nitrogen (0 minutes).
some of the bacteria were moved from a heavy nitrogen medium and cultured in a medium with
only light nitrogen, “4n.
some bacteria were collected after each of three generations. their dna was extracted and
centrifuged.
hybrid dna contains heavy and light nitrogen.
the diagram shows the possible positions (upper, middle and lower) of the bands of dna. the
actual positions of bands in the first two samples are shown.
upper --- ie iy ---- upper
middle --- none noe roe ---- middle
lower --- soe woee4 ---- lower
a 0 50 100 150
sample time: . . . .
minutes minutes minutes minutes
which proportion of the dna of the sample taken at 150 minutes will be at the upper position?
a 25% b 50% c 75% d 100%

19 different tissues in a plant were supplied with a radioactively labelled substance to identify which
tissues were actively synthesising mrna.
which radioactively labelled substances would be most suitable for this experiment?
1 adenine
2 ribose
3. inorganic phosphate
4 uracil
a 1,2,3and4
b 1, 2 and 3 only
c 2and4only
d 4only

20 electron micrographs may show large numbers of ribosomes forming chains along mrna
molecules.
what is the advantage of this arrangement, compared to when ribosomes appear singly on the
mrna?
a different polypeptides can be produced simultaneously.
b fewer trna molecules are required to translate the polypeptide.
c_ large polypeptide chains can be produced.
d_ polypeptides can be produced more rapidly.

21. which row is correct for adenine?
5 joins to its
has a single , ’
hina stricture is a purine complementary base
9 with 3 hydrogen bonds

a v v v key
b v x x /¥ = correct
cc x v x x = incorrect
d x x v

22 the graph shows the loss of mass in a potted plant due to transpiration.
x
mass/g

time/ minutes
what could have occurred at point x on the graph?
a aplastic bag was placed around the plant.
b_ the lower epidermis was sealed with petroleum jelly.
c_ the plant was placed into a dark cupboard.
d warm moving air was blown over the plant.

23 which row is correct for a phloem sieve tube element?
cell surface 80s
cytoplasm nucleus ‘

membrane ribosomes
a jv jv v wv key
b v v v x v= present
cc v v x x x = absent
d x x x x

24 an aphid, such as a greenfly, uses a tubular mouthpart called a stylet to feed on nutrients in the
plant.
it inserts the stylet through the surface of a stem or leaf.
when a stylet is cut near the aphid’s head, leaving the stylet in the plant, a liquid with a low water
potential continues to flow out of the plant.
which statement explains this?
a the stylet is in a phloem sieve tube element in which there is a high concentration of solutes.
b_ the stylet is in a phloem sieve tube element in which there is a low concentration of solutes.
c_ the stylet is in a xylem vessel element in which there is a high concentration of solutes.
d_ the stylet is in a xylem vessel element in which there is a low concentration of solutes.

25 which statement correctly describes transport pathways in dicotyledonous plants?
a _ inthe apoplast pathway, water may move through plasmodesmata.
b_ inthe symplast pathway, water may move through intercellular spaces.
c_ the apoplast pathway may be blocked by the casparian strip.
d_ the symplast pathway may be blocked by the tonoplast.

26 the graph shows pressure changes during a cardiac cycle.
zy
"f n
ff nbr
= ~~
xx || ~l
~
pressure
/kpa
zz
\ /
0 0.2 0.4 0.6 0.8
time/s
which row correctly identifies w, x, y, and z?
ee
a atrioventricular semi-lunar semi-lunar atrioventricular
valves close valves close valves open valves open
b atrioventricular semi-lunar semi-lunar atrioventricular
valves close valves open valves close valves open
[e semi-lunar atrioventricular atrioventricular semi-lunar
valves close valves open valves close valves open
d semi-lunar atrioventricular atrioventricular semi-lunar
valves open valves close valves open valves close
a

27 what is systolic blood pressure?
a the blood pressure in the arteries when the heart is relaxing
b_ the blood pressure in the left ventricle at the end of a contraction
c_ the maximum blood pressure in the arteries
d_ the maximum blood pressure in the right ventricle

28 when they remain at high altitudes the red blood cell count of humans increases.
why does this occur?
1 to increase the bohr effect
2. to increase the diffusion gradient for oxygen in the lungs
3. to maintain transport of oxygen
a 1,2and3 b 1tand2only c 2and3only d_= 3only

29 which comparisons of blood, tissue fluid and lymph are correct?

1 blood has a higher concentration of proteins than tissue fluid because the larger
proteins are too big to pass through the endothelial pores into tissue fluid.

2 lymph has a higher concentration of lymphocytes than tissue fluid as a high number
of lymphocytes are located in lymph nodes.

3 macrophages are too large to leave the blood to enter tissue fluid whereas
neutrophils, which are much smaller, can enter tissue fluid and pass into lymph.

a 1,2and3 b 1tand2only c 2and3only' d_= 3only

30 a number of different tissues occur in the walls of major blood vessels.
which row correctly identifies the main tissues found in the three layers of the wall of an artery?
outer layer middle layer inner layer
(tunica externa) (tunica media) (tunica intima)

a collagen elastic endothelium

b collagen muscle elastic

cc elastic collagen endothelium

d muscle collagen elastic

31 the photomicrograph shows a section through lung tissue.
‘6 ventty lies 8.0 none
sho y cag e b aug es ah es
ec ee se sr ae a ae to
hea ey oa) vicia eee 7g es
ee [ —<— ——) \ nr ae, =
iin macesceion | |p \ on ss ames
ye eet ell i y bb hara @ wut l nop, .
which structures are present in this photomicrograph?
| | artery vein bronchioles | bronchus trachea
a v v x v x key
b v x v x v jv = present
c x v v v x x = absent
d x x x v v
a

32 an athlete who smokes just before a race may not be able to run at their maximum speed
because less oxygen is carried by the blood.
which explanation is correct?
a_ carbon dioxide binds to haemoglobin forming carbaminohaemoglobin.
b_ carbon dioxide binds to haemoglobin forming carboxyhaemoglobin.
c carbon monoxide binds to haemoglobin forming carbaminohaemoglobin.
d carbon monoxide binds to haemoglobin forming carboxyhaemoglobin.

33 some of the requirements of an efficient gas exchange system are a large surface area and a
short diffusion distance.
what is correct about how alveoli are adapted to meet these requirements?
a | collagen and elastin fibres that an extracellular layer round
allow the alveoli to stretch the alveolus wall contains
blood capillaries
b gases dissolve in a layer of walls of alveoli are
liquid to speed up diffusion squamous epithelium
cc many folded capillaries are next to
interconnected alveoli alveolus wall
d sac shape of alveoli formed red blood cells are very
by squamous cells close to capillary walls

34 the diagram shows three types of cell found in the human gas exchange system.
x ¥ zz
apart from causing cancer, which cell types will be directly affected when a person is exposed to
tar in cigarette smoke?
a x,y andz b xandyonly c xandzonly d_ yandzonly

35 some common antibiotics are listed. the action of each antibiotic is described.

1 rifampicin — inhibits rna polymerase
2. streptomycin — inhibits 70s ribosomes
3 neomycin — inhibits dna synthesis
4 ampicillin — inhibits peptidoglycan synthesis

which of these antibiotics will affect the activities of bacterial cells only?

a 1,2,3and4

b= 1, 2 and 3 only

c 2and4only

d 4only

36 what could cause an outbreak of malaria in a country after it had been eliminated?
1 mosquitoes become resistant to insecticides
2 migration of population due to war
3. malarial parasites become resistant to quinine
a 1,2and3 b 1tand2only c 1and3only d = 2and3only

37 which disease is caused by a bacterium and can be spread by airborne droplets?
a cholera
b- measles
c_ smallpox
d tuberculosis (tb)

38 smallpox has been eradicated, but malaria and cholera have not.
which statements correctly explain this?
1 cholera pathogens in the intestines are not destroyed by antibiotics.
2 plasmodium antigens change during the life cycle.
3 smallpox antigens remain stable.
4 vaccines only work against viruses.
a 1,2and3 b 1,2and4 c 1,3 and4 d 2,3and4

39 when a person is given a vaccination immunity to certain pathogens develops.
which of the effects of vaccination are correct?
1. production of antibodies to protect against future infections
2 results in artificial active immunity
3. stimulation of appropriate lymphocytes
a 1,2and3 b 1tand2only c 1and3only d = 2and3only

40 what is the first response by the immune system to a pathogen?
a ingestion of the pathogen by phagocytes
b production of antibodies
c production of antigens
d _ stimulation of b memory cells

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