biology

1 asscale bar on an electron micrograph is 2cm long and represents an actual length of 1 um.
what is the magnification of the electron micrograph?
a x200 b x2000 c x20000 d x200000

2 ~the eyepiece of a microscope is fitted with an eyepiece graticule and a stage micrometer scale is
placed on the microscope.
which statements about the stage micrometer scale are correct?
1 the scale can be used to measure the actual length of cells directly.
2 the scale allows you to calibrate the eyepiece graticule.
3. less of the scale is visible as the objective lens changes from x10 to x40.
a 1,2and3 b 2and3only c_  1only d = 2only

3 four students were asked to match the function with the appearance of some cell structures in an
animal cell.
the functions were listed by number.
1 mrna passes through to the ribosome
2 organises microtubules to produce the spindle during cell division
3. synthesis of polypeptides
the appearances were listed by letter.
vs membranes which surround an enclosed inner cavity
w_non-membrane bound, spherical structures
x adouble membrane interspersed with pores
y —non-membrane bound, cylindrical structures
z membrane-bound sacs, arranged as a flattened stack
which student correctly matched the numbered function with the appearance of the cell structure?
ppt) 2 [8 |
a vv ww xx
b vv y z
c xx ww z
d x y ww

4 which cell structures are required for the formation of lysosomes and the hydrolytic enzymes that
they contain?
mitochondria
endoplasmic golgi
reticulum body

9 vvvhich cell structures contain rrna?
1 chloroplast
2 mitochondrion
3 nucleus
4 smooth endoplasmic reticulum
a 1,2,3and4
b 1,2 and 3 only
c 1,2 and 4 only
d 3and 4 only

6 the single-celled organism thiomargarita namibiensis measures 700um in diameter and is
enclosed in a cell wall. the genetic material of t. namibiensis is located free in the cytoplasm
where it occurs as thousands of copies of circular dna. most of the cell is taken up by a large
vacuole, which stores essential chemicals for metabolism.

which statement is correct?

a it must be a eukaryote because a diameter of 700 uum is too large for a prokaryote.
b_ it must be a plant because it contains a vacuole.

c_ it must be a plant because it is enclosed in a cell wall.

d_ it must be a prokaryote because its dna is circular and located in the cytoplasm.

7 a student carried out four tests on a sample of biological molecules.
emulsion cloudy
benedict’s yellow
biuret purple
iodine yellow
which conclusions made by the student are correct?
1 fat was present.
2 glucose was present.
3 protein was present.
4 starch was not present.
a 1,2,3and4
b 1,2 and 4 only
c 1,3 and 4 only
d = 2and 3 only

8 which general formula is correct for monosaccnarides such as tructose?
a (cho), b_ (cho), c (cho,), d (cho),

9 which statements can be used to describe the structure of cellulose?
1 apolymer of glucose monomers linked by b-1,4 glycosidic bonds
2 a polysaccharide of hexose monomers
3. anunbranched macromolecule made of b-glucose monomers
a 1,2and3 b 1and2only c 1and3only d = 2and3only

10 complete hydrolysis of polysaccharides requires all the glycosidic bonds between the monomers
to be broken.
enzyme x only breaks a-1,4 glycosidic bonds.
which row shows how completely enzyme x can hydrolyse molecules of glycogen and amylose?
a + ++ key
b + a - no hydrolysis
cc para _ + some hydrolysis
d - * ++ most hydrolysis

11. which molecules contain at least two double bonds?
a saturated fatty acid, collagen and haemoglobin
b_ collagen and saturated fatty acid only
c haemoglobin and collagen only
d saturated fatty acid and haemoglobin only

12 the diagram shows an amino acid.
\ pp
n—c—c
/ | \
h h oh
which group is changed to produce different amino acids?
a oh b c=o c ch; d nh,

13 which row is correct about the structure of proteins?
[primary | sesondary—[teriay | auatomary |
determined by occurs by disulfide, ionic, always formed by
the sequence of | hydrogen bonding hydrogen bonds association of two
dna nucleotides | between nh and and hydrophobic or more
c=o groups of interactions are all polypeptides
amino acids involved
the number of in a single the bonds are always formed by
amino acids in polypeptide it is formed at specific two or more
each polypeptide | either an a-helix points determined polypeptides held
chain or a b-pleated by the primary together by bonds
sheet structure formed between
the polypeptides
cc formed by an a-helix is only globular always formed
twenty different formed by proteins have this by two or
amino acids hydrogen bonds level of structure more different
linked ina between side polypeptides to
specific order chains of give the final shape
amino acids
the sequence a b-pleated sheet | reactions between always formed
of amino acids in | is the result of a side chains of by two or
each polypeptide folded specific amino more polypeptides
chain polypeptide acids give a and a metal ion
forming hydrogen | specific 3-d shape
bonds between
adjacent strands

14 which graph correctly shows possible changes in energy levels as a chemical reaction
progresses with or without an enzyme?
a b
energy levels |s wv ." energy levels eos
iad s “xp
progress of reaction progress of reaction
cc d
energy levels |s a energy levels |s “a ms
progress of reaction progress of reaction
key
— with enzyme
------ without enzyme
s substrate
p product

15 the graph shows the relationship between the concentration of substrate and the rate of an
enzyme-catalysed reaction.
rate of
enzyme-catalysed
reaction
0
0 concentration
of substrate
which row shows how kp and vmax for this enzyme would be affected if the same reaction was
carried out in the presence of a competitive inhibitor?
pf mm |
a increases decreases
b increases remains the same
[e remains the same decreases
d remains the same remains the same

16 liver cells contain vesicies that nave proteins in their membranes which are specific tor the
transport of glucose.
when these cells need to take up glucose, the vesicles fuse with the cell surface membrane.
how does the uptake of glucose occur?
a exocytosis
b_ diffusion
c_ endocytosis
d facilitated diffusion

17 astudent set up an experiment to investigate diffusion.
a block of agar, 1.0cm x 1.0cm x 1.0cm, was stained uniformly with a water-soluble blue dye.
the block of agar was put into a test-tube containing 10 cm’ of distilled water at 20°c.
the intensity of the blue colour of the water after five minutes was measured.
four other experiments, a, b, c and d, were then carried out using different numbers of agar
blocks, different sizes of agar blocks and different temperatures. all other variables were
standardised.
which experiment would give a lighter blue colour in the water after five minutes compared to the
first experiment?
size of each number of temperature of
agar block/cm agar blocks distilled water/°c

a 0.5 x 0.5 x 0.5 8 30

b 0.5 x 0.5 x 0.5 2 20

cc 0.5 x 1.0 x 1.0 2 30

d 2.0 x 1.0 x 1.0 1 20

18 which description is correct?

a a centromere holds two chromatids together until the end of prophase and attaches to the
microtubules of the spindle.

b  achromatid is one of two identical parts of a chromosome and is made of proteins and two
molecules of dna.

c achromosome is a structure with two identical parts, made of dna and proteins, found in the
nucleus of a prokaryotic cell.

d_ a telomere is a sequence of dna nucleotides, such as gggtaa, repeated many times and
found at the ends of each chromatid.

19 during metaphase, a scientist stains the chromosomes of a diploid animal cell with tluorescent
dye to allow the telomeres to be observed.
this cell has 26 chromosomes.
how many telomeres will the scientist observe?
a 26 b 52 cc 78 d 104

20 the photomicrographs show cells in various stages of the cell cycle.
1 2 3 4
which cells contain twice as many dna molecules as a cell from the same organism that has
just finished a complete mitotic cell cycle ending with cytokinesis?
a 1,2,3and4
b 1, 2 and 4 only
c 1and3 only
d 2and4 only

21 uncontrolled cell division can result in the formation of a tumour.
which part of the cell cycle would take less time during the formation of a tumour?
a cytokinesis
b interphase
c_ mitosis
d_ telophase

22 a piece of a dna molecule contains 84 base pairs. the table shows the number of adenine and
cytosine bases in one or both of the dna strands in this piece of dna molecule.
[bese [avant | svand2
adenine 28 23
cytosine 18
how many guanine bases are present in this piece of dna molecule?
a 18 b33 c 36 d 41

23 the mrna sequences of the three stop codons are shown.
uaa uag uga

which mutation in the template (transcribed) strand of a dna sequence that codes for a
polypeptide would cause translation to stop prematurely?

a att changed to atc

bact changed to aca

c acc changed to att

d atc changed to tag

24 which features of companion cells are essential to their function?
1 they are connected to the sieve tube elements by plasmodesmata.
2 they have a thicker cell wall than a sieve tube element.
3. they contain a nucleus and mitochondria.
a iand2 b 1and3 c 1only d 2and3

29 which statements about water movement in plants are correct?
1 water can pass through cellulose cell walls.
2 water cannot pass through lignified cell walls.
3 water can pass through cell walls that contain suberin.
a 1,2and3 b 1tand2only c ‘1and3only d = 2and3only

26 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 temperature

27 which sequence of events could lead to mass flow in a phloem sieve tube?
1 sucrose moves into a sieve tube element.
2 protons (h*) and sucrose molecules move into a companion cell through a
co-transporter protein.

3 avery high hydrostatic pressure is produced.
4 the water potential of the sieve tube element decreases.
5 protons (h’*) are actively pumped out of a companion cell.
6 water moves down a water potential gradient by osmosis.

a 132>55>6>54->3

b 3>51>2>55>6>4

c 355391525456

d 5>2>51>4>5653

28 what will happen as a result of the blood pressure in the right ventricle becoming higher than the
blood pressure in the right atrium?
a_ the semilunar valve in the aorta will close.
b_ the semilunar valve in the pulmonary artery will close.
c_ the left atrioventricular valve will close.
d_ the right atrioventricular valve will close.

29 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.
pry y
ij n
new
sy ~~
x |] se
~
~\i! key
——-— aorta
pressure .
— ventricle
seeeeeees atrium
zz
\ /
0 02 0.4 0.6 0.8
time/s
which row correctly identifies w, x, y and z?
ee ee ee
a atrioventricular atrioventricular semilunar semilunar
valve opens valve closes valve opens valve closes
b atrioventricular semilunar semilunar atrioventricular
valve closes valve opens valve closes valve opens
cc semilunar semilunar atrioventricular atrioventricular
valve opens valve closes valve opens valve closes
d semilunar atrioventricular atrioventricular semilunar
valve closes valve opens valve closes valve opens
a

30 which statements are correct?
1 compared with blood, tissue fluid has less protein and no red blood cells.
2 lymph may contain lipids, carbon dioxide and phagocytes.
3 tissue fluid contains glucose, amino acids, urea and carbon dioxide.
a 1,2and3 b 1tand2only c 1and3only d 2and3only

31 which statements about the formation of haemoglobinic acid are correct?
1 it can only occur with the dissociation of oxygen from haemoglobin.
2 it removes excess hydrogen ions, preventing blood from becoming too acidic.
3 it is linked to the action of carbonic anhydrase.
a 1,2and3 b 1tand2only c 1 only d 2and 3 only

32 what explains how the maximum volume of oxygen is taken up as blood passes through the

capillaries of the lungs?

a_ each haemoglobin molecule can temporarily bind to four oxygen atoms.

b_ the dissociation of carbon dioxide from carboxyhaemoglobin allows more haemoglobin to be
available for binding oxygen.

c the binding of the first oxygen molecule to haemoglobin decreases the affinity of
haemoglobin for binding other oxygen molecules.

d oxyhaemoglobin formation increases the ability of red blood cells to transport oxygen.

33 the image shown is a photomicrograph of a transverse section of part of the gas exchange
system.
a we. ’ a ? be
re cga + >
me bs vaihoa® #
fe gf infers je
lif ae <a ge
we so o/h
pore, £2. gue” eae
er hc caine oid ie g sj f ge iis ute.
se ia po | oe
4 ‘ise fe 73% & g .
mn ee 8): ina
what describes the image?
a athin inner layer of ciliated epithelial cells on top of a layer containing cartilage, supported by
elastic fibres
bsa very thin epithelial lining with walls containing elastic fibres, surrounded by many blood
vessels
can inner layer of ciliated epithelial and goblet cells on top of elastic fibres, supported by an
outer layer consisting of cartilage
d_aninner layer of ciliated epithelial and goblet cells on top of loose tissue with mucous glands,
supported by a continuous ring of cartilage

34 which row shows the tissues that are present in the wall of the trachea and the wall of the
bronchus?
smooth squamous goblet
muscle epithelium cells
a jv jv v key
b v v x v= present
cc v x v x = not present
d x v x

35 when a person suffers an asthma attack, the tubes of the gas exchange system narrow and extra
mucus is produced.
which changes occur during an asthma attack?
1 activity of ciliated epithelium increases.
2 endocytosis in goblet cells increases.
3 smooth muscles are more active.
a 1,2and3 b 1tand2only c ‘1and3only d = 2and3only

36 which flow diagram correctly describes the effect of tar entering the lungs?
carcinogens
come into mutation uncontrolled
a . => => ie
contact with occurs cell division
dna
mucus
goblet cells agglriulalss phagocytes
b secrete more > . —> attracted by
causing p :
mucus f : inflammation
infection
mucus phagocytes elastase
cc accumulates — attractedby — destroys the
causing infection inflammation alveolar walls
. phagocytes causes
d sacl > attractedby -—  _ irritation and
occurs ‘ : :
inflammation coughing

37 which control measures would reduce the transmission of tuberculosis (tb)?
boiling water ibioti og.
before drinking it antibiotics vaccination
a yes no no
b yes yes yes
cc no yes no
d no yes yes

38 comorbidity is where an individual has two or more diseases or medical conditions at the same
time. some medical conditions are particularly likely to result in comorbidity. in one example,
initial infection with one pathogen can increase the risk of developing a second disease by a
factor of 15 or more. the second disease is then the major cause of death for these people.
which description could fit this example?

a cholera infection followed by development of malaria
b_ cholera infection followed by development of aids
c_ hiv infection followed by development of tb

d_ malaria infection followed by development of tb

39 which conditions are infectious and result in a high white blood cell count?
1 leukaemia
2 myasthenia gravis
3 tb
a 1,2and3 b 1tand2only c 1and3only d_= 3only

40 which cell type causes the secondary immune response to be much faster than the primary
immune response?
a helper t-lymphocyte
b memory cell
c_ phagocyte
d plasma cell

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