biology

1 the electron micrograph shows a chloroplast from a tobacco leaf.
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coe se
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“es os a
sey sah, *.. 4
ess on ee
ee es
fer, ae ing)
if the actual length of this chloroplast measured along x—y is 10m, what is the magnification of
the image?
a x6.3 b x63 c x630 d = x6300

2 some cell structures are listed.
1 endoplasmic reticulum
2 golgi body
3. mitochondrion
4 chloroplast
which cell structures do not contain cristae?
a 1,2,3and4
b 1,2 and 4 only
c 1 and 2 only
d 3and4 only

3 which letter represents cell structures where mrna may be found?
cytoplasm
mitochondrion nucleus

4 which row is correct for typical prokaryotic cells and mitochondria?
feature prakanyele mitochondria
cells
a 70s ribosomes no yes
b circular dna yes no
cc peptidoglycans yes no
d small size, 1-5 um long no no

5 which statement is correct?
a a virus is composed of a protein coat which surrounds rna or dna.
b_ suberin and cellulose are found in all plant cell walls.
c_ plasmodesmata and centrioles are found in all plant cells.
d_prokaryotic cells contain an endoplasmic reticulum to synthesise proteins.

6 the benedict's test and ethanol emulsion test were carried out on a sample of biological
molecules. the solution became brick-red during the benedict’s test and cloudy during the
ethanol emulsion test.

which molecules did the sample contain?
a_ reducing sugars and lipids

b proteins and reducing sugars only

c _ starch, proteins and reducing sugars
d_ non-reducing sugars and lipids

7 which diagram is correct for a-glucose?
a b
siden va
c—o c— 0.
h | h h | h
hi hz! a a
| | | |
ho c—c oh ho c—_¢ oh
h oh ch,oh oh
cc d
va cl
c—o c—o.
h oh h oh
i7un ni v/a
in on ha te a
| | i i
ho c——c h ho c—c¢ h
ch,oh oh h oh

8 which reaction correctly represents one way sucrose can form?
a (a-glucose — oh’) + (fructose — h*) — sucrose + h20
b (a-glucose + oh) + (a-glucose + h*) — sucrose — h2o
c (a-glucose — oh’) + (b-glucose — h*) — sucrose + h2o
d (a-glucose + oh’) + (fructose + h*) — sucrose — ho

9 the diagram represents part of an alginic acid molecule. alginic acid is a polymer found in the
cell walls of brown seaweeds.
cooh h h
h os h
h oh ho
oh ho cooh
i h h ae a
[e)
h h h n
which statement about alginic acid is correct?
a alginic acid is a linear polysaccharide containing 1,6 glycosidic bonds between each hexose
sugar.
b_ alginic acid is formed from two monomers joined by 1,4 glycosidic bonds.
c_ alternate monosaccharides are arranged in opposite directions; this is also seen in glycogen
molecules.
d_ hexose sugars and water molecules are joined by condensation reactions to make alginic
acid.

10 which features are correct for triglycerides and phospholipids?
1 they have ester bonds between glycerol and fatty acids.
2 fatty acid chains may have single or double bonds between carbon atoms in the
chains.
3. the fatty acid chains are non-polar and hydrophobic.
4 saturated fatty acid chains allow closer packing of the molecules than unsaturated
fatty acid chains.
a 1,2,3and4
b 1 and 3 only
c 2,3 and 4 only
d 2and4only

11 a scientist studying the structure of a protein reported that it consists of two polypeptide chains
joined by disulfide bonds.
which feature of protein structure does this describe?
a primary structure
b_ secondary structure
c tertiary structure
d quaternary structure

12 some molecules fluoresce when illuminated with ultraviolet light. changes in the structure or
shape of such molecules can change the intensity of the fluorescence.
the enzyme tryptophan synthase fluoresces bluish-green because of a phosphate group
associated with the active site. the enzyme catalyses the reaction shown.
serine + indole — tryptophan

adding serine to the enzyme increases the intensity of the fluorescence, but when indole is also
added the bluish-green fluorescence decreases in intensity.
what may be concluded from these observations?

1 serine and indole attach to the active site of the enzyme.

2  anenzyme-serine complex is formed.

3 an enzyme-—serine—indole complex is formed.
a 1,2and3 b 1tand2only c 1and3only d 2and3only

13 yeast contains the enzyme catalase which catalyses the breakdown of hydrogen peroxide (h2o2)
as shown.
2h,0, catalase 2h,o + 0,
yeast was added to a solution of hydrogen peroxide and the total volume of oxygen released was
recorded every 30 seconds for 2 minutes. all other variables were standardised.
the data is shown in the table.
o2/cm
30 157
60 251
90 283
120 285
what explains the pattern of the data?
a_ the rate of reaction increases as more enzyme-substrate complexes are formed.
b_ the rate of reaction increases as the enzyme reaches its maximum velocity (vmax)-
c_ the volume of oxygen released decreases as the enzymes begin to denature.
d_ the volume of oxygen released decreases as more substrate is converted into product.

14 the michaelis-menten constant, kn, is a measure of the affinity of an enzyme for its substrate.
1 the higher the affinity, the lower the k,,.
2 the lower the affinity, the slower the reaction will be.
3 at kn, half the active sites of the enzyme are occupied by the substrate.
which statements about k,, are correct?
a 1,2and3 b 1and2only c 1and3only d = 2and3only

15 which features are correct for active transport and facilitated diffusion?
1 the movement of molecules and ions depends on atp.
2 they are specific for one type of molecule or ion.
3 they use membrane proteins.
a iand2 b 1and3 c 2and3 d- 3only

16 the diagram represents two solutions, p and q, that were separated by a partially permeable
dialysis tubing.
partially permeable
dialysis tubing
oo
eo 2 eo? ae
solution p 8.89 © 6, ,6l] ** solution q key
oo 6 = | 2 90090
a0 fo. ° 56% 1 ° molecule 1
a o[’e0 oo c1 molecule 2
oo °llo ral 070°,
oo °c eo] 9's 0200 = _ molecule 3
6.6 — "> °.lle .
9 co % | 200 0 an — — partially permeable
—s0 0-2 ,li°%° ly dialysis tubing
° oo | 09 %
o ao jo l129
° 2 0000
what will be the initial movement of the molecules, 1, 2 and 3, between solution p and
solution q?
net movement net movement no net
from q to p from p toq movement
a molecule 1 molecule 2 molecule 3
b molecule 1 molecule 3 molecule 2
[e molecule 2 molecule 3 molecule 1
d molecule 3 molecule 1 molecule 2

1/7 a student weighed a cylinder of potato and then put it into a test-tube containing a sait solution.
the potato cylinder was removed from the salt solution after one hour. it was blotted dry and then
reweighed. the student recorded that the potato had lost mass.

which row shows the correct explanation for the results the student collected?
water potential of the eenaitanerthe
potato cells before soaking
potato cells
compared to the aflarsoakin
water potential after soaking g
a higher plasmolysed
b higher turgid
cc lower plasmolysed
d lower turgid

18 which row shows the correct number of each component in a single chromosome at the start of
telophase of mitosis?
strands
a 1 2 2
b 1 4 4
cc 2 4 2
d 2 2 4

19 the photomicrographs show cells in various stages of the cell cycle.
in which stage does semi-conservative replication of dna take place?
a b cc d

20 the diagram shows the epidermis of human skin. this is formed of four layers of cells.
cells in each layer have specific functions which are outlined on the diagram. as the cells are
produced, they move upwards as shown by the arrow.
a

21 the diagram shows some of the stages that take place during the cell cycle.
1
number of dna
molecules in
cell doubles
4 stages 2
nuclear envelope during cell
di cell grows
isappears cycle
3
chromosomes
become visible
which two stages take place during interphase?
a iand2 b 1and3 c 2and4 d 3and4

22 what does a nucleotide contain?
1. anamino acid
2  acodon
3 anitrogenous base
4 asugar
a iand2 b 1and4 c 2and3 d 3and4

23 a diagram can be used to snow some relationships between different nucleic acid bases.
which row is correct for the words that can be placed at positions 1-5?
ee

a adenine purine cytosine pairs with guanine
b cytosine purine guanine pairs with uracil

c guanine pairs with cytosine pyrimidine thymine
d thymine pairs with uracil pyrimidine adenine

24 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.
some of the bacteria were moved from a heavy nitrogen medium and cultured in a medium with
only light nitrogen, “n (0 minutes).
these bacteria continued to reproduce and samples were extracted and centrifuged at regular
intervals.
hybrid dna contains both 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 --- ite al ---- upper
middle --- weeee ---- ----4 ---- middle
lower --- ---- ----+ ---- lower
—_— 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%

25 following translation, the alpha polypeptide chain of haemoglobin, a-globin, undergoes
modification. during this modification, the first amino acid is removed, leaving 141 amino acid
residues.

how many nucleotides does the mrna coding for a-globin contain?
a 141 b 142 c 423 d 426

26 the photomicrograph shows a section through a plant organ.
de ge ee
a es ae eepaen |
pee a a
at eee ane : - ne. je
ie aaearans me ‘ ee svare:. bey",
bie so oocerm cag esser c
eee og ps oe ea
as setar teense eee
which statement could be used to describe this organ?
a_ the central region of this organ has supporting tissue.
b_ the endodermis tissue is a thick layer around the edge of the organ.
c_ the epidermis tissue in this organ has extensions (trichomes).
d_ the xylem tissue is found in greatest density in the centre of the organ.
a

27 the statements describe some of the properties of water.
1 requires a lot of heat energy to evaporate
2 retains a lot of heat energy
3 is able to form hydrogen bonds with other water molecules
4 is able to form hydrogen bonds with other polar and non-polar molecules
which properties are also important for transport in xylem?
a 1,2and3 b 1,2and4 c 1and3 only d 3and4

28 which xerophytic adaptations reduce the water potential gradient between leaf surface and
atmosphere?
1 rolled leaves
2 hairy leaves
3. sunken stomata
4 fewer stomata
5 fleshy leaves
a 1,2,3,4and5
b 1, 2 and 3 only
c 1,3 and 4 only
d 2and5only

29 the diagram shows seven stages of a tulip bulb’s growth.
1 2 3 4 5 6 7
which row identifies the correct stages in which the tulip bulb is acting as a source only or as a
sink only?
source sink
only only
a 1 5
b 3 4
cc 4 6
d 5 ff

30 what would be changed if mitochondrial activity was inhibited by a metabolic poison acting on
cells in the phloem tissue?
1 concentration of hydrogen ions in the cell wall of companion cells
2 concentration of sucrose in the cytoplasm of cells in a leaf
3. hydrostatic pressure gradient in the phloem sieve tube
a 1,2and3 b 1tand2only c 1and3only d = 2and3only

31 by which process does sucrose move through phloem sieve tube elements?
a active transport
b_ diffusion
c facilitated diffusion
d_ mass flow

32 which blood vessels carry blood into the atria?
1 coronary artery
2 vena cava
3 pulmonary artery
4 pulmonary vein
a iand2 b 1and3 c 2and3 d 2and4

33 which statements about the cardiac cycle are correct?
1 the atrioventricular valves close during atrial systole.
2 the left and right ventricles contract together.
3. there is a time delay as the electrical impulse passes from the atrioventricular node
to the sinoatrial node.
4 electrical impulses pass along the purkyne tissue to the ventricles.
a 1,2and3 b 1,3 and4 c 2and4 d 3and 4 only

34 at one point in the cardiac cycle, the pressure in the right ventricle is lower than that in the right
atrium and lower than that in the pulmonary artery.
which row is correct?
atrioventricular ‘
semilunar valve
valve

a closed closed

b closed open

c open closed

d open open

35 which statements about the formation of haemoglobinic acid are correct?
1 itis linked to the action of carbonic anhydrase.
2 it prevents blood from becoming too acidic by removing excess hydrogen ions.
3. it can only occur when oxygen associates with haemoglobin.
a 1,2and3 b 1and2only c1 only d 2and3 only

36 the graph shows the dissociation curves for haemoglobin at two different partial pressures of
carbon dioxide.
at which position on the graph would most chloride ions be found in the red blood cells?
low carbon dioxide
partial pressure
cc
d
percentage saturation of ; —
haemoglobin with oxygen high carbon dioxide
partial pressure
a
b
partial pressure of oxygen/kpa

37 oedema is caused by the accumulation of tissue fluid around body cells.
what would increase the amount of tissue fluid around body cells?
a __ lower blood pressure than normal
b lower blood plasma protein concentration than normal
c higher blood plasma protein concentration than normal
d lower tissue fluid protein concentration than normal

38 certain bacteria develop resistance to an antibiotic by actively transporting the antibiotic out of
the cell. this prevents the antibiotic building up to toxic concentrations.
what must be found in a bacterial cell to allow it to develop this form of antibiotic resistance?
gene coalng top mitochondria
a channel protein
source of
chemical energy

39 which statements explain the differences between a primary and a secondary response to
exposure to the same antigen?
1 the primary response is slow, because there are only a few b-lymphocytes that are
specific to the antigen.
2 the secondary response is faster, because there are many memory cells specific to
the antigen.
3 more antibodies are produced during the secondary response, because many of the
memory cells differentiate into plasma cells specific to the antigen.
a 1,2and3 b 1tand2only c 1and3only d = 2and3only

40 which statement about b-lymphocytes and t-lymphocytes is correct?
a_ they become active only when a specific antibody binds to their surface receptor.
b_ they divide to form clones when meeting an antitoxin in a cell.
c_ they produce memory cells to respond to an antigen when exposed in the future.
d_ they release hormone-like cytokines which stimulate release of antibodies.

Solve 9700_w22_qp_13