biology

1 what are the appropriate units for measuring diameters of alveoli, diameters of white blood cells
and the width of cell walls?
diameters of diameters of width of
alveoli white blood cells cell walls
a mm mm nm
b mm pm um
cc um mm um
d um pm nm

2 the actual diameter of a prokaryotic cell is 0.5um. an electron micrograph of the cell has a
magnification of x50 000.
what is the diameter of the cell in the image?
a 2.5x10'mm
b 2.5x10°mm
c 2.5 10'mm
d 2.5x 107mm

3. the electron micrograph shows some cell structures.
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some cell structures are listed.
1 nucleolus
2. chloroplast
3. microtubules
4 ribosomes
5 mitochondria
6 plasmodesmata
which cell structures can be seen in the electron micrograph?
a 1,2,3and4 b 1,4,5and6 c 2,3,5and6 d 2,4,5and6
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4 which part of the cell is often continuous with the rough endoplasmic reticulum?
a cell surface membrane
b_ golgi body
c_ mitochondrion
d_ nuclear envelope

5 which statements about atp are correct?
1 it is produced in chloroplasts.
2 it is used during protein synthesis.
3. it contains deoxyribose.
4 itis used in facilitated diffusion.
5 it is used to load sucrose into companion cells.
a 1,2and5 b 1,3and5 c 2,3,4and5 d 2and4only

6 four students were asked to matcn the tunction 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 lipids
the appearances were listed by letter.
vs membranes which surround an enclosed inner cavity
w_non-membrane-bound, spherical structures
x adouble membrane with pores
y —non-membrane-bound, cylindrical structures
z membrane-bound sacs, arranged as a flattened stack
which student correctly matched the numbered functions with the appearance of the cell
structure?
|| # | @ | @ |
a vv ww z
b vv y ww
cc x ww vv
d x y vv

7  asstudent carried out tests for biological molecules on the same sample of milk.
the tests and their results were as follows.
e heating to 80°c with benedict’s solution gave a red colour.
e boiling with acid, followed by neutralisation, then heating to 80°c with benedict's
solution also gave a red colour.
e adding biuret solution gave a purple colour.
e adding iodine solution gave a yellow colour.
which biological molecules must be present in the milk?
1 non-reducing sugars
2 protein
3. reducing sugars
4 — starch
a 1,2and3 b tand2only c 2and3o0nly d 3and4

8 which row is correct for carbohydrates?
[monomer | pobmer | mecromeleute
a fructose amylose cellulose
b glucose deoxyribose amylopectin
cc monosaccharide glycogen deoxyribose
d sucrose starch glycogen

9 which molecules contain 1,6 glycosidic bonds?
1 amylopectin
2 glycogen
3 starch
a 1,2and3 b 1tand2only c 1and3only d = 2and3 only

10 which row correctly shows the ratio of carbon atoms to hydrogen atoms for glucose, a saturated
fatty acid and sucrose?
ae te
a 1:2 122 1:1.8
b 1:2 4:1 1:2
cc 2:1 1:4 2:1
d 2:1 261 1.8:1

11. which row shows a correct comparison between a phospholipid molecule and a triglyceride
molecule?
[| prosphoipiémeleoue | tteerde molecule
a | contains a hydrophobic phosphate group is a hydrophobic molecule
b contains one glycerol molecule contains three glycerol molecules
cc fewer ester bonds more ester bonds
d more fatty acids fewer fatty acids

12 adult human haemoglobin typically consists of two a chains and two b chains.
approximately 5% of humans have one amino acid in the b chain that has been changed. this
change affects the structure and stability of haemoglobin.
which levels of protein structure could be affected in the haemoglobin of the humans with the
changed amino acid?
a primary only
b primary and quaternary only
c_ secondary, tertiary and quaternary only
d primary, secondary, tertiary and quaternary

13 lysozyme occurs in human tears, saliva, milk and mucus.
lysozyme has a role in the immune system and hydrolyses peptidoglycan.
which description of lysozyme is correct?
a itis an extracellular antibody.
b_itis an intracellular antibody.
c_ itis an extracellular antibacterial protein.
d_itis an intracellular antibacterial protein.

14 which letter in the flow diagram shows the effect of adding a competitive inhibitor to an
enzyme-catalysed reaction?
yes no
affects the v,,_, value affects the k,, value
of the enzyme of the enzyme
° i a ii
a b cc d

15 the cell surface membrane structure is described as a ‘fluid mosaic’.
which statement describes the ‘mosaic’ part of the cell surface membrane?
a the different patterns that are obtained by the moving phospholipid molecules
b_ the random distribution of cholesterol molecules within the phospholipid bilayer
c_ the regular pattern produced by the phospholipid heads and membrane proteins
d_ the scattering of the different proteins within the phospholipid bilayer

16 solute x is at a higher concentration outside a cell than in the cytoplasm.
which processes may allow solute x to be moved through the cell surface membrane?
a active transport, diffusion and facilitated diffusion
b active transport, diffusion and osmosis
c_ diffusion, facilitated diffusion and osmosis
d_ exocytosis, facilitated diffusion and osmosis

17 three molecules found in prokaryotes are listed.
1 phospholipid
2 protein
3 peptidoglycan
which molecules are found in prokaryotic cell surface membranes?
a 1,2and3 b 1and2only c 1and3only d = 2and3 only

18 what happens to the surface area to volume ratio of a cube when the length of each side is
doubled?
a_ the ratio decreases by a quarter.
b_ the ratio decreases by half.
c_ the ratio doubles.
d_ the ratio increases by four times.

19 three parts of a chromosome and their functions are listed.
p1 centromere fi holds the coils of dna together
p2 histone proteins | f2 holds two chromatids together
p3 telomere f3 prevents loss of genes
which part is matched with its correct function?
a p1and f2 b p2and f2 c p2 and f3 d p3andf1

20 which features of mitosis are important for a single-celled organism?
1 asexual reproduction
2 production of genetically identical cells
3 growth
a 1,2and3 b 1tand2only c 1and3only d = 2and3only

21 some events in the cell cycle are listed.
which events are part of mitosis?
1 interphase
2 metaphase
3 cytokinesis
a 1,2and3 b 1and3only c = 1only d = 2only

22 which row represents the correct features of guanine?
h joins its
asa i :

. : : 4 complementary pairs with

single ting $a. buns base via three thymine

structure

hydrogen bonds

a jv v x v key
b v x v x v= correct
cc x v v x x = not correct
d x x v v

23 bacteria were grown in a medium containing “n. after several generations, all of the dna
contained ‘°n.
some of these bacteria were transferred to a medium containing the common isotope of nitrogen,
‘4n. the bacteria were allowed to divide once. the dna of some of these bacteria was extracted
and analysed. this dna was all hybrid dna containing equal amounts of “n and ‘°n (4n/‘°n).
in another experiment, some bacteria from the medium with ‘sn were transferred into a medium
of ““n. the bacteria were allowed to divide three times. the dna of some of these bacteria was
extracted and analysed.
what is the composition of this dna?
a b
100 100
75 was
percentage percentage
of dna id of dna ie
25 25
0 0
14] 14n] / 15) 14] 14k] / 15
cc d
100 100
75 18
percentage percentage
of dna oa of dna a
25 25
0 0
14] 14] / 15) 14] 14] / 15)

24 a molecule of transfer rna (trna) has the anticodon sequence uac.
what will be the corresponding nucleotide sequence in the dna?
a atg b aug cc tac d tug

25 some of the features present in transport tissues in plants are listed.

1 __ lignified walls
2 cytoplasm
3 many mitochondria
4 pits
5 plasmodesmata
6 sieve plates

which of these features are present in xylem vessel elements?

a 1,2,4and5 b t1and4only c 2,3,5and6 d 2,3 and 5 only

26 er diameter of a tree trunk usually decreases slightly during the day and increases slightly at
night.
which three environmental factors, if increased, could cause the largest decrease in diameter?
a_ humidity, temperature, wind speed
b_ humidity, light intensity, temperature
c humidity, light intensity, wind speed
d light intensity, temperature, wind speed

2/ sucrose moves within a phloem sieve tube trom a source to a sink by mass tlow.
which type of gradient within the phloem sieve tube between the source and sink causes the
movement of sucrose?
a diffusion gradient
b hydrostatic gradient
c_ concentration gradient
d_ water potential gradient

28 which are present in the walls of veins?
|_[wtonn| moor _jetcmne| ses”
muscle fibres
a v x 4 7 bey
b x v x v v= present
s a v v x x = not present
d v v wy, v

29 which row is correct for the location of a type of molecule or cell?
| type of molecule or cell lymph ar
a antibodies x v v key
b plasma proteins v x x v= present
cc lymphocytes jv v v x = not present
d phagocytes v x v

30 what effect does decreasing carbon dioxide concentration have on haemoglobin?
a itis less efficient at taking up oxygen and less efficient at releasing oxygen.
b itis less efficient at taking up oxygen and more efficient at releasing oxygen.
c_itis more efficient at taking up oxygen and less efficient at releasing oxygen.
d_itis more efficient at taking up oxygen and more efficient at releasing oxygen.

31 why does the red blood cell count increase in humans as they start living at high altitude?
a to allow more carbon dioxide to be excreted by the lungs, preventing a fall in blood ph
b to allow more oxygen to be taken up by the haemoglobin as the partial pressure of oxygen is
lower
c_ to allow more oxygen to be taken up by the lungs as there is a lower percentage of oxygen in
the air
d_ to allow more oxygen to be transported as the affinity of haemoglobin for oxygen is lowered

32 the diagram shows a photomicrograph of part of a bronchus.
which label identifies smooth muscle?
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33 which statements about all bronchioles are correct?
1 they have epithelium.
2 they have goblet cells.
3 they have muscle tissue.
a 1,2and3 b 1tand3only c= 2only d= 3only

34 which row shows the effects of emphysema?
‘ ' number of
alveoli elastin se

capillaries

a burst less decrease

b burst more increase

cc shrink less increase

d shrink more decrease

es

35 which row is correct?
' _ infectious or
disease transmission : :

non-infectious

a hiv/aids genetic infectious

b lung cancer pathogen infectious
c | sickle cell anemia genetic non-infectious
d tb pathogen non-infectious

36 the diagrams show the result of incubating two species of bacteria, p and r, on separate petri
dishes each containing nutrient agar.
three filter paper discs have been added to each petri dish.
bacteria (n) (n)
key
n = no antibiotic
x = antibiotic x
® y) ®) y) y = antibiotic y
bacteria p bacteria r

which statement is correct?

a_ antibiotics x and y are resistant to bacteria p.

b_ bacteria p are resistant to both antibiotics.

c_ bacteria r have a mutation that makes them resistant to antibiotic y.

d_ nisacontrol disc showing bacteria r grow when antibiotic y is not present.

37 the statements are about infectious diseases.
1 disease may be spread between humans by contact.
2  disease-causing organism has many antigenic variations.
3 spread of disease may be influenced by climate.
4  avaccination programme is available.
which row matches the correct statement numbers with each disease?
ae
a 1 1 and2 1 and3
b 1 and4 4 2
cc 2 and 3 1 and 3 1 and 4
d 4 1 and4 2 and 3

38 muscle cells have cell surface receptors for the neurotransmitter, ach. these receptors allow the
muscle to respond to a nerve impulse.
in the condition myasthenia gravis, the helper t cells stimulate a clone of b cells to become
plasma cells and secrete antibodies that bind to and block these ach receptors. the muscles
cannot be stimulated and begin to break down.
a short-term treatment for myasthenia gravis is to inject monoclonal antibodies into the blood.
what is the target of these monoclonal antibodies?
a antibodies that bind to ach receptors
b- muscle cell surface ach receptors
c plasma cells secreting anti-ach receptor antibodies
d_ the stimulating neurotransmitter ach

39 the diagram shows the simplified structure of an antibody.
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which statement is correct?

a_ uand x allow the antibody to bind to two different antigens.

bv allows the antibody to fit around the antigen.

c wcean bind to one specific antigen.

d_ xcan bind with a specific phagocyte receptor.

40 why have vaccination programmes eradicated smallpox but not tb?
a_ vaccination can provide immunity only for smallpox but not for tb.
b_ only tb is associated with poor living conditions.
c_ the smallpox virus showed little variation of antigens.
d_ the tb pathogen is a bacterium and the smallpox pathogen is a virus.

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