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TEZE DISTRICT
231/3
BIOLOGY
PRACTICAL
PAPER 3
JULY / AUGUST 2013
MARKING SCHEME
1.
a) i) Asexual / vegetative propagation
ii) – Presence of buds / lateral buds
- Presence of stored food / water
iii) – Oxygen from the soil diffuse through the lenticels
b) i) In solution Q – strips flabby / flexible / faccid / tender / limp
In solution T – stripes firm / turgid / stiff / rigid
ii) Solution T – Hypotomic / less concentrated than cell sap, therefore water was drawn into the cells
by osmosis hence strips become firm / turgid / rigid
solutions Q – hypertomic / more concentrated than the cell sap, therefore cells lost water by osmosis
/ exosmosis hence strip / cell become flaccid / soft / plasmolysed.
c) i)
Observation
Turns blue black / blue / black
No color change
Effervescence occur colour changes to yellow /
orange / brown red
Conclusion
Starch present
Reducing sugar absent
Non – reducing sugar present / reducing sugar
present after hydrolysis of non- reducing sugar
ii) Starch hydrolysed / converted to simple sugar by solution L / acid
iii) Dilute HCl / Acid
e) i) Many / more bubbles /rapid effervescence due to enzymatic activity
ii) – Crushing increased the surface area more in B than in A for enzymatic activity
iii) 2H2O2
2H2O + O2 (Must be balanced)
or
hydrogen peroxide
catalase water + oxygen
iv) Catalase
2.
a) i) M – Lumbar vertebra
H – Humerus
ii) – Neural canal for passage of spinal cord
- Transverse process for attachment of muscles
- Facets for articulation with other vertebra
- Vertebraterial canal for passage of blood vessels and nerves : (NB- nerves only is incorrect)
- Neural spines for attachment of muscles
 Teze 2013
Form four
1
Biology 231/3 Marking scheme
- Neural arch and centrum for protection of spinal cord
(any 2 x 1= 2mks)
iii)
Lumbar vertabra (M)
- Vertebraterial canals absent
- Large transverse process
- Neural spine broad / wide / large
- Neural canal is narrower
- Metapophysis and anapophysis are present
Cervical vertebra (N)
- vertebrial canals present
- Divided transverse process
- Neural spine narrow / small
- Neural canals wider
- Metapophysis and anapophysis are
absent
(any 2 x 1= 2mks)
iv) – Hind limb
v) – P – Thoracic vertebra
(1mk)
Reasons – long neural spine
- Short transverse processes
- Facets for rib articulation/ tubercula facet/ demi facet / capitula facet
(any 1 x 1= 1mk)
b)
A1
- Vascular bundles arranged in a ring
- Has a distinct cortex and pitch
- Vascular cambium present
B1
- Vascular bundles scattered
- Pitch and cortex absent
- Vascular cambium absent
(any 1 x 1= 1mk)
c) i) Arthropoda
(check spelling)
ii) – Presence of exoskeleton
- Have segmented body
- Have jointed appendages
(any 1 x 1= 1mks)
iii)
Forewing / Outer wing
- Hard
- Narrow / smaller
- Stiff / rigid
- Opaque
Hind / Inner wing
- Membranous / soft
- Broad / wide
- Flexible
- Translucent
(any 1 x 1= 1mk)
d) i) I – Artery
II – Vein
ii)
I (artery)
- Walls are thick and elastic
- Have no valves except at the base of large
arteries leaving the heart
- Narrow lumen
II (Vein)
- Walls thin / less muscular and elastic
- Have valves at intervals throughout
their length
- Wider lumen
(any 1 x 1= 1mk)
iii)A – Endothelium
B – Lumen
 Teze 2013
Form four
2
Biology 231/3 Marking scheme
C – Elastic layer
D – Muscular layer
3.
a) i) – Etiolation
ii) – To reach light
iii) Positive phototropism (reject phototropism alone)
iv) Auxins move to the darker side causing faster growth on this side resulting in curraline of the
shoot towards the source of light
A1
A2
- Yellow (yellowish is incorrect)
- Smaller leaves
- Taller / longer internodes
- Thin stems
- Weak / feeble plants
- Green
- Big leaves
- Shorter stem / internodes
- Thick stems
- Firm / sturdy plants
b) i)
Type of evolution
Divergent evolution
Convergent evolution
Type of structures
Homologous
Analogous
ii) – Flying
iii) A1 – Tearing (heavy clamed)
A2 – Wading (webbed)
 Teze 2013
Form four
3
Biology 231/3 Marking scheme