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Biology Paper 231/2 K.C.S.E 1999 Question Paper
Biology Paper 231/2 K.C.S.E 1999
Course:Secondary Level
Institution: Kcse question papers
Exam Year:1999
BIOLOGY PAPER 231/2 K.C.S.E 1999
PRACTICAL MARKING SCHEME
1. Confidential requirement: Specimen S- Mango fruit, mature but not ripe,
Specimen T- Leguminous pod (bean fruit) any legume.
You are provided with specimens labeled S and T. draw a plan diagram of the cut
surface of specimen S. label it.
(b) Open specimen T longitudinally. State three differences between specimen S and
T
S- One seed
- Meso-carp/ epicarp and endocarp
separated
T – Several seeds/ many, two – ten
- Mesocarp fused with epicarp and
endocarp
- Placentation central Rej free central
- Fleshly succulent fruit
- Placentation marginal
- Dry fruit
- Absence of sutures/ lines of
weaknesses
- Pericarp thick
- Presence of sutures/ lines of
weakness
- Pericarp thin
(c) With reasons in each case state the type of fruit and method of dispersal for
specimen S and T
Specimen S
Type of fruit – Drupe
Reason - One seed/ hard endocarp/ fibrous endocarp/owwte
Method of dispersal - Animal/ Man
Reason – Fleshy mesocarp/ scented/ juicy/succulent/ brightly
Coloured. Rej. Edible
Specimen T.
Type of fruit - legume pod/ leguminous fruit
Reason – two sutures/ lines of weakness
Method of dispersal- Mechanical ( self) explosive mechanism
Reason – lines of dehiscence(two) lines of weakness.
2. You are provided with specimen labeled X, Y and Z
(a) Identify the specimens
X – Ulna
Y- Humerus Rej. Humerous
Z- Radius
(b) Name the part of the mammalian body from which the specimens were
obtained.
Forelimb/arm/legs/ humerus/ upper arm/ ulna and radius lower
arm
(c) Make a drawing to show how X, Y, and Z are articulated
State the magnification of your drawing X ¼ - X1
(d) With reasons name the type of joint formed at the proximal and distal ends of
Specimen Y
Proximal end- Ball and socket
Reason- Head shaped like a ball/ ball like/ rounded head/ round head/ allow
movement.
Distal end- Hinge joint
Reason – allow movement in only one plane/ presence of a groove/ presence of
condy/ troches which articulates with sigmoid notch.
(e) What is the significance of the part labelled W
Attachment of muscles/ tendons; formation of hinge joint; with adjacent bone)
Prevent overstretching of forearm backwards; allows movements in only plane/
180 degrees.
You are provided with a specimen labeled R. Examine it
(f) Name the observable features that adapt the specimen to:
Forward movement
- Trail/ tail fin/tail muscles/candal fin
Balancing
- Pectoral fins; pelvic fins
Staying upright
- Dorsal fins; anal fins/ventral fins
Fast movement
- Streamlined body
- backward facing scales,
- Slimy/ Mucoid surface
3. You are provided test for the food substances in the suspension in the table
below.
(a) Using reagents provided test for the food substances in the suspension. In
the table below, record the food tested, your procedures, observations and
conclusions.
Food Substance Procedure Observation Conclusion
Starch Add a drop of
iodine on M on a
white tile
Brown colour/ retain
colour of iodine/
yellow/ reddish
Acc. No colour change
Rej. Red/No change
alone
Starch absent
Reducing sugar Add a few drops of
benedict’s solution
and warm/ heat/
boil
Blue colour of
benedict’s solution/
colour change to
purple/ violet Rej. No
change alone
Reducing sugar
absent/
monosachariaple
sugar absent/ Rej
specific names of
sugars e.g glucose
No reducing sugar Add a few drops of
HCl and heat;
(cool), add sodium
bicarbonate; add
benedict’s solution
and heat Note –
stop heating if step
is omitted.
Fizzing/
effervescence/bubbling;
Red precipitate/ colour
changed from blue to
green, yellow orange/
brown/ red; order of
colour must be
correct.
Acc. Final colour
change. E.g green,
yellow, orange brown
Non- reducing
sugar; presence of
reducing sugar after
hydrolysis.
Protein Add 1% CuSO4;
Sulphate and then
sodium hydroxide
- If formula is used
must be correct.
Order does not
matter
Colour change to
purple/violet
Protein present
- If food substance is omitted or wrong, procedure, observation and
conclusion wrong
- If cooling absent in non- reducing sugars stop marking
(b) Name two enzymes that may be required to digest suspension M in the
alimentary canal in human beings.
Pepsin/ trysin/ erepsin /sucrose/ invertase
(c) State the role of hydrochloric acid and sodium hydrogen carbonate in the
experiment.
- HCl hydrolyze/breakdown/ digest/convert/ change; non- reducing
sugars/disaccharides/ complex sugars/(rej sucrose) for reducing sugars/simple
sugars/ monosaccharides
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