Download muhoroni district joint evaluation exam

MUHORONI DISTRICT JOINT EVALUATION EXAM
BIOLOGY PAPER 2
JULY/AUGUST 2014
MARKING SCHEME
1.
(a)
(i)
Parental genotypes
Gametes :
Aa
X
A
a
Aa ;
(1mk)
A
a
; (1mk)
;(1mk)
F1 generation:
2.
3
Aa
aa; (1mk)
Aa
(ii)
¼ OR 25% ;
(b)
Sickle cell anaemia;
Colourblindness ;
Haemophilia;
(a)
(b)
To determine the rate of transpiration;
(1mk)
Cut the shoot under water to avoid blockage of xylem vessels by air.
- Apply petroleum jelly between the cork/rubber bung and the glass, and between the rubber
and shoot to make the apparatus air tight.
- Open the reservoir tap when assembling to remove the air bubbles from the tubes
- Assemble under water to ensure no air bubbles are enclosed;
(1mk)
(1mk)
(1mk)
(1mk)
(c)
Light ; temperature ; wind; humidity; atmospheric, pressure;
(Any 3 mks)
(d)
In plasma - hydrogen carbonate;
In red blood cells - carbanaminohaemoglobin;
(2mks)
bung
(a)
Osmosis;
(b)
Piece A - was placed in a hypotonic solution. The cortex inner cells gained water by osmosis;
became turgid and increased in size/length. Epidermal cells are covered by a waterproof and inelastic cuticle hence did not gain water; leading to curvature outwards.
(2mks)
(c)
(1mk)
Piece B - was placed in hypertonic solution. Inner cortex cells lost water by osmosis, decreased in
length. Epidermal cells did not lose water due to waterproof cuticle, leading to curvature inwards.
(i)
Absorption of water and mineral salts
(1mk)
(ii)
4.
AA
Micro-organisms present synthesize, vitamins K1 B2 and B2;
(d)
Sap Vacuole;
(a)
(b)
(c)
Photosynthesis;
Carnivorous;
Rej. canivores
Aquatic
(d)
Terrestrial;
Algae
(e)
(1mk)
(1mk)
Zooplanktons
(1mk)
(1mk)
(1mk)
Small fish
Bird J
Large bird
(1mk)
(1mk)
More snails for bird M, hence increase in population of bird M;
- Green plants reduce as are eaten by more snails;
1
©Muhoroni District Form Four 2014
Biology Paper 2
- Population of large birds may remain constant/decrease/increase;
(Accept any 3 correct answer = 1mk)
(f).
Energy is lost through Respiration;/Heat through radiation, conduction and convection
;egestion; excretion; (Accept any one = 1mk)
(g).
5.
(a)
(b)
(c)
(d)
(e)
(a)
Drawn on graph paper
(6mks)
Rate of Reaction
6.
Pollution (accept named pollutants);
- Farming (accept agrochemicals, pesticides, herbicides);
- Fishing;
- Deforestation,
- Poaching/hunting
(Accept any 1 correct answer 1mk)
Primary Oocytes
(1mk)
(i)
Germinal epithelium;
(1mk)
(ii)
Mitosis;
(1mk)
(i)
Oestrogen;
(1mk)
(ii)
Healing and repair of the uterine wall following menstruation;
Stimulates the pituitary glands to secrete lutetinising hormones;LH
(Accept one correct named answer - 1mk)
(i)
Funnel/fallopian tube/oviduct
(1mk)
(ii)
Luteinising hormone
(1mk)
Secretes the hormone progesterone which maintains the thickened uterine wall and hence
pregnancy in the first three months.
(1mk)
Temperature (0C)
(b)
36.50C ± 0.50C
(c)
210C ± 0.50C
(d)
(i)
50C and 350C
rapidly
©Muhoroni District Form Four 2014
(1mk)
(1mk)
As the temperature increased, rate of reaction increased
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Biology Paper 2
because enzymes becames more active with increasing temperature within that range;
(2mks)
(ii)
380C and 500C
As temperature increased rate of reaction decreased rapidly
because the enzyme are getting denatured √ by the high temperatures.
(3mks)
(e)
(f)
(g)
(h)
7.
Through the action of sodium hydrogen carbonate; present in the pancreatic juice; secreted
(within the duodenum).
(2mks)
Pepsin, Rennin
(1mk)
(Any correct 1 answer)
High temperatures
(1mk)
Extreme of PH;
(1mk)
Bascal metabolic rate; Age; Occupation/Activity; sex; body size
(Mark any two correct = 2mks)
(i)
Fossils study (Paleontology)
Fossils describes ancestral forms of organisms that were accidentally preserved in naturally
occurring materials such as sedimentary rocks and resins√. They provide direct evidence of
gradual change from one type of organism to another√. They are preserved in sedimentary
rocks in layers; lowest oldest layers contains oldest fossils while uppermost younger layers
contains recent fossils √; Fossils show morphological changes of given organism over long
period of time e.g human skull, leg of a horse. Earliest fossils were those of monera,
followed by protoctista then fungi √; comparisonof fossils of different organisms may give
phylogenetic relationship between organisms√.
(ii)
Homologous Structure (divergent evolution)
Presence of homologous structures Implies same ancestry at some time of evolutionary
history √; One structure can give rise various different forms - divergent evolution √
divergent forms from same ancestry become adapted to particular function - adaptive
radiation √; examples are pentadactyl limbs present in vertebrates, beak structures in birds
etc√.
(Mark any 1 correct example after explanation)
Analogous structures (Convergent evolution)
The structures show how adaptation to similar environment can lead to a similarity in
structure and function in unrelated organisms; examples wings of birds and wings of insects,
eye structure of the humans and octopus√.
(Mark any 1 correct example after explanation)
(iii)
Vestigial structures (organs)
They have ceased to function or greatly reduced (rudimentary) in course of evolution √as
were selected against as animals became adapted to different modes of life √. Example caecum and appendix in man, coccyx in man, nictitating eye membrane in mammals etc.
(Mark any 1 correct example after explanation)
(iv)
Comparative Embryology
Embryos of different vertebrate species have many common features, suggesting a common
ancestry e.g all vertebrate embryos have tails √ all vertebrate have gill pouches at some
development stage√. The closer the resemblance between the early stage of embryo the
closer their evolutionary relationship (Recapitulation theory) √. Showing or indicating
different ancestry/phylogeny
(v)
Cell biology and biochemistry
All eukaryotic cells contains same cell organelles as mitochondria lysosomes etc and have
chemicals like ATP,RNA,DNA, etc, indicating common ancestry. Blood pigments are of
©Muhoroni District Form Four 2014
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Biology Paper 2
universal occurrences e.g haemolglobin, haemocyanin , thyolobin etc. Plant cells have
cellulose cell wall chloroplast, sap vacuoles etc unlike animal cells√.
(vi)
8.
Comparative Serology
Blood proteins (antigens and antibodies) and their reaction in different animals show
phylogenetic relationship; antibody antigen reaction in an immunological reaction leading to
precipitate formation when blood sera of of different organisms are mixed shows common
ancestry√ . The greater the amount of precipitate formation in two different animals the
closer the phylogenetic relationship;
(vii) Geographical distribution
Initially, the earth was one landmass pangea Due to plate tectonic forces it splited into present
day continents; (continental drift). Before the split areas had similar climates√ after split,
members of some spheres became isolated √ by barriers complied different climatic regions
evolved inadequately adapting√ in the areas isolated landmasses led to evolution of new
forms √ of organisms quite distinct from those found in other areas.
(viii) Taxonomy
Modern classification of organisms id based on the similarities and differences that exists
between various natural characteristics. Organisms in some taxonomic unit share similar
characteristics indicating or showing a common ancestry or origin√.
(35 ticks, maximum 20mks)
(a)
(i)
The auxins are positively geotropic √ diffuse to the lower region of the root tip. High
auxin
concentration inhibits √ growth in roots thus lower region of root grows slowly; then
upper part, thus curvature downwards √.
(3mks)
(ii)
Auxins are positively geotropic, diffuse to lower region of the shoot tip high auxin
concentration stimulates growth in shoot, lower region with high auxin grows faster,
than upper part, thus curvature upwards √.
(3mks)
(b)
Looking at the sunlight jet
 Circular muscles in the iris contract; while
the radial muscles in the iris relax
 The pupil becomes small;
 Less light passes through the pupil to get
into the eye;
 Ciliary muscles in the ciliary bodies relax;
 Suspensary ligments become stot/tension
increases in the suspensory ligaments;
 The lens becomes long and thin;
 The jet is brought to focus
Looking back at a page
 Circular muscles in the iris relax while radial
muscles contact;
 The pupil becomes large;
 More light passes through the pupil to get
into the eye
 Ciliary muscles in the ciliary bodies contract
 Suspensory ligments loosen/tension is
reduced or lost in the suspensory ligaments;
the lens becomes short and thick;
 The printed words in the page are brought to
focus
Maximum 14mks
S – cale
C-urve
A – xes
P-lotting
Total
©Muhoroni District Form Four 2014
(14mks)
23 marks, maximum - 20mks)
02 mks; Horizontal and vertical scale workable, consistent 1mk each
01mk; Be smooth and continuous.
01 mk; x –axis, temperature be in 0C (½ mk)
y-axis, rate of reaction (½ mk)
02 mks; All points be well plotted.
(06mks)
4
Biology Paper 2