NAME:………………………………………..…………….. ADM. NO………………
SCHOOL:……………………………………………………SIGNATURE……………… DATE…………….………………
231
BIOLOGY
(Theory)
TIME: 2 HOURS
OCT/NOVEMBER
FORM 2
INSTRUCTIONS TO CANDIDATES
Write your name and Adm. number in the spaces provided.
Answer ALL the questions in section A and B in the spaces provided,
FOR EXAMINERS USE ONLY
Question
Maximum score
Candidates score
1-17
70
1.The diagram below represents a plant cell organelle
a) Name the organelle. (1mk)
b) In which of the labelled parts does carbon (IV) Oxide fixation occur? (1mk)
c) Name the parts labelled A and B and state how each is adapted to its functions. (4mks)
A………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
B………………………………………………………………………………………………………………………………………………………………………………………………………………………………………
d) Explain what would have happened to the structures labelled X had the plant been kept in darkness for 48 hours. (2mks)
2. The diagram below shows some components of a light microscope.
Name the parts labeled (2mrks)
K ………………………………………………………………………………………………
M ………………………………………………………………………………………………
State the functions of (2mrks)
P ………………………………………………………………………………………………
Q ………………………………………………………………………………………………
A student was viewing a prepared slide of a plant cell under high power microscope. The features of the cell were blurred. Which one of the labelled parts of the microscope would the student use to obtain:-
a sharper outline of the features. (1mrk)
………………………………………………………………………………………………
Give the formula used to calculate magnification in a light microscope. (1mrk)
………………………………………………………………………………………………
A student was preparing a section of a plant cell to be viewed on a light microscope. Give a reason for each of the following steps:-
(i)Cutting a very thin section (1mrk)
(ii)Staining the section (1mrk)
(iii)Putting the section in water (1mrk)
3.The diagram below shows part of a longitudinal section of a root: –
(a) Identify cells K and L :- (2 mks)
K
……………………………………………………………………………………………………….……………………………………………………………………
L
……………………………………………………………………………………………………….……………………………………………………………………
(b) State two adaptations of Cell K to its functions :- (2 mks)
……………………………………………………………………………………………………….……………………………………………………………………………………
……………………………………………………………………………………………………….……………………………………………………………………………………
4.State three main functions of the stomach in human beings:- (3 mks)
5.Name the cell organelles responsible for :
i) Protein synthesis
ii) Destroying worn – out organells and cells
6.a) Lietego school biology student used a microscope with x40 objective lens and x5 eye piece lens which had 2mm radius. Calculate the area of the field of view in micrometers. (2mks)
b) What is the average size of the cell in micrometers (2mks)
7.(a) Identify the organelle shown below:- (1mk)
(b) How is the organelle you have identified in (a) above suited to its function(2mks)
8.State three properties of the cell membrane (3mks)
9.a) What is the formula for calculating linear magnification of a specimen when using a
hand lens (1mk)
10.Distinguish between the following terms :-(4mks)
Magnification and resolution of a microscope
Mounting and staining of a specimen
11.Name the organelle that performs each of the following functions in a cell. (3mks)
Transport of packaged glycoproteins
Destruction of worn out cell organelles
(c) Synthesis of proteins
12.Why are the following procedures done when preparing sections to be observed under a light
microscope? (3mks)
Making of thin sections
Using a sharp blade to make the sections
c)Staining
13.Statethree physiological processes that are involved in movement of substances a cross the cell membrane (3mks)
14Name the diseases caused by deficiency of : (2mks) (a) Iodine
(b) Vitamin C
15.What are the two functions of bile salts during the process of digestion?(2mks)
16.State two adaptations of herbivores which enable them to digest cellulose(2mks)
17.State three factors that affect the rate of osmosis(3mks)
18.State three roles of light in photosynthesis(3mks)
19.Explain how saliva is important in digestion (2mks)
20.Briefly explain the fate of the following products from the light stage of the process of
Photosynthesis (3mks)
(a) Oxygen
b)Hydrogen
ATP
21.State three ways by which plants compensate for lack of the ability to move from one place
to another(3mks)
21.State four difference between monosaccharide and polysaccharides(4mks)
23.Describe how mammalian small intestine is adapted to its function (7mks)
MARKING SCHEME
BIOLOGY F2
1.Chloroplast ; (1mk)
b) B: (1mk)
c) A – Grana; contain chlorophyll, which traps light energy ,enabling light reaction of
photosynthesis to take place ;
B – Stroma ; contains enzyme, which control dark reactions of photosynthesis; (4mks)
d) They would be absent ; because starch they contain would have been hydrolysis to glucose; (2mks)
2 a) K- eye piece
M-coarse adjustment knob.
b) P-concentrate the light/focuses the light
Q- magnification of the image.
c) i) – N
ii) – Eyepiece magnification X objective lens magnification
d) i) For light to pass through easily;
ii) To make the features more clear and distinguishable;
iii) For cells to remain turgid;
3. (a) K – Root hair cell (2 mks)
L – Endodermis
(b) Elongated to increase area for absorption of water and mineral salts
4.(a) (i) Temporary storage of food
(ii) Secretes digestive enzyme
(iii) Secretes mucus – gastric juice
(iv) Secretes Hcl – Endocrine function i.e. Gastrine hormone
5.i) Ribosomes (1
ii) Lysomes (1
6.. a) 1mm = 1000(m
Areas = (r2 = 22/7 x ( 2000)2
= (22/7 x 2000 x 2000);
= 125714.29(m2 ; (2mks)
b) 125714.29
5
= 25142.858(m2
7.a) mitochondria;
b ) -has cristae/inner membrane highly folded to increase surface area; for respiration.
-Has matrix medium for respiratory activities; (reject (b) if (a) is wrong.)
-Has matrix medium for respiratory activities; (reject (b) if (a) is wrong.)
8.Sensitive to change in temp; sensitive to changes in PH; has both negative and positive
charges;
9. Length of drawing ;
Length of object
10a) Magnification – Ability of a microscope to enlarge tiny objects
Resolution – Ability of a microscope to separate between two tiny structures under
magnification to appear distinct
b) Mounting – The placing of prepared slide on stage of a microscope;
Staining – Use of chemical stain on specimen for clear observation
11.(a) Golgi bodies/Golgi apparatus;
(b) Lysosome(s):
(c ) Ribosomes;
. 12. (a) Make the sections transparent:
(b) To produce thin sections/ Not to distort the cells:
(c ) To distinguish between different parts/organelles of the cells
13. Diffusion;
Osmosis ;
Active transport ;
14. a) Goiter;
b) Scurvy; –
15.To emulsify fats;
– To provide an alkaline condition for enzyme activities;
– To provide an alkaline condition for enzyme activities;
16. Long gut / many chambers to provide large surface area for digestion; bacteria in rumen has
enzyme cellulase which digest cellulose (to glucose/ sugars).
17. Concentrated of the solutions separated by a semi-permeable membrane; existence of
concentration gradient; temperature of the solution;
18. Photolysis – Splitting water into H+ and oxygen gas;
– Synthesis of ATP to be used during dark stage;
– Synthesis of chlorophyll necessary for photosynthesis;
19.- Enzymes amylase digests starch to maltose
– Mucus lubricates food
20. Oxygen-releases to the atmosphere or used by plants for respiration;
Hydrogen-enter dark stage, where it combines with CO2 to form simple sugar;
ATP- provide energy during the combination of hydrogen a toms with CO2in dark stage; –
21Plants are able to synthetize their own food
– Plants are able to use pollination rather rhan moving to seek mating partners
– Use seed and fruits dispersal to colonize new habitats (3×1=3mks)
22.
Monosaccharide
Polysaccharides
– Are soluble in water
– Are insoluble in water
– Form sweet tasting solution
– Do not have a sweet taste
– Reduce Copper(II) ions in benedicts solution to
Copper (I) ions when heated together
– They do not reduce
– Are crystalizable
– Are not crystallizable
23.)intestines relatively long/coiled /folded ;this allows food enough time for absorption.
Intestines long /have villi; to increase the surface area for absorption and digestion ;
The walls have glands which secrete enzymes for digestion;(examples of correct enzymes
e.g. Maltose, sucrose lactose etc).some glands /goblet cells also produce mucus; which protects
The intestinal wall from autodigestion/being digested; and reduce friction;
Intestines have opening of ducts which allows bile pancreatic juice into the lumen;
The intestines have circular and longitudinal muscle, whose contraction and relaxation/peristalsis;
Leads to mixing of food with enzymes/juice; facilitating rapid digestion and help push food along the gut; the intestines are well supplied with blood vessels to supply oxygen/ remove digested food from an efficient absorption and transporting system to move the food away from the small intestines;
Have lacteal vessels for transport of fat/lipid; have thin epithelial lining; to facilitating fast absorption /diffusion;
Note. Allow increases in surface are for absorption only once
