BIOLOGY
FORM 4
END TERM EXAMS
TERM 1 2021
PAPER 1
(THEORY)
TIME 2 hrs
INSTRUCTIONS
- Answer ALL the questions
- State the functions of each of the following organelles: (2mks)
- Plasma membrane.
- Ribosome
-
- State two ways by which leaves of plants are adapted to gaseous exchange. (2mks)
- State a function of aerenchyma tissue. (1mk)
- How do identical and fraternal twins arise?
- Identical (2mks)
- Fraternal (1mk)
- State three functions of an exoskeleton. (3mks)
- What is meant by destarching a leaf? (1mk)
- State two ways in which sunlight increases the rate of transpiration. (2mks)
- List two features of flowers that attract insect pollinators. (2mks
-
- State two adaptations of pelvic girdle to its functions. (2mks)
- Name the type of joint found between the femur and pelvic girdle. (1mk)
- The table below shows some nutrients, their sources and disease caused by their deficiencies in man. Complete the table. (2mks)
Nutrient Source Deficiency disease Iron Night blindness -
- Give two ways in which red blood cells are adapted to carry out their functions. (2mks)
- Name chemical forms in which carbon IV oxide is transported in the human body. (2mks
- Name any two divisions of the kingdom plantae. (2mks
-
- Name the hormone produced in human body when one takes in a large amount of water. (1mk)
- What disease results from the inadequate production of the hormone in 12(a) above? (1mk)
- A cow in a paddock was found to be infected with ticks. State the trophic level occupied by the (2mks)
-
- Cow.
- Tick
- Give one disadvantage of using pesticide to eliminate the ticks. (1mk)
-
- What is the role of water in germinating seeds? (2mks)
-
- State two limitations of fossil records as an evidence for organic evolution theory. (2mks)
- State an ideal that led to the formulation of larmacks theory of evolution. (1mk)
- Study the figure below.
A seedling with straight radical and plumule was attached to rotating Klinostat as shown above.- Draw the appearance of the seedling after three days. (1mk)
- Explain your observations (a) above. (2mks)
-
- Write the base sequence of MRNA that would be coded from the DNA strand shown below. (2mks)
- How many nitrogenous bases code for a single amino acid? (1mk)
- Write the base sequence of MRNA that would be coded from the DNA strand shown below. (2mks)
- Why are animal cells put in isotonic solution when performing an experiment? (2mks)
- Study the diagram below
- Suggest the aim of the experiment. (1mk)
- Account for the results observed at the end of the experiment. (2mks)
-
- Name the parts labeled A, B and C. (3mks)
- ……
- ……
- …..
- Name the process by which water passes from the soil to the part labeled A. (1mk)
- Name the parts labeled A, B and C. (3mks)
- State role of the following bacteria in the nitrogen cycle. (3mks)
- Nitrosomonas
- Nitrobacter
- Azotobacter
- Explain the importance of each of the following during digestion in man.
- Teeth (1mk)
- Saliva (1mk)
-
- Distinguish between prokaryotic and eukaryotic cells. (2mks)
- Name one kingdom with:
- Prokaryotic cells (1mk)
- Eukaryotic cells(1mk)
- What would blood gain on passing through each of the following organs:
- The lungs(1mk)
- Active muscles(1mk)
- State two main characteristics of organisms in kingdom fungi. (2mks)
- State two adaptations of fruits dispersed by wind. (2mks)
-
- Describe how white blood cells fight against infection. (2mks)
- A drop of a person’s blood shows clumping with the anti-B serum but not with anti-A serum. State the person blood group. (1mk)
- Calculate the diameter of the cells in micro-metre given that the diameter of the field of view is 3mm and that they are 10 cells across the field of view, the total magnification was 100x. ((2mks)
-
- Apart from AIDs, name one diseases of the reproductive system in man that is caused by viruses. (1mk)
- State one way by which HIV/AIDs is transmitted from mother to child. (1mk)
- Below is a diagram of a specialized cell:
- Name parts (2mks)
A
C - What is the role of part D? (1mk)
- Name parts (2mks)
- State two roles of progesterone. (2mks)
- What is parthenocarpy? (1mk)

MARKING SCHEME
- State the functions of each of the following organelles: (2mks)
- Plasma membrane. - Control movement of materials in and out of the cell;
- Ribosome - Site of protein synthesis;
-
- State two ways by which leaves of plants are adapted to gaseous exchange. (2mks)
- Presence of stomata to allow passage of gases;
- Presence of intercellular spaces/air passages to allow free circulation of air;
- Thin to allow easy diffusion of gases;
- Flattened shape to offer large surface area of air to reach cells;
- Moist inner surface of cells to allow easy diffusion of gases;
- Exposure to air to allow easy diffusion of gases;
- State a function of aerenchyma tissue. (1mk)
- It allows for gaseous exchange between the shoot and the root
- It allows for gaseous exchange between the shoot and the root
- State two ways by which leaves of plants are adapted to gaseous exchange. (2mks)
- How do identical and fraternal twins arise?
- Identical (2mks) - a fertilized ovum divided into two; and develops into two separate embryos;
- Fraternal (1mk) - two different ova are fertilized;
- State three functions of an exoskeleton. (3mks)
- Attachment of muscle;
- Protect inner delicate tissues from mechanical damage;
- Prevent entry of pathogens;
- Prevent drying of organisms;
- What is meant by destarching a leaf? (1mk)
- Process by which the leaf is made devoid of starch; by keeping it in dark (about 48 hours); so that all starch present is used up.
- Process by which the leaf is made devoid of starch; by keeping it in dark (about 48 hours); so that all starch present is used up.
- State two ways in which sunlight increases the rate of transpiration. (2mks)
- By increasing internal leaf temperature thus high rate of evaporation of water from the leaf;
- By increasing the size of stomata opening aperture hence large surface area for water loss;
- List two features of flowers that attract insect pollinators. (2mks
- Brightly colored petals;
- Sweet scented nectar from nectarines (nectarines glands);
-
- State two adaptations of pelvic girdle to its functions. (2mks)
- They have a depression/socket on the side of ileum; which articulates with end of femur to form a ball and socket joint.
- They have a hole;
- Obturator foramen has a small aperture;
- Public symphosis is made of flexible cartilage;
- Hard to support upper part of body;
- Bones are fused to form firm frame to support body.
- Name the type of joint found between the femur and pelvic girdle. (1mk)
- Ball and Socket
- Ball and Socket
- State two adaptations of pelvic girdle to its functions. (2mks)
- The table below shows some nutrients, their sources and disease caused by their deficiencies in man. Complete the table. (2mks)
Nutrient Source Deficiency disease Iron Liver/ greens Anaemia Vitamin A Carrots/ fresh green vegetables Night blindness -
- Give two ways in which red blood cells are adapted to carry out their functions. (2mks)
- lack of nucleus increasing the surface area of haemoglobin package;
- Small in size to squeeze in the small capillaries;
- Numerous/many to increase surface for efficient transport of oxygen;
- Biconcave to increase the surface area for oxygen to diffuse in
- Mark only first two.
- Name chemical forms in which carbon IV oxide is transported in the human body. (2mk)
- Weak carbonic acid;
- hydrogen carbonate;
- Give two ways in which red blood cells are adapted to carry out their functions. (2mks)
- Name any two divisions of the kingdom plantae. (2mks
- Bryophyta;
- Spermatophyte;
- Pteridophyta;
-
- Name the hormone produced in human body when one takes in a large amount of water. (1mk)
- ADH/ Vasepresin;
- ADH/ Vasepresin;
- What disease results from the inadequate production of the hormone in 12(a) above? (1mk)
- Diabetes insipidus; rej. Water diabetes
- Diabetes insipidus; rej. Water diabetes
- Name the hormone produced in human body when one takes in a large amount of water. (1mk)
- A cow in a paddock was found to be infected with ticks. State the trophic level occupied by the (2mks)
-
- Cow. - Primary consumer;
- Tick - Secondary consumer;
- Give one disadvantage of using pesticide to eliminate the ticks. (1mk)
- Pollutes environment;
- kill non-targeted organisms
Mark first one
-
- What is the role of water in germinating seeds? (2mks)
- Hydrolysis of stored food;
- Acts as a solvent for hydrolysed foods;
- Medium of transport;
- Activation of enzymes for hydrolysed foods;
- Medium for enzymatic reactions;
- Soften seed coat to allow plumule and radical to come out
- Marked only first two
-
- State two limitations of fossil records as an evidence for organic evolution theory. (2mks)
- Desctruction of fossils by geological activities;
- Distortion of information due to sedimentation;
- Missing records;
(only first two)
- State an ideal that led to the formulation of larmacks theory of evolution. (1mk)
- the theory of need;
- the theory of use and disuse;
- acquired traits can be inherited;
- State two limitations of fossil records as an evidence for organic evolution theory. (2mks)
- Study the figure below.
A seedling with straight radical and plumule was attached to rotating Klinostat as shown above.- Draw the appearance of the seedling after three days. (1mk)
Ans - Explain your observations (a) above. (2mks)
- Rotating the seedling will evenly distribute the Auxins (on shoot and root); resulting to uniform growth (shoot and foot grow horizontally);
- Rotating the seedling will evenly distribute the Auxins (on shoot and root); resulting to uniform growth (shoot and foot grow horizontally);
- Draw the appearance of the seedling after three days. (1mk)
-
- Write the base sequence of MRNA that would be coded from the DNA strand shown below. (2mks)
Ans - How many nitrogenous bases code for a single amino acid? (1mk)
- three;
- three;
- Write the base sequence of MRNA that would be coded from the DNA strand shown below. (2mks)
- Why are animal cells put in isotonic solution when performing an experiment? (2mks)
- To maintain osmotic pressure of the cells in the tissue; to as to obtain accurate results.
- To maintain osmotic pressure of the cells in the tissue; to as to obtain accurate results.
- Study the diagram below
- Suggest the aim of the experiment. (1mk)
- To indicate the burning food produces carbon IV oxide;
- To show water was produced when food burns;
(Only first one)
- Account for the results observed at the end of the experiment. (2mks)
- Lime water form white precipitate; to show that carbon IV oxide is produced;
- blue cobalt II chloride turns pink; due to the presence of water produced when food burns
- Suggest the aim of the experiment. (1mk)
-
- Name the parts labeled A, B and C. (3mks)
- - cell vacuole;
- - cell wall;
- - cell/plasma membrane;
- Name the process by which water passes from the soil to the part labeled A. (1mk)
- osmosis;
- osmosis;
- Name the parts labeled A, B and C. (3mks)
- State role of the following bacteria in the nitrogen cycle. (3mks)
- Nitrosomonas - Converts Ammonia to nitrites;
- Nitrobacter - Converts nitrites to nitrates;
- Azotobacter - Fix nitrogen into ammonia which is then converted to nitrates;
- Explain the importance of each of the following during digestion in man.
- Teeth - Cut and grind food to increase surface area for digestion; and easy swallowing.
- Saliva - contain water which is a medium for chemical reactions; and acts as a solvent.
-contain salivary amylase/ptyalin which digests starch to maltose. Any first one.
-
- Distinguish between prokaryotic and eukaryotic cells. (2mks)
- Prokaryoli – nuclear materials not membrane bound (naked;)
- Eukaryotic – nuclear bound by membrane;
NB-Use sentence connectors)
- Name one kingdom with:
- Prokaryotic cells - Monera;(1mk)
- Eukaryotic cells - Protoctista/plantae/animalia/fungi; (1mk)
- Distinguish between prokaryotic and eukaryotic cells. (2mks)
- What would blood gain on passing through each of the following organs:
- The lungs - oxygen;(1mk)
- Active muscles- carbon IV oxide; lactic acid.(1mk)
- State two main characteristics of organisms in kingdom fungi. (2mks)
- Eukaryotic;
- Lack chlorophyll;
- Basic unit isophae;
(only first two.)
- State two adaptations of fruits dispersed by wind. (2mks)
- are small and light to be carried easily by wind;
- Have hair like structures or floss to increase buoyancy in the air;
- Develop wing-like extensions to increase surface area for increased buoyancy in the air;
(only first two.)
-
- Describe how white blood cells fight against infection. (2mks)
- By engulfing and digestion pathogens;
- By secretion of antibodies; which destroy pathogens and their products.
- A drop of a person’s blood shows clumping with the anti-B serum but not with anti-A serum. State the person blood group. (1mk)
- blood group B;
- blood group B;
- Describe how white blood cells fight against infection. (2mks)
- Calculate the diameter of the cells in micro-metre given that the diameter of the field of view is 3mm and that they are 10 cells across the field of view, the total magnification was 100x. ((2mks)
- Size of cell = diameter of field of new =
No of cells
=(3×1000)/10
= 300µm.
Actual size =300/100
- Size of cell = diameter of field of new =
-
- Apart from AIDs, name one diseases of the reproductive system in man that is caused by viruses. (1mk)
- Hepatitis B;
- Herpes;
- State one way by which HIV/AIDs is transmitted from mother to child. (1mk)
- Breast feeding;
- Through placenta;
- Apart from AIDs, name one diseases of the reproductive system in man that is caused by viruses. (1mk)
- Below is a diagram of a specialized cell:
- Name parts (2mks)
A - axon;
C - cell body; - What is the role of part D? (1mk)
- Speed up the transmission of the impulses;
- Speed up the transmission of the impulses;
- Name parts (2mks)
- State two roles of progesterone. (2mks)
- growth of mammary glands
- Inhibit FSH;
- Inhibit prolactin release
- Prevents construction of myometrium;
(Only first two)
- What is parthenocarpy? (1mk)
- Formation of fruit without fertilization
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