2011 Biology NECO Theory Past Questions

Hint

1(a)    (i)   Define the term photosynthesis.

Photosynthesis can be defined as the process whereby green plants manufacture their food /carbohydrate from simple inorganic substances such as carbon-dioxide and water the presence of chlorophyll which traps radiant energy food sunlight with oxygen released as a by-product

6CO₂  +    6H₂O         →        C₆H₁₂O₆        +       6O₂

(ii)      State TWO advantages of photosynthesis to man.

1. Production of food: photosynthesis provides food for man
2. Purification of the atmosphere: waste products like CO₂ released during respiration by both plants and animals is removed from the atmosphere for the use during photosynthesis
3. Release of oxygen to the environment: oxygen needed for respiration by man is released into the environment during photosynthesis
4. Photosynthesis provides the building blocks of carbon skeleton on which other food substances such as protein, fats & oil, required by man are built

(iii)     List THREE structural adaptations of leaves for photosynthesis.

1. The leaf blade is flat with large surface area to expose the chloroplasts so as to receive the maximum amount of light
2. The leaf is thin, to allow easy penetration of light to the mesophyll cells

b(i)     List TWO importance of auxins to plants.

1. Auxins are involved in the process of cell division
2. Auxins stimulates fruit development / stimulation the ovary to develop into fruit
3. Auxins promotes growth uniformity on all sides of the stem

(ii)      State THREE forms of vegetative propagation.

• Rhizomes e.g. ginger
• Bulbs e.g. onion
• Corm e.g. cocoyam
• Stem tubers e.g. yam
• Suckers e.g. plantain
• Bulbis e.g. figuil
• Leaves etc e.g. bryophyllum
• Artificial vegetative propagation by mean of cutting e.g. cassava
• Budding e.g. orange
• Layering e.g. tomato
• Grafting e.g. mango

c(i)     Define a joint.

A joint is a region of the skeleton where two or more bones articulate

(ii)      List TWO examples of movable joints.

• Hinge joint
• Sliding / gliding joint
• Ball and socket joint
• Pivot joint

(iii)     State FOUR characteristics of digestive enzymes

1. They are proteins
2. An enzyme increases the speed of a reaction but remains unchanged at the end of the reaction
3. An enzyme is specific in action (i.e. it speeds up a particular reaction)
4. Reactions catalyzed by enzymes are usually reversible
5. An enzyme cuts best within a narrow range of temperature
6. Enzymes are denatured by heat above 60^OC
7. An enzyme acts best within a narrow range of P14
8. A small amount of enzyme can catalyze the reaction of a large amount of substrate
9. In some cases, a digestive enzyme is secreted in an inactive form, a precursor and remains unchanged / inactive until it mixes the activator usually secreted by another organ

Hint

2a(i)   In a tabular form, state FOUR differences between pollination and fertilization in plants.

(ii)      Name TWO agents of pollination.

(i). Wind

(ii). Insect

(iii). Water

(iv). Animals (birds, bats, man)

b(i)     List THREE groups of mammals according to their feeding habits.

Herbivores

Carnivores

Omnivores

(ii)      Give ONE example of animal that belongs to each feeding habit named in2b (i) above.

Herbivores – e.g Goat, Cattle, Sheep

Carnivores – e.g Cat, Lion, Tiger

Omnivores – e.g Man

c(i)     State TWO reasons why Euglena is regarded as a plant and TWO reasons why it is regarded as an animal.

Reasons why euglena is regarded as a plant

1. Presence of chloroplasts used for photosynthesis
2. Stores excess carbohydrate as starch (paramylum granules are starch
3. Definite shape (pear shaped). Plant cells have definite shape.

Reasons why euglena is regarded as an animal

1. Possesses eye spot which is sensitive to light
2. Possesses a flagellum for locomotion
3. Presence of contractile vacuole for osmo-regulation
4. It carries out holozoic feeding in the absence of sunlight, hence the presence of gullet to ingest food particles
5. No cellulose cell wall but flexible living pellicle
6. No contractile vacuole with cell sap vacuole is small and not central

(ii)      List FOUR methods of birth control.

1. Use of diaphragm
2. Use of condom (male or female condom)
3. IUD (intra-uterine device)
4. Use of spermicidal creams or foaming tablets
5. Sterilization
6. Norplant
7. Use of injectable hormonal drugs
8. Family planning pills etc

Hint

3(a)       Copy and complete the table

(b) (i)    Define variation

There are morphological and physiological differences which occur within a species which could be hereditary or acquired through the environment

(ii)   List TWO types of variation.

Continuous variation

Discontinuous variation

(iii)     Mention ONE function each of the following:

(a) Guard cell

It controls the opening and closing of a stoma

(b) Phloem

It transports manufactured food from the leaves mainly to the other parts of the plant either for use or storage

(c) Root hairs

The plants absorbed mineral salts and water from the soil

(d) Sepal

Covers and protect the inner whorls of the flower during the bud stage

Also attracts insects for pollination because it is brightly colored

(e) Xylem

The xylem tissues transport water & dissolved mineral salts from the roots to other parts of plant.

It also gives support & rigidity to plants

(iv)     Using arrows, re-arrange the following in their order of increasing complexity.

Pigeon, Toad, Lizard, Rat and Tilapia

Tilapia       →         Toad    →           Lizard   →          Pigeon      →         Rat

Hint

4a(i)   Define conservation of natural resources.

It is the planned / wise / judicious use / management of earth natural resources in order to ensure substance / availability / continuity and preservation of the quality of the natural / original nature of the environment

(ii)      State FOUR ways by which wildlife can be conserved.

1. establishment of same or forest reserve
2. establishment of zoological gardens
3. control of hunting to prevent extinction of some animals
4. prohibition of killing or poaching of animals in same reserves
5. prohibition of bush burning as this may lead to migration or displacement of wildlife
6. prohibition of deforest and encouragement of afforestation or reforestation
7. prevention of pollution to prevent the destruction of aquatic life

b(i)     State THREE importance of transpiration to plants.

1. Cooling effect: transpiration in plant of water which is a cooling process
2. Transpiration helps move water through the xylem from the roots to the leaves
   and them to other parts of the plant
3. Transpiration promotes mineral salts dissolved min water to be transported to
   the leaves for the synthesis of complex substances

(ii)      With an example each, list TWO types of placentation in flowering plants.

• Axile placentation of tomato
• Parietal placentation e.g. pawpaw
• Free central placentation e.g. cana lily
• Marginal placentation e.g. Beans, Pride of Barbados, Crotalaria e.t.c
• Basal placentation e.g. Sunflower

(iii)     Mention FOUR functions of the mammalian skeleton.

• Support: the rigid framework of the skeleton gives support to the body
• Protection : the skeleton protects important delicate organs of the body e.g. the vertebral
• Column protects the spinal cord
• Movement: the whole skeleton is made up of several pieces of bones which are joined and brings about movement
• Respiration: the skeleton aids respiration. The thoracic bone of the ribs caged together with the muscles attached assist in respiration
• Manufacture of blood cells: white and red blood cells are manufactured in the narrow of long bones.

(iv)     List FIVE adaptive features of Xerophyte to its environment.

• Leaves are modified into spines to reduce water loss
• Succulent stems to conserve water
• Thick waxy cuticle on stems to prevent / reduce water loss
• Stems are green / chlorophyllous to manufacture food
• Flattened stem

Hint

5a.     Define the following terms:

(i) symbiosis

This is an association in which two organism of different species living together derive mutual benefits from each other

(ii) parasitism

This is an association involving two organisms, one is the parasite, living and deriving benefit from the other, the host which suffers harm from relationship.

(iii) commensalism

is an association of two different species of organisms in which one (the commensal) derives some benefit while the other, the lost neither gains nor loses

b(i)     Define the term pollution

Pollution: is defined as the release of toxic or harmful substances into the environment by natural forces or man and other animals to an extent that causes biological damage to man and his resources.

(ii)      Name TWO water pollutants.

• Sewage
• Pesticides and fertilizers
• Chemical waste
• Excreta or feaces
• Crude oil (oil spillage)

(iii)     State TWO effects of water pollution

1. Sewage washed into water bodies supports the growth of pathogens that causes diseases
2. Makes water unfit for human consumption
3. Kills fishes and other aquatic animals by suffocation
4. Water contaminated with heavy metals e.g. mercury and lead is injurious to human health.

c(i)     Name FOUR respiratory structures in animals and ONE example each of the organism possessing them.