SECTION B:
Answer FOUR Questions in ALL; ONE Question from each Course.
BIO 001: GENERAL BIOLOGY
1. A survey was carried out in a community with ten villages (A, B, C……J) to know the prevalence of Plasmodium falciparum. From each of the villages the following number of individuals were found positive to the pathogen. The following are the scores of the students;
| S/N | Villages | Persons positive to the pathogen |
|---|---|---|
| 1 | A | 5 |
| 2 | B | 3 |
| 3 | C | 6 |
| 4 | D | 2 |
| 5 | E | 6 |
| 6 | F | 3 |
| 7 | G | 2 |
| 8 | H | 4 |
| 9 | I | 3 |
| 10 | J | 1 |
Use the information above to answer the following questions
(a) Find the
(i) Mean
(ii) Median
(iii) Mode
(iv) Range [4 Marks]
(b) Define the following:
(i) Variable
(ii) Population
(iii) Parameter
(iv) Sample [4 Marks]
(c) Name FOUR evidences in support of evolution. [2 Marks]
2. (a) i. State any THREE differences between Deoxyribonucleic acid (DNA) and Ribonucleic acid (RNA). [3 Marks]
ii. State any THREE differences between Mitochondrion and Golgi Apparatus. [3 Marks]
(b) i. Outline FOUR properties of enzymes. [2 Marks]
ii. State FOUR categories of enzymes. [2 Marks]
BIO 002 — MICROBIOLOGY
3. (a) i. Name the FOUR cellular arrangement for groups of bacteria and state their characteristics. [4 Marks]
(b) List FOUR biotechnological applications of microorganisms. [2 Marks]
(c) i. Outline the stages of the lytic cycle in Viruses. [3 Marks]
ii. Name the shape of Tobacco Mosaic Virus and Rotavirus. [1 Mark]
4. (a) Explain how vaccination can protect the body from contracting infectious diseases. [2 Marks]
(b) Enumerate any FOUR infectious diseases of human [2 Marks]
(c) Define the following types of mutation
i. Spontaneous mutation
ii. Base substitution mutation [2 Marks]
(d) Make a well labelled diagram of Bacteriophage [4 Marks]
BIO 003: BOTANY
5. (a) i. State FOUR factors that influence the rate of photosynthesis. [2 Marks]
ii. Explain how TWO of the named factors affect the rate of photosynthesis. [2 Marks]
(b) Highlight the characteristic features of monocotyledon and dicotyledon plants in terms of root system, stem, leaves and flower parts in a tabular form. [4 Marks]
(c) With the aid of annotated diagram, describe two types of leaf arrangement in plants [2 Marks]
6. (a) Explain the Cyclic Phosphorylation in plants. [3 Marks]
(b) Name, Describe and Give an example in each case of five methods of Asexual reproduction in plants. [5 Marks]
(c) State FOUR economic importance of plants. [2 Marks]
BIO 004 – INTRODUCTORY ZOOLOGY
7. (a) i. Define respiration. [1 Mark]
ii. State TWO differences between Glycolysis and Krebs' cycle. [2 Marks]
(b) Using a diagram, show the locations of FOUR named endocrine glands. [4 Marks]
(c) i. Define Accommodation. [1 Mark]
ii. Name any TWO eye defects and state how they are corrected. [2 Marks]
8. (a) State SIX characteristics of phylum Annelida. [3 Marks]
(b) In an attempt to ascertain the excretory and respiratory organs of some organisms, Bisi arrived with the table below. Fill in the missing spaces.
| Organisms | Excretory organ | Respiratory organ |
|---|---|---|
| Cnidarians | ||
| Platyhelminths | ||
| Molluscans | ||
| Crustaceans | ||
| Insects |
[5 Marks]
(c) Explain FOUR benefits of insects to man. [2 Marks]
BIO 001: GENERAL BIOLOGY
1(a) Data: 5,3,6,2,6,3,2,4,3,1 (n=10)
- Mean = (5+3+6+2+6+3+2+4+3+1)/10 = 35/10 = 3.5
- Median: Sorted: 1,2,2,3,3,3,4,5,6,6 → average of 5th & 6th values (3,3) = 3
- Mode = 3 (appears 3 times)
- Range = 6 − 1 = 5
(b) Definitions:
- Variable: A characteristic or quantity that can change or take different values in a study
- Population: The entire group of individuals or items being studied
- Parameter: A numerical value describing a characteristic of a population
- Sample: A subset of a population selected for study
(c) Four evidences for evolution:
- Fossil records
- Comparative anatomy (homologous structures)
- Comparative embryology
- Biogeography (distribution of species)
2(a)(i) DNA vs RNA (any three):
- DNA is double-stranded; RNA is single-stranded
- DNA contains deoxyribose sugar; RNA contains ribose sugar
- DNA has thymine; RNA has uracil (instead of thymine)
(ii) Mitochondrion vs Golgi apparatus (any three):
- Mitochondrion produces ATP (energy); Golgi apparatus packages and modifies proteins
- Mitochondrion has a double membrane; Golgi apparatus has a single membrane
- Mitochondrion contains its own DNA; Golgi apparatus does not
(b)(i) Four properties of enzymes:
- Highly specific in action
- Act as biological catalysts (speed up reactions without being used up)
- Affected by temperature and pH
- Can be denatured by heat/extreme pH
(ii) Four categories of enzymes:
- Oxidoreductases
- Transferases
- Hydrolases
- Lyases (also: isomerases, ligases)
BIO 002 — MICROBIOLOGY
3(a) Four cellular arrangements of bacteria:
- Diplococci – bacteria arranged in pairs
- Streptococci – bacteria arranged in chains
- Staphylococci – bacteria arranged in grape-like clusters
- Sarcina – bacteria arranged in cubical packets of eight
(b) Biotechnological applications of microorganisms:
- Production of antibiotics (e.g., penicillin)
- Fermentation (production of alcohol, yoghurt, bread)
- Genetic engineering (insulin production)
- Bioremediation (cleaning up pollutants)
(c)(i) Stages of the lytic cycle:
- Attachment (virus attaches to host cell)
- Penetration (injects genetic material)
- Replication/Biosynthesis (viral DNA/RNA and proteins made)
- Assembly (new virus particles formed)
- Lysis/Release (host cell bursts, releasing new virions)
(ii) Tobacco Mosaic Virus: rod-shaped; Rotavirus: spherical/icosahedral
4(a) Vaccination introduces a weakened/inactivated pathogen (or its antigen) into the body, stimulating the immune system to produce antibodies and memory cells, so the body can quickly recognize and fight the actual pathogen upon future exposure.
(b) Four infectious diseases of humans:
- Malaria
- Tuberculosis
- Cholera
- HIV/AIDS
(c) Types of mutation:
- Spontaneous mutation: A mutation that occurs naturally without exposure to any known mutagen
- Base substitution mutation: A mutation where one nucleotide base is replaced by another in the DNA sequence
(d) Bacteriophage diagram: Label — head (capsid with nucleic acid), collar, tail sheath, tail fibres, base plate, tail pins.
BIO 003: BOTANY
5(a)(i) Four factors affecting photosynthesis rate:
- Light intensity
- Carbon dioxide concentration
- Temperature
- Water availability
(ii)
- Light intensity: As light intensity increases, rate of photosynthesis increases (more energy for light reactions) until it plateaus at light saturation.
- Temperature: Rate increases with temperature (up to optimum, ~25-35°C) due to increased enzyme activity; beyond optimum, enzymes denature and rate falls.
(b) Monocotyledon vs Dicotyledon features:
- Root system: Monocot – fibrous roots; Dicot – taproot system
- Stem: Monocot – vascular bundles scattered; Dicot – vascular bundles arranged in a ring
- Leaves: Monocot – parallel venation; Dicot – reticulate (net-like) venation
- Flower parts: Monocot – parts in multiples of 3; Dicot – parts in multiples of 4 or 5
(c) Leaf arrangements (phyllotaxy):
- Alternate: One leaf arises at each node, alternating sides along the stem
- Opposite: Two leaves arise at each node, directly opposite each other
6(a) Cyclic photophosphorylation: Occurs in Photosystem I; light excites electrons which are ejected and pass through an electron transport chain back to PS I, generating ATP only (no NADPH or O₂ produced; water not split).
(b) Five methods of asexual reproduction in plants:
- Binary fission – parent cell splits into two identical cells (e.g., bacteria/algae)
- Budding – new individual grows as an outgrowth from parent (e.g., yeast)
- Spore formation – production of spores that develop into new plants (e.g., fungi, ferns)
- Vegetative propagation – new plant grows from root/stem/leaf part (e.g., potato tuber)
- Fragmentation – parent body breaks into fragments, each growing into a new plant (e.g., some algae)
(c) Four economic importance of plants:
- Source of food
- Source of medicine
- Source of timber/wood
- Source of raw materials for industries (e.g., cotton, rubber)
BIO 004 – INTRODUCTORY ZOOLOGY
7(a)(i) Respiration: The biochemical process by which cells break down organic molecules (e.g., glucose) to release energy in the form of ATP.
(ii) Glycolysis vs Krebs' cycle:
- Glycolysis occurs in the cytoplasm; Krebs' cycle occurs in the mitochondrial matrix
- Glycolysis does not require oxygen; Krebs' cycle requires oxygen (aerobic)
(b) Four endocrine glands and locations:
- Pituitary gland – base of the brain
- Thyroid gland – neck (in front of the trachea)
- Adrenal glands – on top of each kidney
- Pancreas – behind the stomach (diagram should show a simple human outline with these glands labelled at their positions)
(c)(i) Accommodation: The ability of the eye lens to change its shape/curvature (focal length) in order to focus images of objects at varying distances on the retina.
(ii) Eye defects and correction:
- Myopia (short-sightedness): Corrected using a concave (diverging) lens
- Hypermetropia (long-sightedness): Corrected using a convex (converging) lens
8(a) Six characteristics of phylum Annelida:
- Body is segmented (metameric segmentation)
- Triploblastic and bilaterally symmetrical
- Possess a true coelom
- Have a closed circulatory system
- Possess setae/chaetae for locomotion
- Have a well-developed nervous system with a ventral nerve cord
(b) Excretory and respiratory organs:
- Cnidarians: Excretory – diffusion through body surface; Respiratory – diffusion through body surface
- Platyhelminths: Excretory – flame cells (protonephridia); Respiratory – diffusion through body surface
- Molluscans: Excretory – kidney (nephridia); Respiratory – gills (ctenidia)
- Crustaceans: Excretory – green glands (antennal glands); Respiratory – gills
- Insects: Excretory – Malpighian tubules; Respiratory – tracheae (spiracles)
(c) Four benefits of insects to man:
- Pollination of crops/flowers
- Production of useful substances (e.g., honey from bees, silk from silkworms)
- Serve as food for humans/animals in some cultures
- Biological control of pests (predatory/parasitic insects)