BIO 001: GENERAL BIOLOGY
- Define the following terms:
(a) Autecology
(b) Synecology
© Environment
(d) Biosphere
(e) Habitat
(f) Niche
(g) Biome
(h) Community
(i) Ecosystem
(j) Population
[10 Marks]
- In an experiment to evaluate the effect of light spectra on the weight of rodents, two light spectra were used; Blue light and Yellow light. 10 rats each were exposed to these light spectra for 30 days. At the end of the exposure, the weight of the rodents were taken to the nearest 0.1g. The table below represents the value of the weight recorded for each light spectrum.
| Rat | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
|—|---|—|---|—|---|—|---|—|---|—|
| Blue Light (g) | 39.2 | 37.1 | 36.3 | 38.7 | 40.1 | 39.2 | 39.7 | 37.5 | 38.6 | 37.4 |
| Yellow light (g) | 32.1 | 33.9 | 33.7 | 35.4 | 33.3 | 34.9 | 32.4 | 31.9 | 35.1 | 34.8 |
Use the information above to answer the questions below
(a) i. Calculate the difference between the mean weight of the rodents exposed to blue light and yellow light. [6 Marks]
ii. What can you infer from the experiment between the light spectra? [2 Marks]
(b) State the Mendelian law of segregation. [2 Marks]
BIO 003: MICROBIOLOGY
- (a) Write short notes on the following fungi divisions:
i. Ascomycota
ii. Basidiomycota
iii. Deuteromycota
[6 Marks]
(b) Name FOUR diseases caused by prions. [4 Marks]
- (a) Explain any of the methods of how genetic materials can be transferred from one prokaryote to another? [2 Marks]
(b) Briefly describe the TWO many steps involved in the process of synthesizing protein from mRNA (translation). [4 Marks]
© Define the term “Mutation”. [1 Mark]
(d) Tabulate/differentiate between the following types of mutation:
i. Local and multiple mutations
ii. Somatic and germinal mutations
iii. Spontaneous and induced mutations
[3 Marks]
BASIC BOTANY
- Name and explain the TWO plant nutrition processes represented by the equations below:
6CO₂ + 12H₂O → C₆H₁₂O₆ + 6O₂ + 6H₂O
NH₄⁺ + O₂ → 2NO₂ + 2H₂O + 4H⁺ + energy
[5 Marks]
- (a) State ONE deficiency symptom of each of the following plant nutrient elements:
i. Nitrogen
ii. Phosphorus
iii. Calcium
iv. Iron
[5 Marks]
- (a) Mention FOUR characteristics of Angiosperms. [4 Marks]
(b) State FOUR economic importance of Lichen. [4 Marks]
© How are seeds of gymnosperms different from that of angiosperms? [2 Marks]
BIO 004: INTRODUCTORY ZOOLOGY
(a) What is respiration?
(b) State TWO similarities and three differences between aerobic and anaerobic respiration.
© Briefly explain the mechanism of inspiration in man.
(a) i. Define balance diet.
ii. State FOUR classes of food.
(b) State THREE functions of bile.
© State a function each of the following enzymes:
i. Erepsin
ii. Maltase
iii. Lipase
iv. Sucrase
Solutions
Question 1: Define the Following Terms
(a) Autecology – The study of the relationship between a single species (individual organism) and its environment.
(b) Synecology – The study of the relationships between communities of organisms and their environment.
© Environment – The sum total of all external conditions (biotic and abiotic) that surround and influence an organism.
(d) Biosphere – The part of the Earth (land, water, and atmosphere) where living organisms exist.
(e) Habitat – The specific place or locality where an organism naturally lives and grows.
(f) Niche – The functional role and position an organism occupies in its ecosystem, including its interactions with biotic and abiotic factors.
(g) Biome – A large geographical area characterized by a distinct climate, vegetation, and animal life (e.g., desert, rainforest, savanna).
(h) Community – A group of different species of organisms living and interacting together in the same area at the same time.
(i) Ecosystem – A functional unit comprising a community of organisms and their non-living (abiotic) environment interacting together.
(j) Population – A group of individuals of the same species living in the same area at the same time and capable of interbreeding.
Question 2: Light Spectra Experiment
(a) i. Calculate the difference between the mean weights
Blue Light weights:
39.2 + 37.1 + 36.3 + 38.7 + 40.1 + 39.2 + 39.7 + 37.5 + 38.6 + 37.4
= 383.8 g
Mean (Blue) = 383.8 ÷ 10 = 38.38 g
Yellow Light weights:
32.1 + 33.9 + 33.7 + 35.4 + 33.3 + 34.9 + 32.4 + 31.9 + 35.1 + 34.8
= 337.5 g
Mean (Yellow) = 337.5 ÷ 10 = 33.75 g
Difference = 38.38 − 33.75 = 4.63 g
The mean weight of rodents exposed to blue light (38.38 g) was 4.63 g higher than those exposed to yellow light (33.75 g).
(a) ii. Inference from the experiment
From the experiment, it can be inferred that blue light promotes greater body weight gain in rodents compared to yellow light. This suggests that the type of light spectrum affects the metabolic activity, feeding behaviour, or hormonal response of rodents. Blue light may stimulate more feeding or anabolic processes, while yellow light appears to result in lower weight gain.
(b) Mendelian Law of Segregation
The Law of Segregation (Mendel’s First Law) states that:
“During gamete formation, the two alleles for a gene segregate (separate) from each other so that each gamete carries only one allele for each gene. The separation is random, so each gamete has an equal probability of containing either allele.”
In other words, an organism carries two alleles for each trait, but these alleles separate during meiosis, and each gamete receives only one allele. The two alleles reunite during fertilization.
BIO 003 – MICROBIOLOGY
Question 3
(a) Short Notes on Fungi Divisions
i. Ascomycota (Sac Fungi)
- Largest division of fungi
- Characterized by the production of sexual spores called ascospores contained in a sac-like structure called an ascus
- Examples: Saccharomyces cerevisiae (yeast), Penicillium, Aspergillus
- Economically important in baking, brewing, and antibiotic production
- Some are plant pathogens (e.g., powdery mildew)
ii. Basidiomycota (Club Fungi)
- Characterized by sexual spores called basidiospores produced on club-shaped structures called basidia
- Includes mushrooms, toadstools, puffballs, and bracket fungi
- Examples: Agaricus (edible mushroom), Amanita, Ustilago (smut)
- Important decomposers; some are edible, others are toxic
iii. Deuteromycota (Fungi Imperfecti)
- An artificial grouping of fungi whose sexual reproductive stage is unknown or absent
- Also called “imperfect fungi” because they reproduce only asexually (by conidia)
- Examples: Candida albicans, Alternaria, Fusarium
- Many are human pathogens causing skin infections (e.g., ringworm, athlete’s foot)
(b) FOUR Diseases Caused by Prions
Prions are misfolded proteins that cause fatal neurodegenerative diseases (Transmissible Spongiform Encephalopathies – TSEs):
- Creutzfeldt-Jakob Disease (CJD) – affects humans; causes rapid neurodegeneration
- Bovine Spongiform Encephalopathy (BSE) – “Mad Cow Disease”; affects cattle
- Scrapie – affects sheep and goats
- Kuru – affects humans; associated with cannibalistic practices in Papua New Guinea
Question 4
(a) Methods of Genetic Material Transfer in Prokaryotes
One method is Conjugation:
Conjugation is the direct transfer of genetic material (plasmid DNA) from one bacterial cell to another through a physical connection called a pilus (sex pilus). The donor cell (F⁺) forms a conjugation bridge with the recipient cell (F⁻), and a copy of the plasmid is transferred. This is the most common method of horizontal gene transfer in bacteria and contributes to antibiotic resistance spread.
Other methods include:
- Transformation – uptake of free DNA fragments from the environment
- Transduction – transfer of DNA via bacteriophages (viruses)
(b) TWO Steps in Protein Synthesis (Translation)
i. Initiation
The ribosome assembles around the mRNA start codon (AUG). The small ribosomal subunit binds to the mRNA, and the initiator tRNA carrying methionine (Met) base-pairs with the AUG codon. The large ribosomal subunit then joins to form the complete initiation complex. This marks the beginning of translation.
ii. Elongation
The ribosome moves along the mRNA codon by codon (5’→3’). At each step:
- A complementary aminoacyl-tRNA enters the A site
- A peptide bond forms between the growing polypeptide and the new amino acid (catalyzed by peptidyl transferase)
- The ribosome translocates one codon forward, moving the growing chain to the P site
This continues until a stop codon (UAA, UAG, or UGA) is reached, triggering termination and release of the completed polypeptide.
© Definition of Mutation
A mutation is a permanent, heritable change in the nucleotide sequence of an organism’s DNA (or RNA in RNA viruses) that may occur spontaneously or be induced by mutagens. Mutations can affect a single gene (point mutation) or involve large chromosomal rearrangements.
(d) Types of Mutation – Differentiation Table
Basis
Type 1
Type 2
i. Extent
Local mutation – affects a single gene or nucleotide
Multiple mutation – affects many genes or loci simultaneously
ii. Tissue
Somatic mutation – occurs in body (non-reproductive) cells; not heritable
Germinal mutation – occurs in germ (reproductive) cells; heritable and passed to offspring
iii. Cause
Spontaneous mutation – occurs naturally without known cause; due to errors in DNA replication
Induced mutation – caused by external mutagens such as radiation, chemicals (e.g., colchicine), or viruses
Question 5: TWO Plant Nutrition Processes
Equation 1:
6CO₂ + 12H₂O → C₆H₁₂O₆ + 6O₂ + 6H₂O
This represents Photosynthesis.
Explanation: Photosynthesis is the process by which green plants use sunlight energy (absorbed by chlorophyll), carbon dioxide from the air, and water from the soil to synthesize glucose (organic food) and release oxygen as a by-product. It occurs in the chloroplasts. It is an autotrophic (carbon fixation) process and is the basis of all food chains.
Equation 2:
NH₄⁺ + O₂ → 2NO₂⁻ + 2H₂O + 4H⁺ + energy
This represents Nitrification (specifically, the first step of nitrification).
Explanation: Nitrification is a microbial (chemoautotrophic) process carried out by bacteria such as Nitrosomonas. These bacteria oxidize ammonium ions (NH₄⁺) to nitrite (NO₂⁻), releasing energy which they use for biosynthesis. This is the first stage of nitrification in the nitrogen cycle. The second stage (by Nitrobacter) converts nitrite to nitrate (NO₃⁻), which is then absorbed by plants.
Question 6: Deficiency Symptoms of Plant Nutrient Elements
(i) Nitrogen (N)
Yellowing of leaves (chlorosis), starting from older/lower leaves; stunted growth; pale green to yellow appearance overall due to reduced chlorophyll synthesis.
(ii) Phosphorus §
Purple or reddish-brown discoloration of leaves and stems (due to anthocyanin accumulation); poor root development; delayed flowering and fruiting.
(iii) Calcium (Ca)
Distortion and death of young growing tips (shoot apex and root tips); blossom end rot in fruits; leaves curl or appear crinkled; poor cell wall formation.
(iv) Iron (Fe)
Interveinal chlorosis of young leaves (yellowing between leaf veins while veins remain green); reduced growth; leaves may eventually turn white in severe cases.
Question 7
(a) FOUR Characteristics of Angiosperms
- Enclosed seeds – Seeds are enclosed within a fruit (mature ovary), unlike gymnosperms
- Presence of flowers – They produce flowers for sexual reproduction (pollination)
- Double fertilization – One sperm fertilizes the egg (forming zygote); another fertilizes the polar nuclei (forming endosperm)
- Broad leaves with a well-developed vascular system (xylem and phloem) and net-like (reticulate) or parallel venation
(b) FOUR Economic Importance of Lichen
- Pioneer organisms – Lichens are the first to colonize bare rocks, breaking them down to initiate soil formation (ecological succession)
- Food source – Used as food for animals (e.g., reindeer moss/Cladonia eaten by reindeer) and in some human cultures
- Indicators of air pollution – Lichens are sensitive to sulphur dioxide; their presence or absence indicates air quality (bioindicators)
- Industrial and medicinal uses – Used in production of dyes (litmus from Roccella), perfumes, antibiotics, and in traditional medicine
© How Seeds of Gymnosperms Differ from Angiosperms
Feature
Gymnosperms
Angiosperms
Seed enclosure
Seeds are naked (not enclosed in a fruit)
Seeds are enclosed within a fruit (ovary wall)
Ovule position
Ovules borne on open scales (e.g., cones)
Ovules enclosed within an ovary
Endosperm
Formed before fertilization
Formed after double fertilization
Dispersal
Mainly by wind
By wind, water, animals, or self-dispersal
BIO 004 – INTRODUCTORY ZOOLOGY
Section 1: Respiration
(a) What is Respiration?
Respiration is the biochemical process by which living organisms break down organic molecules (primarily glucose) to release energy in the form of ATP (adenosine triphosphate), which is used to power cellular activities. It occurs in two forms: aerobic (with oxygen) and anaerobic (without oxygen), and takes place primarily in the mitochondria.
(b) TWO Similarities and THREE Differences Between Aerobic and Anaerobic Respiration
Similarities:
- Both begin with glycolysis – the breakdown of glucose to pyruvate in the cytoplasm
- Both produce ATP (energy) and involve the oxidation of glucose
Differences:
Feature
Aerobic Respiration
Anaerobic Respiration
Oxygen requirement
Requires oxygen
Does not require oxygen
ATP yield
High – 36–38 ATP per glucose
Low – 2 ATP per glucose
End products
CO₂ and H₂O
Lactic acid (animals) or ethanol + CO₂ (yeast/plants)
© Mechanism of Inspiration in Man
Inspiration (inhalation) is an active process involving:
- The diaphragm contracts and flattens (moves downward)
- The external intercostal muscles contract, pulling the ribs upward and outward
- This increases the volume of the thoracic cavity
- As volume increases, pressure inside the lungs decreases (below atmospheric pressure)
- Air rushes in from the atmosphere through the nostrils → trachea → bronchi → bronchioles → alveoli to equalize pressure
- Gas exchange then occurs at the alveoli
Section 2: Nutrition
(a) i. Define Balanced Diet
A balanced diet is a diet that contains all the essential nutrients — carbohydrates, proteins, fats, vitamins, minerals, water, and roughage (dietary fibre) — in the correct proportions required for the normal growth, repair, and functioning of the body.
(a) ii. FOUR Classes of Food
- Carbohydrates – primary energy source (e.g., rice, yam, bread)
- Proteins – for growth, repair, and enzyme production (e.g., meat, eggs, beans)
- Lipids (Fats and Oils) – energy storage, insulation, hormone production (e.g., butter, palm oil)
- Vitamins – organic compounds needed in small amounts for metabolic regulation (e.g., Vitamins A, B, C, D)
(Other classes include Minerals and Water)
(b) THREE Functions of Bile
- Emulsification of fats – Bile salts break large fat globules into smaller droplets, increasing surface area for lipase enzyme action
- Neutralization of stomach acid – Bile (alkaline, pH ~8) neutralizes the acidic chyme from the stomach, creating a suitable pH for intestinal enzymes
- Facilitation of fat absorption – Bile salts form micelles with fatty acids and monoglycerides, aiding their absorption through the intestinal wall into the lacteals
© Functions of the Following Enzymes
Enzyme
Site of Action
Function
i. Erepsin
Small intestine (brush border)
Breaks down peptides into amino acids (mixture of peptidases)
ii. Maltase
Small intestine
Hydrolyses maltose into two molecules of glucose
iii. Lipase
Small intestine (pancreatic lipase)
Breaks down fats/triglycerides into fatty acids and glycerol
iv. Sucrase
Small intestine
Hydrolyses sucrose into glucose and fructose