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2021 JUPEB biology essay past questions and answers

2021JUPEB biology past questions and answers.
Type: essay questions. View multi-choice questions here 


Questions.

BIO 001: GENERAL BIOLOGY

  1. (a) What is gaseous exchange?
    (b) What is respiratory surface?
    (c) State FOUR properties required for a cell to be an effective respiratory surface.
    (d) Give FOUR examples of respiratory surfaces.

  2. (a) Define the following Ecological terms:
    i. Niche
    ii. Microhabitat
    iii. Ecosystem
    iv. Population

(b) Give TWO reasons why a small population can easily go into extinction.

(c) Give TWO explanations each on how the population growth of an organism can be affected by density dependent and density independent factors.

BIO 002: 

  1. (a) (i) Mention TEN macro-elements (excluding phosphorus) which are required by plants for healthy growth.
    (ii) State THREE anatomical differences between Monocot and Dicot.

(b) State THREE importance of phosphorus to plants.

(c) State THREE symptoms which can be observed in a plant growing in soil that is deficient in phosphorus.

  1. (a) Mention FOUR roles of cytokinin in plant growth.

(b) Define the following terms:
i. Hypogeal germination
ii. Meristem
iii. Epigeal germination
iv. Geotropism

(c) List TWO conditions necessary for growth.

(d) State ONE feature possessed by a seed or fruit dispersed by wind.

BIO 003: MICROBIOLOGY

  1. (a) Enumerate TWO major historical issues/challenges/events that contributed to the historical development of Microbiology.

(b) Describe the FOUR major groups of fungi based on the spores produced.

(c) Give FOUR differences between bacteria and viruses.

  1. (a) State FOUR differences between mutational and plasmid-mediated drug resistance.

(b) What is bacteriophage?

(c) Describe the life cycle of E. coli.

(d) Define intermediate host.


BIO 004: 

  1. (a) Enumerate FIVE reasons why Monotremes and Marsupials are special categories of mammals.

(b) List FIVE biological advancements of Amphibians over Fishes.

(c) Explain ultrafiltration.

  1. (a) Name the constituents of a balanced diet and state their importance in the diet.

(b) What are the modifications and the mechanisms associated with the following habits:
i. Filter feeding in mosquito larva
ii. Parasitic feeding in tapeworms.



Answers to 2021  BIOLOGY ESSAY Questions- Jupeb 


BIO 001: 

1. (a) What is gaseous exchange? [1 mark]


 Gaseous exchange is the process by which respiratory gases (oxygen and carbon dioxide) diffuse between an organism and its environment, enabling oxygen to enter cells for respiration and carbon dioxide to be removed.

(b) What is respiratory surface? [1 mark]


 A respiratory surface is a thin, moist area across which gases are exchanged between the organism’s internal environment and the external environment.

(c) State FOUR properties required for a cell to be an effective respiratory surface. [4 marks]


 i. Large surface area to volume ratio
ii. Thin walls to facilitate rapid diffusion
iii. Moist surface to allow gases to dissolve
iv. Rich supply of blood or fluid for gas transport

(d) Give FOUR examples of respiratory surfaces. [4 marks]


 i. Alveoli in mammalian lungs
ii. Gills in fish
iii. Skin in amphibians
iv. Tracheal system in insects

2. (a) Define the following Ecological terms: [4 marks]

i. Niche: The role and position an organism occupies in its environment, including its habitat, resources, and relationships with other organisms.

ii. Microhabitat: A small, specific habitat within a larger habitat, where particular conditions favor the existence of certain organisms.

iii. Ecosystem: A community of living organisms interacting with each other and their non-living environment.

iv. Population: A group of individuals of the same species living together in a specific geographic area.

(b) Give TWO reasons why a small population can easily go into extinction. [2 marks]


 i. Reduced genetic diversity leading to inbreeding depression
ii. Greater vulnerability to stochastic events (e.g. diseases, natural disasters)

(c) Give TWO explanations each on how the population growth of an organism can be affected by density-dependent and density-independent factors. [4 marks]

  • Density-dependent factors:
    i. Competition for resources increases with population size, limiting growth.
    ii. Spread of diseases is faster in denser populations.

  • Density-independent factors:i. Natural disasters (e.g. floods, fires) can wipe out populations regardless of size.

  • ii. Sudden climatic changes (e.g. drought) can reduce population size independent of density.

BIO 002: 

3 (a) (i) Mention TEN macro-elements (excluding phosphorus) which are required by plants for healthy growth. [2½ marks]

  1. Nitrogen
  2. Potassium
  3. Calcium
  4. Magnesium
  5. Sulphur
  6. Iron
  7. Manganese
  8. Zinc
  9. Copper
  10. Boron

(ii) State THREE anatomical differences between Monocot and Dicot. [3 marks]

  1. Monocots have parallel leaf venation; Dicots have reticulate (net-like) venation.
  2. Monocots have scattered vascular bundles; Dicots have vascular bundles arranged in a ring.
  3. Monocots have one cotyledon; Dicots have two cotyledons.

(b) State THREE importance of phosphorus to plants. [1½ marks]

  1. Essential component of ATP for energy transfer
  2. Important for root development
  3. Involved in nucleic acid and cell division processes

(c) State THREE symptoms which can be observed in a plant growing in soil that is deficient in phosphorus. [3 marks]

  1. Stunted growth
  2. Purplish or reddish coloration on leaves
  3. Poor root development
4. (a) Mention FOUR roles of cytokinin in plant growth. [4 marks]
  1. Stimulates cell division (cytokinesis)
  2. Delays leaf senescence
  3. Promotes shoot formation in tissue culture
  4. Promotes lateral bud growth

(b) Define the following terms: [4 marks]

i. Hypogeal germination: Germination where the cotyledons remain below the soil surface.

ii. Meristem: A region of actively dividing cells in plants that contribute to growth.

iii. Epigeal germination: Germination where the cotyledons emerge above the soil surface.

iv. Geotropism: Growth response of a plant organ to gravity.

(c) List TWO conditions necessary for growth. [1 mark]

  1. Adequate water supply
  2. Suitable temperature

(d) State ONE feature possessed by a seed or fruit dispersed by wind. [1 mark]
Lightweight or wing-like structures to aid in wind dispersal.


BIO 003: MICROBIOLOGY

5. (a) Enumerate TWO major historical issues/challenges/events that contributed to the historical development of Microbiology. [2 marks]

  1. The invention of the microscope by Anton van Leeuwenhoek
  2. The discovery of sterilization techniques by Louis Pasteur

(b) Describe the FOUR major groups of fungi based on the spores produced. [4 marks]

  1. Zygomycetes – produce zygospores (e.g. Rhizopus)
  2. Ascomycetes – produce ascospores in asci (e.g. yeast)
  3. Basidiomycetes – produce basidiospores on basidia (e.g. mushrooms)
  4. Deuteromycetes (imperfect fungi) – lack a known sexual stage, reproduce by conidia (e.g. Penicillium)

(c) Give FOUR differences between bacteria and viruses. [4 marks]

  1. Bacteria are living cells; viruses are non-cellular.
  2. Bacteria reproduce by binary fission; viruses replicate only inside host cells.
  3. Bacteria have both DNA and RNA; viruses contain either DNA or RNA but not both.
  4. Bacteria can grow on artificial media; viruses cannot grow on artificial media.

6. (a) State FOUR differences between mutational and plasmid-mediated drug resistance. [4 marks]

  1. Origin: Mutational arises from chromosomal gene mutations; plasmid-mediated arises from extra-chromosomal DNA.
  2. Transfer: Mutational is non-transferable between bacteria; plasmid-mediated can transfer horizontally.
  3. Resistance level: Mutational usually confers lower levels of resistance; plasmid-mediated can confer high-level resistance.
  4. Spectrum: Mutational often affects single antibiotics; plasmid-mediated can affect multiple antibiotics.

(b) What is bacteriophage? [1 mark]
A bacteriophage is a virus that infects and replicates inside bacteria.

(c) Describe the life cycle of E. coli. [4 marks]
(Note: The question likely means “bacteriophage in E. coli.”)

  • Attachment: Phage attaches to bacterial surface.
  • Penetration: Phage injects its DNA into the host.
  • Biosynthesis: Phage DNA directs host machinery to produce viral components.
  • Maturation: New phages assemble.
  • Lysis and release: Host cell bursts, releasing new phages.

(d) Define intermediate host. [1 mark]
An intermediate host is a host in which the larval or asexual stage of a parasite develops.

BIO 004: 

7. (a) Enumerate FIVE reasons why Monotremes and Marsupials are special categories of mammals. [2½ marks]

  1. Monotremes lay eggs.
  2. Marsupials give birth to undeveloped young.
  3. Both groups have a cloaca.
  4. Presence of mammary glands but no nipples in monotremes.
  5. Marsupials have a pouch (marsupium) for carrying young.

(b) List FIVE biological advancements of Amphibians over Fishes. [2½ marks]

  1. Development of lungs for breathing air.
  2. Limbs for movement on land.
  3. Three-chambered heart for better circulation.
  4. Eyelids for eye protection on land.
  5. Ears for detecting airborne sounds.

(c) Explain ultrafiltration. [5 marks]


 Ultrafiltration is a process that occurs in the kidneys where blood is filtered under high pressure in the glomerulus. Water, ions, glucose, amino acids, and urea pass through the glomerular filter into Bowman’s capsule, forming glomerular filtrate. Large molecules (e.g. proteins) and blood cells remain in the bloodstream.

8. (a) Name the constituents of a balanced diet and state their importance in the diet. [4 marks]

  1. Carbohydrates: Energy source
  2. Proteins: Body building and repair
  3. Fats and oils: Energy storage and insulation
  4. Vitamins: Regulation of metabolic processes
  5. Minerals: Bone formation, enzyme activation
  6. Water: Medium for biochemical reactions
  7. Fibre: Aids digestion and bowel movement

(b) What are the modifications and the mechanisms associated with the following habits:

i. Filter feeding in mosquito larva [3 marks]

  • Modifications: Brush-like mouthparts and filtering structures
  • Mechanism: The larva uses mouth brushes to sweep water and trap microorganisms and organic particles.

ii. Parasitic feeding in tapeworms [3 marks]

  • Modifications: Hooks and suckers on the scolex for attachment, absence of digestive system.
  • Mechanism: Absorbs pre-digested food directly from the host’s intestine through its body surface.
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