Aga Khan University Examination Board Biology (SSC IX-X) Syllabus

Define taxonomy.

Taxonomy is the branch of biology that deals with the identification, naming, and classification of organisms.

List the taxonomic hierarchy (taxa) from largest to smallest.

Kingdom → Phylum (Division in plants) → Class → Order → Family → Genus → Species.

What is the smallest unit (basic unit) of classification?

The species is the smallest/basic unit of classification — a group of similar organisms capable of interbreeding to produce fertile offspring.

Who proposed the Five Kingdom System of classification and in what year?

Robert H. Whittaker proposed the Five Kingdom System of classification in 1969.

Name the five kingdoms in Whittaker's classification system.

Monera, Protista (Protoctista), Fungi, Plantae, and Animalia.

Which kingdom contains prokaryotic organisms, and give an example.

Kingdom Monera contains prokaryotic organisms such as bacteria and cyanobacteria (blue-green algae).

What types of organisms are placed in Kingdom Protista?

Kingdom Protista includes mostly unicellular eukaryotic organisms, such as Amoeba, Paramecium, Euglena, and algae like diatoms.

Describe the main characteristics of Kingdom Fungi.

Fungi are eukaryotic, mostly multicellular, non-green (lack chlorophyll), heterotrophic organisms that absorb nutrients; their cell walls contain chitin. Examples: mushrooms, molds, yeast.

What mode of nutrition characterizes Kingdom Plantae?

Plants are autotrophic — they make their own food by photosynthesis using chlorophyll. They are eukaryotic and multicellular with cellulose cell walls.

What are the defining features of Kingdom Animalia?

Animals are eukaryotic, multicellular, heterotrophic organisms that lack a cell wall and usually show movement; most have nervous and muscular coordination.

What is binomial nomenclature?

Binomial nomenclature is the system of naming each organism with two Latin names: the first is the genus and the second is the species (e.g., Homo sapiens).

Who introduced the system of binomial nomenclature?

Carolus Linnaeus (Carl Linnaeus) introduced the system of binomial nomenclature.

State two rules for writing a scientific name correctly.

1) The genus name begins with a capital letter and the species name with a small letter. 2) The whole name is written in italics (or underlined when handwritten). The names are in Latin.

Write the correct scientific name of humans and identify the genus and species.

Homo sapiens — 'Homo' is the genus and 'sapiens' is the species.

What is biodiversity?

Biodiversity is the variety of living organisms (different species of plants, animals, and microorganisms) found in a particular area or on Earth.

Define conservation of biodiversity.

Conservation of biodiversity is the protection, preservation, and careful management of living organisms and their habitats to prevent extinction and maintain ecological balance.

Distinguish between in-situ and ex-situ conservation.

In-situ conservation protects organisms in their natural habitat (e.g., national parks, wildlife sanctuaries). Ex-situ conservation protects them outside their natural habitat (e.g., zoos, botanical gardens, seed banks).

Give two human activities that threaten biodiversity.

Deforestation, habitat destruction, pollution, overhunting/over-harvesting, and introduction of invasive species. (Any two are acceptable.)

State the cell theory.

Cell theory states that: 1) all living organisms are made of one or more cells, 2) the cell is the basic structural and functional unit of life, and 3) all cells arise from pre-existing cells.

Who first observed and named cells, and in what structure?

Robert Hooke first observed and named 'cells' in 1665 while examining thin slices of cork under a microscope; the empty box-like compartments reminded him of monks' cells.

Who proposed that all cells come from pre-existing cells?

Rudolf Virchow proposed 'Omnis cellula e cellula' — all cells arise from pre-existing cells.

What is the function of the nucleus in a cell?

The nucleus controls all cell activities and contains the genetic material (DNA/chromosomes); it directs growth, metabolism, and reproduction of the cell.

Which organelle is called the 'powerhouse of the cell' and why?

The mitochondrion is called the powerhouse of the cell because it is the site of aerobic respiration, producing energy in the form of ATP.

What is the function of chloroplasts?

Chloroplasts are organelles in plant cells that contain chlorophyll and carry out photosynthesis to make food (glucose).

What are ribosomes and what do they do?

Ribosomes are tiny non-membranous organelles that are the sites of protein synthesis in the cell.

What is the role of the cell membrane (plasma membrane)?

The cell membrane is a selectively permeable boundary that controls the entry and exit of substances into and out of the cell.

List three main differences between prokaryotic and eukaryotic cells.

1) Prokaryotes lack a true (membrane-bound) nucleus; eukaryotes have one. 2) Prokaryotes lack membrane-bound organelles; eukaryotes have them. 3) Prokaryotes are usually smaller and have circular DNA, while eukaryotes are larger with DNA organized in chromosomes.

Give one example each of a prokaryotic and a eukaryotic organism.

Prokaryotic example: bacteria (e.g., E. coli). Eukaryotic example: Amoeba, plants, animals, or fungi.

State two structural differences between a plant cell and an animal cell.

A plant cell has a cell wall (cellulose), chloroplasts, and a large central vacuole; an animal cell lacks a cell wall and chloroplasts and has small or no vacuoles. (Plant cells also typically lack centrioles.)

Name the four main types of animal tissues.

Epithelial tissue, connective tissue, muscular tissue, and nervous tissue.

What are the main types of plant tissues, and how do meristematic and permanent tissues differ?

The main types are meristematic and permanent tissues. Meristematic tissue consists of actively dividing cells (responsible for growth), while permanent tissue consists of cells that have stopped dividing and are specialized for specific functions (e.g., parenchyma, xylem, phloem).

What is interphase in the cell cycle?

Interphase is the longest phase of the cell cycle during which the cell is not dividing but is preparing for division — it grows, carries out normal functions, and replicates (duplicates) its DNA. It is divided into G1, S, and G2 sub-phases.