Biology Basics – Maharashtra TET (General Awareness & Current Affairs)
Purpose – Provide a concise, clear foundation of core biology concepts that can be used as a study aid for the Maharashtra Teacher Eligibility Test (TET).
Audience – Aspiring teachers, school‑level biology educators, and anyone preparing for general‑awareness sections.
1. Simple Explanation
| Topic | What it Means | Why It Matters |
|---|---|---|
| Biology | The science of life. It studies living organisms, their structure, function, growth, origin, evolution, and interaction with the environment. | Forms the basis for teaching life sciences and understanding health, environment, and technology. |
| Cell | The smallest unit of life; the “building block” of all organisms. | All living processes occur at the cellular level. |
| DNA | Deoxyribonucleic acid – the hereditary material that stores genetic instructions. | Determines traits, guides development, and is central to modern genetics. |
| Evolution | The change in the heritable characteristics of biological populations over successive generations. | Explains biodiversity and is key to ecological and conservation education. |
2. Key Points
| Concept | Core Ideas | Illustrations / Examples |
|---|---|---|
| Cell Theory | 1. All living things are made of cells. 2. The cell is the basic unit of life. 3. All cells arise from pre‑existing cells. |
Prokaryotic cells (bacteria) vs eukaryotic cells (plants, animals). |
| Cell Structure | - Prokaryotes: no nucleus, small, 1–2 µm. - Eukaryotes: nucleus, membrane‑bound organelles, >10 µm. - Common organelles: mitochondria, chloroplasts, ER, Golgi, ribosomes. |
Plant cell: chloroplasts, large central vacuole. Animal cell: no chloroplasts, smaller vacuoles. |
| Levels of Organization | 1. Cell → 2. Tissue → 3. Organ → 4. Organ system → 5. Organism → 6. Population → 7. Community → 8. Ecosystem → 9. Biosphere | Human digestive system (organs) vs forest ecosystem. |
| Classification (Taxonomy) | Domain > Kingdom > Phylum > Class > Order > Family > Genus > Species. Current systems: Five‑kingdom (Monera, Protista, Fungi, Plantae, Animalia) and Three‑domain (Bacteria, Archaea, Eukarya). |
Homo sapiens: Domain Eukarya → Kingdom Animalia → … → Species sapiens. |
| Genetics Basics | - Gene = DNA segment coding for a trait. - Allele = variant of a gene. - Chromosome = DNA + proteins. - Mendelian inheritance: dominance, recessiveness, segregation, independent assortment. |
Pedigree of pea plants: yellow vs green peas. |
| Cell Division | - Mitosis: one cell → two identical daughter cells (growth, repair). - Meiosis: one cell → four haploid gametes (reproduction). |
Stages of mitosis: prophase, metaphase, anaphase, telophase. |
| Evolution & Natural Selection | - Genetic variation arises via mutation, recombination, gene flow. - Selection pressures (environment, predators, resources). - Speciation: divergence over time. |
Galápagos finches – beak shape variation. |
| Ecology | - Biotic: living organisms. - Abiotic: non‑living factors (light, temperature, water). - Food chain / Web, nutrient cycles, biodiversity. |
Coral reef ecosystem: algae, fish, predators, humans. |
| Human Anatomy (Major Systems) | - Circulatory: heart, blood, vessels. - Respiratory: lungs, trachea. - Digestive: stomach, intestines. - Nervous: brain, spinal cord, nerves. - Endocrine: glands, hormones. - Musculoskeletal. |
Teaching the heart’s chambers and valves in primary school. |
3. Worked Example
Problem
A farmer crosses two pea plants. The male plant is homozygous dominant for seed shape (Yy? Actually homozygous dominant = YY), while the female plant is homozygous recessive (yy).
- What will be the genotype and phenotype of the F₁ generation?
- If two F₁ plants self‑fertilize, what is the expected ratio in the F₂ generation?
Solution
| Generation | Cross | Genotype of F₁ | Phenotype of F₁ | F₂ Genotype Ratio | F₂ Phenotype Ratio |
|---|---|---|---|---|---|
| Parental (P) | YY x yy |