Botany — Important Diagrams
Diagrams that appear most frequently in the TS Inter 2nd Year Botany board exam — with labelling notes for each. Practise every diagram from memory at least twice. Paper: 60 marks · 3 hours.
Plant Physiology
1.
Chloroplast ultrastructure — T.S.— label grana, stroma, thylakoid, inner/outer membrane, stroma lamellae
2.
C3 pathway (Calvin cycle) — flow diagram— CO₂ + RuBP → 2×3-PGA → G3P → RuBP; label enzymes at each step
3.
C4 pathway — Kranz anatomy— mesophyll cell → bundle sheath cell; label PEP carboxylase, RuBisCO positions
4.
Stomatal mechanism— open/closed states with guard cells; label chloroplast, starch↔glucose, turgor pressure
5.
Respiration pathway — overview— Glycolysis → Pyruvate → Krebs cycle → ETC; label ATP yield at each stage
6.
Mitochondrion — T.S.— label outer membrane, inner membrane, cristae, matrix, ATP synthase location
Genetics & Molecular Biology
1.
Mitosis — all stages— prophase, metaphase, anaphase, telophase — 4 separate diagrams
2.
Meiosis — key stages— meiosis I (synapsis, crossing over) and meiosis II — 4-6 diagrams
3.
DNA double helix structure— label base pairs (A-T, G-C), sugar-phosphate backbone, 5'→3' direction
4.
DNA replication — replication fork— label leading strand, lagging strand, Okazaki fragments, enzymes
5.
Lac operon — induced vs. repressed state— two diagrams: lactose absent (repressor on) and lactose present (inducer removes repressor)
6.
Transcription — schematic— label template strand, RNA polymerase, mRNA, 3'→5' and 5'→3' directions
Microbiology
1.
Bacterial cell structure— label cell wall, cell membrane, nucleoid, plasmid, flagellum, pilus
2.
Virus structure (Bacteriophage T4)— label head (DNA), collar, tail, tail fibres, base plate
3.
Algal cell — Spirogyra chloroplast— spiral chloroplast, pyrenoids, nucleus — helical arrangement
Biotechnology
1.
Recombinant DNA technology — steps diagram— restriction enzyme cut → ligation → plasmid vector → host cell → clones
2.
Gel electrophoresis — DNA band pattern— label wells, agarose gel, cathode/anode, ladder, sample bands
3.
Polymerase chain reaction (PCR) — cycle diagram— 3 steps per cycle: denaturation, annealing, extension with temperatures