2020 form five biology notes
Table of Contents
TOPIC 1: LEVELS OF ORGANISATION AND DIVERSITY OF LIFE.......................................... 7
Syllabus extract.............................................................................................................................................. 7
IMPORTANCE OF STUDYING BIODIVERISTY .................................................................................. 9
SPECIMEN IDENTIFICATION AND KEYS ........................................................................................... 9
THE DOMAIN SYSTEM........................................................................................................................... 10
THE FIVE KINGDOMS ................................................................................................................................ 10
VIRUSES...................................................................................................................................................... 10
KINGDOM PROKARYOTAE/MONERA............................................................................................... 12
KINGDOM PROTISTA ............................................................................................................................. 14
KINGDOM FUNGI..................................................................................................................................... 16
KINGDOM PLANTAE (plants) ................................................................................................................ 18
ALTERNATION OF GENERATION................................................................................................... 19
KINGDOM ANIMALIA............................................................................................................................. 23
Sample questions ............................................................................................................................................. 32
REFERENCES ................................................................................................................................................ 35
TOPIC 2: CHEMICALS OF LIFE ........................................................................................................... 36
Syllabus extract................................................................................................................................................ 36
Introduction ..................................................................................................................................................... 39
INORGANIC CHEMICALS OF LIFE......................................................................................................... 39
ACIDS AND BASES ................................................................................................................................... 39
MINERAL ELEMENTS............................................................................................................................. 40
WATER........................................................................................................................................................ 43
THE ORGANIC CHEMICALS OF LIFE.................................................................................................... 47
VITAMINS................................................................................................................................................... 48
CARBOHYDRATES .................................................................................................................................. 49
LIPIDS (fats and oils).................................................................................................................................. 58
PROTEINS................................................................................................................................................... 61
ENZYMES ....................................................................................................................................................... 70
REVISION QUESTIONS............................................................................................................................... 79
REFERENCES ................................................................................................................................................ 85
TOPIC 3: INHERITANCE ......................................................................................................................... 86
SYLLABUS EXTRACT ................................................................................................................................. 86
NUCLEIC ACIDS ........................................................................................................................................... 88
PROTEIN SYNTHESIS ............................................................................................................................. 96
CELL DIVISION............................................................................................................................................. 99
THE CELL CYCLE.................................................................................................................................... 99
MITOSIS................................................................................................................................................ 100
MEIOSIS................................................................................................................................................ 103
GENETICS .................................................................................................................................................... 109
MENDEL’S GENETIC EXPERIMENTS AND MONOHYBRID INHERITANCE ......................... 110
MENDEL’S FIRST LAW OF INHERITANCE................................................................................. 112
CO-DOMINANCE ................................................................................................................................ 119
INCOMPLETE DOMINANCE ........................................................................................................... 124
MULTIPLE ALLELES ........................................................................................................................ 125
Inheritance of ABO blood system ........................................................................................................ 126
DIHYBRID INHERITANCE................................................................................................................... 129
INHERITANCE OF COMPLEMENTARY GENES ............................................................................ 132
MODIFICATION OF 9:3:3:1 PHENOTYPIC RATIO......................................................................... 134
EPISTASIS............................................................................................................................................. 134
CROSSOVER VALUE AND CHROMOSOME MAPS.................................................................... 139
INHERITANCE OF SEX......................................................................................................................... 142
Pedigree charts........................................................................................................................................... 147
VARIATION.................................................................................................................................................. 149
OUT OF CLASS EXERCISES ................................................................................................................ 158
TOPIC 4: CYTOLOGY, MICROSCOPY AND HISTOLOGY ......................................................... 177
Syllabus extract.............................................................................................................................................. 177
CELL BIOLOGY.......................................................................................................................................... 178
TYPES OF CELLS.................................................................................................................................... 179
MICROSCOPY ............................................................................................................................................. 184
CELL STRUCTURE................................................................................................................................. 187
The nucleus ................................................................................................................................................ 193
Mitochondria ............................................................................................................................................. 194
Chloroplast................................................................................................................................................. 195
Ribosomes................................................................................................................................................... 197
Endoplasmic reticulum ............................................................................................................................. 197
Lysosomes (suicide bag)............................................................................................................................ 198
Golgi apparatus/body................................................................................................................................ 200
Plant cell wall............................................................................................................................................. 202
Flagella and cilia........................................................................................................................................ 204
Microbodies................................................................................................................................................ 204
Vacuoles...................................................................................................................................................... 204
Protoplasm ................................................................................................................................................. 205
Microtubules.............................................................................................................................................. 205
HISTOLOGY................................................................................................................................................. 207
HISTOLOGY OF PLANTS ..................................................................................................................... 207
MERISTEMS......................................................................................................................................... 207
PERMANENT TISSUES...................................................................................................................... 207
THE VASCULAR TISSUE...................................................................................................................... 210
HISTOLOGY OF ANIMALS .................................................................................................................. 214
EPITHELIAL TISSUE......................................................................................................................... 214
CONNECTIVE TISSUE....................................................................................................................... 220
SAMPLE QUESTIONS................................................................................................................................ 225
REFERENCES .............................................................................................................................................. 229
TOPIC 5: MOVEMENT IN AND OUT OF CELLS ........................................................................... 230
Syllabus extract.............................................................................................................................................. 230
Introduction ................................................................................................................................................... 230
SIMPLE DIFFUSION............................................................................................................................... 231
FACILITATED DIFFUSION .................................................................................................................. 232
ACTIVE TRANSPORT............................................................................................................................ 234
OSMOSIS................................................................................................................................................... 236
Water potential...................................................................................................................................... 237
Solute potential ( s) .............................................................................................................................. 238
Pressure potential ( p).......................................................................................................................... 238
Osmosis and plant cells......................................................................................................................... 239
Plant-water relations............................................................................................................................. 241
Osmosis and animal cells ...................................................................................................................... 243
BULK TRANSPORT ACROSS THE CELL MEMBRANE................................................................. 245
Cytosis......................................................................................................................................................... 245
Endocytosis............................................................................................................................................. 245
Phagocytosis (cellular eating) ............................................................................................................... 246
Pinocytosis (cellular drinking).............................................................................................................. 246
Receptor mediated endocytosis ............................................................................................................ 247
Exocytosis............................................................................................................................................... 247
SAMPLE QUESTIONS................................................................................................................................ 248
REFERENCES .............................................................................................................................................. 255
TOPIC 6: TRANSPORT IN LIVING ORGANISMS................................................................................ 256
Syllabus extract.............................................................................................................................................. 256
Need for a transport system.................................................................................................................. 258
BLOOD....................................................................................................................................................... 259
ERYTHROCYTES (Red blood cells) .................................................................................................. 259
LEUCOCYTES (white blood cells)...................................................................................................... 260
BLOOD PLATELETS (thrombocytes) ............................................................................................... 261
TRANSPORT OF OXYGEN ................................................................................................................... 262
Oxygen tension and oxyhaemoglobin formation ................................................................................ 263
Effect of carbon dioxide on the oxygen dissociation curve (Bohr’s effect)....................................... 264
TRANSPORT OF CARBON DIOXIDE............................................................................................. 270
VASCULAR SYSTEMS IN ANIMALS.................................................................................................. 271
MAMMALIAN BLOOD CIRCULATION......................................................................................... 275
THE MAMMALIAN HEART ................................................................................................................. 275
Initiation of the heart beat.................................................................................................................... 276
Intrinsic control of the heart beat ........................................................................................................ 279
Hormonal control of the heat rate........................................................................................................ 279
Control of the rate of the heart beat .................................................................................................... 279
BLOOD VESSELS.................................................................................................................................... 281
TOPIC 7: DEFENCE AGAINST DISEASES...................................................................................... 286
Clotting of blood .................................................................................................................................... 286
Mechanism of immune responses......................................................................................................... 293
Cell mediated immune response........................................................................................................... 295
THE LYMPHATIC SYSTEM ................................................................................................................. 300
Vaccines.................................................................................................................................................. 301
BLOOD TRANSFUSION..................................................................................................................... 301
RHESUS FACTOR (D-Antigens) ........................................................................................................ 302
UPTAKE AND TRANSPORT IN PLANTS............................................................................................... 304
TRANSPIRATION.................................................................................................................................... 304
STOMATA............................................................................................................................................. 310
LENTICELS .......................................................................................................................................... 314
WATER UPTAKE BY THE ROOTS ................................................................................................. 315
Vascular tissues...................................................................................................................................... 318
THE UPTAKE OF WATER FROM THE ROOTS TO THE LEAVES.......................................... 321
UPTAKE AND TRANSLOCATION OF MINERAL IONS............................................................. 323
TRASLOCATION OF ORGANIC MOLECULES ........................................................................... 326
SAMPLE QUESTIONS................................................................................................................................ 331
Time days........................................................................................................................................................ 334
REFERENCES .............................................................................................................................................. 344
TOPIC 8: EVOLUTION............................................................................................................................... 345
SYLLABUS EXTRACT ............................................................................................................................... 345
THEORIES FOR THE ORIGIN OF LIFE ................................................................................................ 346
THEORIES TO EXPLAIN THE MECHANISM OF EVOLUTION .................................................. 346
DARWINISM ........................................................................................................................................ 346
LAMARCKCISM.................................................................................................................................. 347
NEODARWINISM (Modern synthetic theory of organic evolution) ............................................... 348
EVIDENCE FOR EVOLUTION ............................................................................................................. 349
COMPARATIVE EMBRYOLOGY........................................................................................................... 349
PALEONTOLOGY (The study of fossils)............................................................................................... 350
CELL BIOLOGY...................................................................................................................................... 351
TAXONOMY (CLASSIFICATION)....................................................................................................... 351
COMPARATIVE ANATOMY ................................................................................................................ 352
COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY............................................................ 354
BIOGEOGRAPHY (SPECIES DISTRIBUTION/GEOGRAPHICAL ISOLATION)................... 355
INDUSTRIAL MELANISM................................................................................................................. 357
CROSS BREEDING/ ARTIFICIAL SELECTION ........................................................................... 357
RESISTANCE TO DRUGS AND PESTICIDES ............................................................................... 357
SELECTION.................................................................................................................................................. 358
NATURAL SELECTION......................................................................................................................... 358
ARTIFICIAL SELECTION..................................................................................................................... 362
SEXUAL SELECTION......................................................................................................................... 362
KIN AND GROUP SELECTION ........................................................................................................ 363
SPECIATION ................................................................................................................................................ 363
INTERSPECIFIC HYBRIDISATION........................................................................................................ 363
MECHANISM OF SPECIATION .............................................................................................................. 364
EXTINCTION OF SPECIES ....................................................................................................................... 368
THE HARDY-WEINBERG PRINCIPLE .............................................................................................. 370
SAMPLE QUESTIONS................................................................................................................................ 372
TOPIC 9: ECOLOGY................................................................................................................................... 376
SYLLABUS EXTRACT ............................................................................................................................... 376
Introduction ................................................................................................................................................... 378
2.0 CONCEPT OF THE ECOSYSTEM...................................................................................................... 381
B.O.D (Biological oxygen demand) ...................................................................................................... 386
ECOLOGICAL SUCCESSIONS............................................................................................................. 389
Energy flow through an ecosystem .......................................................................................................... 392
Energy budgets...................................................................................................................................... 394
ECOLOGICAL PYRAMIDS................................................................................................................... 395
BIOLOGICAL AND GEOCHEMICAL CYCLING (NUTRIENT CYCLING)................................. 396
3.0 POPULATION AND NATURAL RESOURCES................................................................................. 400
Population growth ..................................................................................................................................... 401
Population growth and survivorship curves........................................................................................... 405
Determination of population size of organisms ...................................................................................... 407
4.0 INTERDEPENDENCE........................................................................................................................... 412
Interaction within the populations....................................................................................................... 412
Competition................................................................................................................................................ 412
Predation .................................................................................................................................................... 414
Parasitism................................................................................................................................................... 417
5.0 EFFECTS OF HUMAN ACTIVITIES ON ECOSYSTEMS .............................................................. 418
POLLUTION............................................................................................................................................. 418
Chemical pest control................................................................................................................................ 424
NATURAL RESOURCES........................................................................................................................ 427
Conservation of natural resource................................................................................................................. 430
SAMPLE QUESTIONS................................................................................................................................ 430
Table of Contents
TOPIC 1: LEVELS OF ORGANISATION AND DIVERSITY OF LIFE.......................................... 7
Syllabus extract.............................................................................................................................................. 7
IMPORTANCE OF STUDYING BIODIVERISTY .................................................................................. 9
SPECIMEN IDENTIFICATION AND KEYS ........................................................................................... 9
THE DOMAIN SYSTEM........................................................................................................................... 10
THE FIVE KINGDOMS ................................................................................................................................ 10
VIRUSES...................................................................................................................................................... 10
KINGDOM PROKARYOTAE/MONERA............................................................................................... 12
KINGDOM PROTISTA ............................................................................................................................. 14
KINGDOM FUNGI..................................................................................................................................... 16
KINGDOM PLANTAE (plants) ................................................................................................................ 18
ALTERNATION OF GENERATION................................................................................................... 19
KINGDOM ANIMALIA............................................................................................................................. 23
Sample questions ............................................................................................................................................. 32
REFERENCES ................................................................................................................................................ 35
TOPIC 2: CHEMICALS OF LIFE ........................................................................................................... 36
Syllabus extract................................................................................................................................................ 36
Introduction ..................................................................................................................................................... 39
INORGANIC CHEMICALS OF LIFE......................................................................................................... 39
ACIDS AND BASES ................................................................................................................................... 39
MINERAL ELEMENTS............................................................................................................................. 40
WATER........................................................................................................................................................ 43
THE ORGANIC CHEMICALS OF LIFE.................................................................................................... 47
VITAMINS................................................................................................................................................... 48
CARBOHYDRATES .................................................................................................................................. 49
LIPIDS (fats and oils).................................................................................................................................. 58
PROTEINS................................................................................................................................................... 61
ENZYMES ....................................................................................................................................................... 70
REVISION QUESTIONS............................................................................................................................... 79
REFERENCES ................................................................................................................................................ 85
TOPIC 3: INHERITANCE ......................................................................................................................... 86
SYLLABUS EXTRACT ................................................................................................................................. 86
NUCLEIC ACIDS ........................................................................................................................................... 88
PROTEIN SYNTHESIS ............................................................................................................................. 96
CELL DIVISION............................................................................................................................................. 99
THE CELL CYCLE.................................................................................................................................... 99
MITOSIS................................................................................................................................................ 100
MEIOSIS................................................................................................................................................ 103
GENETICS .................................................................................................................................................... 109
MENDEL’S GENETIC EXPERIMENTS AND MONOHYBRID INHERITANCE ......................... 110
MENDEL’S FIRST LAW OF INHERITANCE................................................................................. 112
CO-DOMINANCE ................................................................................................................................ 119
INCOMPLETE DOMINANCE ........................................................................................................... 124
MULTIPLE ALLELES ........................................................................................................................ 125
Inheritance of ABO blood system ........................................................................................................ 126
DIHYBRID INHERITANCE................................................................................................................... 129
INHERITANCE OF COMPLEMENTARY GENES ............................................................................ 132
MODIFICATION OF 9:3:3:1 PHENOTYPIC RATIO......................................................................... 134
EPISTASIS............................................................................................................................................. 134
CROSSOVER VALUE AND CHROMOSOME MAPS.................................................................... 139
INHERITANCE OF SEX......................................................................................................................... 142
Pedigree charts........................................................................................................................................... 147
VARIATION.................................................................................................................................................. 149
OUT OF CLASS EXERCISES ................................................................................................................ 158
TOPIC 4: CYTOLOGY, MICROSCOPY AND HISTOLOGY ......................................................... 177
Syllabus extract.............................................................................................................................................. 177
CELL BIOLOGY.......................................................................................................................................... 178
TYPES OF CELLS.................................................................................................................................... 179
MICROSCOPY ............................................................................................................................................. 184
CELL STRUCTURE................................................................................................................................. 187
The nucleus ................................................................................................................................................ 193
Mitochondria ............................................................................................................................................. 194
Chloroplast................................................................................................................................................. 195
Ribosomes................................................................................................................................................... 197
Endoplasmic reticulum ............................................................................................................................. 197
Lysosomes (suicide bag)............................................................................................................................ 198
Golgi apparatus/body................................................................................................................................ 200
Plant cell wall............................................................................................................................................. 202
Flagella and cilia........................................................................................................................................ 204
Microbodies................................................................................................................................................ 204
Vacuoles...................................................................................................................................................... 204
Protoplasm ................................................................................................................................................. 205
Microtubules.............................................................................................................................................. 205
HISTOLOGY................................................................................................................................................. 207
HISTOLOGY OF PLANTS ..................................................................................................................... 207
MERISTEMS......................................................................................................................................... 207
PERMANENT TISSUES...................................................................................................................... 207
THE VASCULAR TISSUE...................................................................................................................... 210
HISTOLOGY OF ANIMALS .................................................................................................................. 214
EPITHELIAL TISSUE......................................................................................................................... 214
CONNECTIVE TISSUE....................................................................................................................... 220
SAMPLE QUESTIONS................................................................................................................................ 225
REFERENCES .............................................................................................................................................. 229
TOPIC 5: MOVEMENT IN AND OUT OF CELLS ........................................................................... 230
Syllabus extract.............................................................................................................................................. 230
Introduction ................................................................................................................................................... 230
SIMPLE DIFFUSION............................................................................................................................... 231
FACILITATED DIFFUSION .................................................................................................................. 232
ACTIVE TRANSPORT............................................................................................................................ 234
OSMOSIS................................................................................................................................................... 236
Water potential...................................................................................................................................... 237
Solute potential ( s) .............................................................................................................................. 238
Pressure potential ( p).......................................................................................................................... 238
Osmosis and plant cells......................................................................................................................... 239
Plant-water relations............................................................................................................................. 241
Osmosis and animal cells ...................................................................................................................... 243
BULK TRANSPORT ACROSS THE CELL MEMBRANE................................................................. 245
Cytosis......................................................................................................................................................... 245
Endocytosis............................................................................................................................................. 245
Phagocytosis (cellular eating) ............................................................................................................... 246
Pinocytosis (cellular drinking).............................................................................................................. 246
Receptor mediated endocytosis ............................................................................................................ 247
Exocytosis............................................................................................................................................... 247
SAMPLE QUESTIONS................................................................................................................................ 248
REFERENCES .............................................................................................................................................. 255
TOPIC 6: TRANSPORT IN LIVING ORGANISMS................................................................................ 256
Syllabus extract.............................................................................................................................................. 256
Need for a transport system.................................................................................................................. 258
BLOOD....................................................................................................................................................... 259
ERYTHROCYTES (Red blood cells) .................................................................................................. 259
LEUCOCYTES (white blood cells)...................................................................................................... 260
BLOOD PLATELETS (thrombocytes) ............................................................................................... 261
TRANSPORT OF OXYGEN ................................................................................................................... 262
Oxygen tension and oxyhaemoglobin formation ................................................................................ 263
Effect of carbon dioxide on the oxygen dissociation curve (Bohr’s effect)....................................... 264
TRANSPORT OF CARBON DIOXIDE............................................................................................. 270
VASCULAR SYSTEMS IN ANIMALS.................................................................................................. 271
MAMMALIAN BLOOD CIRCULATION......................................................................................... 275
THE MAMMALIAN HEART ................................................................................................................. 275
Initiation of the heart beat.................................................................................................................... 276
Intrinsic control of the heart beat ........................................................................................................ 279
Hormonal control of the heat rate........................................................................................................ 279
Control of the rate of the heart beat .................................................................................................... 279
BLOOD VESSELS.................................................................................................................................... 281
TOPIC 7: DEFENCE AGAINST DISEASES...................................................................................... 286
Clotting of blood .................................................................................................................................... 286
Mechanism of immune responses......................................................................................................... 293
Cell mediated immune response........................................................................................................... 295
THE LYMPHATIC SYSTEM ................................................................................................................. 300
Vaccines.................................................................................................................................................. 301
BLOOD TRANSFUSION..................................................................................................................... 301
RHESUS FACTOR (D-Antigens) ........................................................................................................ 302
UPTAKE AND TRANSPORT IN PLANTS............................................................................................... 304
TRANSPIRATION.................................................................................................................................... 304
STOMATA............................................................................................................................................. 310
LENTICELS .......................................................................................................................................... 314
WATER UPTAKE BY THE ROOTS ................................................................................................. 315
Vascular tissues...................................................................................................................................... 318
THE UPTAKE OF WATER FROM THE ROOTS TO THE LEAVES.......................................... 321
UPTAKE AND TRANSLOCATION OF MINERAL IONS............................................................. 323
TRASLOCATION OF ORGANIC MOLECULES ........................................................................... 326
SAMPLE QUESTIONS................................................................................................................................ 331
Time days........................................................................................................................................................ 334
REFERENCES .............................................................................................................................................. 344
TOPIC 8: EVOLUTION............................................................................................................................... 345
SYLLABUS EXTRACT ............................................................................................................................... 345
THEORIES FOR THE ORIGIN OF LIFE ................................................................................................ 346
THEORIES TO EXPLAIN THE MECHANISM OF EVOLUTION .................................................. 346
DARWINISM ........................................................................................................................................ 346
LAMARCKCISM.................................................................................................................................. 347
NEODARWINISM (Modern synthetic theory of organic evolution) ............................................... 348
EVIDENCE FOR EVOLUTION ............................................................................................................. 349
COMPARATIVE EMBRYOLOGY........................................................................................................... 349
PALEONTOLOGY (The study of fossils)............................................................................................... 350
CELL BIOLOGY...................................................................................................................................... 351
TAXONOMY (CLASSIFICATION)....................................................................................................... 351
COMPARATIVE ANATOMY ................................................................................................................ 352
COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY............................................................ 354
BIOGEOGRAPHY (SPECIES DISTRIBUTION/GEOGRAPHICAL ISOLATION)................... 355
INDUSTRIAL MELANISM................................................................................................................. 357
CROSS BREEDING/ ARTIFICIAL SELECTION ........................................................................... 357
RESISTANCE TO DRUGS AND PESTICIDES ............................................................................... 357
SELECTION.................................................................................................................................................. 358
NATURAL SELECTION......................................................................................................................... 358
ARTIFICIAL SELECTION..................................................................................................................... 362
SEXUAL SELECTION......................................................................................................................... 362
KIN AND GROUP SELECTION ........................................................................................................ 363
SPECIATION ................................................................................................................................................ 363
INTERSPECIFIC HYBRIDISATION........................................................................................................ 363
MECHANISM OF SPECIATION .............................................................................................................. 364
EXTINCTION OF SPECIES ....................................................................................................................... 368
THE HARDY-WEINBERG PRINCIPLE .............................................................................................. 370
SAMPLE QUESTIONS................................................................................................................................ 372
TOPIC 9: ECOLOGY................................................................................................................................... 376
SYLLABUS EXTRACT ............................................................................................................................... 376
Introduction ................................................................................................................................................... 378
2.0 CONCEPT OF THE ECOSYSTEM...................................................................................................... 381
B.O.D (Biological oxygen demand) ...................................................................................................... 386
ECOLOGICAL SUCCESSIONS............................................................................................................. 389
Energy flow through an ecosystem .......................................................................................................... 392
Energy budgets...................................................................................................................................... 394
ECOLOGICAL PYRAMIDS................................................................................................................... 395
BIOLOGICAL AND GEOCHEMICAL CYCLING (NUTRIENT CYCLING)................................. 396
3.0 POPULATION AND NATURAL RESOURCES................................................................................. 400
Population growth ..................................................................................................................................... 401
Population growth and survivorship curves........................................................................................... 405
Determination of population size of organisms ...................................................................................... 407
4.0 INTERDEPENDENCE........................................................................................................................... 412
Interaction within the populations....................................................................................................... 412
Competition................................................................................................................................................ 412
Predation .................................................................................................................................................... 414
Parasitism................................................................................................................................................... 417
5.0 EFFECTS OF HUMAN ACTIVITIES ON ECOSYSTEMS .............................................................. 418
POLLUTION............................................................................................................................................. 418
Chemical pest control................................................................................................................................ 424
NATURAL RESOURCES........................................................................................................................ 427
Conservation of natural resource................................................................................................................. 430
SAMPLE QUESTIONS................................................................................................................................ 430