BIO 101 General Biology 1: Comprehensive University Study Notes

COURSE INFORMATION AND PERSONNEL - Course: BIO 101 General Biology 1 National Open University of Nigeria (NOUN). - Course Coordinator: DR. JARI SANUSI. - Programme Leader: DR. S. I. OGUNRINDE. - Textbooks: Taylor, D.J. et al. (1998) Biological Science; Roberts, M.B.V. (1987) Biology: A Functional Approach. # BIOLOGICAL CHARACTERISTICS AND METABOLISM - Nine Vital Activities: Ingestion, Assimilation, Growth, Reproduction, Waste elimination (Excretion), Responsiveness, Coordination, Regulation, and Movement. - Metabolism: Sum of chemical processes divided into Anabolism (synthesis, e.g., photosynthesis) and Catabolism (breakdown). - Energy: Living things utilize light or chemical energy to produce ATP ($Adenosine Triphosphate$) for work. - Classification by Oxygen: Aerobic (require free oxygen), Anaerobic (respire without oxygen), and Facultative (e.g., Yeast, surviving with or without oxygen). # CELL THEORY AND ORGANELLES - Definition: The cell is the basic unit of structure and function in living organisms. - Historical Milestones: Microscope invented by Jansen ($1590$); term "cell" coined by Robert Hooke ($1665$); nucleus described by Robert Brown ($1831$-$3$); Cell Theory proposed by Schleiden and Schwann ($1838$-$9$); Virchow ($1855$) proved cells arise from pre-existing cells. - Comparison: Plant cells have a rigid cell wall (cellulose), large central vacuole, and chloroplasts. Animal cells lack these but possess centrioles and adrenaline. - Organelles: Nucleus (contains chromatin/$DNA$), Mitochondrion (aerobic respiration), Golgi apparatus (transport), and Ribosomes (protein synthesis). # CELLULAR DYNAMICS: OSMOSIS AND DIVISION - Cell Division: Mitosis results in two daughter cells with identical chromosome numbers. Phases include Interphase, Prophase, Metaphase, Anaphase, and Telophase. Cytokinesis is the subsequent division of cytoplasm. - Osmosis: Selective transmission of solvent through a semi-permeable membrane. - Plasmolysis: Shrinking of the protoplasm from the cell wall when placed in a concentrated solution due to outward osmosis; reversible by Deplasmolysis. # MICROBIOLOGY: VIRUSES AND BAKTERIA - Viruses: Non-cellular parasites, $50$ times smaller than bacteria. Retroviruses like HIV ($Human Immunodeficiency Virus$) use reverse transcriptase to convert $RNA$ to $DNA$. - HIV Progression: Five stages ranging from antibody presence to full-blown AIDS secondary infections (e.g., $Pneumocystis$ $carinii$, Toxoplasmosis). - Prokaryotes (Bacteria): $3,500$ million years old; lack nuclear membranes. Cell walls contain murein. - Bacterial Growth: Occurs in four phases: Lag, Log (exponential), Stationary, and Decline. Common shapes include Cocci, Bacilli, Vibrios, and Spirilla. # MYCOLOGY AND PHYCOLOGY: FUNGI AND ALGAE - Fungi: Heterotrophic eukaryotes with chitinous cell walls. Nutrition types: Saprotrophs (decomposers), Parasites, or Mutualists (e.g., $Rhizobium$). Examples: $Mucor$, $Penicillium$, $Saccharomyces$ (Yeast). - Algae: Photosynthetic aquatic organisms lacking true roots/stems (Thallus body). Groups: Green ($Chlorophyta$, e.g., $Chlorella$), Brown ($Phaeophyta$), and Red ($Rhodophyta$). # BOTANY: PLANT ANATOMY AND PHYSIOLOGY - Root: Tap roots (dicots) and Fibrous roots (monocots). Regions include the root-cap, meristematic zone, elongation zone, and maturation zone. - Stem: Transports water via Xylem (Vessels and Tracheids) and food via Phloem (Sieve tubes and Companion cells). Utilizes forces of Adhesion and Cohesion. - Leaf: Primary site of photosynthesis: CO_2 + H_2O

ightarrow ext{CHO} + O_2. Structure includes the waxy cuticle, palisade mesophyll, and stomata with guard cells for gas exchange. # FLORAL DYNAMICS AND POLLINATION - Flower Parts: Calyx (sepals), Corolla (petals), Androecium (stamens/male), and Gynoecium (carpels/female). - Position on Receptacle: Hypogynous (parts below ovary), Perigynous (around ovary), and Epigynous (above ovary). - Pollination: Transfer of pollen from anther to stigma via wind ($Anemophily$) or insects ($Entomophily$). - Types: Self-pollination (Autogamy) and Cross-pollination (Allogamy/Xenogamy). # FRUITS, SEEDS, AND GERMINATION - Fruit: A ripened ovary. Categories: Simple, Aggregate, and Multiple (Composite, e.g., Pineapple). - Dispersal: Methods include wind (features like Pappus or wings), water, animals (hooks/sticky glands), and explosive mechanisms. - Germination: Epigeal (cotyledons emerge above soil, e.g., Groundnut) and Hypogeal (cotyledons remain below soil, e.g., Maize). # GENETIC PRINCIPLES AND INHERITANCE - Mendel’s Laws: 1st Law of Segregation (alleles separate into gametes); 2nd Law of Independent Assortment (different gene pairs combine randomly). - Ratios: Monohybrid ($3:1$) and Dihybrid ($9:3:3:1$). - Chromosomes: Carry genes (units of heredity). Humans have $46$ ($23$ pairs). - Sex Linkage: Traits carried on the $X$ chromosome (e.g., Haemophilia, Colour blindness). - Human Example: Albinism is a recessive condition where parents (carriers) have a $1/4$ probability of an albino offspring ($aa$). # QUESTIONS & DISCUSSION - Activity 1.3.1: Reflection on human vital activities and the effects of an $18$-hour fast on energy. - TMA 1: Differences between living and non-living things using the build-up and disintegration concept. - TMA 5: Description of the HIV life cycle, including receptor protein attachment, endocytosis, and viral protein transcription. - TMA 10: Bacterial population calculation for descendants dividing every $20$ minutes in a nutrient medium.