Botany 105 Final Exam Reviewer PDF

**BOTANY 105 FINAL EXAMINATION REVIEWER** **I. PLANT DIVERSITY I: HOW PLANTS COLONIZED LAND** **1. Characteristics of Algae** - **Red Algae**: - Appear red due to the pigment *phycoerythrin*, which reflects red light and absorbs blue light. - Found in deep waters where onl...

**BOTANY 105 FINAL EXAMINATION REVIEWER** **I. PLANT DIVERSITY I: HOW PLANTS COLONIZED LAND** **1. Characteristics of Algae** - **Red Algae**: - Appear red due to the pigment *phycoerythrin*, which reflects red light and absorbs blue light. - Found in deep waters where only blue light penetrates. - **Largest Seaweeds**: - Brown algae (*kelp*) are the largest and most complex seaweeds. **2. Origin of Chloroplasts** - **Evolutionary Pathway**: - Cyanobacteria ➞ Green Algae ➞ Land Plants. - Chloroplasts are derived through *primary endosymbiosis*. **3. Closest Relatives of Land Plants** - **Charophytes** (Green Algae): - Similarities with land plants: - Cell wall structure (cellulose). - Chloroplast shape. - Formation of *phragmoplast* during cytokinesis. - Similar sperm structure. - **Unique Characteristics of Land Plants**: - Alternation of generations (sporophyte and gametophyte stages). **4. Adaptations for Life on Land** - **Non-vascular plants (Bryophytes)**: - Gametophyte-dominant life cycle. - Example: Mosses. - **Vascular plants**: - Sporophyte-dominant life cycle. - Presence of xylem and phloem for transport. **II. PLANT DIVERSITY II: THE EVOLUTION OF SEED PLANTS** **1. Seed Plant Characteristics** - **Seed Advantages**: - Protection (seed coat). - Nutrient storage for embryo. - Dormancy until favorable conditions arise. - **Comparison with Spores**: - Seeds are *multicellular* with stored food; spores are *unicellular*. **2. Gymnosperms vs. Angiosperms** - **Gymnosperms**: - Seeds exposed on cones. - Example: Pines, spruces, cycads. - **Angiosperms**: - Seeds enclosed in ovaries (fruits). - Undergo double fertilization (producing embryo and endosperm). **3. Pollination in Seed Plants** - Pollen eliminates the need for water in fertilization. - **Pollen Tube**: - Delivers sperm nuclei to the ovule for fertilization. **4. Reduced Gametophyte in Seed Plants** - **Advantages**: - Gametophyte protected by the sporophyte. - Reduces vulnerability to UV radiation and desiccation. **III. SEEDS** **1. Seed Structure** - **Components**: - Embryo (new sporophyte). - Endosperm (nutrient store). - Seed coat (protection). - **Seed Dispersal Mechanisms**: - Wind, water, animals. - Adaptations like hooks, barbs, or hard protective coats. **2. Fruit Development** - Ovule develops into the seed. - Ovary develops into the fruit (helps in seed dispersal). - Example: Legumes (peas, beans). **IV. FLOWERS** **1. Structure of Flowers** - **Outer to Inner Layers**: - Sepals (protection). - Petals (attraction of pollinators). - Stamens (male reproductive organ ➞ produces pollen). - Carpels (female reproductive organ ➞ contains ovules). - **Megasporangium**: - Found inside the ovule within the ovary. **2. Pollination** - **Wind Pollination**: - Produces large amounts of pollen. - Small, inconspicuous flowers. - **Animal Pollination**: - Flowers are colorful, fragrant, or nectar-producing. **3. Double Fertilization** - **Process**: - One sperm fertilizes egg ➞ embryo. - Second sperm fertilizes polar nuclei ➞ endosperm (nutrient tissue). **4. Seed and Fruit Formation** - Ovule becomes the seed. - Ovary becomes the fruit. **V. PHOTOSYNTHESIS** **1. Light Reactions** - **Location**: Thylakoid membrane. - **Processes**: - Splitting of water (produces oxygen). - ATP and NADPH production. - **Photosystems**: - Photosystem II: Splits water, generates ATP. - Photosystem I: Generates NADPH. **2. Calvin Cycle** - **Location**: Stroma of chloroplasts. - **Uses**: ATP, NADPH, and CO2. - **Product**: Glucose (G3P as an intermediate). **3. Importance of Photosynthesis** - Converts solar energy into chemical energy. - Provides oxygen and organic molecules. **VI. CELLULAR RESPIRATION** **1. Stages of Cellular Respiration** 1. **Glycolysis**: - Occurs in cytoplasm. - Breaks glucose into 2 pyruvate, producing 2 ATP and 2 NADH. 2. **Citric Acid Cycle**: - Occurs in mitochondrial matrix. - Produces CO2, NADH, FADH2, and ATP. 3. **Electron Transport Chain (ETC)**: - Occurs in inner mitochondrial membrane. - Oxygen acts as the final electron acceptor, producing water. - Generates ATP through oxidative phosphorylation. **2. Summary Reaction:** - **C6H12O6 + 6O2 ➞ 6CO2 + 6H2O + Energy (ATP)**. **VII. GROWTH RESPONSES AND REGULATION** **1. Plant Hormones** - **Auxins**: Promote stem elongation and root growth. - **Gibberellins**: Stimulate seed germination and growth. - **Ethylene**: Controls fruit ripening. - **Abscisic Acid (ABA)**: Promotes dormancy and drought tolerance. **2. Tropisms** - **Phototropism**: Growth towards light. - **Gravitropism**: Growth in response to gravity. - **Thigmotropism**: Growth in response to touch. **3. Regulation of Plant Growth** - Hormones coordinate plant responses to environmental stimuli. - Importance for agriculture (e.g., controlling fruit growth). **STUDY TIPS:** 1. **Understand the Terminology**: Focus on keywords like photosystems, gametophytes, sporophytes, and hormones. 2. **Practice Questions**: Go over multiple-choice items and predict related variations. 3. **Focus on Processes**: - Photosynthesis: Light reactions ➞ Calvin Cycle. - Respiration: Glycolysis ➞ Citric Acid Cycle ➞ ETC. 4. **Diagrams**: Review diagrams for flower parts, photosynthesis pathways, and respiration stages. 5. **Essay Preparation**: - Use real-world examples for topics like seed dispersal or photosynthesis. - Follow the essay structure: Background, Principles, Analysis, Solutions, and Conclusion.