Biology: Characteristics of Living Organisms

B1. Characteristics of Living Organisms

• Classification: A scientific method of grouping organisms based on similarities.
• Carl Linnaeus: Considered the Father of Systematic Biology.
• Nomenclature: Giving organisms a two-part name (genus and species).
• Taxonomy: Organizing organisms into groups.
• Kingdoms: Five main groups – Animal, Plant, Monera/Bacteria, Fungi.
• Animal Kingdom: Cells lack cell walls.
• Plant Kingdom: Obtain energy from sunlight.
• Monera/Bacteria: Mostly unicellular, lack a nucleus.
• Fungi Kingdom: Found everywhere, spread via spores.
• MRS GREN: Acronym for characteristics of living organisms: Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, Nutrition.

B2. Cells and Cell Structures

• Animal Cells: Multicellular, contain a nucleus with a membrane, no cell walls or chloroplasts, feed on organic matter.
• Plant Cells: Multicellular, contain a nucleus with a membrane, have cellulose cell walls and chloroplasts, perform photosynthesis, store carbohydrates as starch or sucrose.
• Nucleus: Controls cellular activities, site of ribosome synthesis.
• Nuclear Membrane: Boundary protecting the nucleus.
• Chromosomes: Structures involved in determining an individual's sex. Humans have 23 pairs.
• Ribosomes: Sites of protein synthesis.
• Mitochondria: "Powerhouse" of the cell, produces energy.
• Lysosomes: Protect the cell by removing foreign bodies.
• Chloroplasts: Photosynthesis organelles, contain chlorophyll.
• Vacuoles: Store food, water, and waste.
• Magnification: Calculating actual size from image size.
• Specialized Cells: Ciliated cells (move mucus), Palisade mesophyll cells (photosynthesis), Red blood cells (oxygen transport), Sperm/egg cells (reproduction), Root hair cells (absorption), Neurons (electrical conduction).

B3. Movement into and out of Cells

• Water Potential: Measures a solution's tendency to gain or lose water.
• Diffusion: Movement of molecules from high to low concentration.
• Cell Membrane: Partially permeable, allowing small molecules but not larger ones to pass.
• Brownian Motion: Constant random movement of particles.
• Diffusion Factors: Temperature (higher = faster), particle size (smaller = faster), concentration gradient (larger = faster), diffusion medium (gas > liquid > solid), surface area (larger = faster).
• Osmosis: Diffusion of water across a partially permeable membrane from high water potential to low water potential.
• High Water Potential: Low solute concentration (dilute).
• Low Water Potential: High solute concentration (concentrated).

B4. Biological Molecules

• Biological Molecules: Substances produced by living organisms.
• Elements: Carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur.
• Examples: Carbohydrates, lipids, proteins, nucleic acids.
• Carbohydrates: Sugars, starch, cellulose. Simple (monosaccharides), complex (disaccharides), polysaccharides.
• Lipids: Fats and oils. Formed from fatty acids and glycerol.
• Proteins: Enzymes (control reactions), structural components. Made of amino acids.
• Nucleic Acids: DNA (genetic information), RNA. Double helix structure with paired bases (A-T, C-G).

B5. Enzymes

• Enzymes: Biological catalysts, speed up metabolic reactions, are not changed by the reaction.
• Substrate: Molecule an enzyme acts on.
• Product: Molecule formed after the reaction.
• Active Site: Where substrate binds.
• Anabolic Reactions: Build complex molecules from simpler ones.
• Catabolic Reactions: Break down complex molecules into simpler ones, releasing energy.
• Optimum Temperature: Best temperature for enzyme activity (around 37°C).
• Denaturation: Permanent damage to enzyme structure caused by extreme temperatures or pH.
• Optimum pH: Varies for different enzymes.
• Chemical Digestion: Enzymes breaking down food molecules in the alimentary canal.
• Digestive Enzymes: Carbohydrases (amylase), proteases, lipases. Examples include amylase (starch to sugar), protease (protein to amino acids), lipase (fats to fatty acids and glycerol).
• Mechanical Digestion: Physical breakdown of food (mastication).

B7. Human Nutrition

• Balanced Diet: Contains carbohydrates and fats (energy), protein (amino acids for growth and repair), vitamins, minerals, fiber, and water.
• Fats: Source of energy, essential fatty acids for growth, provide insulation for body, carry vitamins.
• Proteins: Build cells and tissue, repair damaged tissue.
• Vitamins: Essential nutrients for chemical reactions, come in various forms.
• Minerals/Salts: Important for various functions (calcium for bones, iron for blood).
• Water: Essential for numerous bodily functions, involved in temperature regulation, removing waste, transporting nutrients.

B8. Transport in Plants

• Transpiration: Loss of water vapour through leaves.
• Xylem: Transports water and minerals.
• Phloem: Transports sugars and other nutrients.
• Transpiration Factors: Temperature, wind speed.
• Xylem Structure: Dead cells with thickened, lignin-containing walls (hollow tubes).
• Wilting: Loss of structural rigidity in plant tissues due to water loss.
• Translocation: Movement of sucrose and amino acids (sugars) throughout the plant from sources to sinks.
• Sources: Produce sugars (leaves).
• Sinks: Use or store sugars (roots, fruits, growing tissues).

B9. Transport in Animals

• Circulatory System: Transports blood throughout the body, delivering oxygen and nutrients, removing waste.
• Heart: Muscular organ that pumps blood.
• Blood: Composed of red and white blood cells, plasma, and platelets.
• Blood Vessels: Arteries (carry oxygenated blood away from the heart), veins (carry deoxygenated blood back to the heart) , capillaries (exchange of materials).

B11. Gas Exchange in Humans

• (Information on gas exchange is not explicitly detailed in the provided text. If further information is needed, please clarify.)*

B12. Respiration

• (Information on respiration is not explicitly detailed in the provided text. If further information is needed, please clarify.)*

B13. Coordination and Response

• (Information on coordination and response is not explicitly detailed in the provided text. If further information is needed, please clarify.)*