UNDERSTANDING PHYSICAL, CHEMICAL, AND CELLULAR BASIS OF LIFE ORGANIC MOLECULES: contain carbon, found in all living things - Carbohydrates: source of energy (sugars and starches), CHO, 2:1 ration H to O, used in plants and animals to maintain structures within cells - Proteins: CHON, made up of chains of amino acid, 20 amino acids combine to form a variety of protein molecules (enzymes, hormones, antibodies, structural components) - Lipids: water-insoluble, CHO, composed of glycerol and fatty acid, provide insulation, store energy, cushion internal organs, found in biological membranes, saturated and unsaturated - Nucleic Acids: direct instruction of proteins, genetic information an organism receives from parents, DNA and RNA CELL THEORY: - All cells come from preexisting cells, cell is most basic unit of life, all organisms are made of cells CELL TYPES: - Unicellular: organism is a single independent cell - Multicellular: organism exists as specialized groups of cells - Prokaryote: nuclear material at the center of the cell but not enclosed by a nuclear membrane, no membrane bound organelles - Eukaryote: clearly defined nucleus enclosed by a nuclear membrane and membrane bound organelles CELL ORGANELLES AND FUNCTIONS: - Chloroplasts: capture solar energy for photosynthesis - Golgi body: package and distribute products - Lysosomes: digests excess products and food particles - Mitochondria: transform energy through respiration - Ribosome: produce proteins - Vacuole: store substances - Cell membrane: phospholipid bilayer protects and encloses the cell, maintains homeostasis - Cell wall: rigid second layer that protect the cell found in plants and some bacteria - Cytoplasm: fluid like substance that contains various membrane bound organelles - Endoplasmic Reticulum: site of chemical reactions, rough ER contains ribosomes, smooth ER site of lipid production - Cytoskeleton: internal structure, microfilaments = fibers, microtubules = cylinders CELL SPECIALIZATION: - Cell, tissue, organ, organ system, organism - Cells perform specific function for tissue or organ - As cells mature, they shape and contents change - Cells become more specialized, may contain organelles that are not common to all cells (cell wall) - Design and shape of a cell is dictated by conditions - Multicellular organisms exhibit greater specialization (red blood cells, nerve cells, gland cells) CELL TRANSPORT: - Passive: movement of substances without the use of energy - Diffusion: movement from high concentration to low - Osmosis: diffusion of water across a selectively permeable membrane (high conc. to low) - Facilitated transport: carrier protein in the cell membrane transports a substance across the membrane following the concentration gradient - - Active: movement that requires energy, moving against the concentration gradient - Endocytosis: large particles brought in - Exocytosis: large particles leave Concentration on a cell: - Hypotonic: water moves in, cell bursts - Hypertonic: water moves out, cell shrivels - Isotonic: no net movement HOMEOSTASIS: cells ability to maintain living conditions - Negative feedback: glucose/insulin levels - Positive feedback: blood platelets/blood clotting BIOCHEMICAL REACTIONS: chemical bonds are formed and broken within living things - Cellular Respiration: food molecules are converted into energy, 3 stages: stage 1 is glycolysis (anaerobic), next two stages are called citric acid cycle and electron transport chain (anaerobic) - - C6H12O6 + 6 O2 ⇒ 6CO2 + 6H2O + ENERGY (36 ATP) Photosynthesis: plant cells capture energy from sun and convert it into carbohydrates, plant cells convert carbohydrates into energy during cellular respiration - - 6CO2 + 6H2O + ENERGY(from sunlight) ⇒ C6H12O6 + 6O2 ATP: ATP is a molecule that stores and releases energy in its bonds when the cell needs it, does this by removing a phosphate group, ATP turns into ADP. When the cell has energy the energy is stored in the bond when the P group is added to ADP - - ATP ⇔ ADP + P + ENERGY Fermentation: when cells are not provided with oxygen quickly, ATP continues to be produced until oxygen is available again, glucose is broken down. Two types: - Lactic Acid Fermentation (muscle cells): Glucose ⇒ Lactic Acid + 2ATP - Alcoholic Fermentation (plant cells): Glucose ⇒ CO2 + Alcohol + 2ATP AEROBIC VS ANAEROBIC RESPIRATION - Aerobic: requires presence of oxygen, releases energy from glucose breakdown in the presence of oxygen. Energy is released to make ATP, which provides energy for bodily processes. Takes place in almost all living things. - Anaerobic: occurs in the absence of oxygen, breakdown of food substances in the absence of oxygen with the production of a small amount of energy. Produced less energy than aerobic respiration. Often called fermentation, seen as an adaptation for organisms that live in environments without oxygen. COMPARISON OF CELLULAR RESPIRATION, PHOTOSYNTHESIS, CHEMOSYNTHESIS - Cellular Respiration: food broken down, energy from glucose released, CO2 given off, O2 taken in, produced CO2 and H2O, does not require light, occurs in all living cells, organisms often called heterotrophs - Photosynthesis: food synthesized, energy form sun stored in glucose, CO2 taken in, O2 given off, produces sugars (glucose) from PGAL, requires light, occurs only in presence of chlorophyll, organisms called autotrophs - Chemosynthesis: food synthesized, energy from methane or inorganic material, organisms called chemotrophs or extremophiles, live in environments without oxygen, anaerobic bacteria, live in hydrothermal vents. ENZYMES: special proteins that regulate every biochemical reaction in the cell. Provide function to: - Provide energy to cells - Build new cells - Aid in digestion - Break down molecules - Catalysts - pH, temperature, and quantity affect enzyme activity MORE INFO:
