Water and Organic Molecules Flashcards
Why is water considered the medium for life?
Water acts as the medium for life because it enables chemical reactions by dissolving substances, and life likely began in water. Even after evolution, most biological molecules remain in water, which allows for molecular movement and interaction.
How do hydrogen bonds form in water?
Hydrogen bonds in water form due to the polar covalent bonds between oxygen and hydrogen. Oxygen is more electronegative, creating partial charges (positive on hydrogen, negative on oxygen), allowing attraction between water molecules.
What is the significance of cohesion in water?
Cohesion, the mutual attraction between water molecules due to hydrogen bonding, is crucial for water transport in plants (xylem) and the formation of water surfaces that can serve as habitats for certain organisms.
What role does adhesion play in water’s behavior in biological systems?
Adhesion allows water to stick to surfaces of polar or charged materials, aiding in capillary action, which is essential for water transport in plants and the moistening of cell walls for CO2 absorption.
What are the solvent properties of water, and why are they important?
Water’s polarity makes it an excellent solvent for polar and charged substances, which helps facilitate metabolism and transport in both plants and animals, as it dissolves substances like minerals, glucose, and oxygen.
How does water’s physical property of buoyancy affect aquatic organisms?
Water’s buoyancy allows organisms with lower densities to float, aiding in the survival of aquatic life. Fish use swim bladders, and cyanobacteria use gas vesicles to control buoyancy.
Why is water’s high specific heat capacity important for aquatic environments?
Water’s high specific heat capacity stabilizes aquatic environments by absorbing large amounts of heat without significantly changing temperature, helping organisms maintain a stable body temperature.
How did Earth’s distance from the sun contribute to the retention of water?
Earth’s optimal distance from the sun keeps temperatures low enough to retain water as a liquid, while its gravity prevents water vapor from escaping into space.
What is the significance of water movement by osmosis in biological systems?
Osmosis, the movement of water from less concentrated to more concentrated solutions, is vital for cellular function. It helps maintain fluid balance across membranes and regulates water flow in and out of cells.
How do hypertonic and hypotonic solutions affect animal cells?
In a hypertonic solution, animal cells lose water, causing them to shrink. In a hypotonic solution, cells gain water, potentially leading to swelling and bursting.
What is turgidity, and why is it important for plant cells?
Turgidity refers to the swollen state of plant cells due to water absorption via osmosis, which helps maintain structural support and keep non-woody plants upright.
What are the medical applications of isotonic solutions?
Isotonic solutions like normal saline are used in medical procedures to maintain cell stability, preventing cells from shrinking or swelling. They are used for IV drips, wound cleaning, and organ transport.
What chemical property of carbon makes it essential for life?
Carbon’s ability to form four covalent bonds allows it to create diverse and stable molecules essential for life, such as long chains and rings found in organic molecules like proteins and DNA.
How are macromolecules produced by condensation reactions?
Condensation reactions link monomers into polymers by removing a water molecule, forming macromolecules like polysaccharides, polypeptides, and nucleic acids, essential for biological structures and functions.
What happens during the digestion of polymers by hydrolysis reactions?
Hydrolysis reactions break down polymers into monomers by adding water, a crucial process for digestion and the release of energy from carbohydrates, proteins, and nucleic acids.
How do polysaccharides like starch and glycogen store energy?
Saturated fatty acids have no double bonds; solid at room temp.
Unsaturated fatty acids have one or more double bonds; liquid at room temp.Polysaccharides store energy by linking glucose monomers. In plants, starch stores energy, while in animals, glycogen serves this role. Their structure allows for efficient energy release when needed.
