BM: Water Flashcards
Describe the structure and properties of water molecules
Water molecules consist of one oxygen atom bonded to two hydrogen atoms (H₂O). The oxygen atom is more electronegative, creating partial negative and positive charges. This polarity enables water molecules to form hydrogen bonds, making water cohesive and giving it unique properties.
Explain the role of hydrogen bonds in water’s properties
Hydrogen bonds are weak interactions that occur between a positively charged hydrogen atom and an electronegative atom (e.g., oxygen). In water, these bonds pull water molecules together, contributing to water’s high cohesion, surface tension, and its ability to dissolve various substances.
Describe the significance of water as a universal solvent
Water is known as a universal solvent because it can dissolve a wide variety of polar substances. The polarity of water molecules allows them to form hydrogen bonds with solutes, facilitating metabolic reactions and making aqueous solutions essential for cellular processes.
Explain why water has a lower density when frozen
Water has a lower density when frozen because its molecules form a crystalline structure through hydrogen bonding. This arrangement causes water molecules to be spaced further apart in ice than in liquid form, making ice less dense than liquid water, which is why ice floats.
Describe the importance of water’s high specific heat capacity
Water has a high specific heat capacity, meaning it requires a significant amount of thermal energy to raise its temperature by 1°C. This property helps regulate body temperature and maintain stable environmental conditions, making water an ideal medium for metabolic reactions.
Explain the concept of cohesion in water and its biological significance
Cohesion refers to the attraction between water molecules due to hydrogen bonds. This property allows water to “stick” together, contributing to surface tension and enabling processes such as the movement of water through plant vessels (capillary action).
Define capillary action and describe how it is related to cohesion and adhesion
Capillary action is the ability of water to move through narrow spaces against gravity. It occurs due to the combination of cohesion (water molecules sticking together) and adhesion (water molecules sticking to the walls of narrow tubes). This property is essential in processes like water transport in plants.
Explain why 70-95% of cytoplasm is water and its relevance to metabolic reactions
The high water content of cytoplasm (70-95%) is crucial because metabolic reactions occur in aqueous solutions. Water’s ability to dissolve a wide range of substances facilitates biochemical processes like enzyme activity and nutrient transport within cells.
Explain the relationship between water’s polarity and its ability to form hydrogen bonds.
Water’s polarity arises from the unequal sharing of electrons between oxygen and hydrogen atoms, with oxygen being more electronegative. This creates partial positive charges on the hydrogen atoms and a partial negative charge on the oxygen atom. The oppositely charged regions of different water molecules attract, forming hydrogen bonds that contribute to water’s unique properties.
Describe how water’s polarity affects its role in dissolving substances.
Water’s polarity enables it to dissolve polar substances by forming hydrogen bonds with the solutes. The partially charged regions of the water molecules interact with the charged or polar components of the solute, breaking it down into smaller particles. This property is essential in biological processes, as it allows water to transport nutrients, ions, and waste products.
Explain why water’s high heat capacity is important for regulating body temperature.
Water’s high heat capacity allows it to absorb or release large amounts of heat without a significant change in temperature. This helps organisms regulate their body temperature, as water in the bloodstream, tissues, and cells prevents rapid temperature fluctuations that could be harmful to metabolic processes.
Describe how water helps with digestion
Water helps break down food so the body can absorb nutrients. It also moves food through the digestive system.
Explain how water supports the bodys temperature regulation
Water helps regulate body temperature by absorbing heat when it’s hot and releasing it when it’s cold, preventing temperature extremes.
why is water important for the circulatory system?
Water makes up a large part of blood, which carries oxygen and nutrients to cells and removes waste. It keeps blood flowing smoothly.
