A1.1 Water Flashcards
A1.1.1 First cells originated in _____
Water
A1.1.1 _____ remains the medium in which most process of life occur
Water
A1.1.2 Polarity of covalent bonding within water molecules is due to _____
Unequal sharing of electrons
-Nucleus of O atom is more attractive to electrons (electronegative) than that of H atom
A1.1.2 _____ bonding due to polarity occurs _____ water molecules
Hydrogen, between
A1.1.2 Represent two or more water molecules and hydrogen bonds between them with indications of polarity
.
A1.1.3 Role of cohesion in the transport of water under tension in xylem
-Water is sucked upwards from the roots to the leaves along tubular vessels in xylem
-There are continuous columns of water in these vessels
-Each column of water is under tension (in roots, generated by attractions btwn soil particles and water; in leaves, developed as water is lost by evaporation; also due to attractions between water molecules and cell walls of leaf cells)
-Water moves upwards because the pulling forces in the leaves are greater than the forces in the roots
-Water in xylem can withstand tensions because hydrogen bonds make it cohesive (water column remains continuous)
-For a water column to break, many hydrogen bonds must be broken simultaneously (requires a lot of energy) –> water can withstand large tensions
A.1.1.3 Role of surface tension in making water surfaces habitats
-Water surface acts like an elastic membrane that shrinks to the minimum possible area because water molecules are much more attracted to each other hydrogen bonding than to air particles (=surface tension)
-Due to surface tension, it is possible to float objects on water surface, even though they are denser than water
-This is because cohesion between water molecules due to hydrogen bonds is greater than attraction between water and the floating object
-Requires a lot of energy to break many hydrogen bonds simultaneously
-Can be used as habitats (e.g. water striders, mosquito)
A.1.1.4 Role of adhesion in capillary action in soil
A.1.1.4 Role of adhesion in plant cell walls
A1.1.5 A wide variety of _____ molecules dissolve in water
Hydrophilic
A1.1.5 Most enzymes catalyze reactions in _____ solution
Aqueous
A1.1.5 Functions of SOME MOLECULES in cells based on hydrophobicity and insolubility
?
A1.1.6 Contrast the physical properties of water with those of air
A1.1.6 Effect of buoyancy of water
A1.1.6 Effect of viscosity of water
A1.1.6 Effect of thermal conductivity of water
A1.1.6 Effect of specific heat capacity of water
A1.1.6 Consequences of water’s physical properties on the black-throated loon
A1.1.6 Consequences of water’s physical properties on the ringed seal
A1.1.7 Abundance of _____ over billions of years of Earth’s history has allowed life to _____
Water, evolve
A1.1.7 Hypotheses for the origin of water on Earth
Asteroids
A1.1.7 Reasons for retention of water
Gravity, temperatures low enough to condense water
A1.1.8 Goldilocks zone in searching for extraterrestrial life
A1.1 Guiding Q: What physical and chemical properties of water make it essential for life?
A1.1 Guiding Q: What are the challenges and opportunities of water as a habitat?
A1.1 Linking Q: How do the various intermolecular forces of attraction affect biological systems?
A1.1 What biological processes only happen at or near surfaces?
