Biochemistry Chapter 3-AP Bio Part 1 Flashcards
What type of bonds connect the oxygen atom to hydrogen atoms
Single covalent
Water is the only common substance to what
Exist in the natural environment as 3 states of matter
What makes water a polar molecule
The unequal sharing of electrons and water’s v-like shape, overall charge is unevenly distributed
When water is in liquid form, hydrogen bonds are very _______
Fragile, 1/20 as strong as a covalent bond
How do hydrogen bonds exist in movement
The bonds break, reform with great frequency. Constantly forming new bonds with different partners, each lasting only a trillionth of a second
What are the 4 emergent properties of water
Cohesive behavior, ability to moderate temperature, expansion upon freezing, and versatility as a solvent.
What allows water to be more structured than other liquids
The linkages between water and other molecules by hydrogen bonding at various moments.
Cohesion
Hydrogen bonding collectively holding a substance together
What does cohesion contribute to
The transport of water and dissolved nutrients against gravity in plants
How does water from the roots reach the leaves
Through a network of water conducting cells
What happens as water evaporates through a leaf
Hydrogen bonds cause water molecules leaving the veins to tug on molecules farther down and the upward pull is transmitted through the water conducting cells to the roots.
Adhesion
The clinging of one substance to another
How does adhesion help with this transport of water
Adhesion of water by hydrogen bonds to the molecules of cell walls helps counter the downward pull of gravity.
Surface tension
A measure of how difficult it is to stretch or break the surface of a liquid.
What is at the interface between water and air
An ordered arrangement of water molecules hydrogen bonded to one another and the water below. THIS GIVES WATER AN UNUSUALLY HIGH SURFACE TENSION
How does water moderate air temperature
By absorbing heat from air that is warmer and releasing the stored heat to air that is cooler
How come water is effective as a heat bank
It can absorb or release a relatively large amount of heat with only a slight change in its own temperature
Kinetic energy
The energy of motion. Anything that moves has kinetic energy
Thermal energy
The kinetic energy associated with the random movement of atoms or molecules
Temperature
A measure of energy that represents the average kinetic energy of the molecules on a body of matter, regardless of volume
What does the total thermal energy depend on
The atoms volume
What happens when 2 objects of different temperatures are brought together
Thermal energy passes from the warmer to the cooler object until they are the same temperature
Heat
Thermal energy in transfer from one body of matter to the other
Calorie (cal)
One convenient unit of heat, the amount of heat it takes to raise the temperature of 1 g of water by 1°C. Also the same amount of heat it takes for 1 g of water to cool 1 °C
Kilocalorie (kcal)
The quantity of heat required to raise the temperature of 1 kg of water by 1°C
Joule (J)
Another energy unity = 0.239 cal
Specific heat
The amount of heat that must be absorbed or lost for 1 g of that substance to change its temperature by 1°C. Water’s specific heat = 1 calorie/gram • °C
What occurs because of water’s high specific heat
Water will change its temperature less than other liquids when it absorbs or loses a given amount of heat
How does hydrogen bonding come into play with water’s high specific heat
Heat must be absorbed to break hydrogen bonds, and heat is released when they form. A calories of heat causes a relatively small change in temperature because much of the heat is used to disrupt hydrogen bonds before the water can begin moving faster.
What happens when the temp of water drops slightly
Many additional hydrogen bonds form, releasing a considerable amount of energy in the form of heat.
How does water’s high specific heat o cur in biology
Water can moderate air temperature in coastal areas. P 47. Also stabilizes ocean temperatures, creating a favorable environment for marine life.
How does water’s heat affect organisms
They are better able to resist changes in their own temperature because they are made of water
