Water, pH, Buffers Flashcards
water is an ____ molecule
active
What are the two major roles of water in biological systems?
maintain 3D structure, actively participates in reactions
When DNA and RNA are covalently linked, a water molecule is ____
released
Protein digestion does what with water?
uses up
What happens when DNA is dried out?
the structure is changed and it does not function normally
What has a relatively ___ BP
high
When water is heated, H bonds are broken more ____
rapidly
Electrons are drawn to which element in water?
O
Electrons are drawn away from which element in water?
H
Electronegative O and the H atoms form what type of moment?
dipole
Is water polar or non-polar?
polar
H-bonds in liquid water are ____ lived
short
What besides charge causes the dipole moment of water?
bond angle is not 180 (is 104.3)
The H of one water molecule bonds to the ___ of the other water molecule
O
O can make ____ H bonds at a time
2
H can make ____ H bonds at a time
1
H2O can make ____ H bonds at a time
4
What state of water has a fixed, 3D network with an open lattice structure?
solid
Ice has a ____ density
low
Why does ice float on water?
it is less dense
Water is a _____ solvent
good
What does the ability of water to be a good solvent depend on?
the chemical nature of what is being mixed
What type of substances does water form hydrogen shells around?
ionic
Water forms a _____ when making a hydrogen shell
fixed coating
What is a clathrate structure?
cage like
What type of molecules does water make a clathrate structure around?
hydrophobic
Do hydrophobic molecules directly interact with water?
no
Water interacts with what part of the hydrophobic molecule?
surface
What is another term for nonpolar solute molecules?
hydrophobic
Water forms micelles around what type of molecule?
amphiphilic
What is an amphiphilic molecule?
2 chemical natures in 1 molecule
Fatty acids have a ____ head
polar
Fatty acids have a ____ tail
non-polar
What is the nonpolar tail of fatty acids made of?
C-H bonds
Why are C-H bond chains hydrophobic?
They have no interactive chemical group present
What shaped is a micelle?
sphere
What type of molecule forms a lipid bilayer?
a more complex amphiphilic molecule
A lipid bilayer is a ___D structure
2
Lipid bilayers are the same structure as biological _____
membranes
The lipid bilayer acts as a ____ for small molecules
barrier
The charged groups of an amphiphilic molecule ____ with water
interact
Colligative properties depend on what?
number of solute particles per unit volume
Colligative properties do not depend on what?
the chemical nature of the solute
The more you mix in the ____ the freezing point
lower
Water molecules move from the region of ____ H2O concentration to the region of _____ H2O concentration
higher, lower
Osmotic pressure is important in what type of cells?
red blood cells
What is pH a measure of?
hydrogen ion concentration
A large H+ concentration is a ____ substance
acidic
A small H+ concentration is a ____ substance
basic/ alkaline
H+ concentration and OH- concentration are ______ related
inversely
H+ and OH- concentrations are even when a substance is _____
neutral
What is the physiological pH?
7.4
What does a buffer do?
maintain pH value
What must a pH be maintained?
to preserve structure and function
Phosphate buffer system buffers _____
the intracellular fluid of cells
Carbonate buffer system buffers _____
blood plasma
In the phosphate buffer system, OH- is neutralized by _______ to make water and HPO42-
H2PO4-
In the phosphate buffer system, H+ is neutralized by ______ to make H2PO4-
HPO42-
In the carbonate buffer system, H+ is neutralized by ____ to make H2CO3
HCO3-
In the carbonate buffer system, OH- is neutralized by ______ to make HCO3- and water
H2CO3
Ions in solution interact with water to form____
hydrogen shells
The structure of water is hexagonal because there are 6 water molecules in any H-bonded ___ ____
closed path
Each integer on the pH scale increases or decreases H+ concentration by _____
tenfold
