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anaerobic respiration

produces lactic acid

lipid respiration

produces fatty acids and ketones


transports oxygen to cells of the body

weak bases

absorb H+

weak acids

donate H+


examples of electrolytes, inorganic compounds whose ions can conduct electrical current in solution


the gradual addition of a solution of known strength and measuring the volume necessary to convert the constituent to another form

Bicarbonate Buffer System

H+ + HCO3- --> H2CO3 --> CO2 + H2O
strong acid + weak base --> weak acid -->
both are part of equilibrium system

Too much OH- in the blood? bicarb

disfunction of urinary system
OH- + H2CO3 --> HCO3- + H2O
strong base + weak acid --> weak base
HCO3 is excreted by the kidneys
prevent pH changes caused by organic (metabolic) acids

Protein Buffer System

not as much of an equilibrium system
accounts for 75% of all chemical buffering ability of body fluids

lower pH? protein

-COOH --> -COO- + H+
carboxyl group acts like an acid when needed
protein donor

raise pH? protein

-NH2 + H+ --> -NH3+
amino group acts like a base when needed
protein acceptor

maintain acid-base balance

For homeostasis to be preserved, H+ must be REMOVED from body fluids. The RESPIRATORY SYSTEM and KIDNEYS support the buffer systems.
involved balancing H+ loss/gain

Phosphate Buffer System

H2PO4- --> H+ + HPO4-2

in the ECF

phosphate buffer system plays a supporting role because there are more HCO3-

in the ICF

phosphate buffer system is very important where there is a high concentration of phosphate ions

pH < 7.35

acidosis (more common)

pH > 7.45


nervous system and cardiovascular system

particularly sensitive to pH fluctuations

partial pressure of CO2 and pH

inversely related

Protein buffer system

regulates pH in ECF and ICF

Bicarbonate buffer system

important, in the ECF if H+ are removed, they'll be replaced through combining of water with CO2
If H+ are added, most will be removed by forming CO2 and H2O

Bicarbonate buffer system

can cope with large amounts of acid because body fluids contain many bicarb ions, aka bicarb reserve

Phosphate buffer system

consists of an anion, H2PO4-
concentration of bicarb ions is way more than that of phosphate ions
important in buffering pH of ICF--> where phosphate ion concentration is high

respiratory and renal mechanisms

support buffer systems by 1. secreting/absorbing H+; 2. controlling excretion of acids and bases; 3. generating additional buffers
the combo of buffer systems and these respiratory and renal mechanisms maintain body pH within narrow limits

4 major classs of organic compounds in human body

carbs --> sugars, starches
lipids --> fats, oils, waxes
proteins --> hemoglobin, keratin
nucleic acids --> DNA and RNA


an organic molecule that contains carbon, hydrogen, and oxygen in a ratio near 1:2:1
most important energy source
glucose is most important metabolic fuel in body
all must be disassembled through hydrolysis before used as energy
excess sugar is stored as fat

3 major types of carbs

monosaccharides, disaccharides, polysaccharides


3-7 carbon atoms; energy source; manufactured in the body and obtained from food, found in body fluids
ex: glucose, fructose, galactose (all 3 are structural isomers)


2 monosaccharides; energy source; all must be broken down to monosaccharides before absorption
ex: sucrose --> table sugar (glucose and fructose)
lactose --> present in milk (glucose and galactose)
maltose --> milk sugar (glucose and glucose) in germ. wheat


storage of glucose molecules
ex: glycogen --> in animal cells
other starches and cellulose are in plants


a polysaccharide composed of interconnected glucose molecules
stored in muscle cells and liver cells
aka animal starch

4 major types of lipids

fatty acids, fats, steroids, phospholipids

fatty acids

end with carboxyl group; energy source; absorbed from food or synthesized in cells, transported in the blood for use in many tissues
ex: lauric acid, butter, fatty meat, vegetable oils


energy source and storage; insulation and physical protection; stored in fat deposits, broken down to fatty acids and glycerol
ex: oils, monosaccharides, diglycerides, triglycerides (most common) (3 fatty acids bonded to a 3 C glycerol)


large lipid molecules made of 4 connected C rings, structural component of cell membranes, hormones, digestive secretions in bile --> carbon ring framework
ex: cholesterol ("parent steroid") like estrogen and testosterone


glycerol and 2 fatty acids linked to a nonlipid group, structural component of cell membranes, composed of fatty acids and nonlipid molecules
ex: in cell membranes, lecithin

structure of proteins

each amino acid consists of a central carbon atom bonded to a hydrogen atom, an amino group, and a variable R group or side chain; the structure is established by the sequence of amino acids; long chains; 20 different amino acids are building blocks of proteins; shape determines function; large protein = over 100,000 amino acids; typical protein: 1000 amino acids joined by peptide bonds; changing one amino acid chain of 10,000 can cause protein not to work

characteristics of proteins

400,000 different kinds; all contain carbon, hydrogen, oxygen, and nitrogen; long chains of organic molecules called amino acids; 7 categories of protein function; transport through blood; metabolic regulation by enzymes; buffering; cell support structure; movement and muscle contractions; coordination, communication, control by hormones; defense anti-bodies, clotting proteins (blood)

characteristics of enzymes

work best at optimal temp and pH; catalyze reactions that sustain life; substrates must bind to the active site before an enzyme can function as a catalyst; work quickly; they catalyze only 1 type of reaction; substrates are reactants; aren't used up; most important protein

nucleic acids

large organic molecules composed of carbon, hydrogen, oxygen, nitrogen, and phosphorus; store and process info at the molecular level inside cells; ex: DNA and RNA; made of nucleotides which are made of a sugar, phosphate group, and nitrogenous base


double strands; deoxyribose; adenine, guanine, cytosine, thymine; longer; stores info controlling protein synthesis


single strand; ribose; adenine, guanine, cytosine, uracil; short; protein synthesis


breakdown of food; 1 more phosphate group (3); forms ADP; high chem energy


low energy molecule; 2 phosphate groups attached

If the pH of blood needs to increase, which group acts like a base?

amino group

If the pH of the blood needs to decrease, which group acts like an acid?

carboxyl group

If there is too much OH- in the blood, what compound reacts with OH- to produce a weak base?

H2CO3 (carbonic acid)

If there is too much H+ in the blood, which compound will react with H+ to produce a weak acid?

HCO3- (bicarbonate ion)

What compound acts as a weak base?


What compound acts as a weak acid?


R group

what is different for every amino acid


substrate specific
are proteins
all aid in digestion

Buffer lab

It worked because when adding strong base, NAOH, there wasn't a fast change in pH. It was a gradual change because the buffer (vinegar) was trying to resist a pH change. The OH- was accepting a proton from buffer, vinegar.
OH- + H+ --> H2O

Buffer lab equation

vinegar + sodium hydroxide --> sodium acetate + H2O
weak acid (buffer) + strong base --> weak base

enzymes belong to a class of substances called _______, which accelerate chemical reactions without themselves being permanently changed


special molecules called enzymes found in cells ______

speed up reactions that support life, produce energy to start a chemical energy, release activation energy for a reaction to proceed

When an enzyme promotes a chemical reaction by lowering the activation energy, it only affects the ____

rate of reaction

exergonic reactions, which are common in the body, are responsible for _____

generating the heat that maintains your body temperature

the activation energy requirement of a reaction is much lower in the presence of _______

an appropriate enzyme

organic compounds differ from inorganic compounds in that organic compounds are primarily composed of ______

carbon and hydrogen atoms and are much larger and more complex

the most important inorganic compound found in large quantity in the body ____


compounds that contain the elements carbon, hydrogen, and usually oxygen are ______ compounds


acids, bases, and salts are examples of _____ compounds



excellent solvent, high heat capacity, essential reactant in the chemical reactions of living systems

during ionization, water molecules disrupt the ionic bonds of a solute and a mixture of ions is produced. these ions are called ____


most chemical reactions in the body take place in ____


a homogenous mixture containing a solvent and a solute is called a _____


soluble inorganic compounds whose ions will conduct an electric current in a solution are ___


pH is a measure of the concentration of ____ in solution

hydrogen ions

a solution with the pH below 7 is ___


compounds that stabilize pH by either removing or replacing hydrogen ions are ____


least acidic

urine with ph 6 isn't as acidic as lemon juice with ph of 2

pH greater than 7 ____

Alkaline, basic

To maintain homeostasis in the body, the normal pH range of the blood must remain at ___

7.35 to 7.45

A solution with a pH of 7 that contains equal number of hydrogen ions and hydroxide ions is called ____


A solute that dissociates to release hydrogen ions and causes a decrease in pH is ____

an acid

A solute that removes hydrogen ions from a solution is ____

a base

in the body, inorganic compounds _____

serve as buffers

inorganic ions are important in the functions of ____

blood clotting, muscle contractions, nerve impulse conduction

a weak acid that serves at an effective buffer in the body is ___

carbonic acid

a salt may be best described as ___

inorganic molecule created by the reaction of an acid and a base

carbs are most important to the body because they serve as primary sources of ____


most important metabolic fuel molecule in the body ___


the polysaccharide formed by stored glucose in the liver and muscle is ___


most of the fat found in the human body is in the form of ___


butter, fatty meat, and ice cream are examples of sources of fatty acids that are said to be ____


a steroid molecule is an example of ____


the building blocks of proteins consist of chains of small molecules called ___

amino acids

proteins differ from carbohydrates in that they ___

always contain nitrogen

each amino acid differs from others in the ___

nature of the R group

special proteins that are involved in metabolic regulation are called ___


the molecules that store and process info at the molecular level are the ___

nucleic acids

three basic components of a single nucleotide of a nucleic acid are ____

sugar, phosphate group, nitrogen base

in DNA and RNA, a nucleotide containing the nitrogen base cytosine would only base-pair with ___


the most important high-energy compound in cells is ___


why do human bodies need buffers?

When someone exercises a lot, lactic acid starts to build up in the blood stream. This causes the pH to lower. If the pH ever gets below 6.8, the effects can be deadly. Buffers help to neutralize the lactic acid and keep the pH at a healthy level.

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