BIOCHEMISTRY:THE BRANCH OF CHEMISTRY THAT RELATES DIRECTLY TO LIFE PROCESSES

CHEMISTRY OF LIFE: CHAPTER 2

BASIC CHEMISTRY:• Matter:

• Anything that occupies space and has mass• Exists as solid, liquid, or gas

Examples of each state are found in the human body…solid bones, teethliquid bloodgas air we breathe

ENERGY Contrasts to matter because it is massless and does not

take up space Can only be measured by its effects on matter Commonly defined as the “ability to do work” or “put

matter into motion” Really important inside the body and there are several

types….

FORMS OF ENERGY WITH ANATOMY CONNECTIONS:

1.Chemical:• Stored in bonds of chemical

substances

Anatomy Connection:All body cavities are “run” by the chemical energy harvested from the foods we eat

FORMS OF ENERGY WITH ANATOMY CONNECTIONS:

2. Electrical:• Results from movement of charged

particles

Anatomy Connection:In your body, an electrical current is generated when charged particles (ions) move across cell membranes…Why do “tasers” work?

FORMS OF ENERGY WITH ANATOMY CONNECTIONS:

3. Mechanical:• Directly involved in moving matter

Anatomy Connection:As the muscles in your legs shorten, they pull on your bones, causing your limbs to move-so you can do things like pedal a bike, smiling, waving at someone

FORMS OF ENERGY WITH ANATOMY CONNECTIONS:

4. Radiant:• Travels in waves, that is, energy of the

EM spectrum which includes X-rays, infrared, visible light, radio, microwaves, UV light, etc…

Anatomy Connection:Light stimulates your eyes so you can see….UV waves give you your suntan and stimulates production of Vitamin D

ENERGY CONVERSIONS• With few exceptions, energy is

converted from one form to another…

• In the body, chemical energy of foods is trapped in the bonds of a high-energy chemical called ATP and ATP’s energy may ultimately be transformed into the electrical energy of a nerve impulse or mechanical energy of shortening muscles

ENERGY CONVERSIONS & HEAT

Energy Conversions are quite inefficient Some energy is “lost” to the environment as heat. (It is

not really lost because energy cannot be created or destroyed, but the part given off as heat is unusable so we call it lost)

All energy conversions that occur in the body liberate heat It is this heat that makes us warm-blooded animals and

contributes to our relatively high body temperature, which has an important influence on body functioning (the higher the temperature, the faster chemical reactions in the body can occur)

R.A.F.T. & GISTEXPLAINING HOW THE TASER SHOTGUN SHELL WORKS

TASER VIDEOR (Role of Writer): Who are you as the writer? You are a friend trying to explain something to another friend.A (Audience): To whom are you writing? Your troublesome friend who was recently shot with a Taser because he ran from the cops at a party.F (Format): What form will the writing take? A short, easy to comprehend letter (because your friend really doesn’t like to read long, complicated things)T (Topic): What’s the subject or the point of this piece? The point is to explain to your friend how the Taser shotgun shell works…basically, explain to your friend what happened to his body when he was tased.

The Catch: The letter can only be 20 words or less….giving only the GIST of what your friend needs to know!

ELEMENTS:

Periodic Table Basic substances that cannot be broken down into

simpler substances All living and nonliving things are composed of elements There are 92 naturally occurring elements (think about

this…there are only 92 and they make up everything, living and nonliving…pretty cool)

96% of the human body is composed of just 4 elements: Carbon (C) Oxygen (O) Hydrogen (H) & Nitrogen (N)

Common Elements in the body (be sure to review) on Page 28, Table 2.1

ATOMS• An atom is the smallest unit of an element

that still retains the chemical and physical properties of an element

• Atoms are made up of subatomic particles:• Protons-positive charge • Neutrons-no charge or neutral• Electrons-negative charge

• Protons and Neutrons make up the nucleus or core of the atom while Electrons circulate around the core in specific orbital paths

• The number of protons an atom has defines what element it is…for example, Carbon always has 6 protons, if it had 7, it would then be Nitrogen!

• The number of neutrons can vary and electrons are involved in bonding, so in a sense, their number can vary as well.

ISOTOPES

• Isotopes are atoms of the same elements that have different numbers of neutrons

• Why do we care in Anatomy??• Certain isotopes called “radioactive isotopes” undergo

decay…as they decay, they emit radiation. Radiation can be detected using a special counter or scanner.

• Radioactive isotopes are widely used in biological and medical research….

EXAMPLES OF RADIOACTIVE ISOTOPES IN

MEDICAL/BIOLOGICAL RESEARCH:1. The thyroid gland uses Iodine (I). It

is possible to administer a dose of radioactive iodine and then observe later that the thyroid has taken it up!

2. Radiation can interfere with cell division in larger doses. Radioisotopes have been used in the treatment of cancer (a disease characterized by uncontrolled cell division). The radiation interferes with cancer cells multiplying.

3. In your textbook, Page 20, Third Column: PET…also observe picture on Page 21.

BONDING: ATOM TO ATOM INTERACTION Bonding is all about the electrons…

1. Ionic: Transfer of electrons that leaves behind charged particles called “ions:

2. Covalent: Atoms share electrons3. Hydrogen Bond: Occurs whenever a

H is attracted to an H in another molecule. Very common with water. It is a weak bond that is easily broken

Anatomy Connection: H-bonds help determine 3-dimensional structure of large molecules such as proteins and DNA

CHEMICAL REACTIONS Chemical reactions involve the making or breaking of

bonds between atoms The total number of atoms remains the same, but the

atoms appear in new combinations Most chemical reactions you need to know for Anatomy

have one of the three recognizable patterns described next…

CHEMICAL REACTION TYPES WITH ANATOMY CONNECTIONS

1. Synthesis Reactions: 2 or more atoms or molecules combine to form a larger, more

complex molecule

ANATOMY CONNECTION: Synthesis reactions underlie all anabolic (constructive) activities that

occur in body cells. They are particularly important for growth and repair of worn out or damaged tissues

Synthesis reactions are necessary for bone development and hair & nail growth.

CHEMICAL REACTION TYPES WITH ANATOMY CONNECTIONS

2. Decomposition Reactions: Occur when a molecule is broken down into smaller molecules,

atoms, or ions.

ANATOMY CONNECTION: Decomposition reactions underlie all catabolic (destructive) activities

that occur in body cells. Decomposition reactions are necessary for digestion of foods into

their building blocks for our body to use Also, breakdown of glycogen (a large carbohydrate molecule stored in

the liver) to release glucose when blood sugar levels start to decline

CHEMICAL REACTION TYPES WITH ANATOMY CONNECTIONS

3. Exchange Reactions: Involve synthesis and decomposition…Bonds are made and broken. During

exchange reactions, a switch is made between molecule parts and different molecules are made.

ANATOMY CONNECTION: This type of reaction occurs in the body when ATP reacts with glucose and

transfers its end phosphate group, forming glucose-phosphate. At the same time, the ATP becomes ADP. This important reaction, which occurs whenever glucose enters a body cell, effectively traps the glucose fuel molecule inside the cell for use!

INORGANIC VS. ORGANICo All chemicals found in the body fall into one of two major

classes of molecules: inorganic or organico Difference between the 2 is determined solely (with only a few

exceptions CO2 and CO) by the presence of Carbon

o Inorganic: o Lacks Carbon! Tend to be small, simple molecules

o Organic: o Contains Carbon! Are fairly or very large covalently

bonded molecules

o Both are important and equally essential for life!

Is the single most abundant compound in the body

Acts as a universal solvent in which electrolytes (salts, acids, bases) ionize and in which chemical reactions occur

Is the basis of transport and lubricating fluids

Slowly absorbs and releases heat, thus helping to maintain homeostatic body temperature

Protects certain body structures (such as the brain) by forming a watery cushion

1. Water

INORGANIC COMPOUNDS:

In ionic form are involved in nerve transmission, muscle contraction, blood clotting, transport of oxygen by hemoglobin, cell permeability, metabolism, and many other reactions.

Additionally, calcium salts (as bone salts) contribute to bone hardness.

2. Salts

INORGANIC COMPOUNDS:

Are proton donorsWhen dissolved in water, they

release Hydrogen ionsStrong acids dissociate (break

down) completely in water & weak acids dissociate incompletely in water

Example in body: Hydrochloric acid produced in the stomach aids in digestion

3. Acids

INORGANIC COMPOUNDS:

Are proton acceptorsThe most important inorganic

bases are hydroxidesBicarbonate ions are important

bases in the body (part of blood).

When bases and acids interact, neutralization occurs-that is, a salt and water are formed.

4. Bases

INORGANIC COMPOUNDS:

pH Scale: H+ Can be Measured The pH scale is used to indicate the

acidity and basicity (or alkalinity) of a solution.

It is a scale of 0-14 where 7 is neutral and the smaller the number the more acidic and the larger the number the more basic the substance.

As we move down the pH scale, each unit has 10 times the number of H+ ions as the previous unit.

In living things, pH needs to be maintained within a narrow range or there are health consequences.

Norma blood pH ranges from 7.35-7.45. Slight deviations outside this range can be fatal!

Contain carbon, hydrogen, and oxygen

Classified according to size as monosaccharides, disaccharides, or polysaccharides

Their building blocks are monosaccharides (these join to form the “di” and “poly”)

Monosaccharides include glucose, fructose, galactose, deoxyribose, and ribose

Disaccharides include sucrose, maltose, and lactose

Polysaccharides include starch and glycogen

Carbohydrates are ingested as sugars and starches

Carbohydrates (in particular glucose) are the major energy sources for the formation of ATP

1. Carbohydrates

ORGANIC COMPOUNDS:

Include triglycerides, phospholipids, and steroids (including cholesterol)

Triglycerides (neutral fats) are found primarily in adipose tissue where they provide insulation and reserve body fuel

Phospholipids and cholesterol are found in all cell membranes. Cholesterol also forms the basis of certain hormones, bile salts, and vitamin D

2. Lipids

ORGANIC COMPOUNDS:

Are constructed from building blocks called amino acids

20 common types of amino acids are found in the body

Amino acid sequence determines the proteins constructed

Fibrous, or structural proteins are the basic structural materials of the body

Globular proteins are also called functional proteins; examples of these include enzymes, some hormones, and hemoglobin

Disruption of the hydrogen bonds of functional proteins leads to their denaturation and inactivation

Proteins account for over 50% of the organic matter in the body and have the most varied functions

3. Proteins

ORGANIC COMPOUNDS:

Role is fundamental: they make up genes, which provide the basic blueprint of life…not only do they determine what type of organism you will be, but they also direct your growth and development!

Nucleic Acids include: Deoxyribonucleic Acid (DNA) which

maintains genetic heritage by replicating itself before cell division and contains the code-specifying protein structure

Ribonucleic Acid (RNA) which acts in protein synthesis to ensure that instructions of the DNA are executed

4. Nucleic

Acids

ORGANIC COMPOUNDS:

Is the universal energy compound used by all cells of the body

Without ATP, molecules cannot be made or broken down, cells cannot maintain their boundaries, and all life processes grind to a halt!

Although glucose is the most important fuel for body cells, none of the chemical energy contained in its bonds can be sued directly to power cellular work…instead, energy released as glucose is catabolized, captured, and stored in the bonds of ATP molecules as small packets of energy

5. Adenosine

TriphosphateATP

ORGANIC COMPOUNDS:

THE TERRORIST ATTACKS ON NEW YORK CITY’S WORLD TRADE CENTER KILLED MORE THAN 3,000 PEOPLE, THEIR BODIES BURIED

IN MILLIONS OF TONS OF RUBBLE. IN A SITUATION LIKE THIS, HOW CAN WE IDENTIFY INDIVIDUALS WITH ANY

CERTAINTY?

TABLE TALK: