Topic 2

Anatomy and Physiology

Basic Chemistry

Concept of Matter and Energy

Matter

Anything that occupies space and has mass (weight).

Exists in solid, liquid and gaseous states.

Can be changed both physically and chemically.

Physical change – no alteration in the basic nature of the

substance.

Chemical change – with alteration in the composition of the

substance

Energy

The ability to do work or to put matter into motion.

Massless and does not take up space.

Kinetic and Potential energy.

Forms of Energy:

Chemical energy

Electrical energy

Mechanical energy

Radiant energy

Energy Form Conversions

Energy could be converted from one form to another.

Law of Conservation of Energy.

Energy cannot be created nor destroyed but could be

transferred and changed in form.

Composition of Matter

Elements and Atoms

Elements

Substance that composed all matter.

Common elements making up the human body. (p. 30)

Atoms

The building blocks of elements.

Atomic symbol.

From a Greek word that means ‘incapable of being divided”.

Composed of subatomic particles which differ in their mass,

electrical charge and location within the atom.

IONS – an atom that have gained or loss electron.

Identifying Elements Atoms of different elements are composed of different numbers of

protons, neutrons and electrons.

Because protons and neutrons each have a mass of 1, the mass of an atom is equal to the number of protons and neutrons of that atom. The number of electrons does not factor into the overall mass, because their mass is so small.

The atomic number of an element is equal to the number of protons that element contains.

The mass number is the number of protons plus the number of neutrons of that element. Therefore, it is possible to determine the number of neutrons by subtracting the atomic number from the mass number.

Atomic Weight and Isotopes

Isotopes are atoms that have the same number of p+ and e-

but vary in the number of n0 they contain hence have the

same atomic number but have different atomic masses.

Radioisotopes

- heavier isotopes that are unstable and tend to

decompose to become more stable.

• Radioactivity

- the process of spontaneous atomic decay.

Molecules and Compounds

Molecules

Two or more atoms of the same element that combine

chemically.

Compounds

Two or more different atoms that bind together to form a

molecule.

Chemical Bonds and Chemical

Reactions

Types of Chemical Bond

1. IONIC BONDS

Forms when e- are completely transferred from one atom to

another i.e. when they gain or lose e- during bonding.

Generally forms the general category of chemicals called

SALTS.

EXAMPLE:

Types of Chemical Bond

2. COVALENT BONDS

A form of chemical bond wherein an electron is shared by an

atom to fill its valence shell.

Types:

Nonpolar covalent bond – e- have been shared equally between

the atoms of the molecule.

Polar Covalent Bond – a molecule with two charged poles.

Types of Chemical Bond

3. HYDROGEN BONDS

Extremely weak bonds / fragile bonds that bind together

water molecules or different parts of the same molecule

(intramolecular bonds). They are common in large, complex

organic molecules such as proteins and nucleic acids.

Hydrogen Bond

Patterns of Chemical Reactions

1. Synthesis Reaction – occur when two or more atoms or

molecules combine to form a larger, more complex molecule .

Eg. A+B AB

2. Decomposition Reaction – occurs when a molecules is

broken down into smaller molecules, atoms or ions.

Eg. AB A + B

3. Exchange Reaction – involves synthesis and decomposition

reactions.

Eg. AB + CD AC + BD

Factors Increasing the Rate of

Chemical Reactions

Factor Mechanism to Increase the Number

of Collisions

Temperature The kinetic energy of the molecules.

Concentration of reacting

particles

The number of collisions

Particle size Smaller particles have more kinetic

energy and move faster than larger ones.

Presence of catalyst The amount of energy the molecules

need to interact by holding the reactants

in the proper positions to interact.

Biochemistry: The Chemical

Composition of Living Matter

Major Classes of Molecules

1. Inorganic Compounds

eg. Water, salts and most acids and bases.

2. Organic Compounds

eg. Carbohydrates, lipids, proteins and nucleic acids

Inorganic Compounds

Water

Properties of Water

1. High heat capacity

2. Polarity/Solvent properties

3. Chemical reactivity

4. Cushioning

Salt

Ionic compounds involved in nerve transmission, muscle

contraction, blood clotting, transport of oxygen by

hemoglobin, cell permeability, metabolism and many other

reactions.

Acids and Bases

Like salt, acids and bases are ELECTROLYTES.

Acids

a substance that can release hydrogen ions in detectable

amounts.

Proton donors.

Characteristics of ACIDS:

Sour taste

Can dissolve metals.

When dissolve in water, they release hydrogen ions. Strong

acids dissociate completely; weak acids dissociate incompletely.

Bases

Bitter in taste, feel slippery and are PROTON ACCEPTORS.

Ionize and dissociate and released hydroxyl ion.

The most important inorganic bases are hydroxides.

Bicarbonate ions are important bases in the body. When bases

and acids interact, NEUTRALIZATION occurs i.e. salt and

water are formed.

Organic Compounds

Carbohydrates

Contain C, H and O in the general relationship (CH2O)n

Size Classification:

1. Monosaccharides – building blocks of CHO.

1. Glucose

2. Fructose

3. Galactose

4. Ribose

5. Deoxyribose

Classification of CHO

2. Disaccharides – double sugars formed through dehydration

synthesis and broken down by hydrolysis.

- sucrose

- lactose

- maltose

3. Polysaccharides – large, insoluble long branching chains of

linked simple sugars.

- starch (storage polysaccharide formed by plants.)

- glycogen (polysaccharide found in animal tissue.)

LIPIDS

Insoluble in water but readily dissolve in other lipids and in

organic solvents such as alcohol and acetone.

The most abundant lipids in the body are:

Triglycerides

Phospholipids

steroids

Triglyceride

Neutral fats found primarily in adipose tissue where they

provide insulation and reserve body fuel.

Types:

Saturated – fatty acid chain with only single covalent bond

between carbon atom

Unsaturated - fatty acid chain with one(monounsaturated) or

more(polyunsaturated) double bond between carbon atom

Phospholipid

are major constituents of the plasma membrane, the outermost layer of animal cells.

Steroids

Cholesterol is the most common steroid. Cholesterol is mainly synthesized in the liver and is the precursor to many steroid hormones such as testosterone and estradiol, which are secreted by the gonads and endocrine glands.

It is also the precursor to Vitamin D.

Cholesterol is also the precursor of bile salts, which help in the emulsification of fats and their subsequent absorption by cells.

Although cholesterol is often spoken of in negative terms by lay people, it is necessary for proper functioning of the body.

It is a component of the plasma membrane of animal cells and is found within the phospholipid bilayer. Being the outermost structure in animal cells, the plasma membrane is responsible for the transport of materials and cellular recognition and it is involved in cell-to-cell communication.

Proteins CHON

Building blocks: amino acid.

Proteins have different shapes and molecular weights; some proteins are globular in shape whereas others are fibrous in nature.

For example, hemoglobin is a globular protein, but collagen, found in our skin, is a fibrous protein.

Protein shape is critical to its function, and this shape is maintained by many different types of chemical bonds. Changes in temperature, pH, and exposure to chemicals may lead to permanent changes in the shape of the protein, leading to loss of function, known as denaturation.

All proteins are made up of different arrangements of the same 20 types of amino acids.

Structure of Proteins

Fibrous / Structural Proteins – appears on body structure.

Globular / Functional Proteins – biological processes.

The Nucleotide base comes in five varieties:

Adenine (A)

Guanine (G)

Cytosine (C)

Thymine (T)

Uracil (U)

• The nucleotide are named according to the base they contain.

Eg. A-containing bases are adenine nucleotides etc.

Nucleic Acids

They make-up the genes, which provide the basic blueprint

of life and direct growth and development.

Components; C-H-O-N-P

Building blocks: nucleotides

Composition:

Nitrogen-containing base

Pentose sugar

Phosphate group

The two main types of nucleic acids are deoxyribonucleic

acid (DNA) and ribonucleic acid (RNA).

DNA is the genetic material found in all living organisms,

ranging from single-celled bacteria to multicellular

mammals. It is found in the nucleus of eukaryotes and in the

organelles, chloroplasts, and mitochondria.

RNA, is mostly involved in protein synthesis. The DNA

molecules never leave the nucleus but instead use an

intermediary to communicate with the rest of the cell. This

intermediary is the messenger RNA (mRNA).

As you have learned, information flow in an organism takes

place from DNA to RNA to protein.

DNA dictates the structure of mRNA in a process known as

transcription, and RNA dictates the structure of protein in

a process known as translation.

This is known as the Central Dogma of Life, which holds true

for all organisms; however, exceptions to the rule occur in

connection with viral infections.

ATP (Adenosine Triphosphate)

The universal energy compound used by cells of the body.

Energy carrying molecule of the cell.

Glucose enter the cell catabolism stored in the high

phosphate bonds of ATP molecule hydrolysis energy.