the chemical basis of life_001

7/29/2019 The Chemical Basis of Life_001

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The Chemical Basis of Life

Ace Bryan S. Cabal


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Matter, Mass and Weight

Matter- anything that occupies space

Mass- amount of matter in an object

Weight- gravitational force acting on an objectof a given mass


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Elements and Atoms

Element- the simplest type of matter with

unique chemical properties

Atom- is the smallest part of element that has

chemical characteristics of that element


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Atomic Structure

Neutrons- have no electrical charge

Protons- have positive charges

Electrons- have negative charges

Nucleus- protons and neutrons

Electron cloud- region in an atom where electrons aremost likely found

Atomic number- equal the number of protons in eachatom; since the number of protons and electrons are

equal, atomic number is also the number of electrons An atom is electrically neutral because it has the same

number of H+ and e-


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Electrons and Chemical Bonding

When an atom loses or gains electrons, the

number of protons and electrons are no

longer equal and the charged particle is called

ion

Ionic bonding- bonding of oppositely charged

particles

E.g. Na+ + Cl- = NaCl


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Electrons and Chemical Bonding

Covalent bonding- results when atoms share oneor more pairs of electrons forming a molecule

E.g. H-H, O=C=O

Hydrogen bond- attraction between a positiveend and negative end of a molecule

Molecule- formed when two or more atomschemically combine

Compound- made up of two or more differenttypes of atoms are chemically combined


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Ions and Electricity

Ions that dissociate in water are sometimes

called electrolytes because they have the

capacity to conduct an electrical current,

which is the flow of charged particles


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Chemical Reactions

Interxn of atoms, ions, molecules, or

compounds to form or to break chemical

bonds

Reactants- substances that enter into a

chemical reaction

Products- substances that result from the

chemical reaction


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Classification of Chemical Reaction

1. Synthesis reaction- when 2 or more reactants combine to form alarger, more complex product

e.g. A + B -> AB; A-P-P + Pi -> A-P-P-P

2. Decomposition reaction- reactants are broken down into a smaller,less complex products

e.g. AB -> A + B; A-P-P-P -> A-P-P + P i3. Exchange reaction- combination of a decomposition and synthesis

reaction

e.g. AB + CD -> AC + BD;

HCl + NaOH -> NaCl + H2O

4. Reversible reaction- reactants to products and products toreactants, meaning the rate of product formation is the same as therate of reactant formation or at equilibrium


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Energy

Energy- capacity to do work- i.e. to move matter.

Potential energy- stored energy that could do work butis not doing so

Kinetic energy- energy in motion

Mechanical energy- results from the position ormovement of objects

Law of conservation of energy- energy in the world isconstant, i.e. it cannot be created nor destroyed

Chemical energy- form of stored energy that resultsfrom the relative positions and interactions among itscharged subatomic particles


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Factors that Affect the Rates of

Chemical Reaction

Reactants

Concentration- concentration is directly

proportional to the rate of chemical reaction

Temperature- directly proportional to the rate

of chemical reaction


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Energy and Chemical Reactions


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Catalysts

It increase the rate of chemical reaction

Enzyme- protein molecule that acts as catalyst


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Acids and Bases

Acid- is a proton donor. Because a hydrogen

atom without its e- is a proton, any substance

that releases hydrogen ions in water is an acid.

e.g. HCl -> H+ + Cl-

Base- is a proton acceptor

e.g. NaOH -> Na+ + OH-

OH- + H+ -> H2O


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The pH Scale

pH scale indicates the [H

+

] of a solution


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Salts

Salt- is a compound consisting of positive ions

other than H+ and a negative ion other than

OH-. Formed when acid and base reacts

E.g. HCl + NaOH -> NaCl + H2O


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Buffers

Chemicals that resist sudden changes in pH

when either an acid or a base is added to a

solution containing the buffer


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Importance of Water

Stabilizing Body T

Protection

Chemical Reactions Transport


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Carbohydrate


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Carbohydrate


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Carbohydrate


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Lipids


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Proteins


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Nucleic Acids

Deoxyribonuclei acid (DNA)


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Nucleic Acids

Ribonucleic acid


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Nucleic acids

Deoxyribose and ribose

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