The Chemical Level of Organization

The Chemical Level of Organization

Chapter 2Chapter 2

Atoms and MoleculesAtoms and Molecules

Atoms are the smallest units of matter, they consist of protons, neutrons, and electrons

Atoms are the smallest units of matter, they consist of protons, neutrons, and electrons

Structure of an AtomStructure of an Atom

An element consists entirely of atoms with the same number of protons.

Within an atom, an elecron cloud surround the nucleus.

An element consists entirely of atoms with the same number of protons.

Within an atom, an elecron cloud surround the nucleus.

The atomic mass of an atom is equal to the total number of protons and neutron in its nucleus.

Isotopes are atoms of the same element whose nuclei contain different number of neutrons.

The atomic weight of an element takes into account the abundance of its various isotopes.

The atomic mass of an atom is equal to the total number of protons and neutron in its nucleus.

Isotopes are atoms of the same element whose nuclei contain different number of neutrons.

The atomic weight of an element takes into account the abundance of its various isotopes.

Electrons occupy a series of electron shells around the nucleus.

The number of electrons in the outer shell determine an atom’s chemical properties.

Electrons occupy a series of electron shells around the nucleus.

The number of electrons in the outer shell determine an atom’s chemical properties.

Chemical bonds and chemical compoundsChemical bonds and chemical compounds

An ionic bond results from the attraction between ions: atoms that have gained or lost electrons.

Cations are positively charged Anions are negatively charged.

An ionic bond results from the attraction between ions: atoms that have gained or lost electrons.

Cations are positively charged Anions are negatively charged.

Atoms can combine to form a molecule

Combinations of atoms of different elements form a compound

Some atoms share electrons to form a molecule held together by covalent bonds.

Atoms can combine to form a molecule

Combinations of atoms of different elements form a compound

Some atoms share electrons to form a molecule held together by covalent bonds.

Sharing one pair of electron creates a single covalent bond

Sharing two pairs forms a double covalent bond

Unequal sharing of electrons creates a polar covalent bond.

Sharing one pair of electron creates a single covalent bond

Sharing two pairs forms a double covalent bond

Unequal sharing of electrons creates a polar covalent bond.

A hydrogen bond is the attraction between a hydrogen atom with slight positive charge and a negatively charged atom in another molecule or within the same molecule

Hydrogen bond can affect the shaes and properties of molecules

A hydrogen bond is the attraction between a hydrogen atom with slight positive charge and a negatively charged atom in another molecule or within the same molecule

Hydrogen bond can affect the shaes and properties of molecules

Chemical NotationChemical Notation

Chemical notation allows us to describe reactions between reactant tha generate one or more products.

Chemical notation allows us to describe reactions between reactant tha generate one or more products.

Chemical ReactionsChemical Reactions

Metabolisms refers to all the chemical reaction in the body. Our cells capture, store and use energy to maintain homeostasis and support essential functions.

Metabolisms refers to all the chemical reaction in the body. Our cells capture, store and use energy to maintain homeostasis and support essential functions.

Basic energy conceptsBasic energy concepts

Work involves movement of an object or a change in its physical structure.

Energy is the capacity to perform work.

There are two major types of energy: knetic and potential.

Work involves movement of an object or a change in its physical structure.

Energy is the capacity to perform work.

There are two major types of energy: knetic and potential.

Kinetic energy is the energy of motion. Potential energy is stored energy that

results from the position or structre of an object.

Conversions from potential to kinetic energy are not 100% efficient.

Every energy exchange produces heat.

Kinetic energy is the energy of motion. Potential energy is stored energy that

results from the position or structre of an object.

Conversions from potential to kinetic energy are not 100% efficient.

Every energy exchange produces heat.

Types of ReactionsTypes of Reactions

A chemical reaction may be classified as Decomposition Synthesis Exchange

A chemical reaction may be classified as Decomposition Synthesis Exchange

Exergonic reaction release heat Endergonic reactions absorb heat Cells gain energy to power their

functions by catabolism: the breakdown of complex molecules

Much of this energy supports anabolism, the synthesis of new organic molecules

Exergonic reaction release heat Endergonic reactions absorb heat Cells gain energy to power their

functions by catabolism: the breakdown of complex molecules

Much of this energy supports anabolism, the synthesis of new organic molecules

Reversible ReactionsReversible Reactions

Reversible reactions consist of simultaneous synthesis and decomposition reactions.

At equilibrium the rates of these two opposing reactions are in balance.

Reversible reactions consist of simultaneous synthesis and decomposition reactions.

At equilibrium the rates of these two opposing reactions are in balance.

Acids and BasesAcids and Bases

A acid releases hydrogen ions A base removes hydrogen ions

from a solution

A acid releases hydrogen ions A base removes hydrogen ions

from a solution

pHpH

The pH of a solution indicates the concentration of hydrogen ions it contains.

Solutions can be classified as neutral (pH of 7)acidic (pH < 7) or basic (alkaline) (pH > 7) on the basis of pH

The pH of a solution indicates the concentration of hydrogen ions it contains.

Solutions can be classified as neutral (pH of 7)acidic (pH < 7) or basic (alkaline) (pH > 7) on the basis of pH

Buffers maintain pH within normal limits (7.35-7.45 in most body fluids) by releasing or absorbing hydrogen ions.

Buffers maintain pH within normal limits (7.35-7.45 in most body fluids) by releasing or absorbing hydrogen ions.

Inorganic CompoundsInorganic Compounds

Nutrients and metabolites can be broadly classified as organic or inorganic compounds

Living cells in the body generate carbon dioxide and consume oxygen.

Nutrients and metabolites can be broadly classified as organic or inorganic compounds

Living cells in the body generate carbon dioxide and consume oxygen.

Water and it PropertiesWater and it Properties

Water is the most important inorganic component of the body

Water is an excellent solvent, has a high heat capacity, and participates in the metabolic reactions of the body.

Many inorganic compounds will undergo ionization, or dissociation in water to form ions.

Water is the most important inorganic component of the body

Water is an excellent solvent, has a high heat capacity, and participates in the metabolic reactions of the body.

Many inorganic compounds will undergo ionization, or dissociation in water to form ions.

Inorganic Acids and BasesInorganic Acids and Bases

Inorganic acids found in the body include hydrochloric acid carbonic acid, sulfuric acid and phosphoric acid.

Sodium hydroxide is an inorganic base that may form within the body.

Inorganic acids found in the body include hydrochloric acid carbonic acid, sulfuric acid and phosphoric acid.

Sodium hydroxide is an inorganic base that may form within the body.

SaltsSalts

A salt is an ionic compound whose cation is not H+ and whose anion is not OH-

Salts are electrolytes, compounds that dissociate in water and conduct an electrical current.

A salt is an ionic compound whose cation is not H+ and whose anion is not OH-

Salts are electrolytes, compounds that dissociate in water and conduct an electrical current.

Organic CompoundsOrganic Compounds

Organic compounds contain carbon and hydrogen, and usually oxygen as well.

Large and complex organic molecules include carbohydrates, lipids proteins and nucleic acids.

Organic compounds contain carbon and hydrogen, and usually oxygen as well.

Large and complex organic molecules include carbohydrates, lipids proteins and nucleic acids.

CarbohydratesCarbohydrates

Carbohydrates are most important as an energy source for metabolic process.

The three major types are monosaccharides (simple sugars), dissacharides and polysaccharides.

Carbohydrates are most important as an energy source for metabolic process.

The three major types are monosaccharides (simple sugars), dissacharides and polysaccharides.

A. the straight -chain formula for glucose

B. The ring form that is most common in nature.

An abbreviated diagram fo the ring form.

A. the straight -chain formula for glucose

B. The ring form that is most common in nature.

An abbreviated diagram fo the ring form.

LipidsLipids

Lipids are water-insoluble molecules that include fats, oils, and waxes.

There are four important classes of lipids: fatty acids, fats, steroids, and phospholipids.

Lipids are water-insoluble molecules that include fats, oils, and waxes.

There are four important classes of lipids: fatty acids, fats, steroids, and phospholipids.

Triglycerides (fats) consists of three fatty acid molecules attached to a molecule of glycerol

Cholesterol is a precursor of steroid hormones and is a component of cell membranes

Triglycerides (fats) consists of three fatty acid molecules attached to a molecule of glycerol

Cholesterol is a precursor of steroid hormones and is a component of cell membranes

Phospholipids are the most abundant components of cell membranes.

Phospholipids are the most abundant components of cell membranes.

ProteinsProteins

Proteins perform a great variety of function in the body.

Important types of protein include structural proteins, contractile proteins, transport proteins, enzymes, hormones and antibodies.

Proteins perform a great variety of function in the body.

Important types of protein include structural proteins, contractile proteins, transport proteins, enzymes, hormones and antibodies.

Proteins are chains of amino acids linked by peptide bonds.

The sequence of amino acids and the interactions of their R groups influence the final shape of the protein molecules.

Proteins are chains of amino acids linked by peptide bonds.

The sequence of amino acids and the interactions of their R groups influence the final shape of the protein molecules.

The shape of the protein determines its function.

Each protein works best at an optimal combination of temperature and pH.

The shape of the protein determines its function.

Each protein works best at an optimal combination of temperature and pH.

Activation energy is the amount of energy required to start a reaction.

Proteins called enzymes control many chemical reaction within our bodies.

Enzymes are catalysts--substances that accelerate chemical reaction without themselves being permanently changed.

Activation energy is the amount of energy required to start a reaction.

Proteins called enzymes control many chemical reaction within our bodies.

Enzymes are catalysts--substances that accelerate chemical reaction without themselves being permanently changed.

The reactants in an enzymatic reaction, called substrates, interact to form a product by bonding to the enzyme at the active site.

The reactants in an enzymatic reaction, called substrates, interact to form a product by bonding to the enzyme at the active site.

Nucleic AcidsNucleic Acids

Nucleic acids store and process information at the molecular level.

There are two kinds of nucleic acids: DNA and RNA

Nucleic acids are chains of nucleotides.

Each nucleotide contains a sugar, a phosphate group and a nitrogen base.

Nucleic acids store and process information at the molecular level.

There are two kinds of nucleic acids: DNA and RNA

Nucleic acids are chains of nucleotides.

Each nucleotide contains a sugar, a phosphate group and a nitrogen base.

The sugar is always ribose or deoxyribose.

The nitrogenous bases found in DNA are adenine, guanine, cytosine, and thymine. In RNA uracil replaces thymine.

The sugar is always ribose or deoxyribose.

The nitrogenous bases found in DNA are adenine, guanine, cytosine, and thymine. In RNA uracil replaces thymine.

High-Energy CompoundsHigh-Energy Compounds

Cells store energy in high-energy compounds.

The most important high-energy compound is ATP

When energy is available, cells make ATP by adding a phosphate group to ADP

When energy is needed ATP is broken down to ADP and phosphate.

Cells store energy in high-energy compounds.

The most important high-energy compound is ATP

When energy is available, cells make ATP by adding a phosphate group to ADP

When energy is needed ATP is broken down to ADP and phosphate.