Biochemistry Chemistry of Life. Matter – anything that has mass and takes of space Mass – the amount of matter in a substance – measured in grams.

BiochemistryBiochemistryChemistry of LifeChemistry of Life

Matter – anything that has mass and takes Matter – anything that has mass and takes of spaceof space

Mass – the amount of matter in a Mass – the amount of matter in a substance – measured in gramssubstance – measured in grams

Volume – amount of space a substance Volume – amount of space a substance takes up – measured in milliliterstakes up – measured in milliliters

Element – Pure substances that cannot be Element – Pure substances that cannot be broken down into simpler matter.broken down into simpler matter.

Important elements in living organisms: Important elements in living organisms: Hydrogen, Carbon, Oxygen and Nitrogen Hydrogen, Carbon, Oxygen and Nitrogen make up 96% of ALL living things.make up 96% of ALL living things.

ATOMATOM Simplest particle of an Simplest particle of an

element – that still element – that still maintains the maintains the properties of that properties of that element.element.

Made of Protons (+ Made of Protons (+ charge)charge)

Neutrons (neutral)Neutrons (neutral)

Electrons (- charge)Electrons (- charge)

Periodic TablePeriodic Table

Atomic # = # protonsAtomic # = # protons Atomic # = # electronsAtomic # = # electrons Atomic Mass – Atomic # = # neutronsAtomic Mass – Atomic # = # neutrons Electrons are arranged in shells. 2 Electrons are arranged in shells. 2

electrons will fit in the first shell. 8 in the electrons will fit in the first shell. 8 in the second and 18 in the third.second and 18 in the third.

Try drawing the atomic structure for the Try drawing the atomic structure for the following elements: carbon, nitrogen, following elements: carbon, nitrogen, oxygen, hydrogen, sodium and chlorine.oxygen, hydrogen, sodium and chlorine.

BondingBonding

All atoms want 8 electrons in their outer shell. All atoms want 8 electrons in their outer shell. So they react to by creating bonds to form So they react to by creating bonds to form compounds.compounds.

Compounds are pure substances made of two or Compounds are pure substances made of two or more atoms.more atoms.

It is only the electrons in the outer shell that It is only the electrons in the outer shell that cause reactions and create bonds.cause reactions and create bonds.

Look at your drawings of sodium and chlorine. Look at your drawings of sodium and chlorine. How many electrons are in the outer shell for How many electrons are in the outer shell for each of these?each of these?

Ionic BondsIonic Bonds

When electrons are given away.When electrons are given away. Show example of Sodium and chlorine.Show example of Sodium and chlorine. It is the difference in charges after It is the difference in charges after

electrons are exchanged that creates this electrons are exchanged that creates this bond.bond.

Covalent BondsCovalent Bonds When electrons are shared.When electrons are shared. Show example of carbon and Show example of carbon and

hydrogen.hydrogen. PolarPolar covalent bond is when covalent bond is when

the electrons are not shared the electrons are not shared equally. One atom pulls harder equally. One atom pulls harder on the electron than the other on the electron than the other atom. Example Water.atom. Example Water.

Non polarNon polar – atoms share – atoms share electrons equally. electrons equally. Ex.Ex. O O22

Chemical ReactionChemical Reaction

A reaction that creates new bonds A reaction that creates new bonds between atoms or breaks them apart.between atoms or breaks them apart.

ReactantsReactants ProductsProducts

HH22 + O + O2 2 H H22OO

The bonds between the atoms contain The bonds between the atoms contain energy – we get our energy from breaking energy – we get our energy from breaking those bonds – and we store energy by those bonds – and we store energy by making those bonds. In living systems making those bonds. In living systems those bonds are those bonds are primarily primarily covalentcovalent..

EnergyEnergy All living systems need energy to do work. All living systems need energy to do work.

Where does all energy originate from?Where does all energy originate from? reactions that release energy – reactions that release energy – exergonicexergonic reactions that require energy – reactions that require energy – endergonicendergonic.. Most reactions whether exergonic or endergonic Most reactions whether exergonic or endergonic

– they require start up energy and this is called – they require start up energy and this is called activation energyactivation energy.. For example, the food that our bodies break down For example, the food that our bodies break down

gives us energy but some energy is required to start gives us energy but some energy is required to start the reaction.the reaction.

CatalystCatalyst CatalystsCatalysts reduce the amount of activation reduce the amount of activation

energy required and therefore speed up a energy required and therefore speed up a reaction. reaction.

EnzymesEnzymes are catalysts in living systems. are catalysts in living systems. Without enzymes to lower the activation Without enzymes to lower the activation

energy to break down our food, it would energy to break down our food, it would have to be heated MUCH higher than have to be heated MUCH higher than body temperature.body temperature. Ex.Ex. Lactase is an enzyme that breaks down Lactase is an enzyme that breaks down

lactose which is the sugar in milk.lactose which is the sugar in milk.

SolutionsSolutions

SolutionSolution is a mixture of a solute and solvent. is a mixture of a solute and solvent. SoluteSolute is the solid or gas that is dissolved in the is the solid or gas that is dissolved in the

solvent.solvent. SolventSolvent is the liquid that the solute is dissolved is the liquid that the solute is dissolved

in.in. Ex.Ex. Plasma has many solutes dissolved in water. Plasma has many solutes dissolved in water.

ConcentrationConcentration is the measurement of the is the measurement of the amount of solute dissolved in a fixed amount of amount of solute dissolved in a fixed amount of liquid.liquid.

Acids and BasesAcids and Bases

When solutions are made, many solutes will When solutions are made, many solutes will dissociate in the solvent (which is usually dissociate in the solvent (which is usually water).water).

DissociateDissociate means to break apart. means to break apart. Water dissociates a little bit.Water dissociates a little bit.

pHpH

pH pH – is a logarithmic measurement of the – is a logarithmic measurement of the amount of amount of H+H+ present in a solution. present in a solution.

Pure water has an equal amount of H+ and OH- Pure water has an equal amount of H+ and OH- so its pH is 7so its pH is 7

Acid Acid is a solution where the amount of is a solution where the amount of H+ is H+ is greatergreater than OH- than OH-. Acids are less than 7 on the . Acids are less than 7 on the pH scale. Example: HCl pH scale. Example: HCl H+ + Cl- H+ + Cl-

BaseBase is a solution where the amount of is a solution where the amount of OH- is OH- is greater than the H+.greater than the H+. Bases are more than 7 on Bases are more than 7 on the pH scale. Example: NaOH the pH scale. Example: NaOH Na + OH- Na + OH-

Due to the logarithmic scale, a pH of 3 is Due to the logarithmic scale, a pH of 3 is 10 times more acidic than 4.10 times more acidic than 4.

How many more times acidic is a pH of 3 How many more times acidic is a pH of 3 than a pH of 5?than a pH of 5?

Why can we drink acidic beverages?Why can we drink acidic beverages? Our bodies contain Our bodies contain buffersbuffers that can that can

neutralize acids or bases. For example there neutralize acids or bases. For example there are buffers in our blood which keep the blood are buffers in our blood which keep the blood pH at 7.5 which is critical for enzyme function.pH at 7.5 which is critical for enzyme function.