Chemistry of Life

Matter…

Energy…

Life…

Objectives

Objectives:

A. Explain the nature of matter;

B. Discuss the importance of water and solutions;

C. Break down the chemistry of cells, and

D. Recognize chemical reactions.

A: Nature of Matter

• Matter is made of atomsAtom- smallest unit of matter that can not be

broken down by chemical means

Atoms consists of three kinds of particlesProtons- Positively Charged (+)Neutrons- No ChargedElectrons- Negatively Charged (-)

A: Nature of Matter

• Nucleus – Core of an atom made of protons (yellow) and neutrons (red)

• Electron cloud – The space around

the nucleus that electrons

(gray) may occupy at any

time

A: Nature of Matter

• Protons and electrons are oppositely charged so they attract each other

• Typically atoms have no electrical charge

protons = electrons

• Element – substance made of only one kind of atom, and is therefore a pure substance

A: Nature of Matter

• Compound – Substance made of the joined atoms of two or more different elements

• Every compound is identified by a chemical formula that identifies the elements in the compound and their proportions

• Example: – Sodium (Na) joined with Chlorine (Cl) forms

Sodium Chloride (NaCl) or Table salt– Two Hydrogen atoms (H2) joined with one

Oxygen atom (O) forms H20 or water

A: Nature of Matter

• Molecule – a group of atoms bonded together

• Types of bonds– Covalent– Hydrogen– Ionic

A: Nature of Matter

• Covalent Bonds– Atoms generally have a neutral charge– Atoms are stable when they have eight electrons in

their outer energy level– Atoms share electrons so that they have eight in their

outer energy level

A: Nature of Matter• Hydrogen Bonds

– The shared electrons in a water molecule are attracted more strongly by the oxygen nucleus than the hydrogen nucleus

– The water molecule has partially positive and negative ends, or poles

– The opposite poles of two water molecules form a weak bond called a hydrogen bond (similar to opposing poles on a magnet)

Hydrogen bond

A: Nature of Matter

• Ion – An atom or molecule that has gained or lost an electron

• Ions may interact to form ionic bonds

• Ions do not share electrons, but one atom “gives” an electron to the other so they have eight in their outer energy level

• Na+ positive sodium ion & Cl-

Negative chloride ion interact to form NaCl

B: Water and Solutions

• Water is a major component of cells

– 70% of the human body is water

• Water stores heat efficiently

– Water helps regulate body temperature

• Water acts as a transport system for nutrients and wastes for animals.

B: Water and Solutions• Water bonds to its self and other

structures

– Cohesion – the polarity of water molecules cause them to cling to one another like magnets

– Caused by hydrogen bonds

B: Water and Solutions

–Adhesion – water molecules that are attracted to another surface, ie: water droplets stick to your skin after a shower

–Adhesion and cohesion Causes capillary action

B: Water and Solutions

• Compounds that dissolve in water form solutions.

• Dissolved nutrients that are transported along with the water move to the places where they are used.

B: Water and Solutions

• Solution: solute dissolved in a solvent

• Solute: thing that gets dissolved

• Solvent: thing that does the dissolving

B: Water and Solutions

• pH scale: indicates the concentration of H+ ions in a solution

--------------------------------------------0 7 14

Acid Neutral Base

B: Water and Solutions

• Acid: Contain higher concentrations of H+ ions than pure water and have a number lower than 7

• Bases: Contain lower concentrations of H+ ions and have numbers greater than 7

• Neutral: Pure tap water

• Buffers: Weak acids or bases that react with strong acids or bases to prevent a sharp, sudden change in pH

C: Break Down Chemistry of Cells

• Carbon – most common substance found in all living organisms

• Four Main Carbon Compounds: Carbohydrates, Proteins, Lipids, Nucleic acids.

• Carbon has four electrons available for bonding in its outer energy level

• Able to form single (sharing one electron) double (sharing two electrons) or triple sharing (three electrons) covalent bonds with other elements

C: Break Down Chemistry of Cells

• The variety of covalent bond types allows carbon to form different shaped structures

• Isomers – Compounds with the same simple formula but a different three dimensional structure (ie. glucose and fructose C6H12O6)

C: Break Down Chemistry of Cells• Carbon compounds also vary greatly in size

• Polymer – Large molecule formed when two smaller molecules bond together

• Condensation – Process through which polymers are formed when the two smaller molecules release an H and an OH group that can form Water

• Hydrolysis – Process through which polymers are broken apart by adding the H and OH group from a water molecule

C: Break Down Chemistry of Cells

• Four basic types of carbon polymers

– Carbohydrates

– Lipids

– Proteins

– Nucleic acids

C: Break Down Chemistry of Cells

• Carbohydrates– Used by the cell to store and release energy– Composed of Carbon, Hydrogen, and Oxygen

at a ratio of 1:2:1– Monosaccharide – Simplest type (glucose or

fructose)– Disaccharide – Two monosaccharides

(sucrose or table sugar)– Largest type: Polysaccharide (many

monosaccharides hooked together i.e. starch)

C: Break Down Chemistry of Cells

• Lipids (fats and oils)– Used by the cell for energy storage,

insulation, and protective coating– Important part of cell membrane– Have a much larger ratio of C-H than 2:1 and

a much smaller ratio of C-O than 2:1– Insoluble in water– Nonpolar (no electrical charge)

C: Break Down Chemistry of Cells

• Lipids (fats and oils) cont:

• Saturated Fatty Acids– Solid at room temperature– The carbon atom can not bond with any more

hydrogen atoms

• Unsaturated Fatty Acids– Liquid at room temperature– The carbon atom can bond with more

hydrogen atoms

C: Break Down Chemistry of Cells

• Proteins– Provide structure for tissue and organs, carry

out cell metabolism, help muscle tissue contract, provide immunity, and regulate other proteins

– Large complex polymer composed of carbon, hydrogen, oxygen, nitrogen and usually sulfur

– Basic building blocks of proteins are called amino acids

C: Break Down Chemistry of Cells

• Proteins cont.– Twenty (20) common amino acids

– These 20 amino acids in different combinations make thousands proteins

– Enzyme – Type of protein that speeds up chemical reactions

C: Break Down Chemistry of Cells

• Nucleic acids– Store cellular information in the form of a code– DNA and RNA– Made up of smaller subunits called

nucleotides– Composed of Carbon, Hydrogen, Oxygen,

Nitrogen and Phosphorus arranged in three groups, base, simple sugar, and phosphate group

D. Recognize Chemical Reactions• Chemical Reaction: a process that

changes or transforms one set of chemicals into another

• The ------- in a chemical reaction is read “changes to” or “forms”

• CO2 + H2O - H2CO3• Carbon dioxide and water change to

carbonic acid

D. Recognize Chemical Reactions

• Catalyst: is a substance that speeds up the rate of a chemical reaction

• Enzyme: are proteins that act as organic catalysts.