How Matter is Organized

•Chemical Elements•Forms all matter

•Substances that cannot be split into simpler substances by ordinary chemical means.

•Have letter abbreviations called chemical symbols.

•Most common elements in living things C, H, N, O, P, S

•Trace elements are present in tiny amounts (Fe, Mn, Cu)

Structure of Atoms

• An element is a quantity of matter composed of atoms of the same type.

Atoms contain:• Nucleus: protons (p+) &

neutrons (neutral charge)• Electrons (e-) surround the

nucleus as a cloud (electron shells are designated regions of the cloud)

Atomic Number and Mass Number

• Atomic number is number of protons in the nucleus.

• Mass number is the sum of its protons and neutrons.

• Isotope atoms of same element with different number of neutrons (Carbon-14 & Carbon-12)

• A hepatobiliary iminodiacetic acid (HIDA) sc

A hepatobiliary iminodiacetic acid (HIDA) scan

Chemical Bonds

• The atoms of a molecule are held together by forces of attraction called chemical bonds.

• The likelihood that an atom will form a chemical bond with another atom depends on the number of electrons in its outermost shell, also called the valence shell.

• Ionic, Covalent, Hydrogen

Ionic Bonds

•When an atom loses or gains a valence electron, ions are formed (Figure 2.4a).

•Positively and negatively charged ions are attracted to one another.

Covalent Bonds• atoms of molecules sharing

one, two, or three pairs of their valence electrons.

– Covalent bonds are common and are the strongest chemical bonds in the body.

• Covalent bonds may be nonpolar or polar.

– In a nonpolar covalent bond, atoms share the electrons equally; one atom does not attract the shared electrons more strongly than the other atom

Polar Covalent Bonds• Unequal sharing of electrons between atoms.

In a water molecule, oxygen attracts the hydrogen electrons more strongly

Hydrogen Bonds

– are weak intermolecular bonds; they serve as links between molecules.

– help determine three-dimensional shape of large molecules

– Important in giving water its properties essential for life

Van der Waals interactions

• Electrons are not always symmetrically distributed in nonpolar molecules

• Occur only when atoms and molecules are very close to each other

• Weak

Water is:

• Where life first began• Depended on by all life • 70-95% the mass of a cell• ¾ of Earth’s surface • The only common substance to naturally

exist in all 3 states of matter• Dynamic because of its polarity which

allows it to be attracted to other molecules (esp. to other water molecules)

6 Properties of Water

• 1. Water is a Powerful Solvent– Solute, Solution, Solvent– Hydrophobic vs Hydrophilic– Shell of hydration

• 2. Water is attractive– Water adheres to a surface due

to 2 properties:• Adhesion

• Cohesion

– These 2 properties allow for capillary action.

• 3. Water has High Surface Tension– Strong interaction of water molecules– Water striders, whirly gigs, skipping

rocks

• 4. Water has a High Specific Heat– High heat is required to increase the

temp. of water and a great deal of heat must be lost in order to decrease the temp. of water.

• 5. High Heat of Vaporization– A great deal of energy must be

present in order to break the Hydrogen bonds to change water from liquid to gas

• 6. Water has a high freezing point and lower density as a solid than a liquid– Water’s maximum density is 4 degrees Celsius

http://nedbook.adam.com/pages/IPWeb/systems/buildframes.html?fluids/acihomeo/01

Normal pH range of arterial blood 7.35-7.45

Acidosis – blood pH below 7.35*depression of synaptic transmission in CNS

Disorientation, coma, death

Alkalosis – blood pH above 7.45*overexcitability of CNS and peripheral nerves

Nervousness, muscle spasms, convulsions and death

Tryptophan

All living organisms require 4 types of Organic Compounds:

1. Carbohydrates2. Lipids3. Proteins4. Nucleic Acids

**All contain**: Carbon Hydrogen Oxygen

1. Carbohydrates

• All carbs contain C,H,O in a 1:2:1 ratio

• Functions: Energy & structural support

• Exist as:a. Monosaccharides

b. Disaccharides

c. polysaccharides

a. Monosaccharide“simple sugar”

3 Forms1. Glucose - made by plants;

source of energy

2. Fructose - found in fruits; Sweetest!!

3. Galactose – found in milk

These are ISOMERS – same chemical formula but different structures.

b. Disaccharide“double sugar”

3 Forms1. Sucrose – Table Sugar

glucose + fructose

2. Maltose - Malt Sugar glucose + glucose

3. Lactose – Milk Sugarglucose + galactose

•How do monosaccharides form disaccharides?

• Hydrolysis• Dehydration synthesis

– Glycosidic linkage – covalent bond between 2 mono’s

c. Polysaccharide“Many Sugars”

3 Forms – All composed of repeating units of glucose.

1. Glycogen – Energy storage in animals. (Liver & Muscles)

2. Starch - Energy storage in plants (Roots, Stems, Leaves)

3. Cellulose - Gives strength & rigidity to plant cell(Fiber Prevents Colon Cancer)

Pectin & Carrageenan

2. Lipids• Nonpolar / insoluble / hydrophobic

• 5 types: triglycerides, phospholipids, steroids, waxes, glycolipids

• Fx: insulation, cushion, energy storage, hormones, membrane structure, protection against pathogens, repel water, water conservation

Four Ring Structure of Steroids

Glycolipid

• 3rd Carbon in glycerol is bound to a carb chain instead of a phosphate group.

• Behaves like a phospholipid because the carbohydrate is hydrophilic

• Found in cell membrane and functions in identification of the cell

3. Proteins • Found in: meat, eggs, nuts, beans, tofu

• Uses in body: muscle, hormones, enzymes, energy, transport of oxygen (hemoglobin), support, hair, nails, skin, blood clots (fibrin)

• Monomers of proteins are amino acids

• Amino acids join together by peptide bond

Copyright 2009, John Wiley & Sons, Inc.

Formation of a Dipeptide Bond

• Dipeptides formed from 2 amino acids joined by a covalent bond called a peptide bond– dehydration synthesis

• Polypeptides chains contain 10 to 2000 amino acids.

Primary Structure: ex.: lysozome

• Catalyzes hydrolysis of carbohydrates

Secondary Structure:Alpha helix: ex. hair

stabilized by hydrogen bonds

Beta pleat ex. silk

Tertiary Structure:

Protein channels

Quaternary Structure:ex.: hemoglobin

Enzymes

• Most enzymes are proteins; some RNA

• Speed up chemical rxn; biological catalyst

• Shape of protein allows it to bond to specific molecules called substrates, causes a change in shape

• maltase: maltose 2 glucose• lipase: lipids fatty acids• protease: proteins amino acids

**works best under certain temperatures

Enzymes

4. Nucleic AcidsDNA and RNA • Huge organic molecules that

contain carbon, hydrogen, oxygen, nitrogen, and phosphorus.

• Deoxyribonucleic acid (DNA) forms the genetic code inside each cell and thereby regulates most of the activities that take place in our cells throughout a lifetime.

• Ribonucleic acid (RNA) relays instructions from the genes in the cell’s nucleus to guide each cell’s assembly of amino acids into proteins by the ribosomes.

Nucleic Acids

• Each nucleotide has three parts:– A phosphate– A sugar (deoxyribose for DNA

nucleotides)– One of four nitrogenous bases

• adenine (A) • guanine (G) • thymine (T)• cytosine (C)

Nucleic Acids

• There is a base-pairing rule:

– A always bonds across from T

– C always bonds across from G

• A and G, called purines, are structures composed of two rings

• C and T are pyrimidines – singled-ringed structures

• A purine always pairs with a pyrimidine and vice versa

Nucleic Acids• Because of this, if one strand of DNA is

known, the other strand can be deciphered

• If we know that one strand of DNA has the sequence:

ATCGGCA

• The other side must be:TAGCCGT