Atoms Mol Life

8/11/2019 Atoms Mol Life

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Atoms,

Molecules, andLife



electron shell

Carbon (C) Oxygen (O) Phosphorus (P) Calcium (Ca)



Phosphorus (P) Calcium (Ca)



(b)

Sodium ion (+) Chlorine ion ( –)

Attraction between opposite charges



(c)

An ionic compound: NaCl



II. Matter

A. Elements

92 naturally occurring elements

Biologically important elements:

Carbon (C) Hydrogen (H)

Oxygen (O) Nitrogen (N)

Phosphorous (P) Sulfur (S)



II. Matter

B. Atoms

1. Nucleus

• a. Protons and neutrons

• b. Atomic number and atomic mass

2. Electrons

• a. Electron shells, orbitals, energy level



electron

nucleus

Hydrogen (H) Helium (He)



II. Matter

C. Molecules and compounds

Atoms usually exist chemically bonded to

other atoms to form molecules and

compounds

1. Inert atoms

2. Reactive atoms





(a)

Sodium atom (neutral) Chlorine atom (neutral)

Electron transferred

( )



(a)

(b)

(c)

Sodium atom (neutral)Chlorine atom (neutral)

Sodium ion (+) Chlorine ion ( –)

Electron transferred

Attraction betweenopposite charges

An ionic compound: NaCl



II. Matter

D. Types of chemical bonds

1. Bonds between individual atoms

• a. Ionic

• b. Covalent

• 1) Nonpolar

• 2) Polar



(a)nonpolar covalentbonding

(b)polar covalentbonding

(slightly negative)

(slightly positive)

Water (H –O –H or H2O),a polar molecule

Hydrogen (H –H or H2),a nonpolar molecule

Oxygen (O=O or O2),a nonpolar molecule

( )



(a)nonpolar covalentbonding

Hydrogen (H –H or H2),a nonpolar molecule

Oxygen (O=O or O2),

a nonpolar molecule



(b)

polar covalent

bonding

(slightly negative)

(slightly positive)

Water (H –O –H or H2O),

a polar molecule



II. Matter

D. Types of chemical bonds (cont.)

2. Bonds between parts of polar molecules

• a. Hydrogen bonds



hydrogenbonds

III W d lif



III. Water and life

A. Water and chemical reactions

1. Hydrolysis

2. Dehydration synthesis

3. Photosynthesis

4. Respiration

III W t d lif



III. Water and life

B. Water, the solvent of polar and ionic

molecules

C. Water and cohesion

D. Water and pH









hydroxide ion

(OH –

)

hydrogen ion

(H+)

water

(H2O)



stomach acid, lime juice

lemon juice

“acid rain” (2.5-5.5), vinegar, cola,orange juice, tomatoes

beer

black coffee, teanormal rain (5.6),

pure water (7.0), saliva, blood,sweat (7.4)

seawater (7.8-8.3)

baking soda

phosphate detergentschlorine bleach, milk of magnesiahousehold ammonia, somedetergents (without phosphates)

washing soda

oven cleaner

1-molar sodium hydroxide (NaOH)

1-molar hydrochloric acid (HCl)

urine (5.7)

IV Carbon and life



IV. Carbon and life

A. Carbon is versatile

1. Each atom can form four covalent bonds

2. Carbon atoms are joined in short, long chains

or rings

3. Organic molecules

electron shell



Carbon (C) Oxygen (O)



V. Complex biological molecules

are synthesized from simplesubunit molecules

A. Polymers form from bonding two or more

subunit molecules in a dehydration

synthesis reaction



Dehydration synthesis

V C l bi l i l l l



V. Complex biological molecules

are synthesized from simple

subunit molecules

B. Polymers can be broken down into

individual subunit molecules in a hydrolysisreaction

1. Food we eat is hydrolyzed to provide the rawmaterials to build new polymers



Hydrolysis

VI Four classes of biologically



VI. Four classes of biologically

important organic compounds

A. Carbohydrates

Monosaccharides (glucose, fructose)

combine to form Disaccharides (sucrose)and Polysaccharides (complex

carbohydrates: starch and cellulose))





glucose fructose sucrose

Dehydration synthesis



individualcellulose

molecules

bundle ofcellulose

molecules

hydrogen bondscross-linking

cellulose molecules

cellulosefiber






A. Carbohydrates (cont.)

3. Functions

• a. Energy storage (starch, glycogen, simple sugars)

•

b. Structural support (cellulose, chitin)






B. Lipids

1. Fatty acids combine in dehydration synthesis

with glycerol to form triglycerides

2. Are nonpolar



fatty acidsglycerol

3 watermolecules



Beef fat (saturated)

carbon

hydrogen

oxygen



Peanut oil (unsaturated)



Cardiov ascular diseases

Evidence is accum ulat ing th at increasing omega-3 fatty acid intake can decrease

the risk of c ardiovascular diseases by 1) preventing arrhythm ias that can lead to

sud den cardiac death, 2) decreasing th e risk of throm bos is (blood clot fo rmation)

that can lead to heart attack o r stro ke, 3) decreasing serum trig lycerid e levels, 4)slow ing the grow th of atherosclerot ic plaque, 5) imp roving vascular endo thel ial

func t ion, 6) lowering blo od p ressure sl ight ly, 7) decreasing inf lammation. The

American Heart Ass ociat ion foun d the evidence discussed below conv inc ing

enough to recommend that al l adults eat a variety of f ish , part icular ly oi ly f ish , at

least twice weekly, in addit ion to co nsumin g vegetable oi ls rich in ALA

http://circ.ahajournals.org/cgi/content/full/106/21/2747

http://circ.ahajournals.org/cgi/content/full/106/21/2747







fatty acid tails

(hydrophobic)

polar head

(hydrophilic)

glycerolbackbone







B. Lipids (cont.)

3. Functions

• a. Energy storage (fats, oils)

• b. Protection (oils, waxes)

• 1) Waterproof coating of body surfaces

• c. Component of cell membranes

• d. Hormones





C. Proteins

1. Amino acids combine in dehydration

synthesis to form polypeptides

2. Proteins are functional units made of one

or more polypeptide chains



amino

group

carboxyl

group

variable

group

hydrogen



amino

group

amino acidamino acid

amino

group

carboxyl

group

carboxyl

grouppeptide

bond

peptide water

P tid h i f i id



Peptide chain of amino acidsfolds into complex shape

two or more foldedchains may join toform a complex protein



Peptide chain of amino acidsf ld i t l h



folds into complex shape

Two or more foldedchains may join tof l t i



form a complex protein.


i t t i d




C. Proteins (cont.)

3. Protein structure is based on the amino acid

sequence

4. Have varying degrees of polarity based on

amino acid composition


i t t i d




C. Proteins (cont.)

5. Functions

• a. Structural components (cells, tissues)

• b. Enzymes

• c. Transport O2 in blood (hemoglobin)

•

d. Receptors for hormones (insulin receptor)• e. Contractile proteins (actin and myosin in muscle)

• f. Immunoproteins (antibodies)


i t t i d




D. Nucleic acids

1. Nucleotides combine in dehydration synthesis

to form nucleic acids

2. Functions

• a. Hereditary material (genes)

• b. Direct the production of proteins

base



phosphate

Deoxyribose nucleotide

sugar

phosphate base

sugar



Nucleotide chain

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Atoms Mol Life