atomsmollife
TRANSCRIPT
Atoms, Molecules, and Life
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
II. Matter
D. Types of chemical bonds 1. Bonds between individual atoms
• a. Ionic • b. Covalent
• 1) Nonpolar • 2) Polar
(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 between opposite 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 covalentbonding
(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. Water and life
A. Water and chemical reactions 1. Hydrolysis 2. Dehydration synthesis 3. Photosynthesis 4. Respiration
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, tomatoesbeer
black coffee, tea normal rain (5.6),
pure water (7.0), saliva, blood, sweat (7.4)seawater (7.8-8.3)
baking soda
phosphate detergents chlorine bleach, milk of magnesia household ammonia, some detergents (without phosphates) washing soda
oven cleaner
1-molar sodium hydroxide (NaOH)
1-molar hydrochloric acid (HCl)
urine (5.7)
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 simple subunit molecules
A. Polymers form from bonding two or more subunit molecules in a dehydration synthesis reaction
Dehydration synthesis
V. Complex biological molecules are synthesized from simple subunit molecules
B. Polymers can be broken down into individual subunit molecules in a hydrolysis reaction
1. Food we eat is hydrolyzed to provide the raw materials to build new polymers
Hydrolysis
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
VI. Four classes of biologically important organic compounds
A. Carbohydrates (cont.)
3. Functions
• a. Energy storage (starch, glycogen, simple sugars)
• b. Structural support (cellulose, chitin)
VI. Four classes of biologically important organic compounds
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)
Cardiovascular diseases
Evidence is accumulating that increasing omega-3 fatty acid intake can decrease the risk of cardiovascular diseases by 1) preventing arrhythmias that can lead to sudden cardiac death, 2) decreasing the risk of thrombosis (blood clot formation) that can lead to heart attack or stroke, 3) decreasing serum triglyceride levels, 4) slowing the growth of atherosclerotic plaque, 5) improving vascular endothelial function, 6) lowering blood pressure slightly, 7) decreasing inflammation. The American Heart Association found the evidence discussed below convincing enough to recommend that all adults eat a variety of fish, particularly oily fish, at
least twice weekly, in addition to consuming vegetable oils rich in ALA
fatty acid tails
(hydrophobic)
polar head
(hydrophilic)
glycerolbackbone
estradiol
cholesterol testosterone
VI. Four classes of biologically important organic compounds
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
VI. Four classes of biologically important organic compounds
C. Proteins
1. Amino acids combine in dehydration synthesis to form polypeptides
2. Proteins are functional units made of one or more polypeptide chains
aminogroup
carboxylgroup
variablegroup
hydrogen
aminogroup
amino acidamino acid
aminogroup
carboxylgroup
carboxylgroup
peptidebond
peptide water
Peptide chain of amino acidsfolds into complex shape
two or more folded chains may join to form a complex protein
Peptide chain of amino acidsfolds into complex shape
Two or more folded chains may join to form a complex protein.
VI. Four classes of biologically important organic compounds
C. Proteins (cont.)
3. Protein structure is based on the amino acid sequence
4. Have varying degrees of polarity based on amino acid composition
VI. Four classes of biologically important organic compounds
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)
VI. Four classes of biologically important organic compounds
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
phosphate
base
Deoxyribose nucleotide
sugar
phosphate base
Nucleotide chain
sugar