Transcript Chapter 2 - Marion ISD

Chapter 2
The Chemical Basis of Life
Mosby items and derived items © 2007, 2003 by Mosby, Inc.
Slide 1
Basic Chemistry
• Elements and compounds

Matter
Slide 2
Basic Chemistry
• Element—simple form of matter.

“trace elements” - make up less than 2% of body
weight
• Compound—atoms of two or more elements
Slide 3
Basic Chemistry
• Atoms

John Dalton
Slide 4
Basic Chemistry
• Atomic structure

Protons (+ or p)

Neutrons (n)

Electrons (– or e)
Slide 5
Basic Chemistry
• Atomic number and atomic weight

Atomic number (Table 2-1)

Atomic weight
Slide 6
Basic Chemistry
• Energy levels (Figures 2-3 and 2-4)

number of electrons = the number of protons in
the nucleus
(in a stable atom)

“cloud”
Slide 7
Basic Chemistry
• Energy levels (cont.)
 “Bohr
model”
• concentric circles of the electrons from the nucleus
• chemically inert
• chemically active
Slide 8
Basic Chemistry
• Energy levels (cont.)

Octet rule
Slide 9
QuickTime™ and a
decompressor
are needed to see this picture.
Slide 10
Basic Chemistry
• Isotopes

Isotopes

Radioactive isotope - unstable
Slide 11
Basic Chemistry
• Attractions between atoms—chemical bonds

Chemical reaction

Molecule

Compound
Slide 12
Basic Chemistry
• Chemical bonds—two types unite atoms into
molecules:

Ionic, or electrovalent, bond

Covalent bond
Slide 13
QuickTime™ and a
decompressor
are needed to see this picture.
Slide 14
Basic Chemistry
• Chemical reactions

three basic types
•
•
•
•
Synthesis reaction
Decomposition reaction
Exchange reaction
Reversible reactions
Slide 15
Metabolism
• Catabolism

Break down

Release energy

hydrolysis

End products
• Anabolism

Join

dehydration synthesis
Slide 16
Organic and Inorganic Compounds
chemical makeup
• Inorganic compounds
• Organic compounds
Slide 17
Inorganic Compounds
• Water

Properties of water (Table 2-2)
• Polarity

Polarity - allows water to serve as a solvent
• Solvent
• Temperature regulation
Slide 18
Inorganic Compounds cont’d
• Oxygen
• Carbon dioxide - waste product of
cellular respiration and acid/base balance
• Electrolytes
Slide 19
Inorganic Compounds

Acids and bases
• Acids

“acidity”

Release hydrogen
• Bases

Release hydroxide

“alkalinity”
Slide 20
Inorganic Compounds
• pH scale

pH of 7 - neutrality

pH of less than 7 - acidity;

pH of more than 7 - alkalinity
Slide 21
Inorganic Compounds
• Buffers

Maintain the constancy of the pH

Minimize changes in the concentrations of H+
and OH– ionsInorganic Compounds
Slide 22
Organic Compounds
• Carbohydrates, proteins, lipids, nucleic acids
Slide 23
Organic Molecules
• Carbohydrates
 Monosaccharides—simple
 Disaccharides
sugars
and polysaccharides
Slide 24
Organic Molecules
• Proteins (Table 2-5)

Chainlike polymers

Amino acids
• Essential amino acids
• Nonessential amino acids
Slide 25
Organic Molecules
• Levels of protein structure

There are four levels of protein organization:
• Primary structure
• Secondary structure
• Tertiary structure
• Quaternary structure
Slide 26
QuickTime™ and a
decompressor
are needed to see this picture.
Slide 27
Organic Molecules - Two broad
categories
• Structural proteins form the structures of the body
• Functional proteins cause chemical changes in
the molecules

Shape of a protein’s molecules determines its function
• Denatured proteins

denatured by changes in pH, temperature, radiation, and other
chemicals
Slide 28
QuickTime™ and a
decompressor
are needed to see this picture.
Slide 29
Organic Molecules
• Lipids (Table 2-6)
• Types: triglycerides, phospholipids, steroids,
prostaglandins)

Major roles:
• Energy source
• Structural role
• Integral parts of cell membranes
Slide 30
Organic Molecules
• Lipids (cont.)

Triglycerides (fats)
• building blocks of triglycerides : glycerol and fatty acids

Types of fatty acids—
– saturated fatty acid (animal fat)
– unsaturated fatty acid (plant oil)

Triglycerides - formed by a dehydration synthesis
Slide 31
Organic Molecules
• Lipids (cont.)

Phospholipids (make up cell membranes)
• (hydrophilic)(hydrophobic)
• Double layer (bi layer) - cell membranes
Slide 32
Organic Molecules

Steroids
• Main component is steroid nucleus
• Involved in many structural and functional roles
Slide 33
Organic Molecules
Prostaglandins
• “tissue hormones”
• Variety of functions (blood pressure, secretion of
digestive fluids, etc.)
Slide 34
Nucleic Acids
• Two Nucleic acids

DNA

RNA
• Made of thousand of nucleotides.
• Nucleotides - Made of a sugar, a base, and a
phosphate group
Slide 35
DNA
• DNA (deoxyribonucleic acid)
• Made up of Nucleotides
• Nucleotides contain:

sugar (deoxyribose),

phosphate group,

base (the arrangement of the bases codes for the coding of
proteins)
•
•
•
•
cytosine,
guanine
thymine,
Adenine
Slide 36
DNA cont’d

Base pairs attach in the center of the helix and hold two parts of
DNA molecule together

all DNA molecules in one individual are identical and different from
those in all other individuals

molecule of heredity - passes on genetic makeup to next
generation
Slide 37
RNA
• RNA (ribonucleic acid)
 sugar
 phosphate
group,
 base
• adenine, uracil, guanine, or cytosine (uracil
replaces thymine)
 Functions
- carry blue print for protein to
the ribosome, turn off genes in DNA
Slide 38
ATP

ATP - Adenosine tri-phosphate - special kind of
nucleotide
• Adenosine (sugar) and 3 phosphates
• High-energy bonds
• Cleavage releases energy
• energy currency of cells

(ADP) Adenosine diphosphate
• Circulates waiting for another phosphate
• so that it can become ATP
Slide 39
DNA Structure
QuickTime™ and a
decompressor
are needed to see this picture.
Slide 40
DNA replication and protein
synthesis
QuickTime™ and a
decompressor
are needed to see this picture.
Slide 41