Transcript Ch 2 ppt - Dover High School

This PPT Adapted from
Hole’s Human
Anatomy and Physiology
Eleventh Edition
Shier w Butler w Lewis
Chapter 2
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
1
Chapter 2
Chemical Basis of Life
Why study chemistry in an Anatomy and Physiology class?
- body functions depend on cellular functions
- cellular functions result from chemical changes
- biochemistry helps to explain physiological processes,
and develop new drugs and methods for treating
diseases
2
Structure of Matter
Matter – anything that takes up space and has weight;
composed of elements
Elements – composed of chemically identical atoms
• bulk elements – required by the body in large
amounts
• trace elements – required by the body in small
amounts
Atoms – smallest particle of an element
3
Atomic Structure
Atoms - composed of
subatomic particles:
• proton – carries a single
positive charge
• neutron – carries no
electrical charge
• electron – carries a
single negative charge
Nucleus
• central part of atom
• composed of protons and
neutrons
• electrons move around the
nucleus
4
Atomic Number and
Atomic Weight
Atomic Number
• number of protons in the
nucleus of one atom
• each element has a unique
atomic number
• equals the number of
electrons in the atom
Atomic Weight
• the number of protons
plus the number of
neutrons in one atom
• electrons do not
contribute to the weight of
the atom
5
Isotopes
Isotopes
• atoms with the same atomic numbers but
with different atomic weights
• atoms with the same number of protons
and electrons but a different number of
neutrons
• oxygen often forms isotopes (O16, O17, O18)
• unstable isotopes are radioactive; they emit
energy or atomic fragments
6
Molecules and Compounds
Molecule – particle formed when two or more atoms
chemically combine
Compound – particle formed when two or more
atoms of different elements chemically combine
Molecular formulas – depict the elements present
and the number of each atom present in the molecule
H2
C6H12O6
H2O
7
Bonding of Atoms
• bonds form when atoms combine with other atoms
• electrons of an atom occupy regions of space called electron shells
which circle the nucleus
• each shell can hold a limited number of electrons
• for atoms with atomic numbers of 18 or less, the following rules apply:
• the first shell can hold up to 2 electrons
• the second shell can hold up to 8 electrons
• the third shell can hold up to 8 electrons
8
Bonding of Atoms
• lower shells are filled first
• if the outermost shell is full, the atom is stable
9
Ions
Ion
• an atom that gains or loses electrons to become stable
• an electrically charged atom
Cation
• a positively charged ion
• formed when an atom loses electrons
Anion
• a negatively charged ion
• formed when an atom gains electrons
10
Ionic Bond
Ionic Bond
• an attraction between a cation and an anion
• formed when electrons are transferred from one atom
to another atom
11
Covalent Bond
Formed when atoms share electrons
•Hydrogen atoms form single bonds
•Oxygen atoms form two bonds
•Nitrogen atoms form three bonds
•Carbon atoms form four bonds
H―H
O=O
N≡N
O=C=O
12
Ionic Compounds
Covalent Compounds
Made of metal and non-metals
Two or more Non-metals
Dissolve ready in water
Many do not dissolve in water
Dissociate into + or – ions surrounded by
hydration shells
Remain intact molecules
Many inorganic compounds
All organic compounds
Electrolytes in water
Non-electrolytes
Crystalline structure
Amorphous
13
Structural Formula
Structural formulas show how atoms bond and are
arranged in various molecules (covalent compounds)
14
Polar Molecules
Polar Molecule ( polar covalent molecules)
• molecule with a slightly negative end and a slightly positive
end
• results when electrons are not shared equally in covalent
bonds
• water is an important polar molecule
15
Polarity of Water
•
•
•
•
Responsible for properties of water
Adhesion, cohesion, surface tension
Capillary action
“Universal solvent” can dissolve ionic and
some covalent compounds
16
Hydrogen Bonds
Hydrogen Bond
• a weak attraction between the positive end of one polar
molecule and the negative end of another polar molecule
• formed between water molecules
• important for protein and nucleic acid structure
17
Chemical Reactions
Chemical reactions occur when chemical bonds form or
break among atoms, ions, or molecules
Reactants are the starting materials of the reaction- the
atoms, ions, or molecules
Products are substances formed at the end of the chemical
reaction
NaCl  Na+ + ClReactant
Products
18
Types of Chemical Reactions
Synthesis Reaction – more complex chemical structure
is formed
A + B  AB
Decomposition Reaction – chemical bonds are broken to form
a simpler chemical structure
AB  A + B
Exchange Reaction – chemical bonds are broken and new
bonds are formed
AB + CD  AD + CB
Reversible Reaction – the products can change back to the
reactants
19
A + B n AB
Acids, Bases, and Salts
Electrolytes – substances that release ions in water
NaCl  Na+ + Cl-
Acids – electrolytes that dissociate to release hydrogen ions
in water
HCl  H+ + Cl-
Bases – substances that release ions that can combine with
hydrogen ions
NaOH  Na+ + OH-
Salts – electrolytes formed by the reaction between an
acid and a base
HCl + NaOH  H2O + NaCl
20
Buffers
Buffers are the salts of weak acids. They can
keep the pH of a solution from shifting too
rapidly. The can help maintain pH within a
narrow range.
A buffer can neutralize either an acid or a
base. With an acid it acts as a base. With a base it
can act as an acid.
An example is NaHCO3
21
Acid and Base Concentrations
pH scale - indicates the
concentration of hydrogen ions in
solution
Neutral – pH 7; indicates
equal concentrations of H+
and OH-
Acidic – pH less than 7;
indicates a greater
concentration of H+
Basic or alkaline – pH
greater than 7;
indicates a greater concentration
of OH-
22
Organic Versus Inorganic
Organic molecules
• contain C and H
• usually larger than inorganic molecules
• dissolve in water and organic liquids
• carbohydrates, proteins, lipids, and nucleic acids
Inorganic molecules
• generally do not contain C
• usually smaller than organic molecules
• usually dissociate in water, forming ions
• water, oxygen, carbon dioxide, and inorganic
salts
23
Inorganic Substances
Water
• most abundant compound in living material
• two-thirds of the weight of an adult human
• major component of all body fluids
• medium for most metabolic reactions
• important role in transporting chemicals in the body
• absorbs and transports heat
Oxygen (O2)
• used by organelles to release energy from nutrients
in order to drive cell’s metabolic activities
24
• necessary for survival
Inorganic Substances
Carbon dioxide (CO2)
• waste product released during metabolic reactions
• must be removed from the body
Inorganic salts
• abundant in body fluids
• sources of necessary ions (Na+, Cl-, K+, Ca2+, etc.)
• play important roles in metabolism
25
Organic Substances
Carbohydrates
• provide energy to cells
• supply materials to build cell structures
• water-soluble
• contain C, H, and O
• ratio of H to O close to 2:1 (C6H12O6)
• monosaccharides – glucose, fructose
• disaccharides – sucrose, lactose
• polysaccharides – glycogen, cellulose
26
Organic Substances
Carbohydrates
27
Dehydration synthesis
28
Hydrolysis
29
Organic Substances
Lipids
• soluble in organic solvents; insoluble in water
• fats (triglycerides)
• used primarily for energy; most common lipid in the body
• contain C, H, and O but less O than carbohydrates (C57H110O6)
• building blocks are 1 glycerol and 3 fatty acids per molecule
• saturated and unsaturated
30
Organic Substances
Lipids
• phospholipids
• building blocks are 1 glycerol, 2 fatty acids, and 1 phosphate per
molecule
• hydrophilic and hydrophobic
• major component of cell membranes
312-25
Organic Substances
Lipids
• steroids
• four connected rings of carbon
• widely distributed in the body, various functions
• component of cell membrane
• used to synthesize hormones
• cholesterol
32
Organic Substances
Proteins
• structural material
• energy source
• hormones
• receptors
• enzymes
• antibodies
• building blocks are amino acids
• amino acids held
together with
peptide bonds
332-27
34
Organic Substances
Nucleic Acids
• carry genes
• encode amino acid sequences of proteins
• building blocks are nucleotides
• DNA (deoxyribonucleic acid) – double polynucleotide
• RNA (ribonucleic acid) – single polynucleotide
35
Organic Substances
Nucleic Acids
36
DNA
RNA
A-T and G-C
A-U and G-C
Double helix
Single strand
Can’t leave nucleus
Active in cytoplasm
Replication and Transcription
Translation of proteins
1 kind
Many types
37
MacroElements Building blocks
molecule
(monomers)
Example
monomers
Bonding
Use
Key vocabulary Example
polymers
Polymer
formula
Carbohydrates
Glucose,
Fructose,
Ribose
Covalent
COH to
COH
producing
-C-O-Cbonds
Short term
energy
from
Cellular
respiration
Disaccharides,
Polysaccharides
(C1H2O1)n Dehydration
– (H2O)n-1 synthesis
and
Hydrolysis
Glycerol and
Essential fatty
acids such as
linoleic acid
and alpha
linoleic acid
Covalent
COH to
COOH or
POOH
producing
COOC or
COOP
bonds
Long term
energy
storage,
Insulation,
Cushioning
20 essential
amino acids ,
groups acidic,
basic, neutral,
and rings
Covalent
COH to
NH2
producing
C-N bond
Lipids
Proteins
Nucleic
Acids
C1H2O1
CHO (P)
CHON
(S)
CHONP
Monosaccharides
Or
simple sugars
Glycerol and fatty
acids
Amino Acids
Nucleotides
Adenine,
Thymine
Guanine
Cytosine
Uracil
Covalent
COC
COOP and
Hydrogen
bonds
Amylose or
Plant Starch,
Glycogen,
Cellulose
Chemistry
Enzymes =
-ase
Low density
lipids LDL
High density
Lipids HDL
Saturated,
unsaturated,
polyunsaturated
fatty acids
Cholesterol
Triglycerides,
Steroids,
Waxes
Phospholipids
Dehydration
synthesis
and
Hydrolysis
Energy
use,
enzymes,
Transport,
cell
markers,
muscle
Dipeptides,
Polypeptides,
Enzymes,
Transport
proteins,
Hormones
Linear
proteins,
globular
proteins
Making
DNA and
RNA,
informatio
n storage
Double Helix,
Genes,
Genomes,
Ribosomes
DNA, mRNA NA
tRNA, rRNA,
and other
RNA’s
Enzymes =
-ase
(Aa)n –
(H2O)n-1
Dehydration
synthesis
and
Hydrolysis
Enzymes =
-ase
Dehydration
synthesis
and
Hydrolysis
38Enzymes =
-ase