Download Chemical Level of Organization

Chemical Level of Organization
Chapter 2
Chapter Outline
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Atoms
Ions
Chemical Bonds
pH scale
Inorganic molecules
o Water, Acids and Salts
• Organic molecules
o Carbohydrates
o Lipids
o Proteins
o Nucleic Acids – DNA and RNA
• ATP – energy carrier of cells
Atoms and Ions
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All matter is formed of Atoms.
Each atom has protons and neutrons in nucleus.
Protons are positively charged particles.
Neutrons are neutral particles.
Nucleus is surrounded by a cloud of electrons.
Electrons are negatively charged particles.
Ions have different # of protons and electrons.
Human Body and Elements
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Human body has 24 elements
Elements have only 1 type of atoms.
Major Elements – 99.3% H, O, C and N
Mineral Elements – 0.7%
Trace Elements – less than 0.01%
Matter: Atom
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Figure 2-1
Matter: Atoms and Molecules
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Figure 2-2(b)
Importance of # of atomic particles
• Atomic Number: is # of protons determine the
element; 1 = H, 6 = C, 7 = N and so on.
• Mass Number is equal to # of protons + # of
neutrons
• # of neutrons determine the isotope; C12 is the
most common carbon and has 6 p + 6 n but C14
has 6 p + 8 n and is radioactive.
• # of electrons in outer shell determines chemical
behavior of a atom.
Chemical Bonds
• Atoms interact to form molecules. 3 basic type of
interactions between atoms are:
• Covalent bonds
• Ionic bonds
• Hydrogen bonds
Ionic Bonds
• Atoms change into ions by complete transfer
(loss or gain) of electron/s.
• Opposite ions (A positive ion and a negative
ion) attract each other and form an ionic
bond.
• Na+ and Cl- form NaCl = table salt
• Strong bonds.
Matter: Atoms and Molecules
• Ionic Bonding
Figure 2-4(a)
Matter: Atoms and Molecules
• Sodium chloride crystal
Figure 2-4(b)
Matter: Atoms and Molecules
Table 2-2
Figure 2.3a
Isotopes = 6p+, 8n0, 6e-
Covalent Bonds
• Covalent bonds: Atoms share electron pair to
form a covalent bond.
• Unequal sharing of electrons result in Polar
molecules. Equal sharing of electrons result in
non-polar molecules.
• Very strong bonds.
• Non-polar molecule Methane = CH4
• Polar molecules: water = H2O, and ammonia =
NH3
• # of covalent bonds made by H = 1, O = 2, N = 3, C
= 4 and P = 5
Matter: Atoms and Molecules
• Covalent Bonds
Figure 2-5
Polar and Non-polar in Solutions
• Polar substances dissolve in polar solvents
• Non-polar substances dissolve in non-polar
solvents
• Like dissolves like.
• Polar = Hydrophilic (water loving)
• Non-polar = Hydrophobic (water fearing)
• Amphipathic molecule has both polar and
non-polar parts. Bile salts and phospholipids.
Hydrogen Bonds
• Bonds formed between H of one molecule to
O or N of another molecule due to unequal
sharing of electron pairs.
• Weak bonds
• Formed between water molecules
Matter: Atoms and Molecules
• Hydrogen Bonds
Figure 2-6
Recap 1
1. All matter is formed of smallest units --------- to have
properties of the substance.
2. # of ---------- determine the chemical substance (element).
3. # of ---------- determine the isotope.
4. Atomic Number is equal to # of ----------- in an atom.
5. Mass Number is sum of # of -------- and # of ----------- in an
atom
6. ------------ bonds are formed due to complete transfer of
electrons
7. ----------- bonds are formed due to sharing of electrons
8. # of electrons in outer shell determine -------- ---------9. ---------- bonds are very weak bonds formed between
different water molecules
2 basic types of Molecules
• Inorganic molecules do not form chains and
never have Carbon and Hydrogen together,
may not have either of them. H2O, CO2, NaCl
• Organic molecules always have Carbon and
Hydrogen. Most organic molecules also have
Oxygen. CH4 = methane, C6H12O6 = Glucose.
Organic molecules form long chains but have
limited number of functional groups.
• –COOH = Carboxylic acid, -NH2= amino, –OH =
hydroxyl, and –PO4= phosphate.
Inorganic Compounds
• Water Dissociates Ionic Bonds
Figure 2-8
Acids, Bases and pH scale
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pH is a –ve log measure of H+
Acids release H+
Bases accept H+ or release OHSalts release ions other than H+ or OHpH of water is 7
Strongest acid has 0 pH - HCl
Strongest base has 14 pH - NaOH
Buffers are chemicals that resist fast changes
in pH
Inorganic Compounds
•pH and Hydrogen Ion Concentration
Figure 2-9
Recap 2
1. ----------- is sum of all chemical reactions taking place in body
2. ----------- increase the rate of reactions
3. -------- substances have large molecules with carbon and hydrogen
4. ----------- is stored energy
5. ---------- is energy of moving substances
6. ---------- release H+
7. pH scale has a range of 0 - ?
8. pH of water is ---9. ------------ resist fast changes to pH of a system.
10. A substance producing ions other than H+ or OH+ is a -----------11. Enzymes act on substances called -----------------12. Reactants need --------------- energy to change to products
13. --------- -------- is the part of enzyme coming in contact with substrate
Carbohydrates
• Monosaccharide formed of 1 unit – Glucose
• Disaccharides formed of 2 units; glucose and
fructose form Sucrose – table sugar; other
important disaccharides are Maltose – formed
of 2 glucose molecules and Lactose formed of
glucose and galactose molecules
• Polysaccharides are formed of many units.
Starch and glycogen are polymers of α-glucose
molecules; Cellulose is formed of β-glucose
molecules
Organic Compounds
• Glucose
Figure 2-10
Organic Compounds
• Formation of Glycogen
Figure 2-11(c)
Lipids
• Fats and fat like substances form lipids
• True fats and oils are triglycerides formed from 1
glycerol and 3 fatty acids.
• Fats have saturated fatty acids with straight chains
and become solids at room temperature.
• Oils have unsaturated fatty acids with 1-4 double
bonds. Their chain bends at double bond. Oils are
liquids at room temperature.
• Phospholipids are amphipathic molecules with polar
= hydrophobic Head and non-polar = hydrophobic
Tails in them.
• Steroids have 4 fused ring structure. Cholesterol is
building block of steroid hormones.
Organic Compounds
• Fatty Acids
Figure 2-12
Organic Compounds
•Triglycerides—
Formed by three fatty
acid molecules
bonding to a glycerol
molecule
Figure 2-13
Organic Compounds
• Cholesterol
– Building block for steroid hormones
– Component of cell membranes
Figure 2-14
Organic Compounds
•A Phospholipid
Molecule
Figure 2-15
Proteins
• Proteins are polymers of Amino Acids
• Amino acids have an –NH2 and a carboxylic
group –COOH
• 20 kinds of amino acids form proteins
• 2 Amino acids form a covalent bond = peptide
bond between them
• Polypeptide is a long chain of amino acids
joined by peptide bonds
Organic Compounds
•Proteins are
built from
amino acids
Figure 2-16(a)
Organic Compounds
•Peptide bonds join
amino acids into long
strings
Figure 2-16(b)
Organic Compounds
• Protein Structure
Figure 2-17
Nucleic Acids DNA and RNA
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Nucleic Acid: are acidic substances found in nucleus of cells.
2 basic types: DNA = Deoxyribose N.A. and RNA = ribose N.A.
Nucleic acids are polymers of units called Nucleotides.
Each nucleotide is formed of: a) a pentose sugar Ribose or
Deoxyribose b) a Phosphate c) one of 4 N-bases, both have 3
common bases Adenine, Guanine and Cytosine. In DNA Adenine
always bonds to Thymine and Cytosine to Guanine. A-T and C-G
are called Complementary bases.
DNA
RNA
Sugar is Deoxyribose
Sugar is Ribose
N-bases include Thymine
N-bases include Uracil
Genetic material
Executes protein synthesis
Double Helix
Single chain may be coiled
Most lies in nucleus
Most lies in cytoplasm
6/19/2007
Organic Compounds
•The Structure of
Nucleic Acids
Figure 2-19ab
Organic Compounds
•The Structure of Nucleic Acids
Figure 2-19cd
High-Energy Compounds
•Structure of ATP
Figure 2-20
ATP
Energy
from
cellular
catabolism
Energy
released
for cellular
activities
ADP
Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings
Figure 2-21
1 of 5
Summary of Body Chemistry
• Organic Chemical Building Blocks
Figure 2-22
Recap 3
1. Most common source of energy from food is the sugar -------------2. Polysaccharide for storage of glucose in body is ---------------3. True fats are formed of 1 glycerol and 3 ------- ----------4. Proteins are polymers of ----------- ---------5. Starch and glycogen are polymers of ---------- ---------6. ----------- bonds join amino acids to form a protein.
7. Nucleic acids are polymers of -------------------8. Genes are formed of ---------9. Cells break down glucose and store energy in the form of ----------10. DNA has ---- chain/s and RNA has ---------- chain/s.
11. In DNA adenine bonds with ---------- and guanine with ---------- base