Chemistry in Everything Find the chemistry!. What does matter look like?
Chapter 2: Chemistry What does chemistry have to do … 2: Chemistry BIO 105 What does chemistry...
Transcript of Chapter 2: Chemistry What does chemistry have to do … 2: Chemistry BIO 105 What does chemistry...
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Chapter 2: Chemistry
BIO 105
What does chemistry have to do with biology?
Vocabulary
1. Matter – anything that takes up space and has
mass
2. Mass – measure of how much matter is
contained within an object
3. Atom – smallest unit of matter that cannot be
broken down by ordinary chemical
means
Atoms are the smallest
units of matter that can participate in chemical
reactions
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Elements
Definition – an element is a “pure” form of
matter that contains a single type of atom
Of all of the elements listed on the periodic
table, only 20 or so are represented in the
human body.
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The Periodic Table
• Atomic #
• Atomic mass
• Element symbol
Practice
Element # protons # neutrons # electrons
C
H
O
P
Mg
K
Practice
Element # protons # neutrons # electrons
C 6 6 6
H 1 0 1
O 8 8 8
P 15 16 15
Mg 12 12 12
K 19 20 19
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Isotopes & Radioisotopes
Although all the atoms of a particular element contain the same number of protons, they do not
necessarily all have the same number of neutrons.
Atoms that have the same number of protons but differ in # of neutrons are called isotopes.
i.e. C12, C13, C14
Radioisotopes are unstable, radiation-emitting
isotopes.
Uses of Radiation Uses of radiation
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Chemical bonds
When atoms from two or more different
elements are combined to form a new chemical substance, a compound is
formed.
The atoms that make up these compounds are held together by chemical bonds.
Covalent bonding
Covalent bonds form when two or more
atoms share electrons in their outer orbitals.
The number of bonds an atom can form
depends on how many “empty spots” exist in the outer shell.
Each pair of electrons is shared equally between the carbon and individual hydrogen atoms.
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A molecule is a chemical structure held together bycovalent bonds. It may be composed of atoms of
one or more elements.
Ionic bonding
Ionic bonding results from the mutual
attraction of oppositely charged ions.
Ion = charged atom
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Hydrogen bonding
Hydrogen bonding is the result of polar
covalent bonds. Atoms may have a slight negative or positive charge depending on
electron distribution.
Polar molecules Water as a solvent
Water is considered the best polar solvent, due to its ability to form hydrogen bonds with other
molecules.
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Properties of water
• Solvent
• Transport medium
• High heat capacity
• High heat of vaporization
• Lubricant
Dehydration Synthesis
When dehydration reactions occur, a larger
product is formed. In the process, one molecule of H2O is produced.
Dehydration Synthesis example
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Hydrolysis Reactions
These types of reactions occur when we are
breaking down a large molecule into smaller pieces.
Acids, bases, and salts
When an acid is added to water, it dissociates into H+ and one or more ions.
The concentration of hydrogen ions is increased.
H2CO3 ↔ H+ + HCO3-
Acids, bases, and salts cont.
Bases, on the other hand, remove H+ from solution and are therefore proton acceptors.
HCl + NaOH → H+ + Cl- + Na+ + OH- → NaCl + H2O
Bases decrease the amount of free H+ present in an aqueous solution.
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pH scale
• The pH scale is a measure of the concentration of free H+ in a solution in moles/L.
• pH is the negative logarithm of the H+
concentration in a solution
• pH = - log10[H+]
pH
A solution with a H+ concentration of 1 x 10-4 has a pH of _____________. Is this classified as an acid or a base?
**A change of one whole number on the pH scale represents a tenfold change in the H+
concentration.**
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Which solution has the highest
concentration of free H+?
a. pH = 9
b. pH = 7
c. pH = 3
d. pH = 1
A solution with a pH of 6:
a. is an acid
b. is a base
c. has 10 times more H+ ions than a solution with
a pH of 5
d. both a and c above
Buffers
A buffering system is composed of a mixture of two compounds
* One substance can yield free H+ when [H+]
drops
* One substance binds with free H+ when
[H+] increases
Bicarbonate/carbonic acid buffering system
CO2 + H2O ↔ H2CO3 ↔ H+ + HCO3-
What are the four classifications of macromolecules?
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Biomolecules
Biomolecules are made up of repeating
subunits called monomers.
When these monomers are attached together in a chain they are referred to as
polymers.
Carbohydrates
Composed of three types of atoms:
Ratio between the atom types:
Monomer = monosaccharides (simple sugars)
have from 3-9 carbons within their
structure
Monosaccharides
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Disaccharides
Disaccharides are formed by the covalent
linkage of two monosaccharides.
Common disaccharides
Maltose =
Sucrose =
Lactose =
Polysaccharides
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Functions of carbohydrates
1. Energy storage
2. Energy production
3. Cell recognition
Lipids
Biological molecules that are insoluble in water (hydrophobic) but soluble in organic solvents
Simplest type of lipid is called a fatty acid.
Saturated vs. unsaturated fats
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Triglycerides
• Long-term energy storage
• Stored in the cells of adipose (fat) tissue
• Protection
• Insulation
Phospholipids
Steroids
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Nucleic acids
Nucleic acids are made of monomers called
nucleotides.
Sugars that make up nucleotides
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Nitrogenous bases
Cytosine (C) Thymine (T) Uracil (U)
Adenine (A) Guanine (G)
Deoxyribonucleic acid (DNA)
double-stranded molecule
sugar = deoxyribose
nucleotides = A,T,C,G
specific base pairing
A & T
G & C
RNA Structure
Differs from DNA
– single stranded
– uracil replaces thymine
Types of RNA within the cell, each with a specific
function
– messenger (m)RNA
– ribosomal (r)RNA
– transfer (t)RNA