The Chemistry of Life – Matter and Energy
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Transcript The Chemistry of Life – Matter and Energy
The Chemistry of Life –
Matter and Energy
Chapter 2
The Nature of Matter
Atoms
Basic unit of matter
Incredibly small (you could line up 100 million
acros the width of your little finger)
Made of three particles
• Protons – positive charge, located in nucleus
• Neutrons – no charge, located in nucleus
• Electrons – negative charge, located around
nucleus
Usually electrically neutral (protons=electrons)
The Nature of Matter
Elements and Isotopes
Element – pure substance, only one type of atom
• Atomic number – number of protons in nucleus
Isotope – atoms of the same element that have
different numbers of neutrons
• Mass number – number of protons and neutrons in nucleus
• All isotopes of an element have the same chemical
properties
• Radioactive isotopes – nuclei are unstable and breakdown
Used for geologic dating, cancer treatment, protection from
bacterial outbreak in food etc
The Nature of Matter
Chemical
Compounds
A substance formed by chemical combination
of two or more elements
• Physical and chemical properties are different from
the elements it is made of
The Nature of Matter
Chemical
bonds
Created by interaction between electrons
Two major types
• Ionic – occur when electrons are transferred,
causes an electrically charged atom (ion)
• Covalent – occurs when electrons are shared
Creates a molecule
Properties of Water
The
Water Molecule
Found in an liquid state all over the planet
Polarity – unequal attraction between the
shared electrons
Hydrogen bonding – attraction between
molecules because of polarity
• cohesion
• Adhesion
• Heat capacity
Properties of Water
Solutions
and Suspensions
Mixture – physically mixed but NOT
chemically combined
Solution – mixture where things are evenly
distributed
• Solute – substance that is dissolved
• Solvent – substance in which solute dissolves
Suspensions – mixture of water and
nondissolved material
Properties of Water
Acids,
Bases and pH
pH scale – measures concentration of H+
(hydrogen ion) in solution
• Ranges from 0 to 14
7 – neutral
Lower values – acidic
High values – basic
Buffers – weak acids or bases that prevent
sharp, sudden changes
Carbon Compounds
The
Chemistry of Carbon
Carbon atoms have 4 valence electrons
(outermost – needed for reactions)
Allows them to bond with many different
elements
Allows it to bond to itself to create long chains
Carbon Compounds
Macromolecules
Large molecules
Created when monomers (single units) form
polymers (multi-units)
Four major types
Carbon Compounds
Carbohydrates
Made of carbon, hydrogen and oxygen
Main source of energy for living things
Can be used for structural purposes
Simple sugars – monosaccharides (glucose)
Complex – polysaccharides (glycogen and
cellulose
Carbon Compounds
Lipids
Mostly carbon and hydrogen
Used to store energy
Important in membranes and waterproof
coverings
Referred to as saturated (solid) and
unsaturated (liquid)
Carbon Compounds
Nucleic
acids
Made of hydrogen, oxygen, nitrogen, carbon
and phosphorus
Store and transmit hereditary or genetic
information
Nucleotides – monomers
Two kinds – RNA and DNA
Carbon Compounds
Proteins
Made of nitrogen, carbon, hydrogen, and
oxygen
Control the rates of reactions and regulates
cell process
Also used for structure and transport
Amino acids – monomer
Chemical Reactions and Enzymes
Chemical
Reactions
A process that changes or transforms, one set
of chemicals into another
• Changes in chemical bonds
Reactants – what is put into the reaction
Products – what is gotten out of the reaction
Chemical Reactions and Enzymes
Energy
in Reactions
Either released or absorbed when bonds are
formed or broken
Energy sources – examples
• Plants – sunlight
• Animals – consumption (eating) and digesting
Activation energy – energy needed to get a
reaction started
Chemical Reactions and Enzymes
Enzymes
Specialized proteins
Biological catalyst – speeds up the rate of a chemical
reaction
• Lower activation energy
Very specific – one enzyme one chemical reaction
Substrates – the reactants of an enzyme catalyzed
reaction
• Bind at active site (lock and key)
Affected by things such as temperature or pH