The charactistics of life
Responding to environment
Evolve/Change over time
Nuetrons, protons, electrons.
An atom is the basic unit of matter
Elements and Isotopes
Isotopes- Atoms of the same element that differ the number of neutrons they contain
All isotopes have the same chemical properties
Element- A pure substance that consists nearly of one type of atom
Chemical Compound- A substance formed by the chemical combination of 2 or more elements in definite proportions
The physical and chemical properties of a compound are usually very different from those of the element from which it is formed
When one or more electrons are transferred from one atom to another
Positively and negatively charged atoms are called ions
When the electrons actually travel about th nuclei of both atoms
The structure that results whe atoms are joined together by a covalent bond is a called a molecule... The smallest unit of most compounds
The attraction between a hydrogen atom on one water molecule and the oxygen on another
Water is a polar molecule
Cohension and Adhesion
Cohension- An attraction between molecules of the same substance
e.g. Hydrogen Bonding
Adhesion- An attraction betweenmolecules of a different substance
e.g. Water and glass molecules (the "dip" in the water when in a test tube.)
Mixture- A material composed of two ormore elements or comppunds that are physicallyy mixed together but not chemically combined
Solution- A combination of the solute and the solvent
Solute- The substance that is dissolved
Solvent- The substance that dissolves the solute
Water's polarity gives it the ability to dissolve both ionic compounds and other polar molecules
The movement of water molecules keeps the small particles suspended.
e.g. oil and water
The pH Scale
Indicates the concentration of H+ ions in a solution.
The scale goes from 1-14, 1 being the most acidic and 14 being the most basic. 7 is completely neutral.
Most acidic- Stomach acid
Most Basic- Oven Cleaner
Neutral- Pure Water
Acids, Bases, and Buffers
Acid- Any compound that forms H+ ions in solution. Have higher concentration of H+ ions than anything below 7 on the scale
Base- A compound that produced hydroxide (OH-) ions in a solution. Has low concentrations on H+ ions
Buffer- Weak acids or bases that can react with strong acids or bases to prevent sharp, sudden changes in pH
Buffers dissolved in life's fluids play an important role in maintaining homeostasis in organisms.
The Chemistry of Carbon
Carbon can bond with many elements, including hydrogen, oxygen, phosphorus, sulfur, and nitrogen to form the molecules of life.
Monomers- Smaller units that link together and form polymers
Monomers and Polymers create macromolecules
The four major groups of Macromolecules found in living things are:
Compounds made of carbon, hydrogen, and oxygen
Living things use carbohydrates as their main source of energy. Plants, some animals, and other organisms also use carbohydrates for structural purposes.
Monosaccharides- Simple sugar molecules
Polysaccharides- Large macromolecules formed by monosaccharides
e.g. Starch, Glycogen
Made mostly from carbon and hydrogen atoms.
Lipids can be used to store energy. Some lipids are important parts of biological membranes and waterproof coverings.
The term saturated fat is used when the fatty acids contain the maximum amount of hydrogen atoms.
Macromolecules containing hydrogen, oxygen, nitrogen, and phosphorus
Nucleotides- Monomers that consist of 3 parts: a 5-carbon sugar, a phosphate group, and a nitrogenous base
Nucleic acids store and transmit hereditary, or genetic, information.
Contain nitrogen, carbon, hydrogen, and oxygen
Some proteins control the rate of reactions and regulate cell processes. Others form important cellular structures, while still others transport substances into or out of cells or hep to fight disease.
Proteins are most diverse macromolecules
The shape of a protein is maintained by: ionic and covalent bonds, and hydrogen bonds.
Monomers of proteins that are compounds with an amino group.
More than 20 different amino acids are found in nature. All amino acids are identical and can be joined together by a covalent bond bond. This allows any amino acid to be joined to any other amino acid- by bonding an amino group to a carboxyl group.
Organized in a polypeptide chain
A process that changes, or transforms, one set of chemicals into another.
Reactants- The elements or compounds that enter into a chemical reaction
Products- The elements or compounds produced by a chemical reaction
Chemical reactions involve changes in chemical bonds that join atoms in compounds
Energy in Reactions
Chemical reactions that release energy often occur on their own, or spontaneously. Chemical reactions that absorb energy will not occur without a source of energy.
Every organism must have a source of energy to carry out chemical reactions.
Activation Energy- The energy that is needed to get a reaction started
Are proteins that act as biological catalyst
Catalyst- A substance that speeds up chemical reactions
Substrates- The reactants of enzyme reactions
Enzyme is like a lock and key with its substrate.
Temperature, pH, and regulatory molecules can affect the activity of enzymes