Zusammenfassung der Ressource
Biology (level 0
part 2)
- Properties of Matter
- Atoms
- Basic unit of matter;
everything is made of atoms
- Protons
- Positive charge
- Neutrons
- Negative charge
- Combine to form nucleus
- Electrons
- Negative charge
- Surrounds nucleus
- Elements
- pure substance that consists
of one type of atom
- More than 100
elements are known
- Isotopes
- Atoms of the same element that differ
in the number of neutrons they contain
- All isotopes of the same element
have same number of electrons
- Chemical Compounds/Bonds
- Chemical Compounds
- Substance formed by the chemical combination
of two or more elements in definite proportions
- Shown as chemical formula
- Example: water is H20
- Example: table salt is NaCl
- Physical properties of a compound
are usually different from those of
the elements from which it formed
- Chemical Bonds
- Atoms in compounds are held
together by chemical bonds
- Ionic bonds
- Formed when one or more electrons are
transferred from one atom to another
- Ions
- An atom that loses or gains electrons
- Covalent bonds
- Formed when electrons
are shared by atoms
- Molecule
- The structure that results when atoms
are joined together by covalent bonds
- Properties of Water
and Suitabilty for Life
- Polarity
- A molecule in which the
charges are unevenly distributed
- similar to a magnet with two poles
- Hydrogen Bonding
- Solvent
- Substance in which the solute dissolves
- Water expands slightly upon freezing
- Makes ice less dense than water
- That's why ice floats
- Attraction between a hydrogen atom
with a partial positive and another
atom with a partial negative charge
- Heat Capacity
- Takes large amount of heat energy to
cause the molecules to move faster
- Importance of Carbon to Life
- Carbon has four valence electrons,
allowing them to form strong covalent
bonds with many other elements
- One carbon atom can bond to another
which gives carbon the ability to form
chains that are almost unlimited in length
- Macromolecules
- Carbohydrates
- Living things use carbohydrates as their main source
of energy; sometimes used for structural purposes
- Lipids
- Can be used to store energy. Some are important parts
of biological membranes and waterproof coverings
- Nucleic Acids
- Store and transmit hereditary, or genetic, information
- Proteins
- Control rate of reactions and regulate cell processes. Some
form important cellular structures, while still others transport
substances into or out of cells or help fight disease
- Chemical Reactions and Enzymes
- Chemical Reactions
- Process that changes, or transforms,
one set of chemicals into another
- Chemical reactions involve changes in the
chemical bonds that join atoms in compounds
- Chemical reactions that release
energy often occur on their own
- Chemical reactions that absorb energy
will not occur without a source of energy
- Enzymes
- Speed up chemical
reactions that take
place in cells
- Temperature, pH, and
regulatory molecules
can affect the activity
of enzymes