chapter 2 chemistry of life Flashcards
Chemistry is the scientific study of
substances, especially the interaction of substances.
Anything that has weight and occupies space is
matter
All matter is composed of
chemical elements, substances that cannot be broken down by
Carbon,hydrogen are examples of
chemical elements.
Atom
is the functional unit of an element. It consists of the nucleus, which contains protons, neutrons, and surrounding elements.
Molecule,
two or more atoms are joined to form an element.For example—O2
Element
s a substance composed of only one type of atom that cannot be broken into simpler ingredients by chemical means.For example –Oxygen,hydrogen
Compound
is a chemical combination of two or more elements. For example NaCl
An atom is the smallest
unit of element that participates in chemical reactions.
Atoms are composed of three types of subatomic particles,
protons, neutrons and electrons.
Each proton has a _____ electrical charge.
positive
Each electron has a _____ electrical charge.
negative
Each neutron has ___ electrical charge.
no
Protons and neutrons are located in the
centrally located nucleus of an atom.
Electrons rotate at high speed around
the nucleus.
The atom of each element are characterized by specific
atomic number, symbol and atomic weight.
The number of protons in the nucleus is an atom’s
atomic number.
The number of protons and neutrons combined is the atom’s
atomic mass
An atom of an element with different number of neutrons is called as an
isotope
electrons keep darting about within certain limits called
orbitals
Orbitals are arranged into
energy level(shells)
The farther an orbital extends from the nucleus,
the higher its energy level is.
The number of electrons in the outer energy level of an atom determines how it behaves chemically This behavioris called as
chemical bonding.
Most chemicals in the body are in the form of
molecules
Chemical formula
determines atoms present in a compound.
Types of Chemical Bonds
Ionic Bonds•Covalent Bonds
Radioactive isotope:
Isotope that emits radiation
Covalent bonds
Covalent bonds form when atoms share their outer energy to fill up and thusbecome stable
Hydrogen bonds
A kind of weak attraction that helps hold your body’s substance together
Examples of inorganic molecules:
water ,acids, bases, and salts.
When water is the solvent for a mixture (a blend of two or more kinds of molecules), the mixture is called an
aqueous solution.
Dehydration synthesis:
Chemical reaction in which water is removed from small molecules and then strung together to form a larger molecule
Hydrolysis:
Chemical reaction in which water is added to the subunits of a large molecule to break it apart into smaller molecules
pH:
is a measure of how acidic or basic a solution is
Neutralization:
Acids and bases mix to form salts
Buffers:
Chemical systems that absorb excess acids or bases and thus maintain a relatively stable pH
The basic unit of carbohydrate molecules is called a
monosaccharide.
Lipids are
fats and oils.
Triglycerides
Made up of one glycerol unit and three fatty acids–Store energy for later use
Phospholipids
with only two fatty acids, and with a phosphorus-containing group attached to glycerol
Cholesterol
is a steroid lipid. It helps making the steroid hormones.Copyright © 2016 by Elsevier Inc. All
Proteins
very large molecules made up of amino acids
Nucleic acids
Made up of nucleotide units,
Deoxyribonucleic acid (DNA)
Used as the cell’s “master code” for assembling proteins
Ribonucleic acid (RNA)
Used as a temporary “working copy” of a gene (portion of the DNA code)
